Table Contents - gov.bc.ca · Figure 4 – PCIC Climate Change Scenarios (1950 – 2098) The...

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TableofContentsEXECUTIVE SUMMARY ........................................................................................................................ 1

1. INTRODUCTION .............................................................................................................................. 2

1.1 DESIGN CODES AND REFERENCES ........................................................................................ 2

2. SALMON RIVER DESCRIPTION ................................................................................................... 2

2.1 WATERSHED ............................................................................................................................... 2

2.2 REACH AND CHANNEL DESCRIPTION .................................................................................. 3

3. HYDROLOGY ................................................................................................................................... 3

3.1 FLOOD FREQUENCY ANALYSIS ............................................................................................. 4

3.2 ASSESSMENT OF CLIMATE CHANGE .................................................................................... 5

3.3 IMPACT OF MOUNTAIN PINE BEETLE .................................................................................. 7

3.4 DESIGN FLOW RATES ............................................................................................................... 8

4.0 HYDRAULIC ANALYSIS AND ASSESSMENT ........................................................................ 8

4.1 RECOMMENDED BRIDGE WATERWAY OPENING .............................................................. 8

4.2 HEC-RAS MODEL ........................................................................................................................ 8

4.2.1 HEC-RAS MODEL CALIBRATION ........................................................................................ 9

4.2.2 HEC-RAS MODEL RESULTS ............................................................................................... 10

4.3 BRIDGE CLEARANCE .............................................................................................................. 11

4.3.1 FLOOD CLEARANCE ............................................................................................................ 11

4.4 SCOUR ASSESSMENT .............................................................................................................. 11

4.4.1 LONG-TERM AGGREGATION OR DEGRADATION ........................................................ 12

4.4.2 CONTRACTION SCOUR ....................................................................................................... 12

4.4.3 NATURAL SCOUR ................................................................................................................. 13

4.5 RIPRAP PROTECTION .............................................................................................................. 13

5.0 FOUNDATION RECOMMENDATIONS .................................................................................. 14

6.0 HYDRAULIC DESIGN SUMMARY ......................................................................................... 15

7.0 REFERENCES ............................................................................................................................. 15

Appendix A – Site Photos Appendix B – Figure 1 – Salmon River Watershed Appendix C – 1990 Flood Plain Mapping Appendix D – Hec-Ras Model Results Appendix E – Sieve Analysis Appendix F – Sketch 1187-SK1 - Salmon River Bridge Riprap Channel Details

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EXECUTIVESUMMARY This report provides a summary of the hydrotechnical analysis for the proposed Highway # 1 Bridge which is located approximately 200 m downstream from the existing Highway # 1 Bridge, (Salmon River Bridge No. 1187). The following summarizes the hydraulic design parameters required for the design of the proposed Highway # 1 Bridge: Hydraulic Design Parameters:

Q200 design flow rate = 85.5 m3/s Q100 design flow rate = 78.2 m3/s Minimum streambed width perpendicular to direction of flow = 11 m Minimum waterway opening U/S (XS-4) = 21.6 m Minimum waterway opening D/S (XS-3) = 20.7 m Water surface elevation for Q200 for proposed bridge (XS-3) = 351.43 m Water surface elevation for Q100 for proposed bridge (XS-3) = 351.36 m Minimum soffit elevation = 353.06 m Mean channel velocity during Q200 design flood = 1.8 m/s Froude Number = 0.40 Riprap size (700 mm thick and placed on slope of 1.5:1) = 100 kg Class Depth of contraction scour = 0.5

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1. INTRODUCTION The BC Ministry of Transportation and Infrastructure (the Ministry) is proposing to construct a new bridge across the Salmon River near Salmon Arm as part of the Highway #1 Kamloops to Alberta Four-Laning Program. The proposed crossing of the Salmon River is located approximately 200 m downstream from the existing Highway #1 bridge No 1187.

1.1 DESIGNCODESANDREFERENCES

The following design codes and reference documents have been used for the hydrotechnical design at the Graham Bridge crossing: Design Codes:

CAN/CSA-S6-14 and the BC MoT Supplement to CHBCDC S6-14. BC MoT Supplement to TAC Geometric Design Guide, 2007.

Ministry Standards and Guidelines:

BC MOTI Standard Specifications for Highway Construction (2012) Hydrotechnical Design Guidelines:

TAC Guide to Bridge Hydraulics (2001) U.S. Department of Transportation, Federal Highway Administration,

Hydraulic Engineering Circular No. 18, Evaluating Scour at Bridges, Fifth Edition, April 2012.

2. SALMONRIVERDESCRIPTION

2.1 WATERSHED The Salmon River watershed is located within the interior plateau of south central British Columbia. Its headwaters originate in the vicinity of Tahaetkun and Bouleau Mountains, south of Westwold and northeast of Merritt. From its headwaters, the river flows westward to Salmon Lake and then flows in a northeasterly direction to Salmon Arm Bay of Shuswap Lake. The Salmon River is approximately 110 km in length with an elevation difference from approximately 1540 m near the headwaters to approximately 350 m near Shuswap Lake. The watershed area is approximately 1550 km2. As the Salmon River approaches Salmon Arm and Shuswap Lake the channel

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gradient reduces and there is evidence of channel meanders downstream of the existing Highway No. 1 Bridge and the channel bed material consists of predominately sand and gravel.

