Improving managed environmental water use: Shasta River flow and temperature modeling

Urban, agricultural, and industrial water users actively manage water supplies and demands to increase water use efficiency through conservation, water markets, infrastructure changes, and creative operation and management strategies. Improving water use efficiency is just beginning to be incorporated in the environmental sector to extend benefits and reduce costs. This study explores methods to improve environmental water use efficiency, as well as to reduce competition for water between environmental uses and traditional water resources. California's Shasta River is used as a case-study to evaluate restoration alternatives and efficient use of environmental water allocations. Low instream flow and high water temperature conditions are two factors limiting survival of native salmon in the Shasta River. This study examines the potential to enhance fish habitat conditions by better managing environmental water quantity and quality, using theoretical analysis, field monitoring, simulation, and optimization modeling. Many other potential methods to improve environmental water use efficiency exist. Results suggest that environmental water use efficiency can potentially improve environmental performance and perhaps reduce some water management conflicts, and additional research for managing environmental water use is merited. Modeling results specific to the Shasta River indicate that restoring Big Springs Creek is especially promising to enhance fish habitat in the Shasta River, cold water is necessary in the upper reaches for most restoration measures to be effective, and a combination of restoration alternatives most improve instream habitat for native salmon species in the Shasta River.