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DRAFT ENVIRONMENTAL STUDY REPORT for

LOWER HUMBER BARRIER MITIGATION PROJECT

March 2005

Prepared under the MNR Class Environmental Assessment for Resource Stewardship and Facility Development Projects, 2003.

Project Partners:

The Great Lakes Sustainability Fund is a component of the Government of Canada’s Great Lakes Program. The Sustainability Fund provides resources to demonstrate and implement technologies and techniques to assist in the remediation of Areas of Concern and other priority areas in the Great Lakes. The report that follows was sponsored by the Great Lakes Sustainability Fund and addresses fisheries issues in the Humber River Area of Concern in Toronto, Ontario. Although the report was subject to technical review, it does not necessarily reflect the views of the Sustainability Fund or the Government of Canada.

Authors: Siobhan Neil Mark G. Heaton Project Coordinator Fish & Wildlife Biologist Ontario Streams OMNR, Aurora District

Table of Contents

List of Figures i List of Tables ii List of Appendices iii

Introduction 1

1.0 General Information

1.1 Definition of a Fishway 2 1.2 Rationale for Fishways 2 1.3 Alternatives to Fishways 2 1.4 Alternative Types of Fishways 3 1.5 Alternative Locations of Fishways 3 1.6 Impact of Sea Lamprey on Fisheries 3

Step 1 – Project Proposal

2.0 Project Description 2.1 Project Purpose 5 2.2 Rationale 5 2.3 Site Description 7 2.3.1 General 7 2.3.2 Geomorphological Setting 11 2.3.3 Hydrology and Hydraulics 12 2.3.4 Structural Analysis 14 2.3.5 Infrastructure 19 2.3.6 Cultural Heritage Assessment 19

3.0 Project Alternatives 3.1 Removal of Weirs 24 3.2 Partial Removal of Weirs 24 3.3 Transporting Fish around the Barrier 24 3.4 Creation of New Habitat 24 3.5 Improvement of Existing Habitat 24 3.6 “Do Nothing” (Null) Alternative 24 3.7 Alternative Types of Fishways 24

4.0 Mitigation Measures Required 4.1 Maintaining Normal Flow 32 4.2 Minimizing Siltation 32 4.3 Avoid Spawning Periods 32 4.4 Limit Noise Disruption 32 4.5 Public Safety 32 4.6 Revegetation of Disturbed Areas 32 4.7 Protecting Cultural Heritage Resources 32 4.8 Locating Municipal Infrastructure 33 4.9 Locating Former Disposal Sites 34

5.0 Supporting Watershed Objectives 5.1 Supporting Objectives 34 5.2 Permits Required 35

6.0 Project Category 35 7.0 Preliminary Evaluation of Alternatives 36 8.0 Project Evaluation 44 Step 2 – Environmental Analysis 9.0 Environmental Concerns Associated with Fishways 9.1 Introduction of Fish Species Upstream 47 9.2 Resource Use Conflicts 47 9.3 Temporary Obstruction to Fish Migration 48 9.4 Erosion, Sedimentation and Water Quality 48 9.5 Degradation of Scenic Quality 48 9.6 Noise 49 9.7 Dust 49 9.8 Ice Conditions in the Humber River 49 9.9 Public Safety and the Humber River 49 9.10 Watercraft Navigation 50 10.0 Environmental Checklist 51 11.0 Determination of Significance of Effects 51 12.0 Environmental Analysis Study 51 13.0 Environmental Analysis for Weir #1 52 13.1 Denil Fishway 52 13.2 Diversion Channel 54 13.3 “Do Nothing” (Null) Alternative 57 13.4 Vertical Slot Fishway 58 14.0 Environmental Analysis for Weir #2 66 14.1 Denil Fishway 66 14.2 Partial Removal 68 14.3 Diversion Channel 70 14.4 Rocky Ramp 72 14.5 “Do Nothing” (Null) Alternative 73 14.6 Vertical Slot Fishway 74 15.0 Environmental Analysis for Weir #3 83 15.1 Denil Fishway 83 15.2 Partial Removal 85 15.3 Diversion Channel 87 15.4 Rocky Ramp 89 15.5 “Do Nothing” (Null) Alternative 90 15.6 Vertical Slot Fishway 91

16.0 Environmental Analysis for Weir #4 99 16.1 Denil Fishway 99 16.2 Partial Removal 101 16.3 Diversion Channel 103 16.4 Rocky Ramp 105 16.5 “Do Nothing” (Null) Alternative 106 16.6 Vertical Slot Fishway 107 17.0 Environmental Analysis for Weir #5 116 17.1 Denil Fishway 116 17.2 Partial Removal 118 17.3 Diversion Channel 120 17.4 Rocky Ramp 122 17.5 “Do Nothing” (Null) Alternative 123 17.6 Vertical Slot Fishway 124 18.0 Environmental Analysis for Weir #6 132 18.1 Denil Fishway 132 18.2 Partial Removal 134 18.3 Diversion Channel 136 18.4 Rocky Ramp 138 18.5 “Do Nothing” (Null) Alternative 139 18.6 Vertical Slot Fishway 140 19.0 Environmental Analysis for Weir #8 148 19.1 Denil Fishway 148 19.2 Partial Removal 150 19.3 Diversion Channel 152 19.4 Rocky Ramp 154 19.5 “Do Nothing” (Null) Alternative 155 19.6 Vertical Slot Fishway 156 Bibliography 165

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List of Figures Figure 1. Location map. 10 Figure 2. Maximum 3-day sustained daily streamflow (April – May) 14 Figure 3. Initial structural observations of the Humber River weirs 16 Figure 4. Diversion channel 26 Figure 5. Pool and weir fishway. 27 Figure 6. Pool and orifice fishway. 27 Figure 7. Vertical slot fishway. 28 Figure 8. Denil fishway. 29 Figure 9. Fish elevator. 30 Figure 10. Fish lock. 30 Figure 11. Rocky ramp 31 Figure 12. Ice conditions in the Humber River 49 Figure 13. Dangerous hydraulic conditions downstream of low head weirs 50 Figure 14. Weir #1 61 Figure 15. Weir #2 78 Figure 16. Weir #3 94 Figure 17. Weir #4 111 Figure 18. Weir #5 127 Figure 19. Weir #6 143 Figure 20. Weir #8 160

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List of Tables Table 1. Fish species found below weir #1 6 Table 2. Characteristics of low head weirs. 8 Table 3. Notch flow velocities. 8 Table 4. Characteristics of weir at Cruickshank Park. 8 Table 5. Denil fishway flow conditions. 8 Table 6. Endurance time and swimming speeds for

representative fish species. 9

Table 7. Preliminary evaluation of alternatives for weir #1 37 Table 8. Preliminary evaluation of alternatives for weir #2 38 Table 9. Preliminary evaluation of alternatives for weir #3 39 Table 10. Preliminary evaluation of alternatives for weir #4 40 Table 11. Preliminary evaluation of alternatives for weir #5 41 Table 12. Preliminary evaluation of alternatives for weir #6 42 Table 13. Preliminary evaluation of alternatives for weir #8 43 Table 14. Significance of effects for weir #1 62 Table 15. Significance of effects for weir #2 79 Table 16. Significance of effects for weir #3 95 Table 17. Significance of effects for weir #4 112 Table 18. Significance of effects for weir #5 128 Table 19. Significance of effects for weir #6 144 Table 20. Significance of effects for weir #8 161

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List of Appendices Appendix A. Screening criteria Appendix B. Fish collection records for Lower Humber River in 2003 Appendix C. Department of Fisheries and Oceans data for 2003 trapping study at weir

#1 Appendix D Ministry of Natural Resources, Aurora District Fish Collection Records 2004

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Introduction Dams and other man-made barriers are constructed for a variety of reasons including, hydroelectricity, flood control, irrigation, energy dissipation and aesthetics. There are approximately 110 in-stream barriers throughout the Humber River watershed, all of which contribute to the alteration of the natural physical, chemical and biological processes that occur in the river. The presence of a dam or weir in a river greatly affects fish populations in a number of ways. Barriers reduce the flow of water, which can impair the migration motivation in adults. Also, this lack of current can cause young fish to become disoriented and delay their downstream movement. Habitat fragmentation leads to population isolation, which inhibits gene flow and can reduce the biological fitness of fish populations. In addition to this, weirs inhibit the upstream migration of fish to their traditional spawning areas. All of these impacts cause reduced productivity of fish populations in the watershed. One way to mitigate the impacts of weirs on fish populations is to build fishways. Fishways are artificial structures designed to facilitate the upstream movement of fish past existing barriers. The size and design of fishways may vary and will depend on the characteristics of the barrier, the river, and the target fish species for passage. There are currently eight low head concrete weirs blocking fish passage in the main stretch of the Lower Humber River. The weirs were built following Hurricane Hazel in 1954 to control river migration and the subsequent erosion of the surrounding lands. Weir #1, the southern most weir, also serves to limit the migration of sea lamprey from reaching the upper tributaries of the Humber River watershed. This document is an Environmental Study Report completed under the Ministry of Natural Resources Class Environmental Assessment for Resource Stewardship and Facility Development Projects, 2003. This report presents alternatives for the mitigation of barriers to fish passage on the Lower Humber River and the evaluation of those alternatives.

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1.0 General Information 1.1 Definition of a Fishway

A fishway is a waterway designed to allow the passage of a species or a number of different species of fish past a natural or man-made obstruction in a stream (Katopodis, 1992).

1.2 Rationale for Fishways

It is essential that fish of all ages are allowed freedom of movement to fulfill needs such as feeding, growth, and reproduction. Potential situations for which fishways are considered in fisheries management include:

(1) to maintain migrations past new hydraulic structures (2) to re-establish migrations after years of blockage at man-made

barriers (3) to extend migrations upstream of natural barriers

Instream barriers can have long term effects on a fish population by blocking movement to essential spawning grounds. Ensuring unimpeded migration routes allows the fish access to upstream spawning, rearing and feeding habitat thus, increasing reproductive potential.

1.3 Alternatives to Fishways To determine the most appropriate fisheries management direction, alternatives to the fishway option must be considered.

(1) Removal of Obstruction

Many dams and weirs are either in disrepair or no longer serve their intended purpose. Removing these dams would permit unimpeded passage of all species.

(2) Transporting Fish Around the Barrier

Where factors prohibit implementing any of the considered alternatives, the trucking of fish past barriers may be a reasonable option.

(3) Creation of New Habitat

(a) Downstream Spawning Facilities

Lack of access to upstream spawning facilities limits the reproductive potential of fish populations. Construction of spawning beds or artificial spawning channels downstream or adjacent to the

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obstruction may provide adequate alternative habitat for warmwater species.

(b) Artificial Incubation Areas

Migratory fish are collected at the base of the obstruction and the spawn is manually removed. The spawn is then transferred to a hatchery or rearing area.

(4) Improvement of Fish Habitat

Improvement of the existing spawning, rearing and feeding habitat to favour the desired fish population may be carried out below the obstruction.

(5) “Do Nothing” Alternative

This option should be addressed in the event that the need cannot be met through available management and structural techniques.

1.4 Alternative Types of Fishways

A fishway permits fish to migrate upstream past an obstruction in a watercourse. Extending from above the obstruction to the river below, fishways are designed to reduce the velocity of water. This may be accomplished by constructing a series of small waterfalls, baffles or weirs, some of which may have a submerged opening or orifice. The fish move upstream from pool to pool by jumping the barriers, navigating baffles or passing through the submerged orifices. Installation of vanes or baffles, on the bottom or sides of a flume or trough, also reduces water velocity thus allowing for the passage of fish.

Two other types of fishways are fish locks and fish elevators. Fish locks raise fish over an obstruction by filling a chamber with water from the upstream level. Elevators mechanically lift fish in a water-filled chamber upstream over the obstruction. Both of these alternatives require electricity to operate.

In some cases, a diversion channel around an obstruction is constructed to permit passage of fish through a by-pass channel. Diversion channels are typically designed using natural channel principles.

1.5 Alternative Locations of Fishways

Depending on the physical “footprint” of the obstruction, alternative locations can be considered. Suitable locations can be examined within the structure or adjacent to it.

1.6 Impact of Sea Lamprey on Fisheries

Sea lamprey (Petromyzon marinus) is an external parasite which attaches itself to a host fish and feeds on its body fluids. This often leads to the death of the host fish. The first record of sea lamprey in Lake Ontario was in 1835. While there has been recent research to suggest that sea lampreys may be indigenous to Lake

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Ontario (Waldman et al., 2004), the widespread belief is that they were able to colonize the lake after the opening of canals and locks built for the St. Lawrence Seaway in the early 1800’s. Once the sea lamprey became established, it had massive impacts on the native fishes of the Great Lakes and quickly decimated the lake trout and whitefish stocks. The sea lampreys of the Great Lakes enter streams in the early spring and summer to spawn, after which they die. Once the eggs have hatched, the larvae burrow into the sediments where they spend the next three or more years of their life. During this time, they feed on algae and other materials that they filter out of the water. Following this stage, the lampreys emerge from the sediments in the late summer, fall and winter and make their way downstream to the lake. They spend approximately 2 years in the lake environment preying on fish with a single sea lamprey able to decimate up to forty pounds of fish in its lifetime. Some of the species currently at risk from sea lamprey in the Great Lakes include lake trout, salmon, rainbow trout, whitefish, chubs, burbot, walleye and catfish (DFO, 1996). Some of these species are known to migrate into the Humber River during the spawning seasons. The Department of Fisheries and Oceans Sea Lamprey Control Centre (SLCC) has surveyed the sea lamprey spawning run since 1968, and has estimated it to be the largest of any other Lake Ontario tributary. An estimated 3644 sea lampreys attempted to use the Humber River watershed in 2003. Furthermore, DFO has indicated that the range of spawning periods for sea lamprey in the Humber River can vary. For instance, spawning phase sea lamprey have been detected in the river as early as mid-February and as late as the end of September. However, the spawning activity in the Humber River has proven to be unsuccessful (per comm. SLCC 2004). There is a significant concern that sea lamprey could successfully reproduce in the Humber if they were able to access the upper watershed. It is believed that the presence of American brook lampreys in the upper reaches of the Humber attract migratory sea lampreys and that they may be a main driver behind the size of the sea lamprey spawning run in the Humber River (per comm. SLCC 2004). To date, weir #1 has succeeded in preventing sea lamprey from entering the Humber River watershed but also prevents the passage of desirable species. Therefore, the priority of this project is to improve the design of the barrier to enhance fish passage while still maintaining sea lamprey control. This priority is consistent with the direction of the Great Lakes Fisheries Commission (GLFC, 2000) and provincial fisheries management objectives.

DFO has indicated that the preferred location for sea lamprey control remains at weir #1 based on the desire to stop sea lamprey as further down the river as possible. Weir #1 is also the most accessible from an operational perspective as well as for public viewing opportunities. Furthermore, DFO currently operates a trap and sort facility at weir #1 and has expressed a desire to maintain operation of this trap (pers. comm., 2005). Under present conditions the weirs periodically become drowned when water levels are high. There is a concern that this drowning may negatively impact sea

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lamprey control at weir #1. However, this generally occurs in the winter and early spring, which is not a period of active sea lamprey migration. DFO has stated that some occurrences of drowning may continue to occur at weir #1 but only during those periods of low or no sea lamprey migration. Furthermore, the general criteria for the height of a vertical drop in the fishway to prevent sea lamprey control is 0.3 meters. This is a minimum value that was demonstrated under lab conditions and is used as a threshold to define hydrologic events where the barrier is temporarily lost or drowned.

Step 1 – Project Proposal 2.0 Project Description 2.1 Project Purpose

The primary purpose of this project is to restore the movement of non jumping fish species past the existing series of weirs presently blocking migration, while 1) maintaining sea lamprey control 2) keeping capital and maintenance costs reasonable 3) keeping operational complexity to a minimum 4) ensuring the alternative is safe to operate

5) improving public safety near low head weirs

2.2 Rationale There are eight weirs on the main stretch of the Lower Humber River that are acting as barriers to fish migration (Figure 1). Weir #1 is the southern most of the eight weirs and is located 3.6 km from Lake Ontario between Bloor St. and Dundas St. Currently, weir #1 is serving the purpose of preventing the migration of sea lamprey upstream in the Humber River however; the weirs also prevent the migration of native and naturalized fish species from Lake Ontario and the Humber River south of Bloor St. to the upper reaches of the watershed.

In accordance with the recommendations of the Humber River Fisheries Management Plan (MNR/TRCA, 1998), a 4m wide trapezoidal notch was cut out of the top step of the five southern most weirs. The sixth weir remains uncut because it is low enough for fish to jump over. Raymore Park weir, located between Eglinton Ave. and Lawrence Ave., was deemed to high for a notch to be effective therefore, a denil fishway was built instead. The northern most weir, located just north of Lawrence Ave. in Cruickshank Park, has also been notched.

The weir notching project was accepted as a temporary solution for facilitating the migration of jumping species of fish while still controlling sea lamprey movement. In 2001, as a result of this project, rainbow trout have been observed spawning in the East Humber River for the first time (Clayton et. al., 2004). Unfortunately, the series of low head weirs continues to impede the movement of non jumping species and has a low efficiency at passing jumping species. Mitigating these barriers to allow fish passage would restore connectivity in the Humber River and

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make a significant accomplishment toward achieving the goal and objectives of the Humber River Fisheries Management Plan.

There are many native fish species that have been identified as species of concern in the Humber River. American eel has been placed on a group 1 high priority candidate list in 2004 by COSEWIC. Northern redbelly dace, Brassy minnow, Stonecat, Yellow bullhead, and White perch have been placed on a group 2 intermediate priority list and American brook lamprey has been placed on a group 3 lower priority list by COSEWIC in 2004. Of these species, American eel is considered by COSEWIC to be a species that is ‘especially at risk’ within the Lake Ontario basin. American eel was last found in the Lower Humber in 1989 at the mouth of the river. One of the major contributing factors for the decline of the American eel is the large number of dams and weirs throughout the entire Lake Ontario basin. The weirs in the Lower Humber River add to this cumulative effect by fragmenting Lake Ontario from the lacustrine habitats found within the upper watershed. The Great Lakes Fishery Commission for Lake Ontario has stated that “without management intervention, extirpation of the American eel from the Great Lakes Basin is likely” (GLFC, 2002). The impact of these barriers to other species in the river is evident during monitoring of the lamprey control cages at weir #1. Many species making their way upstream get caught in the lamprey cages. Although these fish are hand transferred upstream of the weir, they are still restricted by the remaining barriers. The Three-spine stickleback for instance enters the river only to spawn in the spring. This restriction to potential spawning, rearing and feeding habitat may have detrimental effects to the population of this species. Table 1 lists fish species found below weir #1 in the lower portion of the river during recent fisheries surveys. Important to note that although northern pike do not appear in these surveys, they are known to frequent the Humber River.

Table 1. Fish species found below weir #1 River chub 1,4 Creek chub 1,2,3,4 Common shiner 1,3,4 Johnny darter 1,4 Rainbow darter 1,3,4 Longnose dace 1,2,3,4 Common carp 1,4 Rock bass 1,2,3,4 Brown bullhead 1,2,3,4 Central stoneroller 2 Stonecat 2,3 Three-spine stickleback 2

Gizzard shad4

Horneyhead chub 1 Emerald shiner 1,2,3,4 Pumpkinseed 1,2,3,4 Bluntnose minnow 1,2,4 Blacknose dace 1,2,4 Brook stickleback 1 Spottail shiner 1,4 White sucker 1,2,3,4 Largemouth bass 1,4 Fathead minnow 2,3,4 Golden shiner 2 Blackside darter 3

Goldfish4

Spotfin shiner 1,4 Rainbow trout 1 Brown Trout1

Chinook salmon4 Walleye4 Trout-perch 1 Black crappie 1,2 Fantail darter 1,3 Northern hogsucker 1,4 Bluegill sunfish 1 Sea lamprey 1,2,3 Green sunfish 2 Longnose sucker 3

(Ontario Streams data, 2003)1 Appendix B (Clayton et al., 2004) 2 (Department of Fisheries and Oceans data, 2003)3 Appendix C (Ontario Ministry of Natural Resources Fish Collection Records, 2004)4 Appendix D

Historically, there has been a total of 57 fish species found in the Lower Humber River subwatershed, which constitutes more than 80% of the fish species found historically throughout the entire watershed. The fish found in the Lower Humber

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River include species that are found more commonly in Lake Ontario, indicating the importance of the subwatershed for lake resident species (Clayton et al., 2004). Each year the Ministry of Natural Resources stocks approximately 40,000 brown trout, 20,000 yearling rainbow trout and 15,000 Chinook salmon into the Humber River watershed. The approximate cost of this stocking effort is $75,000 per year. Improving fish passage at the weirs on the Humber River will reduce the need for this on-going stocking effort.

2.3 Site Description 2.3.1 General

The Humber River Watershed is the second largest watershed in the Greater Toronto Area at 908 Km2. The project site is located in the Lower Humber River Subwatershed. At 80 Km2 it is the second smallest of the five major subwatersheds and the most highly urbanized. The series of eight low head weirs extend from weir #1, 3.6 km from Lake Ontario, north to the Cruickshank Park weir south of Hwy. 401 between St.Philips Dr. and Lawrence Ave. This stretch of the Lower Humber River is classified as a sixth order watercourse and flows at a 0.3% slope through a deeply incised valley that has been susceptible to erosion and flooding. The surrounding area is highly developed with the river flowing through urban parkland on either side. The southern six weirs between Bloor St. and Dundas St. are located within Etienne Brule Park on the east side and Home Smith Park on the west side. Weir #8, the northern most weir, is located within Cruickshank Park. Each park contains trail systems and experiences considerable public use. Also, there is urban infrastructure located within the project site such as sewers and watermains.

The project site is located within the category of large riverine habitat as identified in the Humber River Fisheries Management Plan. Flows through this section of the Lower Humber River can fluctuate greatly because it receives water from numerous large sub-basins in the Upper Humber River and two subwatersheds south of the confluence with the West Humber River subwatershed (Clayton et al., 2004). There is considerable ice build up within the river and the floodplain during the winter and spring melt season. The bed of the river consists primarily of shale, which is susceptible to erosion and scour. Also, as with any barrier, there is a build-up of sediment behind each of the weirs. There has been extensive stabilization work done to the river banks, mainly consisting of stone retaining walls and rock rip rap. Also, there is a lack of shade for the river and water temperatures through this section tend to fluctuate due to overland flow, input from upstream watercourses and groundwater sources.

Aligned with a concave curvature facing downstream, weir #1 and five other low head weirs were designed to dissipate the energy by cascading water over a series of concrete steps ranging in size from 30 to 45 cm. The top of each weir is approximately 0.6 m thick and a 1.6 m wide concrete sill protects the downstream limit of the weir from erosion.

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A 4 m wide trapezoidal notch has been cut out of the top step of six of the weirs in order to concentrate the flow and reduce its height. This was done to facilitate the migration of trout and salmon upstream. One of the weirs remains uncut because it was deemed low enough for trout and salmon to jump over and the Raymore Park weir was too high for a notch to be effective therefore, a denil fishway was built at this location. The characteristics of the weirs and the notch flow velocities can be seen in Table 2 and Table 3 respectively. The characteristics of the Cruickshank Park weir can be seen in Table 4. Furthermore, the characteristics of the flow conditions through the denil fishway at the Raymore Park weir are presented in Table 5.