2.2 REACHANDCHANNELDESCRIPTION The flows in Salmon River at the existing and proposed bridge locations are characteristically laminar due to the relatively low channel gradient in this reach, approximately 0.082%. The river bed material predominately consists of sand and gravels. The river banks appear to be relatively stable with vegetation and trees lining the river banks. There has been some bank armoring downstream of the existing bridge on some of the meander bends to protect the banks from erosion, (Appendix A – Site Photos). Erosion of the Salmon River stream banks in the valley flat area has been on-going as a result of agriculture, ranching, and the removal of stream bank vegetation since 1951, M. Miles, 1995. The erosion of the stream banks in the valley flat area is the primary cause of sediment transport in the lower reach of the Salmon River near Salmon Arm. The gradient of the Salmon River tends to flatten out as it approaches Salmon Arm and Shuswap Lake. Aggradation of sands and gravels is anticipated near the proposed Highway #1 bridge location on an on-going basis, however during the annual spring freshets, it is also anticipated that any accumulated sediments will be mobilized and transported downstream to Shuswap Lake, thereby maintaining a relatively stable state at the proposed bridge location. Refer to Section 4.4.1 Long-Term Aggradation or Degradation for further information.

3. HYDROLOGY The drainage area for Salmon River at the existing Highway #1 bridge location was estimated to be approximately 1550 km2, (Appendix B - Figure 1 – Salmon River Watershed). The hydrology and hydraulics have been updated based on the most recent Water Survey of Canada (WSC) hydrometric station data with consideration for Climate Change and the potential impact of the Mountain Pine Beetle infestation in 2003. Floods on the Salmon River are typically freshet driven and typically occur in May or June as shown in Figure 2, Water Survey of Canada – 08LE021 – Daily Discharge for 1996.

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Figure 2 – Water Survey of Canada (WSC) Station 08LE021 Daily Discharge 1996.

3.1 FLOODFREQUENCYANALYSIS A Water Survey of Canada (WSC) hydrometric station 08LE021 Salmon River near Salmon Arm, is located just upstream of the existing Highway #1 Bridge location. Published peak instantaneous flow records are available from Environment Canada for 49 years of record starting from 1912 to 2011. More recent ‘unconfirmed’ peak instantaneous flow records were requested from Environment Canada for 2012, 2013, 2014 and 2015 and were added to the historical record for conducting flood frequency analysis. A single station flood frequency analysis was performed on the peak instantaneous flow records using the IH-Floods1 statistical software package. The following flow rates were estimated for various return periods based on the Extreme Value 1 (EV1) Distribution, which appeared to best fit the annual maximum series, (Figure 3 and Table 1).

1 IH-Floods, Version 1.1, Centre for Ecology & Hydrology, Natural Environment Research Council,

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Figure 3

Table 1 – EV1 Flood Frequency Analysis Return Period

(yrs) Flow Rate

(m3/s) 2 30.8 5 41.6

10 48.7 25 57.8 50 64.5

100 71.1 200 77.8

3.2 ASSESSMENTOFCLIMATECHANGE The impact of climate change has been assessed for the Salmon River watershed based on climate change projection data obtained from the Pacific Climate Impact Consortium (PCIC) in Victoria, B.C.

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Based on climate summaries for the Thompson/Okanagan Region, climate models project warming throughout the 21st century for all seasons. Summer is projected to warm slightly more than other seasons, by 2.20 C by the 2050’s and 3.40 C by the 2080’s. Projected precipitation changes are relatively modest. By the 2080’s the median projection indicates an increase of about 10%, relative to the 1961 – 1990 baseline, in all seasons but summer when a roughly 10% decrease is projected. By the 2050’s, there are substantial projected decreases in spring snowfall and a decrease in heating degree days. Along with these changes, an increase in frost-free days and growing degree days is indicated. The potential impacts include; warming will decrease snowpack, increases to high intensity precipitation and seasonal moisture variability could affect habitats. A seasonal increase in hot and dry conditions could decrease water supply, stress fish, increase wildfire risk and affect recreational use of reservoirs and lakes. Both river flooding frequency and runoff may increase, stream bank erosion and strain on flood protection infrastructure may increase. Stormwater design standards may no longer be adequate. There could be a transition to rainfall-dominated watersheds, causing an increased need for water conservation and storage. PCIC has generated simulated daily streamflow results projected to 2098 for the Salmon River at Salmon Arm, Water Survey of Canada (WSC) hydrometric stream gauge 08LE021. The streamflow results were provided for 23 climate change scenarios which were generated by a hydrologic model driven with climate change projections using eight different global climate models and three different emissions scenarios as well as one base scenario where the hydrologic model was driven using observed climate data. The results of the climate change assessment are shown in Figure 4 – PCIC Climate Change Scenarios (1950 – 2098).

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Figure 4 – PCIC Climate Change Scenarios (1950 – 2098) The results of the climate change projection scenarios indicate that there is a reduction in the projected annual maximum freshet streamflow relative to the base scenario for all projections.

