Mill Creek begins in Shasta County and flows into Tehama County. It is a major salmon-supporting tributary to the Sacramento River. This creek regularly goes dry during summer months when all the natural flow is diverted for agriculture.

The Nature Conservancy (TNC) is leading efforts in implementing a pilot Environmental Water Trust. They will acquire and manage a portfolio of water assets, which will then be used to restore and protect instream flows on priority river systems. A primary goal is to deliver water to create vital wetland habitat for migratory birds downstream.

Kickstarting what will become a larger Sacramento Valley water portfolio, TNC has acquired water rights on Mill Creek. In 2020 and 2021, these water rights will be left instream to support salmon runs and other aquatic ecosystem needs. In addition, a short-term water transfer will be implemented to protect the water as it continues to flow downstream to create and enhance wetland habitat for migratory birds in the Sacramento National Wildlife Refuge Complex.