Presented by Greg Taylor, US Army Corps of Engineers, at Within Our Reach 2012.

1. Willamette Within Our Reach
December 11-12, 2012
Developing, Implementing and
Evaluating Environmental Flows in
the Willamette River Basin
Leslie Bach, The Nature Conservancy
Chris Budai, Corps of Engineers

2. Environmental Flows
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
Brisbane
Declaration
© Leslie Bach/TNC © Michael Durham © Leslie Bach/TNC © Emilie Blevins/TNC

4. Willamette Basin Project,
USACE:
13 Multi-Purpose Dams and
Reservoirs,
132 miles of navigation channel,
100 miles of revetments
© USACE from USACE
Photo
© USACE
© Leslie Bach/TNC
© Leslie Bach/TNC Photo from USACE Photo from USACE

5. Process for Developing and Implementing
Environmental Flow Recommendations
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
Hydrologic
and Hydraulic
Analysis
Environmental Flow
Recommendations

6. Initial Environmental Flow Recommendations
Middle Fork Willamette River

7. Ecosystem Flow Requirements
South Santiam River at Waterloo
Season Fall Winter Spring Summer
Winter Events Above Bankfull
15,000 up to 60,000 cfs
Various events not occurring each year
Create lateral and floodplain habitat
Key
High High Winter Events Up to Bankfull
Low 7,000 to 15,000 cfs
Flows Transition 5-6 events
Linked to storms Spring Flows
Create lateral and floodplain habitat 4,000 gradually declining
to 1,500 cfs
Maintain flows for lateral
and downstream species
movement, promote riparian
vegetation establishment
Spring Events
Low 1,000 to 4,000 cfs
3-8 events
Flows Linked to storms
Create lateral and floodplain
Winter Flows habitat
Fall Flows
1,500 to 3,000 cfs
3,000 cfs Consistent to prevent
For fish dewatering of habitat Summer Flows
passage 800 to 1,200 cfs
and Consistent to prevent
habitat dewatering of habitat
SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG

8. Middle Fork
Willamette

9. Winter High
Flows
Spring High Flows Fall
Fall Pulses and drawdown Transition
Flows
© Leslie Bach/TNC
© Mary Karen Scullion
© Leslie Bach/TNC

10. Ecological Benefits of Flow Restoration
• Germination and
survival of native
riparian vegetation
• Upstream and
© Leslie Bach/TNC Photo from USACE
downstream fish
migration
• Floodplain connectivity
and wetland habitat Photo from USACE
• Survival of native
floodplain species
Photo from USACE © Emilie Blevins/TNC

11. Policy/Management Implications
• Integrating with other project
purposes
• Population distribution (within
floodplain and cities)
• Existing environmental © Leslie Bach/TNC
requirements
– Biological Opinion
– Water quality
• Basin-wide implementation
– Modeling scenarios
– Real time monitoring
– Uncertainty (forecasting; climate © Leslie Bach/TNC
change)

12. TNC/Corps of Engineers Sustainable Rivers Project
E-flows training, Mexico Yangtze River Forum, China E-flows training, Columbia
© Leslie Bach/TNC © Lisa Morales/USACE © Leslie Bach/TNC