3.3 IMPACTOFMOUNTAINPINEBEETLE

The impact of the Mountain Pine Beetle (MPB) infestation that affected many parts of the interior of British Columbia in the late 1990’s and early 2000’s was considered. Scientific research has been on-going with the Ministry of Forests, Faculty of Forestry at UBC and various consultants on the impacts of the MPB on the hydrology of watersheds however there does not appear to be any conclusive results quantifying the potential increase in peak flows as a result of a loss of forest cover within the watershed. Dobson, 2007 prepared a report on the potential impacts of increased runoff due to the loss of forest cover by the MPB but did not quantify the potential increases in peak flows. The impact of the MPB appears to have peaked a few years ago and impacted watersheds are now recovering with re-vegetation and regrowth of the affected areas, therefore the hydrological impact of the MPB on the Salmon River watershed is likely improving each year as the re-vegetation matures.

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0

Annual M

axim

um Daily Discharge (m3/s)

Return Period (yrs)

PCIC Climate Change Scenarios (1950 ‐ 2098)Salmon River at Salmon Arm (08LE021)

cccma cgcm3 A1Brun1 cccma cgcm3 A2run1 cccma cgcm3 B1run1

ccsm3 A1Brun1 ccsm3 A2run1 ccsm3 B1run1

csiro35 A1Brun1 csiro35 A2run1 csiro35 B1run1

echam5 A1Brun1 echam5 A2run1 echam5 B1run1

gfdl A1Brun1 gfdl A2run1 gfdl B1run1

hadcm A1Brun1 hadcm B1run1 hadgem1 A1Brun1

hadgem1 A2run1 miroc 3.2 A1Brun1 miroc 3.2 A2run1

miroc 3.2 B1run1 20c Base 95th Percentile

50th Percentile 5th Percentile

Base Model (1950 ‐ 2006) 95th Percentile

50th Percentile

5th Percentile

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3.4 DESIGNFLOWRATES To account for the uncertainties in the climate change estimates, the impact of the MPB, and potential impact due to clear cut logging practices within the Salmon River watershed, the previously estimated flood frequency flow rates, as shown in Table 1, have been increased by 10%. The design flow rates including a 10% increase are listed in Table 2. Table 2 – Design Flow Rates Return Period

(yrs) Flow Rate

(m3/s) 2 33.9 5 45.8

10 53.6 25 63.5 50 70.9

100 78.2 200 85.5

4.0 HYDRAULICANALYSISANDASSESSMENT

4.1 RECOMMENDEDBRIDGEWATERWAYOPENING The average existing channel base width between the existing Highway No. 1 Bridge and the proposed bridge location is approximately 11.0 m. To avoid a channel constriction at the proposed bridge location the recommended minimum streambed channel width should be approximately 11.0 m.

4.2 HEC‐RASMODEL

The U.S. Army Corps of Engineers, Hydrologic Engineering Centre River Analysis System (HEC-RAS) model, version 5.0.0, February 2016 was used to estimate the water surface profiles and to estimate the streamflow velocities at the proposed bridge location. The HEC-RAS model was developed using channel cross-sections obtained from a recent topographic survey (June 2016) with cross-sections starting upstream of the existing Highway 1 Bridge and ending close to Shuswap Lake. The reach boundary conditions used in the model were assessed based on both the 1:200-year flood construction level (FCL) of 351.0 m for Shuswap Lake, located approximately 3.8 km downstream from the proposed bridge crossing and ‘normal

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depth’, (downstream channel slope of approximately 0.00082 m/s). The ‘normal depth’ governed and provided higher water levels in the downstream reach. The 1:200-year FCL for Shuswap Lake was identified in the Floodplain Mapping, Salmon Arm to Spa Creek, Drawing 89-14-2, Sheet 2 of 6, Crippen Consultants, September 30, 1991 and the associated floodplain mapping report2 . The FCL of 351.0 m includes a freeboard allowance of 0.94 m which was provided to Crippen Consultants by the Ministry of Environment at the time of the floodplain mapping. The corresponding 1:200-year return period lake level for Shuswap Lake was (350.06 m). (Refer to Appendix C – Floodplain Mapping – Salmon River, Salmon Arm to Spa Creek).

4.2.1HEC‐RASMODELCALIBRATION Various WSC recorded discharges and corresponding water levels were obtained from the published data for the hydrometric stream gauge 08LE021 located just upstream from the existing Highway #1 Bridge. These flow rates were input and run in the model. The Manning’s ‘n’ coefficient was adjusted to closely match the recorded water levels. A Manning’s “n’ coefficients of 0.05 was used for the main channel, accounting for vegetation occurring on the banks, with 0.1 for the over bank areas. Results of the calibration are shown in Table 3. Manning’s roughness coefficients that were used in the Floodplain Mapping, Crippen, 1990 varied from 0.03 to 0.07 for the channels, and 0.10 to 0.12 for the overbank areas. Table 3 – Hec-Ras Model Calibration Date Flow Relative

Datum WSC W.L. Elev.

Geodetic WSC W.L.

Elev.