Table 2. Characteristics of lowhead weirs Weir # Width (m) Est. height of weir crest

above water at base during Fall spawn (m) *

Est. water depth at base of weir (m)

Depth of notch (m)

1 48.1 1.6 N/A 0.25 2 42.0 1.8 1.10 0.30 3 42.7 1.8 0.53 0.45 4 51.8 1.2 0.54 0.45 5 43.5 1.2 0.53 0.45 6 – Dundas 40.7 0.9 0.72 Not cut

*refers to height prior to notching Table 3.. Notch flow velocities. Weir # Flow velocity upstream

side of notch (m/s) Flow velocity downstream side of notch (m/s)

Flow velocity halfway between crest and base of weir (m/s)

1 0.91 1.51 3.76 3 1.17 1.99 3.53 5 0.87 1.66 3.53 Average 0.98 1.72 3.61 Stand. Dev. 0.16 0.25 0.13

Table 4. Characteristics of weir at Cruickshank Park.

Width (m) Est. height of weir crest above water (m)

Depth of notch (m)

45 2.0 0.45

Table 5. Denil fishway flow conditions Point Depth

(cm) Current meter depth from water surface (cm)

Velocity (m/s)

Notes

A 33 19.8 0.26 1st baffle downstream from 2nd pool structure

A 33 6.6 0.24 1st baffle downstream from 2nd pool structure

B 34 9.5 0.25 ¼ distance between 2nd and 1st pool structure

B 34 4.8 0.36 ¼ distance between 2nd and 1st pool structure

C 29 17.4 0.21 ½ distance between 2nd and 1st pool

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structure C 29 5.8 0.44 ½ distance between 2nd and 1st pool

structure C 29 0 0.76 ½ distance between 2nd and 1st pool

structure D 36 10.5 0.29 2nd to last baffle before 1st pool structure D 36 5.3 0.27 2nd to last baffle before 1st pool structure D 36 0 0.31 2nd to last baffle before 1st pool structure

The endurance time and swimming speeds for representative fish species can be seen in Table 6.

Table 6. Endurance time and swimming speeds for representative fish species. Species Endurance

Time (s) Swimming Speed (m/s)

Length (mm) Migration Period

Dace 1-20 0.430-2.400 100-200 May-June-July Largemouth bass

300-1800 0.340-0.589 81-224 May-June

White sucker 600 0.480-0.730 170-370 April-May Rainbow trout 1-1800 0.257-2.700 82-310 April-May Sea lamprey 0.8-1635 0.300-3.960 145-508 April – July

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2.3.2 Geomorphological Setting

The Humber River is a sixth order system flowing through a highly urbanized area of Toronto. The subject area is known as the Lower Humber River and is comprised of 80 km2 of drainage area, the majority of which is composed of urbanized residential development and packets of parkland immediately adjacent to the river. Historical analysis of the subject area over the past 51 years has indicated that the surrounding land use has not changed significantly.

The Lower Humber River is a heavily altered channel that flows over bed substrate composed of bedrock, or that is bedrock-controlled. The channel is deeply incised and displays valley wall contact throughout portions of study area. The Lower Humber River through this study area has a channel gradient of approximately 0.3% and exhibits signs of active erosion and sediment deposition. The banks and surrounding parkland areas are susceptible to erosion and flooding.

Channel bankfull widths for this portion of the Humber River range from 40.0 to 75.0 metres, with bankfull depths lying between 0.8 to 1.6 metres. The widths of the weirs ranged from 40.7 to 51.8 metres with associated depths between 0.53 and 1.17 metres. Velocities above these weirs ranged from 0.87 to 1.17 m/s, and from 1.51 to 1.99 m/s for measurements recorded immediately downstream of the notched sections of the weirs.

The majority of banks located at the weir structures are artificial and are composed of materials such as concrete slabs, interlocking bricks and gabion baskets. The natural banks can be found in the stretches of the river between the weirs and are composed of silt and sand with some larger cobbles and pebbles near the toe. Bank angles for these sections range from 8º to 70º and are vegetated by a mixture of trees, shrubs, tall and short grasses, and tall and short herbaceous vegetation.

Bed substrate consists primarily of bedrock in slab, boulder, and cobble form. There is a small amount of woody debris in the channel, along the banks, and immediately downstream of the weirs, however the woody debris was not extensive enough to cause debris jams and impede water flow.

Active channel erosion is evident throughout the river system. Retaining walls housing storm outfalls have begun to erode and collapse. Such was the case for a storm outfall culvert located on the western bank of the river in the retaining wall located between weirs #5 and #6. Also, channel scour is evident downstream of the weirs where the channel bed has been eroded; exposing the base of the weirs and their support sills. Portions of the natural banks exhibit evidence of toe erosion and tree roots have been exposed to the river through bank erosion and undercutting. The notched portions of the weirs have also increased the amount of erosion occurring on the channel bed by directing localized flows to the bed below the weirs where large bedrock slabs have been plucked and uplifted.

The Lower Humber River weirs reduce the flow and dissipate the river’s energy by forcing the water to flow over a series of cascades or drops, thereby providing grade control for the system. This grade control can limit the amount of erosive force acting on the channel through the dissipation of energy. These weirs pool

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water behind their structures during low flow conditions, providing year round habitat for some fish species. The weirs act as sediment traps by accumulating the sediment that flows downstream starving the river’s sediment budget. If the weirs become outflanked during flood conditions, or are removed in the future for other purposes, the sediment that has accumulated behind these structures would travel downstream where it has the potential to bury spawning habitats available for fish.

Rivers and streams meander through their corridor by the continual erosion and deposition of materials along its system. A natural channel will adjust its sinuosity through meandering to maintain a channel slope that impairs the degradation and aggradation of the channel bed. In addition to dissipating a river’s energy and erosiove power, weirs inhibit the migration of the channel throughout its valley corridor. The river cannot correct for the flows and sediment changes occurring in the channel so it remains in a constant state of imbalance.

The Lower Humber River is a bedrock channel characterized by a confined, well entrenched system with a steep channel gradient, low width to depth ratio, a sinuosity between 1.0 and 1.1, and a deep narrow cross-sectional profile (Rosgen, 1996). Generally, the lack of erosion occurring in rock bed channels creates streams that are sediment deprived and cannot easily alter their position in space or their size in response to flows. This also means that there is little sediment in the channel available to supply the floodplain.

Rock bed channels, because of their resistant nature, have very slow rates of morphological change in planform (Tinker and Wohl, 1998). When change does occur it is usually the result of an infrequent, high magnitude, flood condition such as the effects on the Lower Humber River from Hurricane Hazel. The depositional features found are similar to those associated with alluvial channels, however their process of formation is quite different (Cenderalli and Cluer, 1999). The course sediment particles entrained in the flows will be deposited in wider sections of the river where flows are less, whereas, the finer sediment materials will be deposited in ponded locations behind the weirs. The erosion potential of the Humber River can be linked to the transport of sediment in the channel. The erosion of any bedrock channel occurs in constricted areas of the river where the flows and entrained material are forced repeatedly against the bed and bank of the channel. This process is known as channel abrasion or corrosion, in which the entrained particles act as sand paper on the surface of the channel bed and banks (Knighton, 1984). Erosion can also occur through the process of rock plucking and uplift as described previously when the localized flows from the notches get into the cracks/joints of bedrock slabs, forcing the large particles up from the bed. Some other erosional processes working on the Lower Humber River includes cavitation (Knighton, 1984), corrosion or chemical weathering of the rocks, and the migration of knick points throughout the system (Hovius and Slingerland, 2005).

2.3.3 Hydrology and Hydraulics

There were a range of peak flows evaluated in this study that were available from various sources including: • Computed flows from various design storm events provided by past hydrologic

modeling through Toronto Region Conservation Authority.

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• Statistically derived fish habitat flows developed as part of this study.

Design Storm Flows

Design storm events are typically named by the return period of the rainfall depth and by the duration of the storm event. For example, a 25-year/24-hour design storm describes a rainfall depth over a period of 24 hours that has a 4 percent chance of occurring at a particular location in any given year. The design storm depths in this study were based on the values for the IDF curves. Peak flows from the 2, 5, 10, 25, 50, 100 year and Regional design storm events were evaluated in this study.

Fish Habitat Flows There were two types of flow conditions developed to investigate impacts on fish habitat, including: • 10-year/3-day Sustained Streamflow • Average Annual Baseflow

Both flow conditions were determined using data from two long-term streamflow gages in the vicinity of the study area. The following datasets were obtained from the Environment Canada National HYDAT database: • Humber River at Weston (Station No. 02HC003). The gage is located

approximately 3 km u/s of the study area. Daily streamflow data were available for the period 1946-2001 (56 years)

• Black Creek near Weston (Station No. 02HC027). The gage is located just east of the Humber River confluence, approximately 1 km upstream of the study area. Daily streamflow data were available for the period 1967-2001 (35 years)

The methodology used in this evaluation was adapted from the “delay discharge” criterion used by Alberta Environment Fisheries and Wildlife Management Division for fish passage through culverts (Government of Alberta, 2001).

To determine the 10-year/3-day sustained streamflow, a flow frequency analysis was performed for the selected fish migration period (April 1 through July 31). In each year, the largest flow exceeded for a consecutive three-day period was determined and referred to as the “maximum 3-day sustained daily streamflow”. A Log-Pearson Type III analysis was performed on the resulting annual maxima time series, and the respective 10-year return period streamflow was determined as shown in Figure 2.

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Figure 2. Maximum 3-day Sustained Daily Streamflow (April - July)

1

10

100

1 10 100

Return period (years)

Dis

char

ge (

cms)

LPIII Fitted

Humber River

LPIII Fitted

Black Creek

10-yr Flow = 57 cms

10-yr Flow = 4 cms

The maximum 3-day sustained daily streamflow with a 10-year return period was calculated to be 57 cms (cubic meters/second) and 4 cms for the Humber River main branch and Black Creek gages, respectively. The total 10-year/3-day sustained streamflow for the study area was determined by summing these flows. As a result, a discharge rate of 61 cms was used for fish passage calculations at this site.

The average annual baseflow represents another low-flow condition for use in fish habitat evaluation. For each year, the minimum daily streamflow over the low baseflow period (May 1 through September 30) was determined from the same datasets listed above. The average annual baseflow was calculated to be 1.0 cms and 0.1 cms for the Humber River main branch and Black Creek gages, respectively. Summing these two values, a discharge rate of 1.1 cms was determined for this site.

2.3.4 Structural Analysis

The Lower Humber River weirs were constructed in response to erosive impacts of the 1954 Hurricane Hazel event. The weirs were constructed in 1961 in conjunction with park developments as part of the Authority’s Lower Humber Channel Flood Control and Water Conservation Plan.

General

Weir structures throughout the country have been recently, are currently or are soon to be subject to structural assessment. This is due to the structures age. Thousands of dam and weir structures were installed in the mid 1950s, and many are showing signs of deterioration. It has been suggested that the typical life span

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of a hydraulic structure is approximately 50 years, thus 2005 marks the mid decade time period where many structures are nearing the end of their service. The deterioration results from material fatigue, exposure to freeze thaw cycle, and aggregate breakdown. Reinforcing steel is also subject to corrosion if exposed. The life of some structures is extended by periodic resurfacing, patching and repairs.

The service time of the Humber River weirs has been approximately 44 years, this indicates that the structures are nearing the extent of the life cycle duration in comparison with similar structures. The structures were inspected in 1971 and resulted in the recommendation of minor repair to scour areas. They were subsequently inspected in 1979 and found to be in adequate condition. Later inspections of the adjacent retaining walls took place in 1981. In April 1990, all of the weirs were observed to show signs of minor displacement. Weir #1 was noted to have minor erosion on the east downstream side. Other observations related to the retaining walls on some upstream weirs.

Structural Assessment

At the time of our observations in January 2005, high flow levels occupying the full weir width did not allow for an adequate level of condition assessment. In general, on a preliminary assessment basis, it can be suggested that all weirs appeared to be in adequate condition. The weirs are reinforced concrete crescent shaped structures with a stepped downstream spillway and extend the full width between the Humber River banks. The visible concrete surfaces show signs of minor cracking and pitting which are typical of concrete structures of this age. It is intended to re-visit the site to conduct a further assessment of each weir during low flow conditions that would allow a more complete view of the weir components.

Based on the past reports, and assumed degree of upstream sediment accumulations at each weir, it can be suggested that piping of flow underneath the weirs is unlikely. Piping is a potential condition at dam/weir structures that displaces founding soils due to upstream hydrodynamic pressure. Since the amount of sediment is assumed to be located just 0.3 to 0.6m below the weir crest, the likelihood of this occurring is minimal. It should be noted however, depending on the future fish passage alternatives that involve notching of the weir, the foundation may become subject to exposure and must be protected against piping. The weirs are designed with a step down spillway on the downstream sides. This spillway prevents downstream scour to some extent, however, based on observations in January 2005, the hydraulic jump distance at each weir far exceeds the extent of the spillway, therefore each weir is subject to scour potential resulting from the vacuum created below the crest. Subsequent field visits to assess the structures under low flow conditions will also serve to better identify indications of scour.

The retaining walls adjacent to weir #3 were observed to be in an unstable condition. Significant outward displacement of the top of the wall is evidence of undermining of the footings. Interim mitigation can involve protection of the toe from further erosion, however ultimate replacement of the wall will be necessary.

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Figure 3. Initial Structural Observations of the Humber River Weirs

Old Mill weir, (weir #1) looking upstream

Weir #2 looking upstream, note notch at mid span

Weir #3 looking upstream, note heritage character west on masonry retaining wall

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Weir #3 east retaining wall, shows signs of foundation undermining, outward displacement of top of wall, and differential settlement, Concrete surface show minor cracking and spalling

Weir #4 looking upstream, adjacent bank protection consists of gabion, concrete block ,concrete retaining walls and bank revetment

Weir #4, view looking at west bank, note variety of discontinuous bank treatments

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Weir #5, looking upstream

Weir #6, looking upstream from east bank

Weir #6 looking upstream from west bank

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2.3.5 Infrastructure

The lands within the Humber River Valley are used primarily as parkland with trails and parking areas. Municipal infrastructure is located within the valley and consists of road crossings, water, sanitary and storm outfalls.

Within the study area, the main road crossings include Bloor Street, Old Mill Road at the south limit of the study area and Dundas Street at the north limit. All of these structures span the watercourse and do not obstruct the River.

Trails within the parkland are located along the east side of the watercourse, with a significant parking area and service buildings near the Old Mill Road.

There are services located within the Humber River Valley including watermain crossings and a trunk sewer that runs parallel to the watercourse. There are a number of storm sewer outfalls that discharge to the river within the study area. Any works that would be carried out for fish passage, including changes to the weirs and fishways, will consider the location of these services for potential conflicts.

2.3.6 Cultural Heritage Assessment

The Toronto and Region Conservation Authority has conducted a cultural heritage assessment of the project area on behalf of the Ministry of Natural Resources. Although no archaeological sites have been reported within the project area, there have been archaeological finds reported within a 1.5 km radius of the study area. Some cultural heritage features of interest near the project site include the historic Toronto Carrying Place Trail, which passed along the ridge immediately above the study area on the east bank. Furthermore, weirs #1 and #2 are situated on the floodplain surrounding Baby Point, which is the site of a large ossuary and a historic Aboriginal village. Baby Point is also one of the proposed locations for a French trade fort, the Magasin Royale, which would have guarded the Toronto Carrying Place Trail. The preliminary investigation suggests that there is a possibility that buried archaeological resources may be found relatively undisturbed within at least some of the study area components. The areas with the greatest possibility of containing relatively undamaged cultural heritage resources are those around weirs #1, #2, and #4. However, it is possible that the repeated flooding experienced by these areas may have washed away any evidence of previous occupation. Therefore, further investigation will be needed prior to the commencement of any proposed works. The preliminary results of the Lower Humber Barrier Mitigation Project Heritage Impact Assessment: Phase 1 (TRCA, 2005) for each weir are as follows: Weir #1 The area in the vicinity of weir #1 appears to have been minimally effected by Hurricane Hazel after comparison with the aerial photo. Weir #1 is the only weir that appears to have an associated earthwork. It is a sizeable berm on the east

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bank that runs roughly east-west from the dam for nearly the full length of Etienne Brulé Park, measuring approximately 28 m north-south. This could serve as reinforcement for the weir’s superstructure, due to the low level of the river bank into which the dam was built. Depending upon the amount of disturbance caused by the dumping of the fill during berm construction, there is a possibility that it simply capped rather than destroyed any buried remains that may have existed in the location. The work being proposed in this current project seems to be confined to the berm area and, thus, it may be prudent to examine the specific construction locations as they are being uncovered. The potential of the east side of weir #1 is high.

The west bank of weir #1 was difficult to assess due to the steepness of terrain and lack of a safe means of access to the project area. The general steepness of the terrain, while rendering it virtually inaccessible to investigation, also indicates that this area would also have been of limited use to previous users of the project area, and as such, would make the west bank of weir #1 of low archaeological potential. Weir #2 It is in the vicinity of weir #2 where the possible truncation of Baby Point occurs between the 1954 and 2002 aerial photographs. If in fact a small portion of the tip of Baby Point was either washed away by the hurricane or altered during the weir construction, it likely would not affect the archaeological potential of the land that remained. The bulk of the territory in this vicinity seems to have survived the hurricane moderately well.

Weir #2 does not have as elaborate embankments or berms associated with it on the east bank as do most of the other weirs. It appears that some fill was imported, leveling the edge of the bank with the weir embankment. There may be less disturbance because of the comparatively minor revetment that was constructed around this weir, as well as the lesser amount of fill that would have been required in smaller area. Concrete revetments were cut into the river bank up and downstream from the weir. Apart from the areas cut into by the revetments, there may be a higher possibility in this vicinity than in some of the others of encountering buried cultural resources.

A stone embankment is associated with weir #2 on the west bank, even though it does appear to be naturally at a higher elevation than the east bank. A walled up stone arch or barrel vault that may have functioned as an outflow pipe or channel at one point in time can be seen from the east bank near the northern end of the embankment. The floodplain in this area is wider than most others, and there appears to be even less damage to the west bank versus the east, and if the area of the northern outflow pipe is avoided, this project area would have a moderate probability for finding buried cultural remains.

Weir #3 A comparison of the 1954 and the 2002 aerial photographs indicated that there was apparently little damage caused by Hurricane Hazel to the course of the river, and the banks around weir #3. However, it does appear as if a portion of the west

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bank was flooded when the 1954 photograph was taken, obscuring the pre-Hurricane Hazel course of the river slightly.

A concrete and stone embankment runs downstream from weir #3 on the east bank. Just upstream from the weir itself the embankment along the bank cuts into the river bank, forming a sort of retaining wall around the weir on the upstream side. It is likely that the area enclosed by this “retaining wall” and the weir superstructure was built on imported fill after examining the shore line and the topography of the land abutting it upstream. If it was not built upon fill, however, the construction of both the embankment and the retaining wall likely caused some damage to any buried cultural resources that may have been present. This weir is likely at a low probability of retaining any buried cultural remains, unless deeply buried by alluvium.

Upstream on the west bank, there is a stone built retaining wall that disappears into the river bank, but not to the same extent as the one on the east bank. Downstream, the stone wall is replaced by a lower one of concrete. It appears as if there has been less damage to the river bank on the west side versus the east bank. A road, Old Mill Trail, runs along the west edge of Home Smith Park. The bank slopes up from the weir to meet the edge of this path. The construction of this path may have affected cultural resources in the vicinity. The west side of weir #3 should also be considered low archaeological potential. Weir #4

The east bank of weir #4 rests on a broad and flat floodplain that, in the 1954 aerial photographs, appears to have been agricultural fields, and at the time, like many other areas along the river, was partially flooded. Both upstream and downstream, large concrete blocks form the embankment for weir #4. Downstream from the weir on the east bank is a large outflow pipe, as well as a concrete channel. The embankment downstream of the outflow pipe is reinforced by three levels of gabion baskets. Downstream from the channel are another two levels of gabion baskets. Construction of the weir involved cutting deeply into the lower section of the river bank, as the level of the original lower bank is apparent upstream from the weir. While the area immediately abutting the weir was likely heavily damaged during construction, it is unlikely to contain cultural resources. The upper bank appears to be largely intact, and so the potential of finding archaeological remains is high.

Like weir #3, the west bank of weir #4 also appears to have been flooded in the 1954 aerial photograph, but the outline of the bank is clearly visible. The west bank around weir #4 is the largest section of floodplain on this side of the river in the study area. The bank is encircled by an embankment wall of concrete blocks much like the east side of the river. The path running along this side of the river would likely not be of concern to the project area. This area seems to be fairly well preserved and has a higher potential to harbor archaeological resources.

Weir #5

The area surrounding weir #5 in the 1954 aerial photograph on the east bank was farmland. The west bank was heavily shaded by trees to the edge of the

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floodplain. Compared with the 2002 photograph, it does appear as if the river has little altered its course since the pre-Hazel photograph was taken nearly fifty years previously. It is possible that the west bank around weir #5 was also flooded when the 1954 photograph was taken, however this is difficult to clearly discern due to the heavy tree cover.

Similar to weir #3, the retaining wall upstream from weir #5 on the east bank, cuts sharply into the river bank, forming a self-contained retaining wall. While the landward part of this retaining wall is capped with stones like weir #3, the rest of the embankment along the river is made of large concrete slabs. A low-lying portion of the river bank has been cut through by the downstream embankment. This small section is unlikely to yield buried cultural remains. This arrangement of weirs with associated retaining walls into the river bank once again leads one to believe that this weir, like weir #3, was constructed out of imported fill and, therefore, is of lower archaeological potential.

On the west bank upstream from weir #5 is a stone built retaining wall and, downstream, the wall is constructed of concrete and topped with stones. Between weirs #5 and 6, a small outflow pipe is built into the stone retaining wall on the west bank. The west bank rises rapidly to the tableland, leaving a very narrow strip of floodplain. The Old Mill Trail takes up the bulk of this narrow part of the floodplain. The archaeological potential of the project area around weir #5 is low.

Weir #6

Weir #6 seems to have been built from the remains of the old Dundas Street bridge visible in the 1954 aerial photographs The bridge abutment is still visible on the east side of the river . This is now utilized as a scenic lookout point. A paved path runs between the abutment and a slope leading to Old Dundas Street.

The superstructure of the weir itself is composed of concrete that encircles the abutment on the east bank. There is an outflow pipe just upstream from the scenic lookout point. This part of the concrete embankment, like some others, disappears into a cut in the riverbank. Downstream from the abutment, gabion baskets form an embankment. Apart from the bridge abutment itself, it seems highly unlikely that any cultural heritage features would be preserved in this vicinity.

Downstream from the old Dundas Street bridge, it appears as if the west bank floodplain was wider in the 1954 photograph than in the 2002. The disappearance of a portion of the floodplain could have been caused by Hurricane Hazel, or in the work performed after to re-enforce the bank and straighten the river.

Around the weir itself, the west bank is retained by a concrete embankment that veers sharply into the river bank just upstream from the actual weir. This angled embankment, plus its twin on the east bank, serve to direct the water down the concrete embankments between weirs #6 and #5, as it was thought post-Hurricane Hazel that straight rivers carry more water away faster than those that meander. Downstream, the concrete is topped by stones. The land slopes fairly steeply up to Old Mill Trail from the concrete embankment. There is no evidence of a matching bridge abutment on the west side of the river. If this was indeed the old Dundas Street bridge, as hypothesized, coupled with the steep slope of the land in

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this area, the chances of archaeological resources being preserved on the west bank are also low.

