HR: 1340h
AN: H13E-1361    [Abstracts]
TI: Implementing Ecosystem Scale Change on the Trinity River, CA
AU: * Krause, A F
EM: akrause@mp.usbr.gov
AF: Trinity River Restoration Program, PO Box 1300, Weaverville, Ca 96093
AB: The Trinity River is located in far northern California and is the largest tributary to the Klamath River. Trinity Dam was constructed in 1964 by the U.S. Bureau of Reclamation as part of the Central Valley Project to enhance water supply in the Sacramento River Basin through an out-of-basin transfer from the Trinity River. Up to 90 percent of the average annual water yield of the Trinity River has been diverted since construction of Trinity Dam. Flow regulation and the downstream sediment deficit caused by dam operations has created significant changes in the downstream fluvial geomorphology and temperature regime, causing a 50 to 90 percent decline in salmonid populations. The Trinity River Restoration Program is legally mandated to restore and maintain the natural production of salmon and steelhead on the Trinity River. Through nearly two decades of scientific study it was recognized that the fishery restoration is dependant on restoring the attributes of a natural alluvial river. The restoration strategy does not strive to recreate pre-dam conditions; rather, to create a smaller, dynamic alluvial channel exhibiting all the characteristics of the pre-dam river but at a smaller scale. This strategy is intended to best achieve the restoration goals and maintain the purpose and use of the Trinity Dam water supply diversion project. The December 2000 Record of Decision outlines the restoration plan and includes: 1) Flow management to restore geomorphic and riparian processes 2) Flow management for temperature and habitat 3) Channel and watershed rehabilitation 4) Fine and coarse sediment management 5) Adaptive environmental assessment and management Adaptive management requires evaluation of ecosystem response and predictive modeling on an annual time scale to inform annual management decisions. The scientific challenge is to link management actions (flow releases, bank rehabilitation projects, coarse sediment augmentation) to geomorphic and riparian processes, and ultimately link to improved salmonid habitat, habitat utilization, and increasing population levels. To do so requires project implementation and scientific modeling and analysis at a variety of spatial and temporal scales.
DE: 1808 Dams
DE: 1825 Geomorphology: fluvial (1625)
DE: 1856 River channels (0483, 0744)
DE: 1862 Sediment transport (4558)
SC: Hydrology [H]
MN: Fall Meeting 2005