RS-10 Hec-Ras Model WSC Station Location

Elevation N = 0.045 N = 0.05

(cms) (m) (m) (m) (m) 2009 20 1.533 350.454 350.29 350.38 2011 38.5 2.316 351.237 351.24 351.34 2008 50.9 2.688 351.609 351.3 351.39 1997 61.4 2.721 351.642 351.54 351.65

The model was run using a steady, subcritical flow regime due to the typical low gradient, low velocity channel characteristics. The typical channel gradient within the study reach was estimated to be approximately 0.15% (0.0015 m/m).

2 Floodplain Mapping Program, Salmon River – Shuswap Lake to Spa Creek, Design Brief, Crippen Consultants, December 1990.

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4.2.2HEC‐RASMODELRESULTS The model results for the existing Highway #1 Bridge and the proposed Highway #1 Bridge are summarized in Tables 4,5,6, and 7 below. Hydraulics have been assessed for the estimated 2-year, 100-year and 200-year return period peak instantaneous flow rates. Table 4 - Hec-Ras Model Results - Existing Hwy #1 Bridge (XS-7) Upstream

Flood Return Period

Peak Flow Water Surface

Elevation

Water Surface Width

Average Velocity

Froude Number

(T-year) (m³/s) (m) (m) (m/s) 2-year 33.9 351.09 22.04 0.79 0.18

100-year 78.2 352.00 42.74 1.13 0.27 200-year 85.5 352.08 44.95 1.17 0.28

Table 5 - Hec-Ras Model Results - Existing Hwy #1 Bridge (XS-6) Downstream

Flood Return Period


Elevation

Water Surface Width

Average Velocity

Froude Number


100-year 78.2 351.83 68.92 1.04 0.24 200-year 85.5 351.88 72.28 1.11 0.25

Table 6 - Hec-Ras Model Results - Proposed Hwy #1 Bridge, (XS-4) Upstream.

Flood Return Period


Elevation

Water Surface Width

Average Velocity

Froude Number


100-year 78.2 351.43 23.91 1.67 0.38 200-year 85.5 351.50 24.24 1.76 0.40

Table 7 - Hec-Ras Model Results - Proposed Hwy #1 Bridge (XS-3) Downstream

Flood Return Period


Elevation

Water Surface Width

Average Velocity

Froude Number


100-year 78.2 351.36 24.59 1.53 0.34 200-year 85.5 351.43 24.90 1.62 0.36

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The Hec-Ras model results are included in Appendix D – Hec Ras Model Results.

4.3 BRIDGECLEARANCE

4.3.1FLOODCLEARANCE The Ministry’s standard for flood clearance is 1.5 m above the 200-year peak flood level. The proposed bridge will be super elevated with the lower elevations of the bridge on the downstream side, refer to Table 6, (XS-3). The 200-year return period water elevations plus the 1.5 m freeboard requirement for the downstream side of the proposed bridge is summarized in Table 8: Table 8 - 200-Year Water Elevations Plus 1.5 m Freeboard.

Station 200-Year Water Level (m)

Plus 1.5 m Freeboard (m)

XS-3 351.43 352.93

1.1.1. Navigable Waters Protection Act Clearance Requirements The Navigable Waters Protection Act (NWPA) requires 1.7 m of clearance above the 100-year flood level. The 100-year return period water elevations plus the 1.7 m freeboard requirement for the downstream side of the proposed bridge is summarized in Table 9. Table 9 - 100-Year Water Elevations Plus 1.7 m Freeboard.

Station 100-Year Water Level (m)

Plus 1.7 m Freeboard (m)

XS-3 351.36 353.06 The Navigable Waters Protection Act clearance requirement will govern therefore the minimum soffit elevation for the proposed bridge on the downstream side shall be 353.06 m.

4.4 SCOURASSESSMENT The existing bed form in the lower reach of the Salmon River from the existing Highway #1 Bridge to Shuswap Lake which includes the proposed Highway #1 Bridge located approximately 200 m downstream from the existing Highway #1 Bridge, consists predominately of gravelly sand (SW) based on bed load sampling and a sieve analysis performed on the bed material. The D50 of the bed material was estimated to

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be approximately 0.9 mm. Refer to Appendix E – Sieve Analysis of Fine and Coarse Aggregate, Golder Associates Ltd, July 27, 2015. Various methods of scour prediction have been considered such as contraction scour and natural scour.

4.4.1LONG‐TERMAGGREGATIONORDEGRADATION An assessment of sediment transport in the Salmon River, from the headwaters to the Salmon River Delta at Salmon Arm, was conducted in 1995 by M. Miles and Associates Ltd, ‘Salmon River Channel Stability Analysis’ for the Fraser River Action Plan, Department of Fisheries and Oceans. The author reviewed air photos which indicated that the quantity of sediment being delivered by tributary streams (including Salmon River above Westwold) is small compared to that which is being generated by bank erosion within the valley flat. Extensive areas of the valley flat had been cleared for agricultural, ranching or other activities. Much of the riparian areas had either no woody vegetation or only a narrow strip of vegetation bordering the stream. The sediment supply to the Salmon River Delta appears to be principally derived from river bank erosion that has been caused by the removal of the riparian vegetation adjacent to the river banks. The sand-sized or smaller materials supplied from tributary streams or bank erosion is eventually transported to the Salmon River Delta and Shuswap Lake. The larger fractions of these sediments are deposited within the delta, while the finer fractions can be carried further into the lake. The sediment supply to the Salmon River Delta is anticipated to continue and aggradation of sediments near the proposed Highway #1 Bridge location is also anticipated. However, it is also anticipated that during flood events, which occur almost annually, that the higher streamflow velocities will mobilize and flush the aggraded sediments into Shuswap Lake resulting in a somewhat stable state with regard to aggradation and degradation of sediments at the proposed bridge location.