Weir #8

Weir #8, north of the first six, is found in Cruickshank Park, near Lawrence Avenue and Weston Road. Along this section of the river, the bank rises in two stages, the lowest is only slightly above water level, and is likely frequently submerged. On the east side, weir #8 is comprised of a long and high concrete embankment that cuts into this lower bank. This dam seems to be more curvilinear versus the angular construction of the six dams to the south. A number of maintenance covers are scattered throughout the park, including at least two that would be within the proposed project area. This would indicate that much of the park, including the section under investigation, would yield, at best, only greatly disturbed cultural remains. If the pipe runs parallel to the river, rather than flowing into it, there is a slightly greater chance of undisturbed remains being encountered, however the archaeological potential of the east bank of weir #8 is low. On the east bank, there is little evidence of a dam superstructure. However, the bank rises very steeply on the west side of the river, with little-to-no floodplain. This side of the river has very low archaeological potential.

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3.0 Project Alternatives

Presented in this section is a generic description of the alternatives considered. The evaluation of each alternative at each weir is provided in the subsequent sections.

3.1 Removal of the Weirs

Removing the series of weirs would permit unimpeded movement. At a minimum this would involve the complete removal of the concrete weir from one side of the river bank to the other. Portions of concrete below the river bed, along the river banks and within the floodplain would not necessarily be removed.

3.2 Partial Removal of the Weirs

This would involve creating a deep notch in the weir to allow unimpeded movement through this section. The notch would be located to best suit the passage of fish and the morphology of the river.

3.3 Transporting Fish around the Barrier

The manual transportation of fish beyond the series of weirs would facilitate access to spawning areas upstream.

3.4 Creation of New Habitat

(a) Downstream spawning facilities – lack of access to upstream spawning sites limits the reproductive potential of fish populations. Construction of spawning beds or artificial spawning channels downstream or adjacent to the obstruction may provide alternative spawning habitat for warmwater species.

(b) Artificial incubation areas – migratory fish are collected at the base of the obstruction and the spawn is manually removed. The spawn is then transferred to an artificial incubation or rearing area.

3.5 Improvement of Existing Fish Habitat

Improvement of existing spawning, rearing and feeding habitat to favour the desired fish population may be carried out below the obstruction.

3.6 “Do nothing” (Null) Alternative

This option should be evaluated in relation to social and environmental effects.

3.7 Alternative Types of Fishways

(a) Diversion Channel (Pool and Riffle Design) – A diversion channel around an obstruction can be constructed to permit the passage of fish around the existing structure. This type of fishway consists of a series of pool and riffle

25

sequences constructed with stone, gravel, log deflectors or weirs and vegetation for stability. See figure 4.

(b) Pool and Weir Type – This consists of vertical partitions installed at intervals down the length of a specially constructed channel or flume. Water flows over the top of successive partitions, each slightly lower than the last, creating a series of step pools. Pools are carefully designed to dissipate the energy of cascading flow. This is effective where flow rates are constant or where flow rates can be adjusted to optimize passage. This type of fishway does not allow passage of non jumping species. See figure 5.

(c) Pool and Orifice Type – This is a modification of the pool and weir type.

Openings in the weir provide flow through for ascending fish. Although the openings in the weir allow for the passage of non jumping fish, this type does not generally work well under variable flow conditions. See figure 6.

(d) Vertical Slot Type – Similar to the pool and weir fishway but pools are

separated by narrow slots which extend the full height of the partitions. This fishway is well suited for large rivers as it is able to self adjust to flow levels, providing passage over a range of changing volumes. See figure 7.

(e) Denil Fishway – Is the short section of flume with interior baffles secured to the

floor and walls. The energy of the water is dissipated through the baffles leaving a narrow zone of low velocity. Denil fishways can be installed on steeper slopes and are not as expensive as conventional fishways. See figure 8.

(f) Fish Elevator – Mechanically lifts the fish upstream over the obstruction.

Electricity is required to operate this fishway. See figure 9.

(g) Fish Lock – Fish locks raise fish over an obstruction by filling a chamber with water from the upstream level. Electricity is required to operate this fishway. See figure 10.

(h) Rocky Ramp – Creation of a ramp on the downstream side of the weir to allow

fish to swim up over the barrier. This is a relatively inexpensive solution. See figure 11.

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Figure 4. Diversion channel (Pool and Riffle)

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Figure 5. Pool and Weir Fishway

Figure 6. Pool and Orifice Fishway

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Figure 7. Vertical Slot Fishway

29

Figure 8. Denil Fishway

30

Figure 9. Fish Elevator

Figure 10. Fish Lock

31

Figure 11. Rocky Ramp Fishway

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4.0 Mitigation Measures Required

Mitigation has been defined as “actions taken during the planning, design, construction and operation of works and undertakings to alleviate potential effects on the productive capacity of fish habitats” (DFO, 1986). Mitigation measures that will be implemented during this project include:

4.1 Maintaining Normal Flow Conditions

Keeping the flow as close to normal as possible during construction will minimize erosion. If the main flow is shifted out of place, erosion and undercutting of the downstream banks may occur.

4.2 Minimizing Siltation

During construction there will be measures in place to minimize siltation and subsequent turbid water conditions.

4.3 Avoid Spawning Periods

Construction will be halted during spawning periods.

4.4 Limit Noise Disruption

Limit construction to during the day between 7:00 am and 7:00 pm to minimize disturbance to nearby residents and to comply with the noise bylaw for the City of Toronto No. 111-2003.

4.5 Public Safety

Limit access to construction site by the use of safety fences and post public notices to advise public of the situation. Design fishways which do not increase the risks to public safety. This may include measures which do not increase possible hazards associated with falls or drowning through public use of the park and the waterway, and by operators of the fishway.

4.6 Revegetation of Disturbed Areas

Areas that may have been disturbed during construction such as through the use of heavy equipment will be revegetated to minimize post disturbance erosion and restore and/or improve aesthetic qualities to the existing parkland.

4.7 Protecting Cultural Heritage Resources

The Ministry of Natural Resources has developed a set of guidelines for the consideration of cultural heritage resources that are to be carried out as part of the MNR Class Environmental Assessment process. The purpose of these guidelines is to provide MNR staff with the knowledge, procedures, and techniques to ensure

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that Ontario’s cultural heritage resources are protected and recognized in the Class Environmental Assessment process. Cultural heritage resources have been defined in the Reference Manual for MNR Class Environmental Assessments (2003) as any feature of archeological, historical, or traditional use significance. This includes built heritage resources such as buildings or structures which are important to the community, and cultural heritage landscapes which are areas valued by the community that are of significance to the understanding of the history of a people or place. Under these guidelines, projects are screened as to their potential to affect cultural heritage resources. The project is first screened for known cultural heritage resources that are already registered, designated, or identified. If there are no known cultural heritage resources, the project area will be screened for the potential for discovery of cultural heritage resources. Where the area is found to have known cultural heritage resources or a high potential for discovering such resources, the project will undergo a cultural heritage assessment by a qualified professional who will then confirm the existence of cultural heritage resources, determine their significance, assess the vulnerability of these resources to the proposed project, and recommend mitigation measures. Based on these findings, the project may either proceed, proceed with conditions, or be rejected. Where the area is found to have low or no cultural heritage potential, the project is approved, possible with cautionary conditions. Where there is any potential for discovery of cultural heritage resources, a monitoring plan will be developed and carried out during the implementation phase of the project. This will involve the presence of a qualified archeologist on site to evaluate the effectiveness of mitigation measures. Furthermore, if cultural heritage resources are discovered during excavation for example, the archeologist will ensure that the resource is adequately assessed and protected. The archeologist for the Toronto and Region Conservation Authority has conducted an archeological assessment of this proposal on behalf of the Ministry of Natural Resources. This assessment provides guidance with regards to selecting a preferred alternative for each weir and providing impact mitigation conditions. Based on the findings of the archaeological assessment, it is recommended that the areas deemed with a moderate or high probability rating be subjected to an archaeological field investigation prior to commencement of the construction program to modify the barriers. A test pitting strategy will likely be employed once the specific limits and location of the proposed construction disturbances are identified on the ground. The project areas with low probability should either be monitored by a TRCA archaeologist during construction, or should also be investigated by test-pitting beforehand to ensure that any unexpected cultural resources are not destroyed.

4.8 Locating Municipal Infrastructure

The location of municipal infrastructure such as sewer lines and watermains will be identified and confirmed prior to the selection of a preferred alternative and the completion of detailed design plans.

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4.9 Locating Former Disposal Sites

The location of former disposal sites will be confirmed prior to implementation so as to not disturb these sites and cause a contaminant release. This is not a significant concern as it is expected that the work will take place in close proximity to the river bank and it is not likely that a disposal site is located in the immediate area.

5.0 Supporting Watershed Objectives 5.1 Supporting Objectives

The Humber River Fisheries Management Plan was developed under the context of provincial fisheries management plans and the Strategic Plan for Ontario Fisheries II (SPOF II). The goal of SPOF II is to achieve: “Healthy aquatic ecosystems that provide sustainable benefits, contributing to society’s present and future requirements for a high quality environment, wholesome food, employment and income, recreational activity and cultural heritage.” The preferred management option for the Humber River watershed as outlined in the HRFMP (Clayton et al., 2004) was defined as follows: “the mitigation of the Old Mill dam north of Bloor Street to allow jumping species access upstream and the removal/mitigation of upstream dams to north of Highway 7 and the mitigation of the Board of Trade barrier to selectively allow native and naturalized species past and on to the headwaters of the upper Humber River.” The longer term fish community objective of this plan is to provide: “passage of all species to upstream habitats” The project site is located in the Lower Humber River subwatershed in Management Zone 9. The goal of this management zone is to mitigate all barriers with the target being free range for all native and naturalized species from Lake Ontario to Steeles Ave (Clayton et al., 2004). This barrier mitigation project assists in the restoration goals under the Canada-Ontario Agreement through the rehabilitation of aquatic habitat leading to the reestablishment of fish populations. This is accomplished by restoring environmental quality and beneficial use of the resource and making progress towards the rehabilitation of ecological systems.

In addition, this project is based on the Metro Toronto Remedial Action Plan direction to rehabilitate fish and wildlife habitat, specifically goals 2a and 2b which state: “Any fish species indigenous to the Metro Toronto waterfront and its watersheds should be able to return to the region, to live and naturally reproduce here.”;

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and

“Opportunities to sustain and create fish and wildlife habitat throughout the Metro Toronto and Region watersheds should be pursued in parallel with water quality objectives.” This project will help achieve these goals by meeting specific targets identified in the RAP Stage 2 Document “Clear Waters, Clear Choices”. These targets are as follows: “Biotic corridor linkages are protected, enhanced, or rehabilitated across the waterfront and throughout the stream and valley system.”; “Formerly abundant fish populations are rehabilitated where locally depressed or extinct.”;

and

“Specific targets contained in watershed plans should be used.”

5.2 Permits Required Before beginning any rehabilitation work, necessary approval may need to be obtained from Transport Canada, MNR, TRCA, City of Toronto and the Department of Fisheries and Oceans.

6.0 Project Category

Based on the results of the screening criteria (Appendix A), the project was determined to be Category “C” as defined in the MNR Class Environmental Assessments Reference Manual for Resource Stewardship and Facility Development Projects (2003). The rationale for assigning a Category “C” as identified in the MNR Class Environmental Assessments Reference Manual for Resource Stewardship and Facility Development Projects (2003) are as follows:

(i) The appropriate type of management direction is in place for the project, but does not fully define the project, or the plan suggests that alternatives should be considered or additional evaluation carried out.

(ii) Effects will require mitigation techniques.

(iii) Consultation and consideration of the proposal and reasonable alternatives

may reveal appropriate solutions and common understandings. (iv) Medium to high potential for significant net negative effects

(v) Potential to reduce negative effects or increase public understanding by

examining alternatives.

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7.0 Preliminary Evaluation of Alternatives

The relative merits of each alternative, including perceived environmental effects, estimated cost and the effectiveness of satisfying the watershed fisheries objective or project purpose for each weir are presented in the following table format. Further explanation of the selection of alternatives continuing further in study is presented in section 8.0 Project Evaluation.

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Table 7. Preliminary evaluation of alternatives for weir #1

Alternatives Environmental Effects Estimated Capital Cost ($)

Satisfies Watershed Objective

Satisfies Project

Purpose

Continues Further in

Study Removal of Barrier

-erosion and sedimentation -altered flows -allows exotics access to upstream

>250,000

Yes

No – sea

lamprey control concern

No

Partial Removal

-erosion and sedimentation -allows exotics access -altered flows

80,000

Yes

No – sea

lamprey control concern

No

Transporting Fish Around Barrier

-targets single species -stress to fish/mortality -safety hazard during spring freshet

10,000/yr

No

No

No

Creation d/s Spawning Facilities

-increase poaching -continued fragmentation of watershed

50-100,000

No

No

No

Artificial Incubation Areas

-targets single species -marginal reproductive success

30-50,000

No

No

No

Improve Existing Habitat

-continued fragmentation of watershed

100-150,000

No

No

No

Do Nothing -fishery is not improved -habitat not improved -not meeting watershed objectives

0

No

No

Yes

Diversion Channel

-construction noise -public safety -sedimentation

180,000 2

Yes

Yes – Sea

lamprey control required

Yes

Pool and Weir Type

-construction noise -public safety -aesthetics -allows jumping species only

100,000

No

No

No

Pool and Orifice Type

-construction noise -public safety -aesthetics

100,000

Yes

No

No

Vertical Slot -construction noise -public safety -aesthetics

225,000 2

Yes

Yes

Yes

Denil Fishway -construction noise -public safety -aesthetics

200,000 2

Yes

Yes

Yes

Fish Elevator -construction noise -public safety -aesthetics -

150,000

Yes

Yes

No 1

Fish Lock -construction noise -public safety -aesthetics

150,000

Yes

Yes

No 1

Rocky Ramp -allows exotics upstream -may get washed out by strong flows

75,000

Yes

No – sea

lamprey control

No

1. Fish elevator and fish locks were not considered further due to high operational and maintenance costs. 2. Capital costs include consideration for sea lamprey control.

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Table 8. Preliminary evaluation of alternatives for weir #2.

Alternatives Environmental Effects

Estimated Capital Cost ($)


Satisfies Project

Purpose



-erosion and sedimentation -altered flows

>250,000

Yes

No

No

Partial Removal


50,000

Yes

Yes

Yes



10,000/yr

No

No

No



50-100,000

No

No

No



30-50,000

No

No

No



100-150,000

No

No

No


0

No

No

Yes

Diversion Channel


150,000

Yes

Yes

Yes

Pool and Weir Type

-construction noise -public safety -aesthetics -targets jumping species only

100,000

No

No

No



100,000

Yes

No

No


125,000

Yes

Yes

Yes


100,000

Yes

Yes

Yes

Fish Elevator -construction noise -public safety -aesthetics

150,000

Yes

No

No 1


150,000

Yes

No

No 1

Rocky Ramp -may get washed out by strong flows

75,000

Yes

Yes

Yes

1. Fish elevator and fish locks were not considered further due to high operational and maintenance costs.

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Satisfies Project

Purpose




>250,000

Yes

No

No

Partial Removal


50,000

Yes

Yes

Yes



10,000/yr

No

No

No



50-100,000

No

No

No



30-50,000

No

No

No



100-150,000

No

No

No


0

No

No

Yes

Diversion Channel


150,000

Yes

Yes

Yes

Pool and Weir Type

-construction noise -public safety -aesthetics -targets jumping species

100,000

No

No

No



100,000

Yes

No

No


125,000

Yes

Yes

Yes


100,000

Yes

Yes

Yes


150,000

Yes

No

No 1


150,000

Yes

No

No 1


75,000

Yes

Yes

Yes


40


Alternatives Environmental Effects Estimated Capital Cost ($)


Satisfies Project

Purpose




>250,000

Yes

No

No

Partial Removal


50,000

Yes

Yes

Yes



10,000/yr

No

No

No



50-100,000

No

No

No



30-50,000

No

No

No



100-150,000

No

No

No


0

No

No

Yes

Diversion Channel


80,000

Yes

Yes

Yes

Pool and Weir Type


65,000

No

No

No



65,000

Yes

No

No


125,000

Yes

Yes

Yes


100,000

Yes

Yes

Yes


100,000

Yes

No

No 1


100,000

Yes

No

No 1


75,000

Yes

Yes

Yes


41





Satisfies Project

Purpose




>250,000

Yes

No

No

Partial Removal


50,000

Yes

Yes

Yes



10,000/yr

No

No

No



50-100,000

No

No

No



30-50,000

No

No

No



100-150,000

No

No

No


0

No

No

Yes

Diversion Channel


80,000

Yes

Yes

Yes

Pool and Weir Type


65,000

No

No

No



65,000

Yes

No

No


125,000

Yes

Yes

Yes


100,000

Yes

Yes

Yes


100,000

Yes

No

No 1


100,000

Yes

No

No 1


75,000

Yes

Yes

Yes


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Satisfies Project

Purpose




>250,000

Yes

No

No

Partial Removal


50,000

Yes

Yes

Yes



10,000/yr

No

No

No



50-100,000

No

No

No



30-50,000

No

No

No



100-150,000

No

No

No


0

No

No

Yes

Diversion Channel


80,000

Yes

Yes

Yes

Pool and Weir Type


65,000

No

No

No



65,000

Yes

No

No


125,000

Yes

Yes

Yes


100,000

Yes

Yes

Yes


100,000

Yes

No

No 1


100,000

Yes

No

No 1


75,000

Yes

Yes

Yes


43

Weir #7 – Raymore Park • Existing Denil Fishway Table 13. Preliminary evaluation of alternatives for weir #8




Satisfies Project

Purpose




>250,000

Yes

No

No

Partial Removal


50,000

Yes

Yes

Yes



10,000/yr

No

No

No



50-100,000

No

No

No



30-50,000

No

No

No



100-150,000

No

No

No


0

No

No

Yes

Diversion Channel


150,000

Yes

Yes

Yes

Pool and Weir Type


100,000

No

No

No



100,000

Yes

No

No


125,000

Yes

Yes

Yes


100,000

Yes

Yes

Yes


150,000

Yes

No

No 1


150,000

Yes

No

No 1


75,000

Yes

Yes

Yes


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8.0 Project Evaluation

Refer to section 7.0 Preliminary Evaluation of Alternatives. The following four alternatives for weir #1 were selected for further study: 1) Diversion Channel

This alternative satisfies both the watershed objective and project purpose. It will allow upstream access for all fish species as well as provide additional aquatic habitat. A sea lamprey control structure can be incorporated into the design of the channel.

2) Do Nothing (Null) Alternative

This alternative is selected for future study as a requirement of the Environmental Assessment process. It does not satisfy the watershed objective or project purpose.

3) Vertical Slot Fishway

This type of fishway satisfies the watershed objective and project purpose. It functions well under a range of changing volumes and allows for the passage of both jumping and non-jumping fish. A sea lamprey control cage can be incorporated into the design.

4) Denil Fishway

This type of fishway satisfies the watershed objectives and project purpose. It provides passage for fish of all sizes and allows for a sea lamprey control cage to be incorporated.

The following six alternatives for the remaining six weirs were selected for further study: 1) Diversion Channel

This alternative satisfies both the watershed objective and project purpose. It will allow upstream access for all fish species as well as provide additional aquatic habitat.

2) Do Nothing (Null) Alternative

This alternative is selected for future study as a requirement of the Environmental Assessment process. It does not satisfy the watershed objective or project purpose.

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3) Vertical Slot Fishway

This type of fishway satisfies the watershed objective and project purpose. It functions well under a range of changing volumes.

4) Denil Fishway

This type of fishway satisfies the watershed objectives and project purpose. It provides passage for fish of all sizes.

5) Partial Removal

This alternative satisfies the watershed objective and project purpose. It is less expensive than full removal and would allow for the movement of all species of fish.

6) Rocky Ramp

This alternative satisfies the watershed objective and project purpose. It is a relatively inexpensive solution that would allow for the passage of all fish species.

The selected alternatives are examined further in sections 13 through 19. The following alternatives were rejected: 1) Creation of Downstream Spawning Facilities

This alternative does not satisfy the watershed objective or project purpose. It does not allow the movement of any fish species beyond the barrier. Continued fragmentation of the watershed will occur.

2) Creation of Artificial Incubation Areas

This alternative does not satisfy the watershed objective or project purpose. It targets only single species with estimated marginal reproductive success and does not allow for the movement of fish beyond the barrier.

3) Improvement of Fish Habitat

This alternative does not satisfy the watershed objective or project purpose. It does not allow the movement of any fish species beyond the barrier. Continued fragmentation of the watershed will occur.

4) Transporting Fish Around the Barrier

This alternative does not satisfy the watershed objective or project purpose. It targets single species and is very labour intensive which would become quite costly over time.

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5) Pool and Weir Fishway

This alternative does not satisfy the watershed objective or project purpose. It only allows for the passage of fish capable of jumping.

6) Pool and Orifice Fishway

This type of fishway satisfies the watershed objective however, it does not satisfy the project purpose. This fishway is effective only over a small range of flows, therefore this type of fishway would increase the operational complexity of the structure and be subject to operational safety hazards as it would not operate well under the variable flow conditions demonstrated by the Lower Humber River.

7) Fish Elevator

This type of fishway satisfies the watershed objective but does not satisfy the project purpose due to high operational and maintenance costs and operational complexity. This alternative requires the use of electricity therefore; in addition to constructing the fishway, a separate auxiliary building would need to be constructed to house the electrical equipment. This increases the construction and maintenance costs as well as the operational complexity.

8) Fish Lock

This type of fishway satisfies the watershed objective but does not satisfy the project purpose due to high operation and maintenance costs and operational complexity. This alternative requires the use of electricity therefore; in addition to constructing the fishway, a separate auxiliary building would need to be constructed to house the electrical equipment. This increases the construction and maintenance costs as well as the operational complexity.

9) Removal of the Barrier

Removing the existing barrier satisfies the watershed objectives but does not satisfy the project purpose. It does not allow for the implementation of sea lamprey control and, at an estimated cost of over $250,000, this alternative is very expensive.

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Step 2 – Environmental Analysis 9.0 Environmental Concerns Associated with Fishways 9.1 Introduction of Fish Species Upstream The current habitat and fish communities upstream in the Humber River represent a

highly fragmented section of a larger watershed system. The following list indicates effects that may occur through the reconnection of fish communities and habitat.

Potential Positive Effects: a) increased diversity in fish communities upstream. b) increased genetic diversity within fish species as a result of reconnecting

fragmented gene pools. c) increased distribution of resident non-jumping species. d) increased reproductive success of native and naturalized cold water species

as a result of increased access to upstream habitat. e) increased reproductive success of native and naturalized warm water

species as a result of introducing access to upstream habitat. f) increased angling and viewing opportunities upstream Potential Negative Effects: a) increased predation or competition pressures between introduced and

resident fish populations. b) introduction of diseases or parasites as a result of reconnecting fragmented

habitats. c) introduction of undesirable species such as sea lamprey or carp into

upstream sections of the watershed.

The introduced species of concern for the watershed include common carp and Goldfish. Other introduced species such as round goby, river ruffe or grass carp have not been detected in the lower Humber and are not considered a potential threat at this time. The most significant undesirable species of concern is the sea lamprey.

