Ecologically Functional Treatments for CAWS

Fish Habitat Restoration Scenarios in an Urban

Impaired Waterway

In a sustainable human environment, departure from the

natural condition requires a management strategy that can maintain ecosystem function

Chicago Area Waterways System is Typical of other Working

Waterways

Artificial Canals Navigable Rivers Working Waterfronts Ports and Harbors Long History of Commerce and Development Patterns

Current Situation Affecting Waterways

Policy and Economics Drivers Reinvestment in Ports/Harbors/Navigation Sustainable transportation method Shifts from “dirty waterfront” uses to high end real estate Recreational pressure Water Quality Compliance: No more free passes for working waterways!

Current Situation Affecting Waterways

1960’s: Legal function of river is waste conveyance & navigation 1970’s: Too bad we can’t have it all… 1980’s: How do we make smart trade-offs? 1990’s: Or can we have it all? 2000’s: Reclaiming waterfront land is happening We just forgot about dealing with the water itself because we never paused to devise a plan for effective restoration

Stewardship: Evolving Perception of the Opportunity for Restoration

What would it look like? How would it function? What would it cost? Where has it been done before? How do we set clear goals and match expectations?

How can we Restore Ecological Function Here?

CAWS Habitat Study Limitations

• Not to consider water quality improvement—Consent Order focused

• Techniques implemented within banks • Original pre-CAWS hydrology/ecology not

researched or considered • Techniques allow continued waterway use

for navigation, stormwater conveyance, CSO overflows and WWTP discharge

Netherlands Germany Japan Malaysia Miscellaneous US applications

Research Study to Identify, Document, and Evaluate Global Examples

Literature Search

• Bibliography includes 71 references • 27 on assessing fish habitat, life history or

natural environmental variables related to fish life stages or macroinvertebrates

• 26 on fish habitat enhancement methods • 2 on improvement of aquatic or riparian

vegetation • 4 on physical water quality property of

suspended sediment

Objectives

Reduce Negative Habitat Variables: • Navigation—direct wave impacts on fish,

sediment resuspension and abrasion • Riprap Banks--reduces riparian vegetation,

isolates channel from floodplain

Wave damping

Objectives

Increase Positive Habitat Variables: • Overhanging Vegetation--provides shade,

refuge, food source and plant debris • Natural Banks--dissipate waves, provides

refuge and shallow littoral zone • Bank Pocket Areas--provides refuge and

sheltered littoral zone

Habitat Functions Food Web:

Phytoplankton

Herbivores Zooplankton

Carnivores Zooplankton

Pelagic

Non-carnivores

Pelagic

carnivores

Objectives

Increase Positive Habitat Variables: • Large Substrate in Shallows—provides

habitat structure and refuge • Plant Debris on Bed--provides food and

habitat for macroinvertebrates • Off-Channel Bays--provides refuge and

habitat

Colonization of macro-zoobenthon and heterotrophic organisms

Reports of more than 5000 Individuals (heterotrophic colonization) per cm2 proves high biological activity within constructed measures

Method Location Positive/Negative Effect Habitat Objectives

Artificial Seaweed Along bank below water line, on river bed

• Reduce Current Velocity/Turbulence • Creates “drag” on sediment particles causing them to settle • Creates riverbed depth diversity • Increases density/stability of bottom sediments • Fronds used as habitat for periphyton, microbes and fish

Provides in-channel refuge Instream, near-shore structure for

wave energy dissipation

Sunken Structures On river bottom, submerged near banks and within shallows

• Provides habitat/refugia for fish • Provides protection from Wave Energy • Attracts different species depending on the deployment method

and location used • Provides piscivores needed ambush points

Provide in-channel refuge Alternate overhanging cover Near-shore structure Large substrate in shallow areas

Floating Islands Virtually anywhere in river where their occurrence will not interfere

with navigation

• Provides habitat for many types of organisms: fish, birds, insects, herptiles, microorganisms

• Dissipates wave energy • Provides shelter for aquatic organisms • Provides isolated nesting areas for waterfowl • Improves water quality

Provide in-channel refuge Increase riparian vegetation Near-shore structure for

refuge/habitat Decrease impacts of wave energy

Vegetated Revetment At the river’s edge and on the banks, above and below the waterline

• Protects banks from erosion-dissipates wave energy • Provides natural vegetation on the river bank • Provides habitat diversity • Allows for growth of stable riparian vegetative community,

contributing shading, POC/detritus, and other plant debris

Increase bank slopes/Recontour banks

Alternate overhanging cover Incorporate vegetation into

unvegetated riparian area Dissipate wave energy

Chamber Revetments (unvegetated))

Below the waterline at the river’s edge

• Dissipates wave energy • Provides refuge for young fish • Collects sediment

Large substrate in shallow areas Increase bank slopes Near-shore structure

Linear Constructed Shallows

Parallel to the canal bank

• Dissipates wave energy • Creates refugia • Allows for aquatic plant growth and shallow water habitat • Creates food source and source of plant debris • Provides habitat for many types of organisms, including fish (many

life forms), herptiles, insects/macroinvertebrates • Introduction of shallow water breeding/nesting grounds

Increase off channel refuge & shallow water habitat

Increase bank slopes Near-shore structure to dissipate

wave energy Provide near-shore cover and

refuge Increase riparian vegetation Increase large substrate in shallow

areas

Artificial Seaweed •Originally developed to mitigate scour around pipes and oil rig footings in the ocean •Attenuates wave energy •Entraps suspended sediment •Provides cover from and for predation •Provide surfaces for colonization by algae and microbes

Sunken Structures •Provides refugia for microorganisms, invertebrates and fish •Re-purpose precast concrete box culverts or other appropriate discarded materials •Recycle demolition debris, eg ceramic tubs and toilets etc •Purchase specially designed habitat modules

Floating Islands

•Provides shade to water surface •Provides suitable area for emergent macrophytes •Reduced disturbance zone for birds and herptiles •Increases oxygen locally for fish •Substrate for aquatic macroinvertebrates and microbes

Varying degrees of shelter habitat under water:

Chamber Revetments •Employed in high energy areas to attenuate waves •Provide surface structure for microorganisms to colonize •Controls erosion •Used by zoo/phytoplankton •Enhances oxygenation

Vegetated Revetments

•Adds structure to the littoral bank zone •Dampens wave reflection •Mitigates erosion •Provide habitat for birds and reptiles •Enhances food supply for fish •Adds oxygenation •Enhances macroivertebrate habitats

Linear Shallows

•Provides spawning and nesting habitat for multiple species •Provide temporary refugia for adult fish •Provides soft substrate for herptile burrows •Provide habitat for rooted aquatic and emergent macrophytes

Implement pilot projects Monitor Aquatic habitat functions Monitor physical and social performance Adapt and refine approaches Identify further sites that would benefit

Next Steps

Closing

Restoration Opportunity Exists: • To demonstrate and evaluate habitat

improvement • To document costs, including O&M • To assess issues affecting navigation,

recreation, tax base, etc. • To increase awareness & support

2011 ADC WINTER FORUM | PAGE 35

QUESTIONS?