4.4.2CONTRACTIONSCOUR Contraction scour occurs when the flow area of the stream at flood stage is reduced, either by a natural contraction of the stream channel or by a bridge. It also occurs when overbank flow is forced back to the channel by roadway embankments at the approaches to the bridge. A scour depth of approximately 0.5 m below the existing channel bed was estimated based on the live bed contraction scour equation, HEC-18.

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4.4.3NATURALSCOUR Natural scour would occur due to flow alongside or impinging upon rock outcrops or other hard points or rigid materials along the channel boundaries. The 200-year depth of natural scour has been estimated using North West Hydraulic Consultants - Modified Blench procedure (TAC 2001 & NHC) with the following inputs:

200-year water surface width = 21 m Design flow = 85.5 m3/s Slope = 0.0031 m/m D50 of bed material = 9 mm Z factor = 2.0

The estimated natural scour depth is 3.6 m below the 200-year water level estimated to be 351.48 m at XS-3 (Downstream side of proposed bridge location). The scour elevation is determined by subtracting the estimated natural scour depth of 3.6 m from the design water surface elevation. The natural scour depth was estimated to be approximately 0.3 m below the existing bed elevation.

4.5 RIPRAPPROTECTION The mean channel velocity at the proposed bridge location was estimated to be approximately Vm = 1.8 m/s. Riprap sizing was estimated based on the BC Supplement to TAC, Figure 1030.A Riprap Design Chart for impinging flow against a curved bank, Vs = 4/3 Vm = 2.6 m/s. Consideration was also given to a minimum riprap size for bridges on major routes and the potential for vandalism. Class 100 kg riprap has been specified with a D50 = 415 mm and a nominal layer thickness of 700 mm. The proposed Class 100 kg riprap gradation is listed in Table 9.

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Table 9 - Riprap Gradation Table.

Riprap Gradation Table

Percent Lighter

(Finer) Than

Class 100-kg

Mass (kg) Equivalent Size* (mm)

15 10 195

50 100 415

85 300 600

100 715

Layer Thickness 700 mm (min.) (MoTI)

*Equivalent size is an approximate dimension for a spherical

stone for each given mass. Stone mass governs each class

and its gradations. Above gradation table is based on an

assumed specific gravity of 2.64 for riprap (S=2.64).

Note: Riprap shall be hard, durable, angular, and generally

good quality quarry rock that does not generate acids.

Riprap shall be free of structural defects, clean, and

generally well-graded according to the above gradation

table.

Minimum freeboard allowances range from 300 mm (BC Supplement to TAC) to 600 mm (MoE Riprap Design and Construction Guide). The minimum freeboard allowance has been specified as 600 mm which is consistent with the Supplement to CHBDC S6-14. The existing channel embankment on the north-west side at the proposed bridge location consists of vegetated slopes with no existing riprap bank protection. The existing channel embankment on the south-east side at the proposed bridge location has riprap that was previously installed which appears to meet the proposed riprap specification and could be re-used for the proposed riprap bank protection works. The riprap design for the proposed bridge is shown in Appendix F – Sketch 1187-SK1 - Salmon River Bridge – Riprap Channel Details.

5.0 FOUNDATIONRECOMMENDATIONS Pile foundations are recommended for the proposed bridge location due to the soils in the area which are assumed to consist of a combination of alluvial river deposits and lacustrine lake deposits.

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6.0 HYDRAULICDESIGNSUMMARY

Q200 design discharge = 85.5 m3/s Q100 discharge = 78.2 m3/s Minimum streambed width perpendicular to direction of flow = 11 m Minimum waterway opening U/S (XS-4) = 21.6 m Minimum waterway opening D/S (XS-3) = 20.7 m Elevation of Q200 water level for proposed bridge at (XS-3) = 351.43 m Elevation of Q100 water level for proposed bridge at (XS-3) = 351.36 m Minimum clearance above Q200 design water level = 1.5 m Minimum clearance above Q100 design water level = 1.7 m Minimum soffit elevation (downstream side proposed bridge) = 353.06 m Mean channel velocity during Q200 flood at (XS-3) = 1.8 m/s Riprap size (700 mm thick and placed on slope 1.5H:1V = 100 kg Class Depth of contraction scour = 0.5 m

