Using Existing Data to Examine Fish Community Changes Due to Stream Flow Alterations

A diversity of ecological flow issues will continue to arise due to climate change and increased demand for water, making stream flow management a complex and long-term issue. To bolster the ecological basis for stream flow management, we established a spatial framework using existing data for Missouri streams. Initial datasets included 1,855 fish community sites, 431 stream gages, and the locations of 5,517 dams, 4,456 springs, and 4,591 losing stream segments. To better understand how flow alterations affect riverine systems and their biota we developed metrics that define basic attributes of impoundments (reservoir area, maximum storage) and metrics for the hydrologic effect of withdrawals, using their natural surrogate, losing streams. Working downstream from each headwater segment, we used RivEX software to accumulate values of these metrics for every stream segment within the Missouri stream network. Accumulated values of impoundment and withdrawal metrics were applied for every fish community sampling site of the Missouri Department of Conservation’s Resource Assessment and Monitoring Program and for every gage site. The resulting datasets will be used to evaluate differences in fish communities as a function of flow alterations, and to test newly developed flow-ecology hypotheses about potential responses to flow conditions.