9.2 Resource Use Conflicts The project site is located adjacent to public parkland allowing free access to the area. The installation and operation of a fishway may attract a considerable number of people to the park for various reasons such as viewing, picnicking, education, research, and fishing. On-site environmental effects may include: a) vandalism b) accumulation of litter c) disturbance of fish and wildlife d) trampling of streambed and backshore vegetation e) increased poaching near fishway entrances f) increased risk to public safety g) boating/river navigation hazard

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h) conflicts with existing trails/pathways Off-site environmental effects may include: a) increased traffic flow b) parking congestion 9.3 Temporary Obstruction to Fish Migration The construction of the fishway may temporarily obstruct the upstream migration of fish during migratory periods. However, this is easily mitigated by scheduling construction activities during non-spawning periods. 9.4 Erosion, Sedimentation and Water Quality

Silt and sediment generated from the construction and maintenance of fishways may cause turbidity and cover downstream spawning beds reducing the fish reproduction potential of the area.

As a result of the use of heavy equipment during the construction of the fishway, the soils may become compacted which may cause an increase in surface runoff and erosion leading to sedimentation of the river. However, it is believed that the impacts of soil compaction at this location are negligible.

Flow conditions must be kept as close to normal as possible. If the fishway is improperly placed or the flow is improperly aligned toward the shoreline, erosion and undercutting of the downstream banks may result. In the case of a partial removal of the weir, initial sedimentation may occur as the sediment that has been built up behind the weir is released. This may be mitigated through the use of stop logs to control the amount and timing of the release of sediment. Also, partial removal may increase the risk of scour on the downstream end of the weir. If a cofferdam is required to establish a dry construction site, both its installation and removal in a flowing water situation may result in a considerable amount of erosion, turbidity, and sedimentation. Over time, sediment and debris may accumulate in the fishway and cause a blockage. As part of the maintenance, the removal of debris and sediment in the fishway may cause downstream siltation and turbidity. This will most likely be of minimal consequence as it will be a relatively short-lived disturbance.

9.5 Degradation of Scenic Quality

Degradation of the scenic quality of the local landscape (including physical and aesthetic characteristics) may result from construction operations such as clearing, excavation, stockpiling of construction materials, work in the streambed as well as accumulation of waste materials in and around the work area. Also, some types of fishways may be less aesthetically pleasing than others. The design of the fishway will take this into account in order to mitigate this effect.

49

9.6 Noise

Local residents and park patrons may be disturbed by noise resulting from the use of equipment during construction. Fish and wildlife populations may also be disturbed by the noise.

9.7 Dust

Dust generated from drilling and blasting operations, aggregate crushers, vehicles moving over exposed areas, and wind action may become irritating to local residents and park visitors.

9.8 Ice Conditions in the Humber River

The Lower Humber River typically experiences strong ice flows in the spring. These ice flows have the potential to cause damage to a fishway and/or affect the timely operation of a trap. Fishways which potentially alter river hydraulics such as partial removal, may also alter and/or reduce the formation and transport of ice in the river. Figure 12 shows the parking lot and lands adjacent to the Humber River in April of 2003.

(Photo courtesy DFO Sea Lamprey Control Center)

Figure 12. Ice conditions in the Humber River

9.9 Public Safety and the Humber River

The existing weirs and valley system provide some level of public risk that will require consideration, particularly related to changing existing structures or building new structures. Some fishway alternatives may be located within the floodplain and are thus accessible to the public. Proper measures will be taken with the design of these fishways such that hazards related to falls or drowning are not created. Measures to ensure operator safety will also be considered in the design of the fishway, particularly those which require maintenance and fish sorting operations.

50

Due to the size of the contributing watershed, the Humber River can experience high flows following storm events and during spring freshet. These high flows can translate into serious public safety hazards near the river. Of particular interest is the occurrence of hydraulic conditions below low head barriers that result in “drowning machines”. These hydraulic conditions are extremely dangerous for small watercraft. The following picture of the Humber River was taken in January 2005. Notice the turbulence on the downstream side of the weir. This is a strong undertow which continuously pulls objects under the face of the weir.

Figure 13. Dangerous hydraulic conditions downstream of low head weirs

9.10 Watercraft Navigation

In their current state, the barriers are obstructing watercraft navigation in this area of the Humber River. The installation of a fishway would not negatively change this situation as the barriers would remain as obstructions to navigation. However, including a portage in the final design of the fishway or partial removal alternative would result in a positive effect. Furthermore, the construction of other types of fishways such as diversion channels and rocky ramps could result in positive impacts by facilitating watercraft navigation at the barriers.

51

10.0 Environmental Checklist

The definition of each category has been derived from the Reference Manual for MNR Class Environmental Assessments (2003). For each expressed concern, one of the following levels of significance will be assigned and entered into the appropriate category in the checklist:

• High A “high” net effect may reflect a high level of certainty that a significant effect will occur, or a low level of certainty about one or more effects and a need for further evaluation and exploration of mitigation measures. One or more “high” negative net effects may result in a decision to seek other ways of resolving a problem or meeting program objectives.

• Medium A “medium” net effect may be based on reasonable certainty, and may be significant in combination with other medium and high net effects.

• Low A ”low” net effect would be assigned where there is a high degree of certainty as to the effect, and where the effect has minimal significance.

• Nil A “nil” effect would be assigned where a criterion clearly does not apply.

• Unknown An “unknown” would be assigned where the effects are unknown.

A negative net effect refers to a change to the environment so as to seriously disturb the integrity, distribution, operation or abundance of the environmental component as a result of implementing the project.

11.0 Determination of Significance of Effects

The significance of effects are presented in Tables 14 through 20. The Environmental Screening Criteria from the Reference Manual for MNR Class Environmental Assessments (2003), has been used to determine the significance of effects for each of the alternatives listed for each weir structure. As a matter of clarity, each of the criteria should be prefaced with the phrase: “This project has the potential to effect…”.

12.0 Environmental Analysis Summary

An Environmental Analysis Summary has been completed for each selected alternative. The analysis is based on the Environmental Screening Criteria outlined in the Reference Manual for MNR Class Environmental Assessments (2003). The following information has been included in each analysis summary: 1. An identification of the environmental effects and their estimated significance; 2. An indication of the potential for mitigation of the environmental effects;

52

3. An estimation of the effectiveness of the alternative to meet its intended purpose;

4. An estimation of the cost and feasibility of carrying out the alternative; and 5. The monitoring requirements of the alternatives.

13.0 Environmental Analysis for Weir #1

Weir #1 is 48.1 meters wide and approximately 1.6 meters high from the top of the structure to the water surface. See figure 14 (p. 61).

13.1 Denil Fishway

Effectiveness of the Alternative to Meet Intended Purpose:

This fishway meets both the watershed and project objectives. It will provide unimpeded access upstream for a wide range of fish species and sizes. A lamprey control structure can be incorporated into the design of the fishway to maintain lamprey control.

This fishway can be effectively operated within a wide range of fluctuating water levels and conditions common to the Lower Humber River. A denil fishway is also effective at maximizing attraction flows. Environmental Effects and Significance: There are several environmental effects that are considered minor and are short term, associated with the construction phase. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all of low significance as they are based on short term concerns associated with the construction of the fishway. The effects to aesthetic qualities following the construction of the fishway are expected to be low. Anticipated effects can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation designs. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 14 based on the condition to include revegetation plans. The effects to public health and safety are considered to be of low significance as mitigation measures can be implemented to address this issue. Access to the site will be restricted during the construction phase and signs will be clearly posted. Following construction, access into the fishway will be restricted to personnel only and sings will be clearly posted warning of any dangers associated with the fishway. Furthermore, a fishway can be built as an enclosed structure with safety grates over

53

the top as well as at the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and taking the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an important factor to consider. Effects to drainage during the construction of the fishway are expected to be minimal and therefore, considered of low significance. Based on the findings of the cultural heritage assessment that was completed for this project, it is suggested that there may be a high possibility that buried cultural resources exist at this site. The area surrounding this weir on the east bank was the site of a historic village and ossuary. Therefore, this is reflected in Table 14 as having a high negative impact to cultural heritage resources. However, this impact can be mitigated by conducting further investigation, such as test pitting, prior to construction and, if necessary, having a qualified archaeologist on site during construction. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 14 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect. Positive effects are in relation to fish productivity and fisheries potential. Installing a denil fishway would provide access to upstream habitat for spawning, rearing and feeding activities. This has the potential to dramatically increase fish productivity within the watershed. Also, by allowing access to otherwise fragmented fish communities and habitats, there will be an increase in genetic diversity among fish populations which will lead to increased fish productivity. These benefits to fish populations will provide increased recreation and tourism potential by increasing angling opportunities. In addition, the need for fish stocking will be reduced, resulting in a decreased cost of the current fish stocking program. Mitigation Measures Required: Mitigation of the identified negative effects can be achieved through:

• Using standard sedimentation and erosion control practices during construction;

• Maintaining flow conditions as close to normal as possible to prevent erosion of downstream banks;

• Restricting construction activities to between the hours of 7:00 am and 7:00 pm to minimize disturbance to nearby residents and to comply with the noise bylaw for the City of Toronto;

54

• Halt construction during spawning periods to minimize the disturbance to migrating fish;

• Limit access to the construction site by the use of safety fences and post public notices to advise park patrons of the risk;

• Revegetation of any areas that may have been disturbed during construction to reduce erosion. This will also help to restore ecological integrity and aesthetic qualities to the parkland following the construction;

• Ensure significant trees and vegetation communities are protected; • Archeological assessment to be completed in order to ensure the

preservation of cultural heritage resources; • Location of municipal infrastructure to be confirmed prior to any work being

done; • Ensure invasive or nuisance species do not get past weir #1. To do this, a

trap and sort facility will be an integral part of the fishway. It is likely that the manual sorting of sea lamprey and non-jumping fish will be required for the months of April, May and June at this location.

• Creation of a portage to facilitate navigation around the barrier. Estimated Cost and Feasibility: The estimated cost for this type of fishway with a sea lamprey control facility is approximately $200,000. This type of fishway has previously been constructed and is operating at another location (Milne Reservoir, Markham) on the Rouge River under similar conditions therefore, it is very feasible that it can be successfully constructed and operated at this location also. A denil fishway at this location, operating on a 10% slope, would need to be approximately 16 meters in length (excluding resting pools). The construction of a fishway at this location is more feasible for the east side of the river. Monitoring Requirements: Frequent monitoring of the stream during April, May, June, July, September and October is recommended as a means of determining the peak periods of fish migration. Water temperatures and flood conditions in the stream should be monitored to determine safe periods of operation of the fishway. There is another denil fishway further north on the river at Raymore Park. The operation of this fishway can be used for clarifying monitoring and conveyance requirements. A monitoring station should be set up at the fishway to monitor the fish passing through the fishway and to control the sea lamprey from moving through. During sampling activities the fish will be monitored for fin clips, weight, length, sex, disease and evidence of wounds. The upstream areas will also be sampled for juvenile fish produced from adults that have passed through the fishway.

13.2 Diversion Channel Effectiveness of the Alternative to Meet Intended Purpose:

This alternative meets both the watershed objective and the project purpose. Creating a diversion channel will allow unrestricted access for all species to migrate beyond the barrier. In order to address the concerns of sea lamprey moving

55

upstream in the Humber River watershed, the design of the channel must incorporate a sea lamprey control structure.

Environmental Effects and Significance:

Many of the effects identified in Table 14 are of low significance and result from the construction of the diversion channel. The effects of sedimentation and erosion, noise, and use of the park are temporary and can be easily mitigated. The effects to drainage and flooding are considered of low significance and are a result of reducing the volume of water moving over the weir in order to divert it through the channel. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 14 based on the condition to include revegetation plans. In terms of public safety, access to the site will be restricted during the construction phase and warning signs will be clearly posted. Following construction, signs will be posted to warn of potential dangers around the diversion channel, for example, during high flow conditions. Access to the trap and sort portion of the channel will be restricted and signs clearly posted. Personnel working in and around the fishway during construction and operation will be properly trained and will take the appropriate safety measures. These concerns are considered to be of low significance as they can be addressed through the use of mitigation techniques. However, an additional risk to public safety may ensue from creating an additional channel within the floodplain. There may be an increased risk of falls or an increased risk of drowning, particulary during high flow conditions. As a result, this impact is considered to be of medium significance as indicated in Table 14. Another important factor to consider for this alternative is referred to as “lands subject to natural hazards” in Table 14. The Humber River experiences strong ice flows which could potentially cause damage to a diversion channel. This is seen as being of medium significance due to the potential to cause significant damage to the integrity of the diversion channel, and thus creating the possibility of high maintenance costs. Based on the findings of the cultural heritage assessment that was completed for this project, it is suggested that there may be a high possibility that buried cultural resources exist at this site. The area surrounding this weir on the east bank was the site of a historic village and ossuary. Therefore, this is reflected in Table 14 as having a high negative impact to cultural heritage resources. However, this impact can be mitigated by conducting further investigation, such as test pitting, prior to construction and, if necessary, having a qualified archaeologist on site during construction.

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The alternative will have negative effects in relation to watercraft navigation. This is seen in Table 14 as “potential to affect access to inaccessible areas” and “obstruct navigation”. The barriers currently obstruct navigation and creating a diversion channel will not improve this, as the required sea lamprey control structure will still create an obstruction. This issue is considered to be of low significance as there will be no change in navigability as a result of constructing a diversion channel. Also, a portage could be included in the design to mitigate this problem in which case, there would be a resulting positive effect. There are many expected positive effects resulting from the construction of a diversion channel. Increased habitat due to access to upstream reaches as well as additional habitat created within the channel will help increase fish productivity. A diversion channel will help restore ecological integrity to the river as well as improve aesthetic qualities to the existing parkland. Increased angling opportunities will increase recreational importance and potentially increase tourism opportunities within the area. Terrestrial wildlife will also benefit from this alternative as there will be riparian planting along the length of the channel. There will also be a reduced need to stock fish resulting in decreased costs of the current stocking effort. Mitigation Measures Required: Mitigation of the identified negative effects can be achieved through:









done; • Ensure invasive or nuisance species do not get past weir #1. To do this, a

trap and sort facility will be an integral part of the fishway. It is likely that the manual sorting of sea lamprey and non-jumping fish will be required for the months of April, May and June at this location.

• Creation of a portage to facilitate navigation around the barrier.

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Estimated Cost and Feasibility: The estimated cost of constructing a diversion channel at this location is approximately $180,000. A diversion channel operating at a 5% slope at this location would need to be approximately 32 meters in length. There is sufficient room on the east bank of the river for a diversion channel to be built. Monitoring Requirements:

The river should be monitored during April, May, June, July, September and October as a means of determining the peak fish migration periods. The sea lamprey control structure will need to be monitored during the months of April, May and June. Water temperature and flow conditions of the river should also be monitored as a means of determining safe periods for collection. Monitoring should take place upstream and downstream of the channel and also within the diversion channel to determine the types of fish using the channel. During this monitoring, fish should be sampled for weight, length, sex, disease, wounds and fin clips.

13.3 “Do Nothing” (Null) Alternative Effectiveness of the Alternative to Meet Intended Purpose:

This alternative does not satisfy the watershed objectives or the project purpose as it is not a solution to providing fish passage on the Lower Humber River.


This alternative has four natural environment effects as identified in Table 7 that are considered of high significance. The identified effects are a result of the inability of this alternative to meet the objectives of the Humber River Fisheries Management Plan. Allowing the obstruction to remain in the river and continue to impede fish movement results in the lack of access for migratory species to upstream spawning, rearing and feeding habitat. Effects resulting from the inability to migrate can be expressed as a loss of potential habitat, loss of potential migration, loss of potential spawning areas and continued loss of ecological integrity. This habitat fragmentation can be expected to cause further declines in fish productivity as populations will continue to be genetically isolated from one another. Furthermore, the “potential to obstruct navigation” and “potential to affect inaccessible areas” as identified in Table 14, are considered to be of low significance. These effects refer to the continued obstruction to navigation if the barrier remains in its current state. Sea lamprey will continue to be controlled by the existing weir and traps.

Mitigation Measures Required:

N/A

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Estimated Cost and Feasibility:

The estimated cost of the “Do Nothing” alternative would be zero capital expenses however, this does not take into account the cost of lost fish productivity which will cause a loss of recreation potential, a loss of potential tourism revenue, and the continued cost of stocking programs. Currently, the fish stocking effort is approximately $75,000 per year.

Monitoring Requirements:

N/A

13.4 Vertical Slot Fishway

Effectiveness of the Alternative to Meet its Intended Purpose:

This alternative meets both the watershed objective and project purpose. This type of fishway is able to function well under a wide range of changing volumes and fluctuating flow conditions making it suitable for this location. It is able to pass both jumping and non jumping fish species and a sea lamprey control structure can be incorporated into the design. A vertical slot fishway generally operates with less water flowing through it and is therefore not as well suited to maximizing attraction flow than a denil fishway. Environmental Effects and Significance:

This alternative has several effects under the Natural Environment components and Land Use components, many of which are considered of low significance. These effects are short term in nature and are a result of construction activities. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all expected to be effected by the construction of a vertical slot fishway. The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation designs. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 14 based on the condition to include revegetation plans. The effects to public health and safety are considered of low significance as mitigation measures can be implemented to address this issue. Access to the site will be restricted during the construction phase and signs will be clearly posted. Following construction, access into the fishway will be restricted to personnel only and sings will be clearly posted warning of any dangers associated with the fishway.

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Furthermore, the fishway can be built as an enclosed structure with safety grates over top as well as at the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and taking the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an important factor to consider. Effects to drainage during the construction of the fishway are expected to be minimal and therefore, considered of low significance. Based on the findings of the cultural heritage assessment that was completed for this project, it is suggested that there may be a high possibility that buried cultural resources exist at this site. The area surrounding this weir on the east bank was the site of a historic village and ossuary. Therefore, this is reflected in Table 14 as having a high negative impact to cultural heritage resources. However, this impact can be mitigated by conducting further investigation, such as test pitting, prior to construction and, if necessary, having a qualified archaeologist on site during construction. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 14 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect.

Positive effects that are expected to result include access to additional habitat for spawning, rearing and nursing activities. Although this type of fishway is limited to the size of fish that can pass, it is estimated that most fish will be able to navigate through it. Therefore, there will be an increase in the number of fish migrating upstream. This increased fish productivity will lead to increased fisheries potential and a potential to benefit tourism within the watershed. The need for stocking fish will be reduced and therefore the costs associated with the current stocking program will be reduced. Mitigation Measures Required:

Mitigation of the identified negative effects can be achieved through:

• Using standard sedimentation and erosion control practices during

construction; • Maintaining flow conditions as close to normal as possible to prevent

erosion of downstream banks; • Restricting construction activities to between the hours of 7:00 am and

7:00 pm to minimize disturbance to nearby residents and to comply with the noise bylaw for the City of Toronto;


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• Limit access to the construction site through the use of safety fences and post public notices to advise park patrons of the risk;

• Revegetation of any areas that may have been disturbed during construction to reduce erosion. This will also help to restore ecological integrity and aesthetic qualities to the parkland following the construction


preservation of cultural heritage resources; • Location of municipal infrastructure to be confirmed prior to any work

being done; • Ensure invasive or nuisance species do not get past weir #1. To do this,

a trap and sort facility will be an integral part of the fishway. It is likely that the manual sorting of sea lamprey and non-jumping fish will be required for the months of April, May and June at this location.



The construction of this type of concrete fishway with a sea lamprey control facility is expected to cost approximately $225,000. A vertical slot fishway operating on a 10% slope would be 16 meters in length excluding resting pools. A vertical slot fishway at this location will require more resting pools than a denil fishway and therefore will need to be longer than the denil alternative. This will require more concrete work and greater excavation, resulting in higher costs. The construction of a fishway is more feasible for the east side of the river. This type of fishway has been in successful operation on other large rivers such as the Fraser River in British Columbia and the Nine Mile River in Port Albert, Ontario. Monitoring Requirements: Frequent monitoring of the fishway in the months of April, May, June, July, September and October is recommended in order to determine the peak periods of fish migration. Water temperatures and flood conditions in the river should be monitored to determine safe periods to operate the fishway.

A monitoring station should be set up at the upstream end of the fishway for collecting migrating fish. These fish should then be monitored for weight, length, sex, disease and evidence of wounds. This sampling will also allow for monitoring the types and number of fish using the fishway. Any sea lamprey or other nuisance species attempting to make their way up the fishway will be stopped.

Periodic monitoring of upstream sections of the river should take place in order to determine the effectiveness of the fishway by checking for juvenile fish produced from adults that have passed through the fishway.

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Figure 14. Weir #1

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Table 14. Significance of effects for weir #1. Level of Significance High Medium Low Nil Unk Positive Criteria: Denil fishway Diversion

channel Do nothing Vertical slot

Natural Environment: 1. air quality

2. water quality & quantity

3. species at risk or their habitat

4. significant earth or life science features

5. fish or other aquatic species and habitat

6. lands subject to natural or human-made hazards

7. recovery of a species under special management program

8. ecological integrity

9. terrestrial wildlife

10. natural vegetation and terrestrial linkages

11. permafrost

12. soils and sediment quality

13. drainage or flooding

14. sedimentation or erosion

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Table 14 (cont.). Significance of effects for weir #1 Level of Significance High Medium Low Nil Unk Positive Criteria Denil fishway Diversion


Natural Environment cont.: 15. release of contaminants in soils, sediments

16. natural heritage features

Land Use, Resource Management: 1. Access to trails or inaccessible areas

2. Obstruct navigation

3. Other resource mngmt projects

4. Traffic patterns of infrastructure

5. Recreational importance – public or private

6. Create excessive waste materials

7. Commit a significant amount of a non-renewable resource

8. Noise levels

9. Views or aesthetics

10. Be a justification for implementing another project

11. Adjacent or nearby uses, persons, or property

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Table 14 (cont.). Significance of effects for weir #1 Level of Significance High Medium Low Nil Unk Positive Criteria Denil fishway Diversion


Social, Cultural, and Economic: 1. Cultural heritage resources

2. Displace people, businesses, institutions, or public facilities

3. Community character, enjoyment of property or local amenities

4. Increase demands on government services or infrastructure

5. Public health and or safety

6. Local, regional, or provincial economies or businesses

7. Tourism values

Aboriginal Considerations: 1. First nation reserves or communities

2. Spiritual, ceremonial, or cultural sites

3. Traditional land or resources used for harvesting, activities

4. Aboriginal values

5. Lands subject to land claims

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Table 14 (cont.). Significance of effects for weir #1 Alternative Est. Capital

Costs ($) Annual Operational Cost ($)

Total # Nil Effects

Total # Low Neg. Effects

Total # Medium Neg. Effects

Total # High Neg. Effects

Total # Positive Effects

Denil Fishway

200,000 5000 24 6 0 1 8

Diversion Channel

180,000 2000 23 4 2 1 9

Do Nothing

0 75,000 1 33 2 0 4 0

Vertical Slot

225,000 2000 24 6 0 1 8

1. Reflects cost of maintaining current fish stocking program

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The weir at this location is 42 meters wide with a 1.8 meter vertical drop from the top of the weir structure to the water surface. See figure 15 (p. 78).

14.1 Denil Fishway Effectiveness of the Alternative to Meet Intended Purpose:

This fishway meets both the watershed and project objectives. It will provide unimpeded access upstream for a wide range of fish species and sizes.