7.0 REFERENCES BC MoTI Supplement to Canadian Highway Bridge Design Code (CHBDC), CSA S6-14, Bridge Standards and Procedures Manual, BC MoTI, October 2016. BC MoTI – BC Supplement to TAC, Geometric Design Guide, 2007 Edition. CAN/CSA Canadian Highway Bridge Design Code, S6-14, CSA Group, December 2014. CAN/CSA Commentary on CSA S6-14, Canadian Highway Bridge Design Code, S6.1-14, CSA Group, December 2014. Crippen, 1990 – Floodplain Mapping Program – Salmon River, Shuswap Lake to Spa Creek, Design Brief, Crippen Consultants, December 1990. Dobson, 1995 – Review of Public Road Crossing Capacities on the Mainstem of the Salmon River & Potential Impacts of Increased Runoff Due to the Loss of Forest Cover by the Mountain Pine Beetle, Dobson Engineering Ltd., March 2007. M. Miles, 1995 – Salmon River Channel Stability Analysis, Canadian Manuscript Report of Fisheries and Aquatic Sciences No. 2309, M. Miles, 1995. PCIC – Climate Summary for Thompson/Okanagan Region, Pacific Climate Impact Consortium (PCIC), University of Victoria.

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Transportation Association of Canada (TAC) Guide to Bridge Hydraulics (2nd Edition), June 2001. U.S. Army Corps of Engineers (USACE), 2016 – Hydrologic Engineering Center – River Analysis System (HEC-RAS), Version 5.0.0, Hydrologic Engineering Center, Davis CA. U.S. Department of Transportation Federal Highway Administration, Hydraulic Engineering Circular (HEC) No. 18, Evaluating Scour at Bridges, Fifth Edition, April 2012.

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APPENDIX ‘A’ – SITE PHOTOS

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Photo 1 – View from upstream of existing bridge looking downstream.

Photo 2 – Looking upstream from pedestrian walkway upstream of existing bridge.

2

Photo 3 – View looking downstream of existing bridge.

Photo 4 – View looking downstream at proposed bridge location.

3

Photo 5 – View looking upstream from proposed bridge location.

Photo 6 – View looking downstream from proposed bridge location.

4

Photo 7 – Looking upstream from proposed bridge location. Note existing rock on right bank (left side).

Photo 8 – Looking upstream from bend just upstream of proposed bridge location.

5

Photo 9 – Looking downstream from proposed bridge location.

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APPENDIX ‘B’ – Figure 1 – Salmon River Watershed

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APPENDIX ‘C’ – 1990 Floodplain Mapping

rdabrows

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APPENDIX ‘D’ – HEC-RAS MODEL RESULTS

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13 12

9

6

5.5

5

4.5

4.2

4

3

2.5

2

1

Salmon River Proposed Bridge

Legend

WS Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

0 200 400 600 800346

348

350

352

354

356

Salmon River Proposed Bridge

Main Channel Distance (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

EG Q100 (78.2 m3/s)

WS Q100 (78.2 m3/s)

Crit Q200 (85.5 m3/s)

Crit Q100 (78.2 m3/s)

Ground

Left Levee

Right Levee

XS

2 (

Sta

1+

41...

XS

-2.5

(S

ta 1

01+

8...

XS

-3 (

Sta

2+50

.65)

(...

XS

-4 (

Sta

2+

80)

(...

XS

-4.5

(S

ta 3

+60

)

XS

-5 (

Sta

3+

95)

XS

-5.5

(S

ta 4

+29

)

XS

-6 (

Sta

4+

59)

(DS

...

Exi

stin

g H

wy

1 B

ridg.

..

XS

-9 (

Sta

4+

98.5

)X

S-1

1 (S

ta 5

+17

...

XS

-12

(Sta

5+

41.0

6)

XS

-13

(Sta

7+

17.9

7)

XS

-14

(Sta

8+

60.8

)

Salmon River 1

0 200 400 600 800 1000 1200348

349

350

351

352

353

Salmon River Proposed Bridge RS = 13 XS-13 (Sta 7+17.97)

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

0 200 400 600 800 1000 1200 1400348

349

350

351

352

353


Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

0 200 400 600 800 1000 1200348

349

350

351

352

353


Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

0 200 400 600 800 1000 1200347

348

349

350

351

352

353

354


Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

0 200 400 600 800 1000 1200347

348

349

350

351

352

353

354


Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05 .1

0 50 100 150 200 250 300 350348

349

350

351

352

353


Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05 .1

0 50 100 150 200 250 300 350348

349

350

351

352

353


Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05 .1

0 50 100 150 200 250 300 350348

349

350

351

352

353

Salmon River Proposed Bridge RS = 7 XS-7 (Sta 4+80) (US of Existing Bridge)

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05 .1

0 50 100 150 200 250 300 350348

349

350

351

352

353

Salmon River Proposed Bridge RS = 6.5 BR Existing Hwy 1 Bridge

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05 .1

0 100 200 300 400 500 600 700348

349

350

351

352

353

354

Salmon River Proposed Bridge RS = 6.5 BR Existing Hwy 1 Bridge

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

0 100 200 300 400 500 600 700348

349

350

351

352

353

354

Salmon River Proposed Bridge RS = 6 XS-6 (Sta 4+59) (DS of Existing Bridge)

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

-250 -200 -150 -100 -50 0 50 100 150348

349

350

351

352

353

Salmon River Proposed Bridge RS = 5.5 XS-5.5 (Sta 4+29)

