Development of a Simplified Approach for Assessing the Effects of Water Release Temperatures on Tailwater Habitat Downstream of Fort Peck, Garrison, and Fort Randall Dams.

摘要

Increased water resources demand in the main stem Missouri River regulated by Corps of Engineers dams has intensified the conflict between the economic benefits of stream regulation and the need to protect natural river ecosystems. Credible predictive tools that can be quickly and easily applied are required to explore and screen alternative reservoir operating plans to determine the downstream water temperature effects on tailwaters supporting temperature-sensitive fishes. The screening model was developed in a two-step process. First, a one-dimensional, longitudinal, riverine model, CE-QUAL-RIV1, was used to predict the downstream water temperature in the 52-mile tailwater of Fort Randall Dam, the 70-mile tailwater of Garrison Dam, and the 186-mile tailwater of Fort Peck Dam on the Missouri River. The power of the comprehensive water-quality model was required to predict the complex downstream water temperature patterns resulting from variable year-to-year stratification, complex peaking hydropower release patterns, and variable meteorologic conditions. Downstream water temperatures were simulated for 108 scenarios for each tailwater, covering the expected range of boundary conditions. Second, the output from the 108 scenarios for each tailwater was statistically evaluated to identify major trends and patterns in the results. CE-QUAL-RIV1, Garrison Dam, Water temperature, Fort Randall Dam, Missouri River, Fort Peck Dam, Tailwaters.