Refining the Baseline Sediment Budget for the Klamath River, California

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Abstract

Four dams in the Klamath River Hydroelectric Project (KHP) in Oregon and California (Figure 1) are currently scheduled to be removed over a period of a few weeks or months, beginning in January 2021. The Klamath dam removal will be the largest in the world by almost all measures, and is an unprecedented opportunity to advance science of river responses to such events. The KHP contains approximately 10-12 million cubic meters of mostly fine sediment and model estimates suggest approximately 1/3-2/3 of this volume is expected to be eroded from reservoirs. Much of this sediment is expected to be eventually transported by the river to, or through, the Klamath River Estuary, a distance of more than 300 kilometers. To improve the success of restoration activities following dam removal, agencies must understand the baseline conditions for biological, chemical, and physical processes, prior to the removal. We expect large changes in water quality (turbidity, suspended sediment, dissolved oxygen, temperature, and algal toxins) and in fish habitat in the Hydroelectric Reach and the main-stem of the Klamath River to the ocean. For example, modeled sediment concentrations in the Klamath River during dam removal were estimated exceed 10,000 – 15,000 mg/L, depending on streamflows, location, and the dam removal process, and to remain > 100 – 1000 mg/L for months at a time. Final time to achieve background concentrations post dam removal may take over two years (Reclamation, 2011). Plans to assess many of these changes post-dam removal are still being formulated.

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Publication type Conference Paper
Publication Subtype Conference Paper
Title Refining the Baseline Sediment Budget for the Klamath River, California
Year Published 2019
Language English
Publisher SEDHYD
Contributing office(s) California Water Science Center, New England Water Science Center, Oregon Water Science Center, Pacific Coastal and Marine Science Center
Description 4 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title Proceedings of SEDHYD 2019
Conference Title SEDHYD 2019
Conference Location Reno, NV
Conference Date Jun 24-28, 2019
Country United States
State California, Oregon
Other Geospatial Klamath River
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