This fishway can be effectively operated within a wide range of fluctuating water levels and conditions common to the Lower Humber River. Denil fishways are effective in maximizing attraction flows. Environmental Effects and Significance: There are several minor environmental effects associated with the building of a fishway. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all of low significance as they are based on short term concerns associated with the construction. The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation plans into the design. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 15 based on the condition to include revegetation plans. The effects to public health and safety are considered of low significance. Access to the site will be restricted during the construction phase and warning signs will be clearly posted. Following construction, access into the fishway will be restricted to personnel only and signs will be clearly posted warning of any dangers associated with the fishway. Furthermore, the fishway can be built as an enclosed structure with safety grates over the top and at the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and taking appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an

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important factor to consider. Effects to drainage during the construction of the fishway are expected to be minimal and therefore, considered of low significance. Based on the findings of the cultural heritage assessment that was completed for this project, it is suggested that there may be a high possibility that buried cultural resources exist at this site. The area surrounding this weir on the east bank was the site of a historic village and ossuary. Therefore, this is reflected in Table 15 as having a high negative impact to cultural heritage resources. However, this impact can be mitigated by conducting further investigation, such as test pitting, prior to construction and, if necessary, having a qualified archaeologist on site during construction. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 15 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage would result in a positive effect. Positive effects are in relation to fish productivity and fisheries potential. Installing a denil fishway would provide access to upstream habitat for spawning, rearing and feeding activities. This has the potential to dramatically increase fish productivity within the watershed. Also, by allowing access to otherwise fragmented fish communities and habitats, there will be an increase in genetic diversity among fish populations which will lead to increased fish productivity. These benefits to fish populations will provide increased recreation and tourism potential by increasing angling opportunities. Also, the need for fish stocking will be reduced and thus decrease the costs associated with the current fish stocking program. Mitigation Measures Required: Mitigation of the identified negative effects can be achieved through:








preservation of cultural heritage resources;

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• Location of municipal infrastructure to be confirmed prior to any work being done.


Estimated Cost and Feasibility: The estimated cost for this type of fishway is approximately $100,000. This type of fishway has previously been constructed and is operating at another location (Milne Reservoir, Markham) on the Rouge River under similar conditions therefore, it is very feasible that it can be successfully constructed and operated at this location also. A denil fishway operating on a 10% slope would need to be 18 meters in length at this location (excluding resting pools). The construction of a denil fishway is more feasible for the east bank of the river. Monitoring Requirements: Frequent monitoring of the fishways during April, May, June, July, September and October is recommended as a means of determining the peak periods of fish migration. Water temperatures and flood conditions in the stream should be assessed to determine safe periods of operation of the fishways. As the majority of the fisheries monitoring will take place at weir #1, the focus of monitoring efforts at this location will be for flow conditions and debris clogging the fishway.

14.2 Partial Removal Effectiveness of Alternative to Meet its Intended Purpose: This alternative meets both the project purpose and watershed objectives. Removing a section of the weir will allow the movement of non-jumping species past the barrier. Environmental Effects and Significance: Table 15 indicates several environmental effects, which are of low significance, resulting from construction activities. These effects involve noise, and aesthetics around the construction area. The effects to public health and safety are considered of low significance and will generally be limited to the construction phase. This type of construction activity is generally brief, only lasting one or two days. Therefore, the general public will not be at risk from the hazards associated with a longer term construction site. The workers involved in the construction will be properly trained and will take the appropriate safety measures. Also, warning signs will be posted to warn park patrons of potential risks such as walking on the weir during low flow conditions. Furthermore, the effects to drainage and flooding are considered of low significance as no major alterations to flow are expected. The effects to erosion are also considered of low significance. The bed of the river is largely made up of shale. As the weirs were created to dissipate the energy of the river in order to control erosion, partial removal may cause additional scouring and erosion downstream. These effects can be mitigated through proper design.

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Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and increase fish productivity. As a result, there will be an increase in fisheries potential and possibly an increase in tourism for the surrounding area. Also, the need for fish stocking will be reduced and thus decrease the costs associated with the current stocking program. A positive effect to the ice conditions in this part of the Lower Humber River is expected as a result of partial removal. This can be seen in Table 15 as “lands subject to natural hazards”. Partial removal of the weir may result in a reduction in the production and thickness of ice in the river as a result of reduced backwater depths upstream of the weir. These lower depths and the remaining weir structure may also provide storage capacity for the ice within the river system, thereby reducing the quantity of river ice available for deposition within the flood plain. There is also a potential for a resulting positive impact from improving watercraft navigation through this area. The barrier currently obstructs navigation however, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect. Mitigation Measures Required: Many of the negative effects identified in Table 15 can be addressed through the following mitigation techniques:






• Revegetation of any areas that may have been disturbed during construction to reduce erosion. This will also help to restore ecological integrity and aesthetic qualities to the parkland following the construction.

• Creation of a portage to facilitate navigation around the barrier. Estimated Cost and Feasibility: The estimated cost involved in partially removing a section of the weir is approximately $50,000. This work will be similar to the notching that has already taken place as it will most likely involve creating a deeper notch in the weir.

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Monitoring Requirements: As the majority of the fisheries monitoring will take place at weir #1, the focus of monitoring efforts at this location will be on flow conditions, water velocity, structure instability and changes in channel form, such as downstream erosion. Fisheries monitoring will take place to determine changes in the upstream fish community. During this sampling, fish will be monitored for size, sex, weight, and evidence of wounds or disease.

14.3 Diversion Channel Effectiveness of Alternative to Meet its Intended Purpose:

This alternative meets the project purpose and watershed objectives. It will allow unrestricted movement for all fish species past the obstruction. Environmental Effects and Significance: This alternative has several environmental effects associated with it. Temporary effects resulting from the construction of the channel involve sedimentation and erosion, construction noise, and aesthetics. The effect to drainage and flooding is considered of low significance and is a result of reducing the amount of water flowing over the weir in order to direct flow towards the channel. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 15 based on the condition to include revegetation plans. In terms of public safety, access to the site will be restricted during the construction phase and warning signs will be clearly posted. Personnel working in and around the fishway during construction and maintenance will be properly trained and taking the appropriate safety measures. These concerns are considered to be of low significance however, there may be an increased public safety risk resulting from the addition of a channel within the floodplain. Despite warning signs being posted, this alternative has the potential to create an increased risk to public safety as a result of persons falling in the channel or voluntarily entering into the channel. This creates an additional risk of drowning, particularly during high flow conditions. For this reason, the effect to public safety is considered to be a medium negative effect as identified in Table 15. Based on the findings of the cultural heritage assessment that was completed for this project, it is suggested that there may be a high possibility that buried cultural resources exist at this site. The area surrounding this weir on the east bank was the site of a historic village and ossuary. Therefore, this is reflected in Table 15 as

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having a high negative impact to cultural heritage resources. However, this impact can be mitigated by conducting further investigation, such as test pitting, prior to construction and, if necessary, having a qualified archaeologist on site during construction. Another important factor to consider for this alternative is referred to as “lands subject to natural hazards” in Table 15. The Humber River experiences strong ice flows which could potentially cause damage to a diversion channel. This is seen as being of medium significance due to the potential to cause significant damage to the integrity of the diversion channel, thus creating high maintenance costs. Positive effects include creating additional habitat for fish while also re-connecting upstream and downstream habitats, and creating additional habitat for wildlife as a result of riparian planting along the diversion channel. This will enhance aesthetic qualities in the park and provide additional recreation and tourism potential. In addition, the costs associated with the current fish stocking program will be reduced as the need for stocking decreases. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, constructing a diversion channel may help facilitate watercraft navigation at this location particularly if a portage is required. Mitigation Measures Required: Many of the negative effects identified in Table 15 can be addressed through the following mitigation techniques:









being done.

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Estimated Cost and Feasibility: The estimated cost of constructing a diversion channel around the obstruction is approximately $150,000. Feasibility of this alternative is based on the placement of the channel within park lands. A diversion channel operating on a 5% slope would need to be approximately 36 meters in length at this location. This option is feasible for the east bank only as the west bank is too close to a roadway. Monitoring Requirements: Monitoring of flow conditions and the overall condition of the channel should occur throughout the year. Fisheries monitoring of the channel, as well as upstream and downstream of the channel, should take place throughout the year to determine the effectiveness of the channel and how many species are benefiting from it. During sampling, fish should be weighed, measured, and checked for disease and evidence of wounds. The upstream section should also be monitored for juveniles produced from adults using the channel.

14.4 Rocky Ramp Effectiveness of Alternative to Meet its Intended Purpose:

This alternative meets both the project purpose and the watershed objectives. The creation of a rocky ramp will provide unrestricted access for all fish to freely swim beyond the barrier. Environmental Effects and Significance: This alternative has only a few environmental concerns as identified in Table 15 including noise levels, and aesthetics. These are considered of low significance and are a result of construction activities. The effects to public health and safety are considered of low significance and are limited to the construction phase. During construction of the rocky ramp, access to the immediate area will be restricted and warning signs will be posted. The personnel involved in the construction will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to effect lands subject to natural or human made hazards as identified in Table 15. This concern refers to the potential damage that could be inflicted on the rocky ramp resulting from strong ice flows typical of the Lower Humber River. Damage to the rocky ramp could potentially cause for high maintenance costs. However, it is considered to be of low significance as the large size of rock that would likely be used (2-3 ton) may be less susceptible to ice movement. The potential to affect fish habitat is considered to be of medium significance as constructing a rocky ramp will involve the addition of a significant amount of rock being placed in the stream bed which will alter the existing habitat.

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Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and increase fish productivity. As a result, there will be an increase in fisheries potential and possibly an increase in tourism for the surrounding area. Also, the need for fish stocking will be reduced and thus decrease the costs associated with the current stocking program. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, constructing a rocky ramp may facilitate watercraft navigation at this location. Mitigation Measures Required: The identified environmental concerns can be mitigated in the following ways:


• Conduct work only under ideal flow conditions; • Limit access to the construction site through the use of safety fences and

post public notices to advise park patrons of the risk; • Revegetation of disturbed areas following the construction.

Estimated Cost and Feasibility: The estimated cost of constructing a rocky ramp at this weir is approximately $75,000. Although relatively inexpensive, this alternative may not be feasible for this site as the strong ice flows experienced by the river may wash out the ramp, rendering it useless. Monitoring Requirements: The river should be monitored following strong flow conditions to make sure the structure is still intact. Fisheries monitoring should take place throughout the year to measure the effectiveness of the structure and how many fish species are able to make it up the ramp. Monitoring of upstream sites should take place to check for juveniles produced from fish that made it up the ramp past the obstruction. During the sampling, fish should be checked for size, weight, sex, disease and evidence of wounds.

14.5 “Do Nothing” (Null) Alternative Effectiveness of Alternative to Meet its Intended Purpose:

This alternative does not meet the project purpose or the watershed objectives. This is not a solution for providing fish passage on the Lower Humber River.

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Environmental Effects and Significance: This alternative has four environmental effects as identified in Table 15 that are considered of high significance. The identified effects are a result of the inability of this alternative to meet the objectives of the Humber River Fisheries Management Plan. Allowing the obstruction to remain in the river and continue to impede fish movement results in the lack of access for migratory species to upstream spawning, rearing and feeding habitat. Effects resulting from the inability to migrate can be expressed as a loss of potential habitat, loss of potential migration, loss of potential spawning areas and continued loss of ecological integrity. This habitat fragmentation can be expected to cause further declines in fish productivity as populations will continue to be genetically isolated from one another. Furthermore, the “potential to obstruct navigation” and “potential to affect inaccessible areas” as identified in Table 15, are considered to be of low significance. These effects refer to the continued obstruction to navigation if the barrier remains in its current state. Mitigation Measures Required: N/A Estimated Cost and Feasibility: The estimated cost of the “Do Nothing” alternative would be zero capital expenses however; this does not take into account the cost of lost fish productivity, lost recreation and tourism potential within the watershed, and continuing costs resulting from the fish stocking program. Currently, the fish stocking effort is approximately $75,000 per year. Monitoring Requirements: N/A



This alternative meets both the watershed objectives and project purpose. This type of fishway is able to function well under a wide range of changing volumes and fluctuating flow conditions making it suitable for this location. It is able to pass both jumping and non jumping fish species. A vertical slot fishway generally operates with less water flowing through it and is therefore not as well suited to maximizing attraction flow than a denil fishway.


This alternative has several effects under the Natural Environment components and Land Use components, many of which are considered of low significance. These effects are short term in nature and are a result of construction activities. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all

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expected to be effected by the construction of a vertical slot fishway. The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation plans into the design. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 15 based on the condition to include revegetation plans. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an important factor to consider. Effects to drainage during the construction of the fishway are expected to be minimal and therefore, considered of low significance. The effects to public health and safety are also considered to be of low significance. Access to the site will be restricted during the construction phase and warning signs will be posted. Following construction, access to the fishway will be restricted to personnel only and signs will be clearly posted warning of any dangers associated with the fishway. Also, the fishway can be built as an enclosed structure with safety grates over the top as well as at the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and will take the appropriate safety measures. Based on the findings of the cultural heritage assessment that was completed for this project, it is suggested that there may be a high possibility that buried cultural resources exist at this site. The area surrounding this weir on the east bank was the site of a historic village and ossuary. Therefore, this is reflected in Table 15 as having a high negative impact to cultural heritage resources. However, this impact can be mitigated by conducting further investigation, such as test pitting, prior to construction and, if necessary, having a qualified archaeologist on site during construction. The alternative will have negative effects in relation to watercraft navigation. This is seen in Table 15 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect. Positive effects that are expected to result include access to additional habitat for spawning, rearing and nursing activities. Although this type of fishway is limited to the size of fish that can pass, it is estimated that most fish will be able to navigate through it. Therefore, there will be an increase in the number fish migrating

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upstream. This increased fish productivity will lead to increased fisheries potential and a potential to benefit tourism within the watershed. Also, the need for continued fish stocking will decline and thus reduce the costs associated with the current fish stocking program.












being done. • Creation of a portage to facilitate navigation around the barrier.


The construction of this type of concrete fishway is expected to cost approximately $125,000. A vertical slot fishway operating on a 10% slope would be 18 meters in length (excluding resting pools). A vertical slot fishway will require more resting pools than a denil fishway and will therefore be longer, resulting in more concrete work and excavation. The construction of a fishway is more feasible for the east bank of the river. This type of fishway has been in successful operation on other large rivers such as the Fraser River in British Columbia and the Nine Mile River in Port Albert, Ontario. Monitoring Requirements:

Frequent monitoring of the fishways in the months of April, May, June, July, September and October is recommended in order to determine the peak periods of fish migration. Water temperatures and flow conditions in the river should be monitored to determine safe periods to operate the fishways. Also, the fishways should be checked to make sure that there is no debris clogging the passage.

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78

West bank East bank

Figure 15. Weir #2

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Table 15. Significance of effects for weir #2 Level of Significance High Medium Low Nil Unk Positive Criteria: Denil fishway Partial

removal Diversion channel

Rocky ramp

Do nothing

Vertical slot

Natural Environment : 1. air quality


* * *




6. subject to natural or human-made hazards





11. permafrost




* Positive effects are conditional based on revegetation plans.

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Table 15 (cont.). Significance of effects for weir #2 Level of Significance High Medium Low Nil Unk Positive Criteria Denil fishway Partial


Rocky ramp

Do nothing

Vertical slot






4. Traffic patterns or infrastructure




8. Noise levels



11. Affect adjacent or nearby uses, persons, or property

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Table 15 (cont.). Significance of effects for weir #2 Level of Significance High Medium Low Nil Unk Positive Criteria Denil fishway Partial


Rocky ramp

Do nothing

Vertical slot







7. Tourism values

Aboriginal considerations: 1. First nation reserves or communities





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Table 15 (cont.). Significance of effects for weir #2 Alternative Est. Capital

Cost ($) Annual Operational Cost ($)

Total # Nil Effects





Denil Fishway

100,000 5000 24 6 0 1 8

Partial Removal

50,000 0 26 5 0 0 8

Diversion Channel

150,000 2000 21 4 2 1 11

Rocky Ramp

75,000 5000 28 4 1 0 6

Do Nothing

0 75,000 1 33 2 0 4 0

Vertical Slot

125,000 2000 24 6 0 1 8


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15.0 Environmental Analysis for Weir #3 The weir at this location is 42.7 meters wide with a 1.8 meter vertical drop from the top of the weir structure to the water surface. See figure 16 (p. 94).

15.1 Denil Fishway



This fishway can be effectively operated within a wide range of fluctuating water levels and conditions common to the Lower Humber River. A denil fishway is also effective at maximizing attraction flows at the entrance to the fishway. Environmental Effects and Significance: There are several minor environmental effects associated with the building of a fishway. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all of low significance as they are based on short term concerns associated with the construction. The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation plans into the final design. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 16 based on the condition to include revegetation plans. The effects to public health and safety are considered of low significance. Access to the site during the construction phase will be restricted and warning signs will be clearly posted. Following construction, access to the fishway will be restricted to personnel only and sings will be clearly posted warning of any dangers associated with the fishway. Furthermore, the fishway can be constructed as an enclosed structure with safety grates over top and at the inlet and oulet. Personnel working in and around the fishway during construction and operation will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an important factor to consider. Effects to drainage during the construction of

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the fishway are expected to be minimal and therefore, considered of low significance. This area is unlikely to contain any remaining buried cultural resources. The area around the weir on the east bank is believed to be enclosed by a retaining wall with the weir structure built on imported fill. Therefore, it is likely that significant damage has already occurred to any possible cultural heritage resources. This is reflected in Table 16 as having a low negative impact. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 16 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will result in a positive effect. Positive effects are in relation to fish productivity and fisheries potential. Installing a denil fishway would provide access to upstream habitat for spawning, rearing and feeding activities. This has the potential to dramatically increase fish productivity within the watershed. Also, by allowing access to otherwise fragmented fish communities and habitats, there will be an increase in genetic diversity among fish populations which will lead to increased fish productivity. These benefits to fish populations will provide increased recreation and tourism potential by increasing angling opportunities. Furthermore, the need for fish stocking in the Humber River will be reduced, thus decreasing the costs associated with annual stocking efforts. Mitigation Measures Required: Mitigation of the identified negative effects can be achieved through:









done.

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Estimated Cost and Feasibility: The estimated cost for this type of fishway is approximately $100,000. This type of fishway has previously been constructed and is successfully operating at another location (Milne Reservoir, Markham) on the Rouge River under similar conditions therefore, it is very feasible that it can be successfully constructed and operated at this location also. A denil fishway operating on a 10% slope at this location would need to be 18 meters in length (excluding resting pools). There is sufficient room on either side of the river to accommodate a denil fishway however, it may be more feasible to construct on the east side of the river. Monitoring Requirements: Frequent monitoring of the stream during April, May, June, July, September and October is recommended as a means of determining the peak periods of fish migration. Water temperatures and flow conditions in the stream should be assessed to determine safe periods of operation of the fishway. As the majority of the fisheries monitoring will take place at weir #1, the focus of monitoring efforts at this location will be for flow conditions and debris clogging the fishway.

15.2 Partial Removal Effectiveness of Alternative to Meet its Intended Purpose: This alternative meets both the project purpose and the watershed objectives. Partial removal of the weir will allow unrestricted movement to all native and naturalized fish species past the barrier. Environmental Effects and Significance: Table 16 indicates several environmental effects, which are of low significance, resulting from construction activities. These effects involve noise and aesthetics around the construction area. Also considered of low significance is the potential to effect public health and safety. This type of construction is generally brief, only lasting one or two days. Therefore, the general public will not be at risk from the hazards associated with a longer term construction site. The workers involved in the construction will be properly trained and will take the appropriate safety measures. Also, warning signs will be clearly posted warning patrons of the potential risks associated with the weir, such as walking across the weir during low flow conditions. Furthermore, the effects to drainage and flooding are considered of low significance as no major alterations to flow are expected. Similarly, the effects to erosion are considered of low significance. The bed of the river is largely made up of shale. As the weirs were created to dissipate the energy of the river in order to control erosion, partial removal may cause additional scouring and erosion downstream. These impacts can be mitigated with proper design considerations. Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and

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increase fish productivity. As a result, there will be an increase in fisheries potential and possibly an increase in tourism for the surrounding area. Furthermore, the need to continue the current fish stocking program will be reduced, thus decreasing the costs associated with the stocking effort. A positive effect to the ice conditions in this part of the Lower Humber River is expected as a result of partial removal. This can be seen in Table 16 as “lands subject to natural hazards”. Partial removal of the weir may result in a reduction in the production and thickness of ice in the river as a result of reduced backwater depths upstream of the weir. These lower depths and the remaining weir structure may also provide storage capacity for the ice within the river system, thereby reducing the quantity of river ice available for deposition within the flood plain. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, the creation of a portage around the barrier will safely facilitate navigation at this location. Mitigation Measures Required: Many of the negative effects identified in Table 16 can be addressed through the following mitigation techniques:






• Revegetation of any areas that may have been disturbed during construction to reduce erosion. This will also help to restore ecological integrity and aesthetic qualities to the parkland following the construction.

• Creation of a portage to facilitate navigation around the barrier. Estimated Cost and Feasibility: The cost to partially remove a section of the weir is approximately $50,000. This work will most likely involve creating a deeper notch in the weir, similar to the notching that has already taken place. Monitoring Requirements: As the majority of the fisheries monitoring will take place at weir #1, the focus of monitoring efforts at this location will be on flow conditions, water velocity, structure instability and changes in channel form, such as downstream erosion. Some

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fisheries monitoring will take place to determine changes in the upstream fish community. During this sampling, fish will be monitored for size, sex, weight, and evidence of wounds or disease.

15.3 Diversion Channel Effectiveness of Alternative to Meet its Intended Purpose: This option satisfies both the project purpose and watershed objectives. Creating a diversion channel around the barrier will not only allow unrestricted access for fish to move beyond the weir but also create additional habitat. Environmental Effects and Significance: This alternative has several environmental effects associated with it as identified in Table 16. Temporary effects resulting from the construction of the channel involve water quality, sedimentation and erosion, construction noise, and aesthetics. The effect to drainage and flooding is considered of low significance and is a result of reducing the amount of water flowing over the weir in order to direct flow towards the channel. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 16 based on the condition to include revegetation plans. In terms of public safety, access to the site will be restricted during the construction phase and warning signs will be clearly posted. Personnel working in and around the fishway during construction and maintenance will be properly trained and taking the appropriate safety measures. These concerns are considered to be of low significance however, there may be an increased public safety risk resulting from the addition of a channel within the floodplain. Despite warning signs being posted, this alternative has the potential to create an increased risk to public safety as a result of persons falling in the channel or voluntarily entering into the channel. This creates an additional risk of drowning, particularly during high flow conditions. For this reason, the effect to public safety is considered to be a medium negative effect as identified in Table 16. This area is unlikely to contain any remaining buried cultural resources. The area around the weir on the east bank is believed to be enclosed by a retaining wall with the weir structure built on imported fill. Therefore, it is likely that significant damage has already occurred to any possible cultural heritage resources. This is reflected in Table 16 as having a low negative impact.

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Another important factor to consider for this alternative is referred to as “lands subject to natural hazards” in Table 16. The Humber River experiences strong ice flows which could potentially cause damage to a diversion channel. This is seen as being of medium significance due to the potential to cause significant damage to the integrity of the diversion channel, thus creating high maintenance costs. Positive effects include creating additional habitat for fish while also re-connecting upstream and downstream habitats, and creating additional habitat for wildlife as a result of riparian planting along the diversion channel. This will enhance aesthetic qualities in the park and provide additional recreation and tourism potential. Furthermore, the need for continuing with the current fish stocking program will be reduced, thus decreasing the costs associated with the stocking effort. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, constructing a diversion channel may help facilitate watercraft navigation at this location particularly if a portage is included. Mitigation Measures Required: Many of the negative effects identified in Table 16 can be addressed through the following mitigation techniques:









being done.