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05 .1

-300 -200 -100 0 100 200348

349

350

351

352

353

354

Salmon River Proposed Bridge RS = 5 XS-5 (Sta 3+95)

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05 .1

-250 -200 -150 -100 -50 0 50 100 150348

349

350

351

352

353


Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05 .1

-250 -200 -150 -100 -50 0 50 100 150347

348

349

350

351

352

353


Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05 .1

0 100 200 300 400 500 600 700347

348

349

350

351

352

353

354

Salmon River Proposed Bridge RS = 4 XS-4 (Sta 2+80) (US of Proposed Bridge)

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

0 100 200 300 400 500 600 700346

348

350

352

354

356

Salmon River Proposed Bridge RS = 3.5 BR

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

0 200 400 600 800 1000348

349

350

351

352

353

354

355

Salmon River Proposed Bridge RS = 3.5 BR

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

0 200 400 600 800 1000348

349

350

351

352

353

354

355

Salmon River Proposed Bridge RS = 3 XS-3 (Sta2+50.65) (DS of Proposed Bridge)

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

-25 -20 -15 -10 -5 0 5 10 15348

349

350

351

352


Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Ground

Bank Sta

.1 .05 .1

0 200 400 600 800 1000347

348

349

350

351

352

353

354

355

Salmon River Proposed Bridge RS = 2 XS 2 (Sta 1+41.74)

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

0 200 400 600 800348

349

350

351

352

353

Salmon River Proposed Bridge RS = 1 XS 1 (Sta 0+34.069)

Station (m)

Ele

vatio

n (m

)

Legend

EG Q200 (85.5 m3/s)

WS Q200 (85.5 m3/s)

Crit Q200 (85.5 m3/s)

Ground

Levee

Bank Sta

.1 .05

.1

HEC-RAS Plan: Plan 11 River: Salmon River Reach: 1

Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(m3/s) (m) (m) (m) (m) (m/m) (m/s) (m2) (m)

1 14 Q2 (33.9 m3/s) 33.90 348.70 351.32 349.86 351.33 0.000515 0.55 129.19 225.70 0.15

1 14 Q100 (78.2 m3/s) 78.20 348.70 352.16 350.54 352.16 0.000234 0.48 407.93 452.16 0.11

1 14 Q200 (85.5 m3/s) 85.50 348.70 352.25 350.63 352.25 0.000228 0.48 450.36 467.79 0.11

1 13 Q2 (33.9 m3/s) 33.90 348.58 351.26 349.70 351.27 0.000370 0.54 131.13 271.58 0.13

1 13 Q100 (78.2 m3/s) 78.20 348.58 352.13 350.26 352.13 0.000172 0.48 405.54 359.33 0.10

1 13 Q200 (85.5 m3/s) 85.50 348.58 352.22 350.33 352.23 0.000166 0.49 439.19 362.33 0.09

1 12 Q2 (33.9 m3/s) 33.90 348.28 351.13 349.49 351.17 0.001003 0.85 39.67 23.73 0.21

1 12 Q100 (78.2 m3/s) 78.20 348.28 352.11 350.17 352.11 0.000115 0.37 690.01 972.88 0.08

1 12 Q200 (85.5 m3/s) 85.50 348.28 352.20 350.26 352.20 0.000102 0.36 785.10 1021.28 0.07

1 11 Q2 (33.9 m3/s) 33.90 347.81 351.12 349.26 351.14 0.000779 0.74 45.90 28.29 0.19

1 11 Q100 (78.2 m3/s) 78.20 347.81 352.10 349.88 352.10 0.000147 0.39 631.94 989.33 0.08

1 11 Q200 (85.5 m3/s) 85.50 347.81 352.20 349.96 352.20 0.000124 0.37 728.85 1019.07 0.08

1 10 Q2 (33.9 m3/s) 33.90 347.86 351.11 349.16 351.13 0.000646 0.67 50.69 32.30 0.17

1 10 Q100 (78.2 m3/s) 78.20 347.86 352.06 349.77 352.10 0.001039 0.89 88.18 53.18 0.22

1 10 Q200 (85.5 m3/s) 85.50 347.86 352.15 349.86 352.19 0.001220 0.92 93.38 60.75 0.24

1 9 Q2 (33.9 m3/s) 33.90 348.10 351.11 349.32 351.13 0.000523 0.70 48.67 24.68 0.16

1 9 Q100 (78.2 m3/s) 78.20 348.10 352.03 349.90 352.09 0.000891 1.05 74.37 30.25 0.21

1 9 Q200 (85.5 m3/s) 85.50 348.10 352.12 349.98 352.18 0.000964 1.11 77.04 30.62 0.22

1 8 Q2 (33.9 m3/s) 33.90 348.37 351.10 349.38 351.12 0.000778 0.76 44.42 26.36 0.19

1 8 Q100 (78.2 m3/s) 78.20 348.37 352.03 349.97 352.08 0.001355 1.01 80.65 72.72 0.25

1 8 Q200 (85.5 m3/s) 85.50 348.37 352.12 350.05 352.17 0.001398 1.05 87.35 79.04 0.26

1 7 Q2 (33.9 m3/s) 33.90 348.41 351.09 349.37 351.12 0.000708 0.79 43.11 22.04 0.18

