Validation of Environmental Flow Regimes in the Brazos, Guadalupe and San Antonio Rivers, Texas, USA

Few recommended environmental flow regimes are validated to quantify the management of a river system towards set of ecological goals. Rivers in Texas are currently managed under the theories of the Natural Flow Paradigm and established environmental flow recommendations. The purpose of our study is to validate instream flow recommendations implemented on the Lower Brazos, Guadalupe, and San Antonio Rivers. The objective of this study is to investigate macroinvertebrate and fish assemblages to determine an ecological response to instream flow recommendations (e.g., subsistence, base, 1 per season, 1 per year). Fourteen sites associated with USGS gaging stations were visited over a period of twelve months with visits classified into flow tiers based on the preceding twelve days. Riffle and run habitats were sampled for swift water specialists and diet (gut fullness) and reproduction (GSI) was investigated. This insight will be used to understand ecological responses to the current implemented flow recommendations to maintain a sound ecological environment.