Estimated Cost and Feasibility: The cost of constructing a diversion channel around the current weir is approximately $150,000. The feasibility of this alternative depends on the availability of space within the existing park adjacent to the river. A diversion channel operating on a 5% slope would require a length of 36 meters. A diversion

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channel is feasible for the east bank only as the west bank is located adjacent to a roadway. Monitoring Requirements: Monitoring of flow conditions and the overall condition of the channel should occur throughout the year. Fisheries monitoring of the channel, as well as upstream and downstream of the channel, should take place throughout the year to determine the effectiveness of the channel and how many species are benefiting from it. During sampling, fish should be weighed, measured, and checked for disease and evidence of wounds. The upstream section should also be monitored for juveniles produced from adults using the channel.


This alternative meets both the project purpose and the watershed objectives. The creation of a ramp will allow fish to swim up and over the obstruction. Environmental Effects and Significance: This alternative has only a few environmental concerns as identified in Table 16 including noise levels, and aesthetics. These are considered of low significance and are a result of construction activities. The effects to public health and safety are considered of low significance and are limited to the construction phase. During construction of the rocky ramp, access to the immediate area will be restricted and warning signs will be posted. The personnel involved in the construction will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to effect lands subject to natural or human made hazards as identified in Table 16. This concern refers to the potential damage that could be inflicted on the rocky ramp resulting from strong ice flows typical of the Lower Humber River. Damage to the rocky ramp could potentially cause for high maintenance costs. However, it is considered to be of low significance as the large size of rock that would likely be used (2-3 ton) may be less susceptible to ice movement. The potential to affect fish habitat is considered to be of medium significance as constructing a rocky ramp will involve the addition of a significant amount of rock being placed in the stream bed which will alter the existing habitat. Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and increase fish productivity. As a result, there will be an increase in fisheries potential and possibly an increase in tourism for the surrounding area. Also, the need for fish stocking will be reduced and thus decrease the costs associated with the current stocking program.

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In addition to restoring fish connectivity in the river, another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, constructing a rocky ramp may facilitate watercraft navigation at this location. Mitigation Measures Required: The identified environmental concerns can be mitigated in the following ways:


• Conduct work only under ideal flow conditions; • Limit access to the construction site through the use of safety fences

and post public notices to advise park patrons of the risk; • Revegetation of disturbed areas following the construction.


The cost to construct a rocky ramp at this weir is approximately $75,000. Although relatively inexpensive, this alternative may not be feasible for this site as the strong ice flows experienced by the river would likely wash out the ramp rendering it useless.


The river should be monitored following strong flow conditions to make sure the structure is still intact. Fisheries monitoring should take place throughout the year to measure the effectiveness of the structure and how many fish species are able to make it up the ramp. Monitoring of upstream sites should take place to check for juveniles produced from fish that made it up the ramp past the obstruction. During the sampling, fish should be checked for size, weight, sex, disease and evidence of wounds.


This alternative does not meet the project purpose or the watershed objectives and is not a solution to providing fish access to upstream habitats. Environmental Effects and Significance: This alternative has four environmental effects as identified in Table 16 that are considered of high significance. The identified effects are a result of the inability of this alternative to meet the objectives of the Humber River Fisheries Management Plan. Allowing the obstruction to remain in the river and continue to impede fish movement results in the lack of access for migratory species to upstream spawning, rearing and feeding habitat. Effects resulting from the inability to

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migrate can be expressed as a loss of potential habitat, loss of potential migration, loss of potential spawning areas and continued loss of ecological integrity. This habitat fragmentation can be expected to cause further declines in fish productivity as populations will continue to be genetically isolated from one another. Furthermore, the “potential to obstruct navigation” and “potential to affect inaccessible areas” as identified in Table 16, are considered to be of low significance. These effects refer to the continued obstruction to navigation if the barrier remains in its current state.

Mitigation Measures Required: N/A Estimated Cost and Feasibility:

The estimated cost of the “Do Nothing” alternative would be zero capital expenses however; this does not take into account the cost of lost fish productivity, lost recreation and tourism potential, and the costs of continuing with the current fish stocking program within the watershed. Currently, the fish stocking effort is approximately $75,000 per year. Monitoring Requirements: N/A



This alternative meets both the watershed objectives and project purpose. This type of fishway is able to function well under a wide range of changing volumes and fluctuating flow conditions making it suitable for this location. It is able to pass both jumping and non jumping fish species. A vertical slot fishway generally operates with less water flowing through it and is therefore not as well suited to maximizing attraction flow than a denil fishway.


This alternative has several effects under the Natural Environment components and Land Use components, many of which are considered of low significance. These effects are short term in nature and are a result of construction activities. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all expected to be effected by the construction of a vertical slot fishway. The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation plans into the design. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or

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petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 16 based on the condition to include revegetation plans. The effects to public health and safety are considered to be of low significance. During construction, access to the site will be restricted and warning signs will be clearly posted. Following construction, access to the fishway will be restricted to personnel only and signs will be clearly posted warning of any dangers associated with the fishway. Furthermore, the fishway can be constructed as an enclosed structure with safety grates over the top as well as on the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an important factor to consider. Effects to drainage during the construction of the fishway are expected to be minimal and therefore, considered of low significance. This area is unlikely to contain any remaining buried cultural resources. The area around the weir on the east bank is believed to be enclosed by a retaining wall with the weir structure built on imported fill. Therefore, it is likely that significant damage has already occurred to any possible cultural heritage resources. This is reflected in Table 16 as having a low negative impact. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 16 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect. Positive effects that are expected to result include access to additional habitat for spawning, rearing and nursing activities. Although this type of fishway is limited to the size of fish that can pass, it is estimated that most fish will be able to navigate through it. Therefore, there will be an increase in the number fish migrating upstream. This increased fish productivity will lead to increased fisheries potential and a potential to benefit tourism within the watershed. Also, the need to continue the current fish stocking program will be reduced, thus decreasing the costs associated with the stocking effort.



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The construction of this type of concrete fishway is expected to cost approximately $125,000. A vertical slot fishway operating on a 10% slope would be 18 meters in length at this location (excluding resting pools). A vertical slot fishway will require more resting pools than a denil fishway as part of the design. This will involve more concrete work as well as excavation, and thus increase the costs. There is sufficient space on either side of the river to accommodate a vertical slot fishway however, it may be more feasible to construct on the east side of the river. This type of fishway has been in successful operation on other large rivers such as the Fraser River in British Columbia and the Nine Mile River in Port Albert, Ontario. Monitoring Requirements:

Frequent monitoring of fishways in the months of April, May, June, July, September and October is recommended in order to determine the peak periods of fish migration. Water temperatures and flow conditions in the river should be monitored to determine safe periods to operate the fishways. Also, the fishways should be checked for to make sure that there is no debris clogging the passage.

Periodic monitoring of upstream sections of the river should take place in order to determine the effectiveness of the fishways by checking for juvenile fish produced from adults that have passed through the fishways.

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West bank East bank

Figure 16. Weir #3

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Table 16. Significance of Effects for Weir #3 Level of Significance High Medium Low Nil Unk Positive Criteria: Denil fishway Partial


Rocky ramp Do nothing

Vertical slot



* * *









11. permafrost





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Table 16 (cont.). Significance of Effects for Weir #3 Level of Significance High Medium Low Nil Unk Positive Criteria Denil fishway Partial



Vertical slot










8. Noise levels




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Vertical slot







7. Tourism values






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Table 16 (cont.). Significance of Effects for Weir #3 Alternative Est. Capital


Total # Nil Effects





Denil Fishway

100,000 5000 24 7 0 0 8

Partial Removal

50,000 0 26 5 0 0 8

Diversion Channel

150,000 2000 21 5 2 0 11

Rocky Ramp

75,000 5000 28 4 1 0 6

Do Nothing

0 75,000 1 33 2 0 4 0

Vertical Slot

125,000 2000 24 7 0 0 8


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The weir at this location is 51.8 meters in width with a 1.2 meter vertical drop from the top of the structure to the water surface. See figure 17 (p. 111).

16.1 Denil Fishway



This fishway can be effectively operated within a wide range of fluctuating water levels and conditions common to the Lower Humber River. A denil fishway is also effective at maximizing attraction flows at the entrance to the fishway. Environmental Effects and Significance: There are several minor environmental effects associated with the building of a fishway. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all of low significance as they are based on short term concerns associated with the construction. The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation plans into the design. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 17 based on the condition to include revegetation plans. The effects to public health and safety are considered to be of low significance. Access to the construction site will be restricted during the construction phase and warning signs will be clearly posted. Following construction, access to the fishway will be restricted to personnel only and signs will be clearly posted warning of any dangers associated with the fishway. Furthermore, the fishway can be constructed as an enclosed structure with safety grates over the top as well as at the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an important factor to consider. Effects to drainage during the construction of

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the fishway are expected to be minimal and therefore, considered of low significance. Based on the results of the cultural heritage assessment, it is suggested that there may be a high potential of finding buried cultural heritage resources at this site. Although it is expected that the bank immediately adjacent to the weir has been heavily damaged during previous construction, the larger area around the weir may still contain buried cultural resources. Therefore, this is reflected in Table 17 as a high negative impact to cultural heritage resources. These impacts can be mitigated by conducting further investigation, such as test pitting, and by having a qualified archaeologist on site during construction, if necessary. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 17 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage will facilitate navigation around the barrier and result in a positive effect. Positive effects are in relation to fish productivity and fisheries potential. Installing a denil fishway would provide access to upstream habitat for spawning, rearing and feeding activities. This has the potential to dramatically increase fish productivity within the watershed. Also, by allowing access to otherwise fragmented fish communities and habitats, there will be an increase in genetic diversity among fish populations which will lead to increased fish productivity. These benefits to fish populations will provide increased recreation and tourism potential by increasing angling opportunities. Furthermore, the need for fish stocking will be reduced thus, decreasing the costs associated with the current stocking program. Mitigation Measures Required: Mitigation of the identified negative effects can be achieved through:









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Estimated Cost and Feasibility: The estimated cost for this type of fishway is approximately $100,000. This type of fishway has previously been constructed and is operating at another location (Milne Reservoir, Markham) on the Rouge River under similar conditions therefore, it is very feasible that it can be successfully constructed and operated at this location also. A denil fishway operating at a 10% slope would require a length of approximately 12 meters (excluding resting pools). The construction of a denil fishway is more feasible for the west bank of the river. Monitoring Requirements: Frequent monitoring of the fishways during April, May, June, July, September and October is recommended as a means of determining the peak periods of fish migration. Water temperatures and flood conditions of the river and of the fishways should be monitored to determine safe periods of operation of the fishway. Also, the fishways should be checked for to make sure that there is no debris clogging the passage. There is another denil fishway further north on the river at Raymore Park. The operation of this fishway can be used for clarifying monitoring and conveyance requirements.

16.2 Partial Removal Effectiveness of Alternative to Meet its Intended Purpose: This alternative meets both the project purpose and watershed objectives. Partial removal of the weir will allow non-jumping fish species access to upstream habitats. Environmental Effects and Significance: There are several environmental effects associated with this alternative as indicated in Table 17. The effects to noise and aesthetics are a result of the construction and are all considered of low significance. The effects to public health and safety are considered to be of low significance. This type of construction is generally brief, only one or two days. Therefore, the general public will not be at risk from the dangers associated with a longer term construction site. The workers involved in the construction will be properly trained and will take the appropriate safety measures. Also, signs will be clearly posted to warn of potential dangers such as walking across the weir during low flow conditions. Furthermore, the effects to drainage and flooding are considered of low significance as no major alterations to flow are expected. Similarly, the effects to erosion are considered of low significance. The bed of the river is largely made up of shale. As the weirs were created to dissipate the energy of the river in order to

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control erosion, partial removal may cause additional scouring and erosion downstream. These impacts can be mitigated with proper design considerations. Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and increase fish productivity. As a result, there will be an increase in fisheries potential and possibly an increase in tourism for the surrounding area. Furthermore, the need for fish stocking will be reduced thus, decreasing the costs associated with the current stocking program. A positive effect to the ice conditions in this part of the Lower Humber River is expected as a result of partial removal. This can be seen in Table 17 as “lands subject to natural hazards”. Partial removal of the weir may result in a reduction in the production and thickness of ice in the river as a result of reduced backwater depths upstream of the weir. These lower depths and the remaining weir structure may also provide storage capacity for the ice within the river system, thereby reducing the quantity of river ice available for deposition within the flood plain. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, the creation of a portage will facilitate safe watercraft navigation at this location. Mitigation Measures Required: Many of the negative effects identified in Table 17 can be mitigated in the following ways:


• Maintaining flow as close to normal as possible to prevent erosion of downstream banks;




• Revegetation of disturbed areas to reduce erosion and restore ecological integrity to the area following construction.


Estimated Cost and Feasibility: The cost of partially removing the weir will be approximately $50,000. This work will most likely involve creating a deeper notch in the weir, similar to the notching that has already taken place.

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Monitoring Requirements: As the majority of the fisheries monitoring will take place at weir #1, the focus of monitoring efforts at this location will be on flow conditions, water velocity, structure instability and changes in channel form, such as downstream erosion. Some fisheries monitoring will take place to determine changes in the upstream fish community. During this sampling, fish will be monitored for size, sex, weight, and evidence of wounds or disease.


This option satisfies both the project purpose and watershed objectives. Creating a diversion channel around the weir will create additional habitat as well as allow unrestricted access for all fish species to reach upstream habitat. Environmental Effects and Significance: This alternative has several environmental effects associated with it as identified in Table 17. Temporary effects resulting from the construction of the channel involve sedimentation and erosion, noise, aesthetics and public safety. The effect to drainage and flooding is considered of low significance and is a result of reducing the amount of water flowing over the weir in order to direct flow through the channel. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 17 based on the condition to include revegetation plans. In terms of public safety, access to the site will be restricted during the construction phase and warning signs will be clearly posted. Personnel working in and around the fishway during construction and maintenance will be properly trained and taking the appropriate safety measures. These concerns are considered to be of low significance however, there may be an increased public safety risk resulting from the addition of a channel within the floodplain. Despite warning signs being posted, this alternative has the potential to create an increased risk to public safety as a result of persons falling in the channel or voluntarily entering into the channel. This creates an additional risk of drowning, particularly during high flow conditions. For this reason, the effect to public safety is considered to be a medium negative effect as identified in Table 17. An important factor to consider for this alternative is referred to as “lands subject to natural hazards” in Table 17. The Humber River experiences strong ice flows

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which could potentially cause damage to a diversion channel. This is seen as being of medium significance due to the potential to cause significant damage to the integrity of the diversion channel, thus creating high maintenance costs. Based on the results of the cultural heritage assessment, it is suggested that there may be a high potential of finding buried cultural heritage resources at this site. Although it is expected that the bank immediately adjacent to the weir has been heavily damaged during previous construction, the larger area around the weir may still contain buried cultural resources. Therefore, this is reflected in Table 17 as a high negative impact to cultural heritage resources. These impacts can be mitigated by conducting further investigation, such as test pitting, and by having a qualified archaeologist on site during construction, if necessary. Positive effects include creating additional habitat for fish while also re-connecting fragmented habitats, and creating additional wildlife habitat as a result of riparian planting along the channel. This will enhance aesthetics qualities in the park and provide additional recreation and tourism opportunities. Furthermore, the need for fish stocking in the Humber River will be reduced thus, decreasing the costs associated with the current stocking program. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, constructing a diversion channel may help facilitate watercraft navigation at this location particularly if a portage is included. Mitigation Measures Required: Many of the negative effects identified in Table 17 can be addressed through the following mitigation techniques:









being done.

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Estimated Cost and Feasibility: The cost to construct a diversion channel around this weir is approximately $80,000. The feasibility of this alternative depends on the availability of space within the existing park adjacent to the river. A diversion channel is not feasible for the east bank as there are two large outflow pipes located adjacent to the weir structure. There is also a baseball diamond relatively close to the east bank. A diversion channel is feasible for the west bank only however, there may not be sufficient room to accommodate it. The channel would require a length of approximately 24 meters to operate on a 5% slope. Monitoring Requirements: Monitoring of flow conditions and the overall condition of the channel should occur throughout the year. Fisheries monitoring of the channel, as well as upstream and downstream of the channel, should take place throughout the year to determine the effectiveness of the channel and how many species are benefiting from it. During sampling, fish should be weighed, measured, and checked for disease and evidence of wounds. The upstream section should also be monitored for juveniles produced from adults using the channel.


This alternative meets both the project purpose and the watershed objectives. The creation of a ramp will allow fish to swim up over the barrier.


This alternative has only a few environmental concerns as identified in Table 17 including noise levels, and aesthetics. These are considered of low significance and are a result of construction activities. Also considered of low significance is the potential to effect public health and safety. These concerns are associated with the construction phase as general public access to the area will not change. Personnel working on the construction will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to effect lands subject to natural or human made hazards as identified in Table 17. This concern refers to the potential damage that could be inflicted on the rocky ramp resulting from strong ice flows typical of the Lower Humber River. Damage to the rocky ramp could potentially cause for high maintenance costs. However, it is considered to be of low significance as the large size of rock that would likely be used (2-3 ton) may be less susceptible to ice movement. The potential to affect fish habitat is considered to be of medium significance as constructing a rocky ramp will involve the addition of a significant amount of rock being placed in the stream bed which will alter the existing habitat.

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Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and increase fish productivity. As a result, there will be an increase in fisheries potential and possibly an increase in tourism for the surrounding area. Also, the need for fish stocking will be reduced and thus decrease the costs associated with the current stocking program. In addition to restoring fish connectivity in the river, another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, constructing a rocky ramp may facilitate watercraft navigation at this location. Mitigation Measures Required: The environmental concerns identified in Table 17 can be mitigated in the following ways:


• Conduct work only under ideal flow conditions; • Limit access to the construction site by the use of safety fences and

post public notices to advise park patrons of the risk; • Revegetation of disturbed areas following the construction will help

reduce erosion and restore ecological integrity to the area. Estimated Cost and Feasibility: The cost for installing a rocky ramp at this weir is approximately $75,000. This alternative may not be feasible for this site as the river experiences strong flows which may wash out the structure, rendering it useless. Monitoring Requirements: The river should be monitored following strong flow conditions to make sure the structure is still intact. Fisheries monitoring should take place throughout the year to measure the effectiveness of the structure and how many fish species are able to make it up the ramp. Monitoring of upstream sites should take place to check for juveniles produced from fish that made it up the ramp past the obstruction. During the sampling, fish should be checked for size, weight, sex, disease and evidence of wounds.


This alternative does not satisfy the project purpose or the watershed objectives and is not a solution to providing fish access to the upstream habitats.

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Environmental Effects and Significance: This alternative has several environmental effects associated with it that are considered of high significance. The identified effects are a result of the inability of this alternative to meet the objectives of the Humber River Fisheries Management Plan. Allowing the obstruction to remain in the river and continue to impede fish movement results in the lack of access for migratory species to upstream spawning, rearing and feeding habitat. Effects resulting from the inability to migrate can be seen as a loss of potential habitat, loss of potential migration, loss of potential spawning areas and continued loss of ecological integrity. This habitat fragmentation can be expected to cause further declines in fish productivity as populations will continue to be genetically isolated from one another. Furthermore, the “potential to obstruct navigation” and “potential to affect inaccessible areas” as identified in Table 17, are considered to be of low significance. These effects refer to the continued obstruction to navigation if the barrier remains in its current state. Mitigation Measures Required: N/A Estimated Cost and Feasibility: The estimated cost of the “do nothing” alternative is zero capital expenses however; this does not take into account the cost of lost fish productivity, lost recreation and tourism potential, and the costs of the current stocking program within the watershed. Currently, the fish stocking effort is approximately $75,000 per year. Monitoring Requirements: N/A



This alternative meets both the watershed objectives and project purpose. This type of fishway is able to function well under a wide range of changing volumes and fluctuating flow conditions making it suitable for this location. It is able to pass both jumping and non jumping fish species. A vertical slot fishway generally operates with less water flowing through than a denil fishway and thus is not as well suited to maximizing attraction flows.

Environmental Effects and Significance: This alternative has several effects under the Natural Environment components and Land Use components, many of which are considered of low significance. These effects are short term in nature and are a result of construction activities. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all expected to be effected by the construction of a vertical slot fishway.

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The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating vegetation for screening. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 17 based on the condition to include revegetation plans. The effects to public health and safety are considered of low significance. Access to the site will be restricted during the construction phase and warning signs will be clearly posted. Following construction, access into the fishway will be restricted to personnel only and signs will be clearly posted warning of any dangers associated with the fishway. Furthermore, the fishway can be constructed as an enclosed structure with safety grates over the top as well as at the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an important factor to consider. Effects to drainage during the construction of the fishway are expected to be minimal and therefore, considered of low significance. Based on the results of the cultural heritage assessment, it is suggested that there may be a high potential of finding buried cultural heritage resources at this site. Although it is expected that the bank immediately adjacent to the weir has been heavily damaged during previous construction, the larger area around the weir may still contain buried cultural resources. Therefore, this is reflected in Table 17 as a high negative impact to cultural heritage resources. These impacts can be mitigated by conducting further investigation, such as test pitting, and by having a qualified archaeologist on site during construction, if necessary. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 17 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect. Positive effects that are expected to result include access to additional habitat for spawning, rearing and nursing activities. Although this type of fishway is limited to the size of fish that can pass, it is estimated that most fish will be able to navigate

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through it. Therefore, there will be an increase in the number fish migrating upstream. This increased fish productivity will lead to increased fisheries potential and a potential to benefit tourism within the watershed. Also, the need for fish stocking in the Humber River will be reduced thus, decreasing the costs associated with the current stocking program.














The construction of this type of concrete fishway is expected to cost approximately $125,000. A vertical slot fishway at this location operating on a 10% slope would be 12 meters in length (excluding resting pools). The design of a vertical slot fishway requires more resting pools than a denil fishway. This would involve more concrete work and excavation, resulting in higher costs. There is sufficient space on either side of the river to accommodate a vertical slot fishway however, it may be more feasible to construct a fishway on the west bank. This type of fishway has been in successful operation on other large rivers such as the Fraser River in British Columbia and the Nine Mile River in Port Albert, Ontario.

Monitoring Requirements: Frequent monitoring of the fishways in the months of April, May, June, July, September and October is recommended in order to determine the peak periods of fish migration. Water temperatures and flood conditions in the river should be

110

monitored to determine safe periods to operate the fishways. Also, the fishways should be checked for to make sure that there is no debris clogging the passage.


111

West bank East bank

Figure 17. Weir #4

112




Vertical slot



* * *









11. permafrost





113




Vertical slot










8. Noise levels




114




Vertical slot







7. Tourism values






115



Total # Nil Effects





Denil Fishway

100,000 5000 24 6 0 1 8

Partial Removal

50,000 0 26 5 0 0 8

Diversion Channel

80,000 2000 21 4 2 1 11

Rocky Ramp

75,000 5000 28 4 1 0 6

Do Nothing

0 75,000 1 33 2 0 4 0

Vertical Slot

125,000 2000 24 6 0 1 8


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The weir at this location is 43.5 meters wide with a vertical drop of 1.2 meters from the top of the weir structure to the water surface. See figure 18 (p. 127).