1 7 Q100 (78.2 m3/s) 78.20 348.41 352.00 349.97 352.06 0.001651 1.13 69.58 42.74 0.27

1 7 Q200 (85.5 m3/s) 85.50 348.41 352.08 350.05 352.15 0.001738 1.17 73.42 44.95 0.28

1 6.5 Bridge

1 6 Q2 (33.9 m3/s) 33.90 348.36 351.06 349.35 351.09 0.000644 0.78 47.92 35.49 0.17

1 6 Q100 (78.2 m3/s) 78.20 348.36 351.83 349.94 351.88 0.001298 1.04 94.44 68.92 0.24

1 6 Q200 (85.5 m3/s) 85.50 348.36 351.88 350.02 351.94 0.001426 1.11 98.04 72.28 0.25

1 5.5 Q2 (33.9 m3/s) 33.90 348.24 351.03 349.34 351.07 0.000762 0.86 39.99 22.80 0.19

1 5.5 Q100 (78.2 m3/s) 78.20 348.24 351.73 349.97 351.82 0.002355 1.36 63.40 48.87 0.33

1 5.5 Q200 (85.5 m3/s) 85.50 348.24 351.86 350.06 351.89 0.001000 0.93 181.61 210.63 0.22

1 5 Q2 (33.9 m3/s) 33.90 348.26 351.01 349.34 351.03 0.001149 0.75 45.35 37.82 0.22

1 5 Q100 (78.2 m3/s) 78.20 348.26 351.76 349.95 351.77 0.000460 0.62 248.28 262.26 0.15

1 5 Q200 (85.5 m3/s) 85.50 348.26 351.85 350.03 351.87 0.000426 0.61 273.90 264.74 0.14

1 4.5 Q2 (33.9 m3/s) 33.90 348.23 350.96 349.32 351.00 0.001040 0.82 41.35 27.43 0.21

1 4.5 Q100 (78.2 m3/s) 78.20 348.23 351.67 349.93 351.74 0.001550 1.16 83.04 81.96 0.27

1 4.5 Q200 (85.5 m3/s) 85.50 348.23 351.77 350.02 351.83 0.001549 1.18 90.97 84.09 0.27

1 4.2 Q2 (33.9 m3/s) 33.90 347.80 350.88 349.38 350.92 0.000982 0.89 38.26 21.36 0.21

1 4.2 Q100 (78.2 m3/s) 78.20 347.80 351.49 350.01 351.60 0.002355 1.49 52.55 26.06 0.33

1 4.2 Q200 (85.5 m3/s) 85.50 347.80 351.57 350.09 351.69 0.002547 1.56 54.68 26.71 0.35

1 4 Q2 (33.9 m3/s) 33.90 347.97 350.86 349.41 350.91 0.001467 1.00 33.90 21.42 0.25

1 4 Q100 (78.2 m3/s) 78.20 347.97 351.43 350.15 351.57 0.003113 1.67 46.76 23.91 0.38

1 4 Q200 (85.5 m3/s) 85.50 347.97 351.50 350.23 351.66 0.003347 1.76 48.55 24.24 0.40

1 3.5 Bridge

1 3 Q2 (33.9 m3/s) 33.90 348.19 350.84 349.22 350.87 0.000871 0.87 39.14 20.34 0.20

1 3 Q100 (78.2 m3/s) 78.20 348.19 351.36 349.85 351.48 0.002439 1.53 51.08 24.59 0.34

1 3 Q200 (85.5 m3/s) 85.50 348.19 351.43 349.93 351.56 0.002660 1.62 52.77 24.90 0.36

1 2.5 Q2 (33.9 m3/s) 33.90 348.02 350.80 350.83 0.000496 0.73 46.99 23.05 0.16

1 2.5 Q100 (78.2 m3/s) 78.20 348.02 351.27 351.36 0.001401 1.37 60.24 32.58 0.27

1 2.5 Q200 (85.5 m3/s) 85.50 348.02 351.32 351.43 0.001552 1.46 62.14 33.06 0.28

1 2 Q2 (33.9 m3/s) 33.90 347.64 350.76 349.10 350.80 0.001186 0.84 40.57 28.77 0.22

1 2 Q100 (78.2 m3/s) 78.20 347.64 351.16 349.79 351.26 0.003391 1.46 53.67 36.64 0.38

1 2 Q200 (85.5 m3/s) 85.50 347.64 351.20 349.89 351.32 0.003683 1.54 55.46 37.02 0.40

1 1 Q2 (33.9 m3/s) 33.90 348.01 350.66 349.06 350.69 0.000821 0.81 43.23 41.92 0.19

1 1 Q100 (78.2 m3/s) 78.20 348.01 351.06 349.65 351.08 0.000819 0.81 219.09 351.78 0.19

1 1 Q200 (85.5 m3/s) 85.50 348.01 351.11 349.73 351.13 0.000820 0.83 238.82 390.01 0.20

0

APPENDIX ‘E’ – SIEVE ANALYSIS

0

APPENDIX ‘F’ – SKETCH 1187-SK1

BRITISHCOLUMBIA

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