Ecosystem modeling Lake Shasta

Computer modeling to explore what options are available to protect fish habitats

Shasta Lake on the Sacramento River is a key component of managing water resources in California. As the largest storage reservoir in California, it provides water for energy (through generation of hydropower), agriculture, cities, and the environment. It also has the ability to store water to prevent flooding. However, there are fish that naturally should migrate between freshwater on the Sacramento River and the ocean, and Shasta Dam, which creates Shasta Lake, has prevented the fish from reaching cold water habitats they need for spawning.

We have been using a computer model to model Shasta Lake to see what options are available to control water releases from the reservoir or to capture fish and move them around the dam. We look at these issues for dry, wet, and normal years, and also under climate change.

Our studies have shown that options are limited under extreme dry conditions due to lack of water in the system, and under extreme wet conditions because of mandated reservoir operations for flood protection and water quality. However, model results indicate that controlling release temperature by withdrawing water from specific reservoir elevations does help to reduce impacts to downstream fisheries without negatively affecting fish in the reservoir itself.