Implementing the Right Flow Regime for the lower American River
Implementing farsighted Flow Standard solutions within the lower American River is one of the most critical elements—and perhaps the biggest challenge—in implementing the Water Forum Agreement. An updated and effective Flow Standard has long been needed to ensure that flow releases and water temperatures from Folsom Reservoir best match the needs of anadromous fish and preserve recreational and aesthetic values, secure reliable water supplies for the region, and contribute to the Delta’s ecological health downstream. Adaptive mechanisms set the Water Forum Flow Standard apart from those developed for other California streams. With American River water conditions varying from year to year, it is imperative that Flow Standard flows and temperature targets be recomputed every season.
The State Water Resources Control Board and local stakeholders agree that current flow requirements are creating unhealthy – and in some cases, lethal – river conditions for the 43 species of fish inhabiting the lower American River. Low flows and subsequent higher water temperatures affect both the federally endangered Steelhead and struggling fall-run Chinook salmon. Additionally, existing operations are problematic for the region’s water supply reliability; if water storage in the Folsom Reservoir falls below the water supply intake at Folsom Dam, local water agencies are unable to make critical water deliveries. To improve these conditions, a rigorous flow management standard needed to be developed.
Beginning in 2000, the Water Forum began working with state and federal agencies to identify the fishery’s needs and develop a rigorous science-based standard to managing water temperatures and flows. Many experts indicated that water temperature is equally, if not more important, than flows for improving conditions for the fishery. In 2006, the Water Forum released the first version of the Flow Management Standard (FMS). However, while the 2006 FMS specified minimum releases from Folsom Dam and introduced a new approach to managing water temperatures, the potential for too-low water levels and too-high temperatures remained.
In 2007 the Bureau of Reclamation began voluntarily implementing the 2006 version of the FMS. In 2009, the National Marine Fisheries Service incorporated the FMS into their Biological Opinion on Federal Central Valley Project Operations. Since then, the Water Forum has employed adaptive management techniques to develop a Modified FMS that further improves salmonid habitat and water temperature and helps to protect Folsom Reservoir levels – a significant water supply reliability benefit.
The Modified FMS is based on 22 years of study and refinement and reflects the best path forward. Overseen by an interagency work group, the American River Group, the Modified FMS builds and improves upon the 2006 FMS to include minimum release requirements and adjustments, water temperature management, and monitoring and adaptive management. The Modified FMS also includes a Seasonal Release Allocation, which banks cold water in the event of dry conditions. It also simplifies the types of adjustments that can be made to the minimum release requirements. Today, these modified flow standards are protecting local water supplies and the environment.