17.1 Denil Fishway



This fishway can be effectively operated within a wide range of fluctuating water levels and conditions common to the Lower Humber River. A denil fishway is also effective at maximizing attraction flows at the entrance to the fishway. Environmental Effects and Significance: There are several minor environmental effects associated with the building of a fishway. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all of low significance as they are based on short term concerns associated with the construction. The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation plans into the design. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 18 based on the condition to include revegetation plans. The effects to public health and safety are considered to be of low significance. Access to the site will be restricted during the construction phase and warning signs will be clearly posted. Following construction, access to the fishway will be restricted to personnel only and signs will be clearly posted warning of any dangers associated with the fishway. Also, the fishway can be constructed as an enclosed structure with safety grates over the top as well as at the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an important factor to consider. Effects to drainage during the construction of

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the fishway are expected to be minimal and therefore, considered of low significance. This area is unlikely to contain any remaining buried cultural resources. Similar to weir #3, the area around the weir on the east bank is believed to be enclosed by a retaining wall with the weir structure built on imported fill. Therefore, it is likely that significant damage has already occurred to any possible cultural heritage resources. This is reflected in Table 18 as having a low negative impact. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 18 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect. Positive effects are in relation to fish productivity and fisheries potential. Installing a denil fishway would provide access to upstream habitat for spawning, rearing and feeding activities. This has the potential to dramatically increase fish productivity within the watershed. Also, by allowing access to otherwise fragmented fish communities and habitats, there will be an increase in genetic diversity among fish populations which will lead to increased fish productivity. These benefits to fish populations will provide increased recreation and tourism potential by increasing angling opportunities. Furthermore, the need for fish stocking will be reduced thus, decreasing the costs associated with the current stocking program. Mitigation Measures Required: Mitigation of the identified negative effects can be achieved through:









done.

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Estimated Cost and Feasibility: The estimated cost for this type of fishway is approximately $100,000. This type of fishway has previously been constructed and is operating at another location (Milne Reservoir, Markham) on the Rouge River under similar conditions therefore, it is very feasible that it can be successfully constructed and operated at this location also. A denil fishway operating at a 10% slope would require a length of approximately 12 meters (excluding resting pools). The construction of a denil fishway is more feasible for the east side of the river. Monitoring Requirements: Frequent monitoring of the fishways during April, May, June, July, September and October is recommended as a means of determining the peak periods of fish migration. Water temperatures and flow conditions of the river and of the fishways should be monitored to determine safe periods of operation of the fishway. Also, the fishways should be checked for to make sure that there is no debris clogging the passage. There is another denil fishway further north on the river at Raymore Park. The operation of this fishway can be used for clarifying monitoring and conveyance requirements.

17.2 Partial Removal

Effectiveness of Alternative to Meet its Intended Purpose: This alternative meets both the project purpose and watershed objectives. Partial removal of the weir will allow non-jumping fish species access to upstream habitats. Environmental Effects and Significance: There are several environmental effects associated with this alternative as indicated in Table 18. The effects to noise and aesthetics are a result of the construction and are all considered of low significance. The effects to public health and safety are considered to be of low significance. This type of construction is generally brief, only lasting one or two days. Therefore, the general public will not be at risk from the dangers associated with a longer term construction site. Personnel involved in the construction will be properly trained and will take the appropriate safety measures. Also, signs will be clearly posted to warn of potential dangers such as walking across the weir during low flow conditions. Furthermore, the effects to drainage and flooding are considered of low significance as no major alterations to flow are expected. Similarly, the effects to erosion are considered of low significance. The bed of the river is largely made up of shale. As the weirs were created to dissipate the energy of the river in order to control erosion, partial removal may cause additional scouring and erosion downstream. Also, increasing the flow of water through the notch may impact

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future flood events. However, these impacts can be mitigated with proper design considerations. Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and increase fish productivity. As a result, there will be an increase in fisheries potential and possibly an increase in tourism for the surrounding area. Also, the need for fish stocking will be reduced thus, decreasing the costs associated with the current stocking program. A positive effect to the ice conditions in this part of the Lower Humber River is expected as a result of partial removal. This can be seen in Table 18 as “lands subject to natural hazards”. Partial removal of the weir may result in a reduction in the production and thickness of ice in the river as a result of reduced backwater depths upstream of the weir. These lower depths and the remaining weir structure may also provide storage capacity for the ice within the river system, thereby reducing the quantity of river ice available for deposition within the flood plain. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, the creation of a portage would help facilitate safe watercraft navigation at this location. Mitigation Measures Required: Many of the negative effects identified in Table 18 can be mitigated in the following ways:







• Creation of a portage to facilitate navigation around the barrier. Estimated Cost and Feasibility: The cost of partially removing the weir will be approximately $50,000. This work will most likely involve creating a deeper notch in the weir, similar to the notching that has already taken place.

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17.3 Diversion Channel

Effectiveness of Alternative to Meet its Intended Purpose:

This option satisfies both the project purpose and watershed objectives. Creating a diversion channel around the weir will create additional habitat as well as allow unrestricted access for all fish species to reach upstream habitat. Environmental Effects and Significance: This alternative has several environmental effects associated with it as identified in Table 18. Temporary effects resulting from the construction of the channel involve sedimentation and erosion, noise, and aesthetics. The effect to drainage and flooding is considered of low significance and is a result of reducing the amount of water flowing over the weir in order to direct flow through the channel. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 18 based on the condition to include revegetation plans. In terms of public safety, access to the site will be restricted during the construction phase and warning signs will be clearly posted. Personnel working in and around the fishway during construction and maintenance will be properly trained and taking the appropriate safety measures. These concerns are considered to be of low significance however, there may be an increased public safety risk resulting from the addition of a channel within the floodplain. Despite warning signs being posted, this alternative has the potential to create an increased risk to public safety as a result of persons falling in the channel or voluntarily entering into the channel. This creates an additional risk of drowning, particularly during high flow conditions. For this reason, the effect to public safety is considered to be a medium negative effect as identified in Table 18. Another important factor to consider for this alternative is referred to as “lands subject to natural hazards” in Table 18. The Humber River experiences strong ice flows which could potentially cause damage to a diversion channel. This is seen as

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being of medium significance due to the potential to cause significant damage to the integrity of the diversion channel, thus creating high maintenance costs. This area is unlikely to contain any remaining buried cultural resources. Similar to weir #3, the area around the weir on the east bank is believed to be enclosed by a retaining wall with the weir structure built on imported fill. Therefore, it is likely that significant damage has already occurred to any possible cultural heritage resources. This is reflected in Table 18 as having a low negative impact. Positive effects include creating additional habitat for fish while also re-connecting fragmented habitats, and creating additional wildlife habitat as a result of riparian planting along the channel. This will enhance aesthetics qualities in the park and provide additional recreation and tourism opportunities. Furthermore, the need for fish stocking will be reduced thus, decreasing the costs associated with the current stocking program. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, constructing a diversion channel would help facilitate watercraft navigation at this location. Mitigation Measures Required: Many of the negative effects identified in Table 18 can be addressed through the following mitigation techniques:









being done. Estimated Cost and Feasibility: The cost to construct a diversion channel around this weir is approximately $80,000. The feasibility of this alternative depends on the availability of space within the existing park adjacent to the river. A diversion channel is feasible for the east bank only as the west bank is close to an adjacent roadway. A diversion

122

channel operating at a 5% slope would require a length of approximately 24 meters. There is sufficient space on the east bank to construct a diversion channel. Monitoring Requirements: Monitoring of flow conditions and the overall condition of the channel should occur throughout the year. Fisheries monitoring of the channel, as well as upstream and downstream of the channel, should take place throughout the year to determine the effectiveness of the channel and how many species are benefiting from it. During sampling, fish should be weighed, measured, and checked for disease and evidence of wounds. The upstream section should also be monitored for juveniles produced from adults using the channel.




This alternative has only a few environmental concerns as identified in Table 18 including noise levels and aesthetics. These are considered of low significance and are a result of construction activities. The effects to public health and safety are considered to be of low significance and are limited to the construction phase. Personnel working on the construction of the rocky ramp will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to effect lands subject to natural or human made hazards as identified in Table 18. This concern refers to the potential damage that could be inflicted on the rocky ramp resulting from strong ice flows typical of the Lower Humber River. Damage to the rocky ramp could potentially cause for high maintenance costs. However, it is considered to be of low significance as the large size of rock that would likely be used (2-3 ton) may be less susceptible to ice movement. The potential to affect fish habitat is considered to be of medium significance as constructing a rocky ramp will involve the addition of a significant amount of rock being placed in the stream bed which will alter the existing habitat. Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and increase fish productivity. As a result, there will be an increase in fisheries potential and possibly an increase in tourism for the surrounding area. Also, the need for fish stocking will be reduced and thus decrease the costs associated with the current stocking program. In addition to restoring fish connectivity in the river, another positive impact that may result is improved watercraft navigation through this area. The barrier is

123

currently obstructing navigation however, constructing a rocky ramp may facilitate watercraft navigation at this location. Mitigation Measures Required: The environmental concerns identified in Table 18 can be mitigated in the following ways:




Estimated Cost and Feasibility: The cost for installing a rocky ramp at this weir is approximately $75,000. This alternative may not be feasible for this site as the river experiences strong flows which may wash out the structure, rendering it useless. Monitoring Requirements: The river should be monitored following strong flow conditions to make sure the structure is still intact. Fisheries monitoring should take place throughout the year to measure the effectiveness of the structure and how many fish species are able to make it up the ramp. Monitoring of upstream sites should take place to check for juveniles produced from fish that made it up the ramp past the obstruction. During the sampling, fish should be checked for size, weight, sex, disease and evidence of wounds.


This alternative does not satisfy the project purpose or the watershed objectives and is not a solution to providing fish access to upstream habitats. Environmental Effects and Significance: This alternative has several environmental effects associated with it that are considered of high significance. The identified effects are a result of the inability of this alternative to meet the objectives of the Humber River Fisheries Management Plan. Allowing the obstruction to remain in the river and continue to impede fish movement results in the lack of access for migratory species to upstream spawning, rearing and feeding habitat. Effects resulting from the inability to migrate can be seen as a loss of potential habitat, loss of potential migration, loss of potential spawning areas and continued loss of ecological integrity. This habitat

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fragmentation can be expected to cause further declines in fish productivity as populations will continue to be genetically isolated from one another. Furthermore, the “potential to obstruct navigation” and “potential to affect inaccessible areas” as identified in Table 18, are considered to be of low significance. These effects refer to the continued obstruction to navigation if the barrier remains in its current state. Mitigation Measures Required: N/A Estimated Cost and Feasibility: The estimated cost of the “do nothing” alternative is zero capital expenses however; this does not take into account the cost of lost fish productivity, lost recreation and tourism potential, and the costs of the current fish stocking program within the watershed. Currently, the fish stocking effort is approximately $75,000 per year. Monitoring Requirements: N/A



This alternative meets both the watershed objectives and project purpose. This type of fishway is able to function well under a wide range of changing volumes and fluctuating flow conditions making it suitable for this location. It is able to pass both jumping and non jumping fish species. A vertical slot fishway generally operates with less water flowing through than a denil fishway and is therefore, not as well suited to maximizing attraction flows.


This alternative has several effects under the Natural Environment components and Land Use components, many of which are considered of low significance. These effects are short term in nature and are a result of construction activities. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all expected to be effected by the construction of a vertical slot fishway. The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation plans into the design. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be

125

permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 18 based on the condition to include revegetation plans. The effects to public health and safety are considered to be of low significance. Access to the site will be restricted during the construction phase and warning signs will be clearly posted. Following the construction, access into the fishway will be restricted to personnel only and signs will be clearly posted to warn of the dangers associated with the fishway. Also, the fishway can be constructed as an enclosed structure with safety grates over the top as well as at the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an important factor to consider. Effects to drainage during the construction of the fishway are expected to be minimal and therefore, considered of low significance. This area is unlikely to contain any remaining buried cultural resources. Similar to weir #3, the area around the weir on the east bank is believed to be enclosed by a retaining wall with the weir structure built on imported fill. Therefore, it is likely that significant damage has already occurred to any possible cultural heritage resources. This is reflected in Table 18 as having a low negative impact. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 18 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect. Positive effects that are expected to result include access to additional habitat for spawning, rearing and nursing activities. Although this type of fishway is limited to the size of fish that can pass, it is estimated that most fish will be able to navigate through it. Therefore, there will be an increase in the number fish migrating upstream. This increased fish productivity will lead to increased fisheries potential and a potential to benefit tourism within the watershed. Furthermore, the need for fish stocking will be reduced thus, decreasing the costs associated with the current stocking program.




construction;

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The construction of this type of concrete fishway is expected to cost approximately $125,000. A vertical slot fishway operating on a 10% slope at this location would be 12 meters in length (excluding resting pools). The design of a vertical slot fishway at this location would require more resting pools than a denil fishway. This results in more concrete work and excavation, creating higher costs. The construction of a fishway is more feasible for the east bank of the river. This type of fishway has been in successful operation on other large rivers such as the Fraser River in British Columbia and the Nine Mile River in Port Albert, Ontario.


Frequent monitoring of the fishways in the months of April, May, June, July, September and October is recommended in order to determine the peak periods of fish migration. Water temperatures and flood conditions in the river should be monitored to determine safe periods to operate the fishways. Also, the fishways should be checked for to make sure that there is no debris clogging the passage.


127

West bank East bank

Figure 18. Weir #5

128




Vertical slot



* * *









11. permafrost





129




Vertical slot










8. Noise levels




130




Vertical slot







7. Tourism values






131



Total # Nil Effects





Denil Fishway

100,000 5000 24 7 0 0 8

Partial Removal

50,000 0 26 5 0 0 8

Diversion Channel

80,000 2000 21 5 2 0 11

Rocky Ramp

75,000 5000 28 4 1 0 6

Do Nothing

0 75,000 1 33 2 0 4 0

Vertical Slot

125,000 2000 24 7 0 0 8


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The weir at this location is 40.7 meters wide with a vertical drop of approximately 0.9 meters from the top of the weir structure to the water surface. See figure 19 (p. 143).

18.1 Denil Fishway



This fishway can be effectively operated within a wide range of fluctuating water levels and conditions common to the Lower Humber River. A denil fishway is also effective at maximizing attraction flows at the entrance to the fishway. Environmental Effects and Significance: There are several minor environmental effects associated with the building of a fishway. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all of low significance as they are based on short term concerns associated with the construction. The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation plans into the design. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 19 based on the condition to include revegetation plans. The effects to public health and safety are considered to be of low significance. Access to the site will be restricted during the construction phase and warning signs will be clearly posted. Following construction, access into the fishway will be restricted to personnel only and signs will be clearly posted warning of any dangers associated with the fishway. Also, the fishway can be constructed as an enclosed structure with safety grates over the top as well as at the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is

133

still an important factor to consider. Effects to drainage during the construction of the fishway are expected to be minimal and therefore, considered of low significance. Based on the results of the cultural heritage assessment, this area is unlikely to contain any remaining buried cultural resources. Weir #6 is adjacent to the old Dundas St. bridge abutment. In addition to this, there have been other extensive works in the area in the form of gabion baskets and a discharge pipe. Therefore, it is highly unlikely that any cultural heritage resources are remaining in the vicinity. This is reflected in Table 19 as having a low negative impact. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 19 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect. Positive effects are in relation to fish productivity and fisheries potential. Installing a denil fishway would provide access to upstream habitat for spawning, rearing and feeding activities. This has the potential to dramatically increase fish productivity within the watershed. Also, by allowing access to otherwise fragmented fish communities and habitats, there will be an increase in genetic diversity among fish populations which will lead to increased fish productivity. These benefits to fish populations will provide increased recreation and tourism potential by increasing angling opportunities. Furthermore, the need for fish stocking would be reduced thus, decreasing the costs associated with the current stocking program. Mitigation Measures Required: Mitigation of the identified negative effects can be achieved through:









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• Creation of a portage to facilitate navigation around the barrier. Estimated Cost and Feasibility: The estimated cost for this type of fishway is approximately $100,000. This type of fishway has previously been constructed and is operating at another location (Milne Reservoir, Markham) on the Rouge River under similar conditions therefore, it is very feasible that it can be successfully constructed and operated at this location also. A denil fishway operating at a 10% slope would require a length of approximately 9 meters (excluding resting pools). The installation of a denil fishway is more feasible for the west bank as there is a large sewer outflow pipe on the east bank. Monitoring Requirements: Frequent monitoring of the fishways during April, May, June, July, September and October is recommended as a means of determining the peak periods of fish migration. Water temperatures and flow conditions of the river and of the fishways should be monitored to determine safe periods of operation of the fishway. Also, the fishways should be checked for to make sure that there is no debris clogging the passage. There is another denil fishway south on the river at Raymore Park. The operation of this fishway can be used for clarifying monitoring and conveyance requirements.


Effectiveness of Alternative to Meet its Intended Purpose: This alternative meets both the project purpose and watershed objectives. Partial removal of the weir will allow non-jumping fish species access to upstream habitats. Environmental Effects and Significance: There are several environmental effects associated with this alternative as indicated in Table 19. The effects to noise and aesthetics are a result of the construction and are all considered of low significance. The effects to public health and safety are considered to be of low significance. This type of construction activity is generally brief, only lasting one or two days. Therefore, the general public will not be at risk from the hazards associated with a longer term construction site. Also, signs will be clearly posted to warn of potential dangers such as walking across the weir during low flow conditions. Furthermore, the effects to drainage and flooding are considered of low significance as no major alterations to flow are expected. Similarly, the effects to erosion and sedimentation are considered to be of low significance. The bed of the river is largely made up of shale. As the weirs were created to dissipate the energy

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of the river in order to control erosion, partial removal may cause additional scouring and erosion downstream. These impacts can be mitigated with proper design considerations. Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and increase fish productivity. As a result, there will be an increase in fisheries potential and a potential increase in tourism for the surrounding area. Furthermore, the need for fish stocking will be reduced, thus decreasing the costs associated with the current stocking program. A positive effect to the ice conditions in this part of the Lower Humber River is expected as a result of partial removal. This can be seen in Table 19 as “lands subject to natural hazards”. Partial removal of the weir may result in a reduction in the production and thickness of ice in the river as a result of reduced backwater depths upstream of the weir. These lower depths and the remaining weir structure may also provide storage capacity for the ice within the river system, thereby reducing the quantity of river ice available for deposition within the flood plain. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, the creation of a portage would help facilitate safe watercraft navigation at this location. Mitigation Measures Required: Many of the negative effects identified in Table 19 can be mitigated in the following ways:









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This option satisfies both the project purpose and watershed objectives. Creating a diversion channel around the weir will create additional habitat as well as allow unrestricted access for all fish species to reach upstream habitat. Environmental Effects and Significance: This alternative has several environmental effects associated with it as identified in Table 19. Temporary effects resulting from the construction of the channel involve sedimentation and erosion, noise, and aesthetics. The effect to drainage and flooding is considered of low significance and is a result of reducing the amount of water flowing over the weir in order to direct flow through the channel. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 19 based on the condition to include revegetation plans. In terms of public safety, access to the site will be restricted during the construction phase and warning signs will be clearly posted. Personnel working in and around the fishway during construction and maintenance will be properly trained and taking the appropriate safety measures. These concerns are considered to be of low significance however, there may be an increased public safety risk resulting from the addition of a channel within the floodplain. Despite warning signs being posted, this alternative has the potential to create an increased risk to public safety as a result of persons falling in the channel or voluntarily entering into the channel. This creates an additional risk of drowning, particularly during high flow conditions. For this reason, the effect to public safety is considered to be a medium negative effect as identified in Table 19. Another important factor to consider for this alternative is referred to as “lands subject to natural hazards” in Table 19. The Humber River experiences strong ice flows which could potentially cause damage to a diversion channel. This is seen as

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being of medium significance due to the potential to cause significant damage to the integrity of the diversion channel, thus creating high maintenance costs. Based on the results of the cultural heritage assessment, this area is unlikely to contain any remaining buried cultural resources. Weir #6 is adjacent to the old Dundas St. bridge abutment. In addition to this, there have been other extensive works in the area in the form of gabion baskets and a discharge pipe. Therefore, it is highly unlikely that any cultural heritage resources are remaining in the vicinity. This is reflected in Table 19 as having a low negative impact. Positive effects include creating additional habitat for fish while also re-connecting fragmented habitats, and creating additional wildlife habitat as a result of riparian planting along the channel. This will enhance aesthetics qualities in the park and provide additional recreation and tourism opportunities. Furthermore, the need for fish stocking will be reduced thus, decreasing the costs associated with the current stocking program. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, constructing a diversion channel may facilitate watercraft navigation at this location. Mitigation Measures Required: Many of the negative effects identified in Table 19 can be addressed through the following mitigation techniques:









being done.

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Estimated Cost and Feasibility: The cost to construct a diversion channel around this weir is approximately $80,000. The feasibility of this alternative depends on the availability of space within the existing park adjacent to the river. There is not adequate space to construct a diversion channel on either side of the river. There is a large sewer outflow on the east bank and the west bank is adjacent to the roadway. Therefore, this option is not feasible for this location. Monitoring Requirements: Monitoring of flow conditions and the overall condition of the channel should occur throughout the year. Fisheries monitoring of the channel, as well as upstream and downstream of the channel, should take place throughout the year to determine the effectiveness of the channel and how many species are benefiting from it. During sampling, fish should be weighed, measured, and checked for disease and evidence of wounds. The upstream section should also be monitored for juveniles produced from adults using the channel.




This alternative has only a few environmental concerns as identified in Table 19 including noise levels, and aesthetics. These are considered of low significance and are a result of construction activities. The effects to public health and safety are considered to be of low significance and are a result of the construction phase. Personnel working on the construction of the rocky ramp will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to effect lands subject to natural or human made hazards as identified in Table 19. This concern refers to the potential damage that could be inflicted on the rocky ramp resulting from strong ice flows typical of the Lower Humber River. Damage to the rocky ramp could potentially cause for high maintenance costs. However, it is considered to be of low significance as the large size of rock that would likely be used (2-3 ton) may be less susceptible to ice movement. The potential to affect fish habitat is considered to be of medium significance as constructing a rocky ramp will involve the addition of a significant amount of rock being placed in the stream bed which will alter the existing habitat. Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and increase fish productivity. As a result, there will be an increase in fisheries

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potential and possibly an increase in tourism for the surrounding area. Also, the need for fish stocking will be reduced and thus decrease the costs associated with the current stocking program. In addition to restoring fish connectivity in the river, another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, constructing a rocky ramp may facilitate watercraft navigation at this location. Mitigation Measures Required: The environmental concerns identified in Table 19 can be mitigated in the following ways:




Estimated Cost and Feasibility: The cost for installing a rocky ramp at this weir is approximately $75,000. This alternative may not be feasible for this site as the river experiences strong flows which may wash out the structure, rendering it useless. Monitoring Requirements: The river should be monitored following strong flow conditions to make sure the structure is still intact. Fisheries monitoring should take place throughout the year to measure the effectiveness of the structure and how many fish species are able to make it up the ramp. Monitoring of upstream sites should take place to check for juveniles produced from fish that made it up the ramp past the obstruction. During the sampling, fish should be checked for size, weight, sex, disease and evidence of wounds.


