Willamette Sustainable Rivers Project - Taylor, Bach, & Budai

Willamette Within Our Reach December 11-12, 2012

Developing, Implementing and Evaluating Environmental Flows in

the Willamette River Basin

Leslie Bach, The Nature ConservancyChris Budai, Corps of Engineers

Quantity, timing and quality of water flows required to sustain freshwater

and estuarine ecosystems and the human livelihood and well-being that

depend on these ecosystems

Environmental Flows

Brisbane Declaration

© Leslie Bach/TNC © Leslie Bach/TNC © Emilie Blevins/TNC © Michael Durham

Willamette Basin Project, USACE: 13 Multi-Purpose Dams and Reservoirs, 132 miles of navigation channel, 100 miles of revetments

© USACE

© Leslie Bach/TNC

© USACE

Photo from USACE

Photo from USACE

© Leslie Bach/TNC

Photo from USACE

Process for Developing and Implementing Environmental Flow Recommendations

Hydrologic and Hydraulic Analysis

Hydrologic Analysis: Pre- and Post- dam flow data

Flow-Ecology Relationship:•Salmon and other native fish

•Native riparian vegetation

•Amphibians, mussels, invertebrates, birds

•Floodplain wetlands

•Geomorphic and hydrologic processes

Environmental Flow Recommendations

Initial Environmental Flow Recommendations Middle Fork Willamette River

Ecosystem Flow RequirementsSouth Santiam River at Waterloo

Low

Flows

High

Flows

Fall Flows1,500 to 3,000 cfsFor fish passage

and habitat

Spring Flows4,000 gradually declining

to 1,500 cfsMaintain flows for lateral and downstream species

movement, promote riparian vegetation establishment

Key

TransitionLowHigh

Summer Flows800 to 1,200 cfs

Consistent to prevent dewatering of habitat

SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG

Season Fall Winter Spring Summer

Winter Events Above Bankfull15,000 up to 60,000 cfs

Various events not occurring each yearCreate lateral and floodplain habitat

Winter Events Up to Bankfull7,000 to 15,000 cfs

5-6 events Linked to storms

Create lateral and floodplain habitat

Winter Flows3,000 cfs

Consistent to prevent dewatering of habitat

Spring Events1,000 to 4,000 cfs

3-8 events Linked to storms

Create lateral and floodplain habitat

Middle Fork Willamette

© Mary Karen Scullion

© Leslie Bach/TNC

© Leslie Bach/TNC

Winter High Flows

Spring High Flows and drawdownFall Pulses

Fall Transition Flows

• Germination and survival of native riparian vegetation

• Upstream and downstream fish migration

• Floodplain connectivity and wetland habitat

• Survival of native floodplain species

Ecological Benefits of Flow Restoration

Photo from USACE

Photo from USACE

Photo from USACE

© Leslie Bach/TNC

© Emilie Blevins/TNC

Policy/Management Implications

• Integrating with other project purposes

• Population distribution (within floodplain and cities)

• Existing environmental requirements– Biological Opinion– Water quality

• Basin-wide implementation– Modeling scenarios– Real time monitoring– Uncertainty (forecasting; climate

change)

© Leslie Bach/TNC

© Leslie Bach/TNC

TNC/Corps of Engineers Sustainable Rivers Project

© Leslie Bach/TNC © Leslie Bach/TNC © Lisa Morales/USACE

E-flows training, Mexico Yangtze River Forum, China E-flows training, Columbia