This alternative does not satisfy the project purpose or the watershed objectives and is not a solution to providing fish access to the upstream habitats. Environmental Effects and Significance: This alternative has several environmental effects associated with it that are considered of high significance. The identified effects are a result of the inability of

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this alternative to meet the objectives of the Humber River Fisheries Management Plan. Allowing the obstruction to remain in the river and continue to impede fish movement results in the lack of access for migratory species to upstream spawning, rearing and feeding habitat. Effects resulting from the inability to migrate can be seen as a loss of potential habitat, loss of potential migration, loss of potential spawning areas and continued loss of ecological integrity. This habitat fragmentation can be expected to cause further declines in fish productivity as populations will continue to be genetically isolated from one another. Furthermore, the “potential to obstruct navigation” and “potential to affect inaccessible areas” as identified in Table 19, are considered to be of low significance. These effects refer to the continued obstruction to navigation if the barrier remains in its current state. Mitigation Measures Required: N/A Estimated Cost and Feasibility: The estimated cost of the “do nothing” alternative is zero capital expenses however; this does not take into account the cost of lost fish productivity, lost recreation and tourism potential, and the continued costs of the fish stocking program within the watershed. Currently, the fish stocking effort is approximately $75,000 per year. Monitoring Requirements: N/A



This alternative meets both the watershed objectives and project purpose. This type of fishway is able to function well under a wide range of changing volumes and fluctuating flow conditions making it suitable for this location. It is able to pass both jumping and non jumping fish species. A vertical slot fishway generally operates with less water flowing through than a denil fishway and is therefore, not as well suited to maximizing attraction flows.


This alternative has several effects under the Natural Environment components and Land Use components, many of which are considered of low significance. These effects are short term in nature and are a result of construction activities. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all expected to be effected by the construction of a vertical slot fishway. The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation plans into the design.

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There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 19 based on the condition to include revegetation plans. The effects to public health and safety are considered to be of low significance. During the construction phase, access to the site will be restricted and warning signs will be clearly posted. Following construction, access into the fishway will be restricted to personnel only and signs will be posted to warn of the hazards associated with the fishway. The fishway can be constructed as an enclosed structure with safety grates over the top and at the inlet and outlet. Personnel working in and around the fishway will be properly trained and take the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an important factor to consider. Effects to drainage during the construction of the fishway are expected to be minimal and therefore, considered of low significance. Based on the results of the cultural heritage assessment, this area is unlikely to contain any remaining buried cultural resources. Weir #6 is adjacent to the old Dundas St. bridge abutment. In addition to this, there have been other extensive works in the area in the form of gabion baskets and a discharge pipe. Therefore, it is highly unlikely that any cultural heritage resources are remaining in the vicinity. This is reflected in Table 19 as having a low negative impact. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 19 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect. Positive effects that are expected to result include access to additional habitat for spawning, rearing and nursing activities. Although this type of fishway is limited to the size of fish that can pass, it is estimated that most fish will be able to navigate through it. Therefore, there will be an increase in the number fish migrating upstream. This increased fish productivity will lead to increased fisheries potential and a potential to benefit tourism within the watershed. Furthermore, the need for fish stocking will be reduced and thus, decrease the costs associated with the current stocking program.

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The construction of this type of concrete fishway is expected to cost approximately $125,000. A vertical slot fishway at this location operating on a 10% slope would be approximately 9 meters in length (excluding resting pools). A vertical slot fishway requires more resting pools than a denil fishway. This involves more concrete work and excavation resulting in higher costs. It is more feasible to construct a fishway on the west bank as there is a sewer outflow pipe on the east bank. This type of fishway is feasible for the Lower Humber as it has been in successful operation on other large rivers such as the Fraser River in British Columbia and the Nine Mile River in Port Albert, Ontario.


Frequent monitoring of the fishways in the months of April, May, June, July, September and October is recommended in order to determine the peak periods of fish migration. Water temperatures and flow conditions in the river should be monitored to determine safe periods to operate the fishways. Also, the fishways should be checked for to make sure that there is no debris clogging the passage.


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West bank East bank

Figure 19. Weir #6

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Vertical slot



* * *









11. permafrost





145




Vertical slot










8. Noise levels




146




Vertical slot







7. Tourism values






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Total # Nil Effects





Denil Fishway

100,000 5000 24 7 0 0 8

Partial Removal

50,000 0 26 5 0 0 8

Diversion Channel

80,000 2000 21 5 2 0 11

Rocky Ramp

75,000 5000 28 4 1 0 6

Do Nothing

0 75,000 1 33 2 0 4 0

Vertical Slot

125,000 2000 24 7 0 0 8


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The weir at this location is approximately 45 meters in width with a vertical drop from the top of the structure to the water surface of approximately 2 meters. See figure 20 (p. 160).

19.1 Denil Fishway



This fishway can be effectively operated within a wide range of fluctuating water levels and conditions common to the Lower Humber River. A denil fishway is also effective at maximizing attraction flows at the entrance to the fishway. Environmental Effects and Significance: There are several minor environmental effects associated with the building of a fishway. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all of low significance as they are based on short term concerns associated with the construction. The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation plans into the design. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 20 based on the condition to include revegetation plans. The effects to public health and safety are considered to be of low significance. Access to the site will be restricted during the construction phase and warning signs will be clearly posted. Following construction, access to the fishway will be restricted to personnel only and signs will be posted warning of any hazards associated with the fishway. Furthermore, the fishway can be constructed as an enclosed structure with safety grates over the top as well as at the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is

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still an important factor to consider. Effects to drainage during the construction of the fishway are expected to be minimal and therefore, considered of low significance. Based on the results of the cultural heritage assessment, it is unlikely that there are buried cultural resources at this site. There are a number of maintenance covers scattered throughout the park indicating the presence of a pipe system. The construction of this infrastructure likely damaged any cultural resources that were there, if any. Therefore, this is reflected in Table 20 as a low negative impact to cultural heritage resources. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 20 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect. Positive effects are in relation to fish productivity and fisheries potential. Installing a denil fishway would provide access to upstream habitat for spawning, rearing and feeding activities. This has the potential to dramatically increase fish productivity within the watershed. Also, by allowing access to otherwise fragmented fish communities and habitats, there will be an increase in genetic diversity among fish populations which will lead to increased fish productivity. These benefits to fish populations will provide increased recreation and tourism potential by increasing angling opportunities. Furthermore, the need for fish stocking will be reduced thus, decreasing the costs associated with the current stocking program. Mitigation Measures Required: Mitigation of the identified negative effects can be achieved through:









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Estimated Cost and Feasibility: The estimated cost for this type of fishway is approximately $100,000. This type of fishway has previously been constructed and is operating at another location (Milne Reservoir, Markham) on the Rouge River under similar conditions therefore, it is feasible that it can be successfully constructed and operated at this location also. A denil fishway operating at a 10% slope at this location would require a length of approximately 20 meters (excluding resting pools). A denil fishway would be more feasible for the east bank as the west bank is adjacent to a very steep slope. Monitoring Requirements: Frequent monitoring of the fishways during April, May, June, July, September and October is recommended as a means of determining the peak periods of fish migration. Water temperatures and flood conditions of the river and of the fishways should be monitored to determine safe periods of operation of the fishway. Also, the fishways should be checked for to make sure that there is no debris clogging the passage. There is another denil fishway south on the river at Raymore Park. The operation of this fishway can be used for clarifying monitoring and conveyance requirements.


Effectiveness of Alternative to Meet its Intended Purpose: This alternative meets both the project purpose and watershed objectives. Partial removal of the weir will allow non-jumping fish species access to upstream habitats. Environmental Effects and Significance: There are several environmental effects associated with this alternative as indicated in Table 20. The effects to noise and aesthetics are a result of the construction and are all considered of low significance. Also considered to be of low significance is the effect to public health and safety. This type of construction activity is generally brief, only lasting one or two days. Therefore, the general public will not be at risk from the hazards associated with a longer term construction site. Personnel involved in the construction will be properly trained and will take the appropriate safety measures. Also, signs will be clearly posted to warn of potential dangers such as walking across the weir during low flow conditions. Furthermore, the effects to drainage and flooding are considered of low significance as no major alterations to flow are expected. Similarly, the effects to erosion are considered of low significance. The bed of the river is largely made up

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of shale. As the weirs were created to dissipate the energy of the river in order to control erosion, partial removal may cause additional scouring and erosion downstream. These impacts can be mitigated with proper design considerations. Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and increase fish productivity. As a result, there will be an increase in fisheries potential and possibly an increase in tourism for the surrounding area. Furthermore, the need for fish stocking will be reduced thus, decreasing the costs associated with the current stocking program. A positive effect to the ice conditions in this part of the Lower Humber River is expected as a result of partial removal. This can be seen in Table 20 as “lands subject to natural hazards”. Partial removal of the weir may result in a reduction in the production and thickness of ice in the river as a result of reduced backwater depths upstream of the weir. These lower depths and the remaining weir structure may also provide storage capacity for the ice within the river system, thereby reducing the quantity of river ice available for deposition within the flood plain. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, creating a portage at this location would help facilitate watercraft navigation. Mitigation Measures Required: Many of the negative effects identified in Table 20 can be mitigated in the following ways:









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This option satisfies both the project purpose and watershed objectives. Creating a diversion channel around the weir will create additional habitat as well as allow unrestricted access for all fish species to reach existing upstream habitat. Environmental Effects and Significance: This alternative has several environmental effects associated with it as identified in Table 20. Temporary effects resulting from the construction of the channel involve sedimentation and erosion, noise, aesthetics and public safety. The effect to drainage and flooding is considered of low significance and is a result of reducing the amount of water flowing over the weir in order to direct flow through the channel. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 20 based on the condition to include revegetation plans. In terms of public safety, access to the site will be restricted during the construction phase and warning signs will be clearly posted. Personnel working in and around the fishway during construction and maintenance will be properly trained and taking the appropriate safety measures. These concerns are considered to be of low significance however, there may be an increased public safety risk resulting from the addition of a channel within the floodplain. Despite warning signs being posted, this alternative has the potential to create an increased risk to public safety as a result of persons falling in the channel or voluntarily entering into the channel. This creates an additional risk of drowning, particularly during high flow conditions. For this reason, the effect to public safety is considered to be a medium negative effect as identified in Table 20. An important factor to consider for this alternative is referred to as “lands subject to natural hazards” in Table 20. The Humber River experiences strong ice flows

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which could potentially cause damage to a diversion channel. This is seen as being of medium significance due to the potential to cause significant damage to the diversion channel, thus creating high maintenance costs. Based on the results of the cultural heritage assessment, it is unlikely that there are buried cultural resources at this site. There are a number of maintenance covers scattered throughout the park indicating the presence of a pipe system. The construction of this infrastructure likely damaged any cultural resources that were there, if any. Therefore, this is reflected in Table 20 as a low negative impact to cultural heritage resources. Positive effects include creating additional habitat for fish while also re-connecting fragmented habitats, and creating additional wildlife habitat as a result of riparian planting along the channel. This will enhance aesthetic qualities in the park and provide additional recreation and tourism opportunities. Furthermore, the need for fish stocking will be reduced thus, decreasing the costs associated with the current stocking program. Another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, constructing a diversion channel may help facilitate watercraft navigation at this location. Mitigation Measures Required: Many of the negative effects identified in Table 20 can be addressed through the following mitigation techniques:









being done.

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Estimated Cost and Feasibility: The cost of constructing a diversion channel around the current weir is approximately $150,000. The feasibility of this alternative depends on the availability of space within the existing park adjacent to the river. The west bank consists of a very steep slope. A diversion channel is feasible for the east bank only. A diversion channel at this location, operating at a 5% slope, would require a length of approximately 40 meters.

Monitoring Requirements: Monitoring of flow conditions and the overall condition of the channel should occur throughout the year. Fisheries monitoring of the channel, as well as upstream and downstream of the channel, should take place throughout the year to determine the effectiveness of the channel and how many species are benefiting from it. During sampling, fish should be weighed, measured, and checked for disease and evidence of wounds. The upstream section should also be monitored for juveniles produced from adults using the channel.




This alternative has only a few environmental concerns as identified in Table 20 including noise levels and aesthetics. These are considered of low significance and are a result of construction activities. The effects to public health and safety are also considered to be of low significance and are a result of construction activities. Personnel working on the construction of the rocky ramp will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to effect lands subject to natural or human made hazards as identified in Table 20. This concern refers to the potential damage that could be inflicted on the rocky ramp resulting from strong ice flows typical of the Lower Humber River. Damage to the rocky ramp could potentially cause for high maintenance costs. However, it is considered to be of low significance as the large size of rock that would likely be used (2-3 ton) may be less susceptible to ice movement. The potential to affect fish habitat is considered to be of medium significance as constructing a rocky ramp will involve the addition of a significant amount of rock being placed in the stream bed which will alter the existing habitat. Positive environmental effects are a result of allowing free movement of migrating fish past the barrier. This will allow fish access to potential spawning grounds and

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increase fish productivity. As a result, there will be an increase in fisheries potential and possibly an increase in tourism for the surrounding area. Also, the need for fish stocking will be reduced and thus decrease the costs associated with the current stocking program. In addition to restoring fish connectivity in the river, another positive impact that may result is improved watercraft navigation through this area. The barrier is currently obstructing navigation however, constructing a rocky ramp may facilitate watercraft navigation at this location. Mitigation Measures Required: The environmental concerns identified in Table 20 can be mitigated in the following ways:



and post public notices to advise park patrons of the risk; • Revegetation of disturbed areas following the construction to reduce

erosion and restore ecological integrity to the park.

Estimated Cost and Feasibility: The cost for installing a rocky ramp at this weir is approximately $75,000. Although relatively inexpensive, this alternative may not be feasible for this site as the river experiences strong flows which may wash out the structure, rendering it useless. Monitoring Requirements: The river should be monitored following strong flow conditions to make sure the structure is still intact. Fisheries monitoring should take place throughout the year to measure the effectiveness of the structure and how many fish species are able to make it up the ramp. Monitoring of upstream sites should take place to check for juveniles produced from fish that made it up the ramp past the obstruction. During the sampling, fish should be checked for size, weight, sex, disease and evidence of wounds.


This alternative does not satisfy the project purpose or the watershed objectives and is not a solution to providing fish access to the upstream habitats.

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Environmental Effects and Significance: This alternative has several environmental effects associated with it that are considered of high significance. The identified effects are a result of the inability of this alternative to meet the objectives of the Humber River Fisheries Management Plan. Allowing the obstruction to remain in the river and continue to impede fish movement results in the lack of access for migratory species to upstream spawning, rearing and feeding habitat. Effects resulting from the inability to migrate can be seen as a loss of potential habitat, loss of potential migration, loss of potential spawning areas and continued loss of ecological integrity. This habitat fragmentation can be expected to cause further declines in fish productivity as populations will continue to be genetically isolated from one another. Furthermore, the “potential to obstruct navigation” and “potential to affect inaccessible areas” as identified in Table 20, are considered to be of low significance. These effects refer to the continued obstruction to navigation if the barrier remains in its current state. Mitigation Measures Required: N/A Estimated Cost and Feasibility: The estimated cost of the “do nothing” alternative is zero capital expenses however; this does not take into account the cost of lost fish productivity, lost recreation and tourism potential, and continued costs of fish stocking within the watershed. Currently, the fish stocking effort is approximately $75,000 per year. Monitoring Requirements: N/A



This alternative meets both the watershed objectives and project purpose. This type of fishway is able to function well under a wide range of changing volumes and fluctuating flow conditions making it suitable for this location. It is able to pass both jumping and non jumping fish species. A vertical slot fishway generally operates with less water flowing through it than a denil fishway and therefore, is not as well suited to maximizing attraction flow. Environmental Effects and Significance:

This alternative has several effects under the Natural Environment components and Land Use components, many of which are considered of low significance. These effects are short term in nature and are a result of construction activities. Sedimentation and erosion, noise levels, aesthetics, and use of the park are all expected to be effected by the construction of a vertical slot fishway.

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The effects to aesthetic qualities following the construction of the fishway are expected to be low as they can be mitigated by designing a fishway that has minimal aesthetic impact and by incorporating revegetation plans in the design. There may be negative impacts to water quality as a result of construction of the fishway. Although it is unlikely, the presence of heavy machinery near the water body may contribute to the addition of pollutants in the river, such as sediment or petroleum products. This effect will be minimal as the construction will occur during dewatered conditions with sediment controls in place. Machinery will not be permitted to refuel within 30 meters of the watercourse. The planting of trees and shrubs along the river’s edge will help stabilize soils and reduce the possibility of sediments entering the river from storm runoff. Due to the minor potential to negatively affect water quality, this impact is categorized as a positive one in Table 20 based on the condition to include revegetation plans. The effects to public health and safety are considered to be of low significance. Access to the construction site will be restricted and warning signs will be clearly posted. Following construction, access to the fishway will be restricted by locked fences and signs will be clearly posted to warn of any hazards associated with the fishway. Also, the fishway can be constructed as an enclosed structure with safety grates over the top as well as at the inlet and outlet. Personnel working in and around the fishway during construction and operation will be properly trained and will take the appropriate safety measures. Also of low significance is the potential to affect drainage and/or flooding. The site is located within an area that has been prone to flooding in past years, and although major alterations to flow are not expected during or after construction, it is still an important factor to consider. Effects to drainage during the construction of the fishway are expected to be minimal and therefore, considered of low significance. Based on the results of the cultural heritage assessment, it is unlikely that there are buried cultural resources at this site. There are a number of maintenance covers scattered throughout the park indicating the presence of a pipe system. The construction of this infrastructure likely damaged any cultural resources that were there, if any. Therefore, this is reflected in Table 20 as a low negative impact to cultural heritage resources. The alternative may have increased negative effects in relation to watercraft navigation. This is seen in Table 20 as “potential to affect access to inaccessible areas” and “obstruct navigation”. These effects are considered to be of low significance as the barriers obstruct navigation in their current state. Therefore, installing a fishway will maintain the “status quo”. Furthermore, the creation of a portage at this location will help facilitate watercraft navigation, thereby resulting in a positive effect. Positive effects that are expected to result include access to additional habitat for spawning, rearing and nursing activities. Although this type of fishway is limited to the size of fish that can pass, it is estimated that most fish will be able to navigate through it. Therefore, there will be an increase in the number fish migrating upstream. This increased fish productivity will lead to increased fisheries potential

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and a potential to benefit tourism within the watershed. Furthermore, the need for fish stocking will be reduced thus, decreasing the costs associated with the current stocking program.














The construction of this type of concrete fishway is expected to cost approximately $125,000. A vertical slot fishway operating on a 10% slope would be 20 meters in length at this location (excluding resting pools). A vertical slot fishway requires more resting pools than a denil fishway. This involves more concrete work and excavation resulting in higher costs. This type of fishway is feasible for the Lower Humber as it has been in successful operation on other large rivers such as the Fraser River in British Columbia and the Nine Mile River in Port Albert, Ontario. A vertical slot fishway would be more feasible for the east bank as the west bank is adjacent to a very steep slope.


Monitoring of the fishways in the months of April, May, June, July, September and October is recommended in order to determine the peak periods of fish migration. Water temperatures and flow conditions in the river should be monitored to determine safe periods to operate the fishways. Also, the fishways should be checked for to make sure that there is no debris clogging the passage.

159


160

West bank East bank

Figure 20. Weir #8

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Table 20. Significance of effects for weir #8 Level of Significance High Medium Low Nil Unk Positive Criteria: Denil fishway Partial



Vertical slot



* * *









11. permafrost





162




Vertical slot










8. Noise levels




163




Vertical slot







7. Tourism values






164



Total # Nil Effects





Denil Fishway

100,000 5000 24 7 0 0 8

Partial Removal

50,000 0 26 5 0 0 8

Diversion Channel

150,000 2000 21 5 2 0 11

Rocky Ramp

75,000 5000 28 4 1 0 6

Do Nothing

0 75,000 1 35 0 0 4 0

Vertical Slot

125,000 2000 24 7 0 0 8


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Bibliography Cenderelli, Daniel A., and Brian L. Cluer, 1998. Depositional Processed and Sediment Supply in Resistant-Boundary Channels: Examples from 2 Case Studies. Rivers Over Rock: Fluvial Processes in bedrock Channels. American Geophysical Union. Pg 105-108. Clayton, J., Hayes, K., and Heaton, M.G. 2004. Humber River fisheries management plan. Published by the Ontario Ministry of Natural Resources and the Toronto and Region Conservation Authority. COSEWIC. 2003. Prioritized Candidate List. http://www.cosewic.gc.ca/eng/sct3/sct3_1_e.cfm. Downloaded February 12, 2004. Department of Fisheries and Oceans. 1986. Policy for the Management of Fish Habitat. Department of Fisheries and Oceans. 1996. Backgrounder. Great Lakes Sea Lamprey Control Program. http://www.dfo-mpo.gc.ca/media/backgrou/1996/nq-ac62_e.htm. Downloaded January 21, 2004. Dollenmayer, Kate, Noah P. Snyder and Kelin X Whipple. Rates and Processes of bedrock incision by the Upper Ukak River since the 1912 Nova rupter ash flow in the valley of Ten Thousand Smokes, Alaska. Trans. Am. Geophys. Union., Sept. 2000, v. 28, no. 9, Pg 835-838. GLFC - Great Lakes Fisheries Commission. 2002. Position Statement on American Eel. http://www.glfc.org/lakecom/loc/eelposition.htm. Downloaded February 12, 2004. GLFC – Great Lakes Fisheries Commission. 2000. Sea Lamprey Barriers – New Technologies Help Solve an Old Problem. Fact Sheet 5. Government of Alberta. 2001. Alberta Transportation Fish Habitat Manual: Guidelines and Procedures for Watercourse Crossings in Alberta. Ministry of Infrastructure and Transportation. Accessed March 1, 2005. http://www.trans.gov.ab.ca/Contenet/doctype123/production/fishhabitatmanual.htm Hovius, Neil S. and Rudy Slingerland. Sediment Transport and Fluvial Bedrock Erosion in an Evolving Mountain Belt: A Field Study. Accessed February 16, 2005. http://www.geosc.psu.edu/-sling/BDRCH_EROS/hovius_summary.html Katopodis, C. 1992. Introduction to Fishway Design. Department of Fisheries and Oceans, Freshwater Institute. Winnipeg, Manitoba. Knighton, David., 1984. Fluvial Forms and Processes. Edward Arnold, London. Pg 60, 158, 180-183. MacBroom, James Grant. 1998. The River Book. Connecticut Department of Environmental Protection. Pg. 6, 15, 24, 28, 31, 35, 45, 55-56, 64.

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Metro Toronto and Region Remedial Action Plan. Clean Waters, Clear Choices. Recommendations for Action. Ontario Ministry of Natural Resources. 2003. A Class Environmental Assessment for MNR Resource Stewardship and Facility Development Projects. Queen’s Printer for Ontario. Rosgen, Dave. 1996. Applied River Morphology. Wildland Hydrology, Pagosa Springs, Colorado., Pg 4-6. Sea Lamprey Control Center. October 29, 2004. Personnal Communication. Tinkler, Keith J. and Ellen E, Wohl, 1998. A primer of Bedrock Channels. Rivers Over Rock : Fluvial Processes in bedrock Channels. American Geophysical Union. Pages iii – v. Toronto and Region Conservation Authority. March 2, 2005. Lower Humber Barrier Mitigation Project Heritage Impact Assessment: Phase 1. TRCA Archaeological Resource Management Unit. Waldman, J.R., Grunwald, C., Roy, N.K., and Wirgin, I.I. 2004. Mitochondrial DNA Analysis Indicates Sea Lampreys Are Indigenous to Lake Ontario. Transactions of the American Fisheries Society 133: 950-960. Wohl, Ellen E., 1998. Bedrock Channel Morphology in Relation to Erosional Processes. Rivers Over Rock : Fluvial Processes in bedrock Channels. American Geophysical Union. Pg 133-136.

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