2010 SAC report on moving from instream flow regime matrix development to environmental flow standard recommendations

During 2009, the SB3 Texas Environmental Flows Science Advisory Committee (SAC) prepared several guidance documents for the BBESTs to consider in their development of environmental flow regime recommendations. Specifically, with respect to the instream flow component of the flow regime, the SAC provided information on hydrology-based environmental flow methodology, geographic scope, and biological, water quality and sediment transport overlays on the hydrology-based results. The two BBEST groups that have produced their final reports (Trinity/San Jacinto and Sabine/Neches basins) both depended, at least in large measure, upon the environmental flow matrix generated by the Hydrology-Based Environmental Flow Regime (HEFR) model. The BBASCs are now charged with the task of developing environmental flow standards and strategies for implementing these standards. In doing so, they are to consider the science-based recommendations of their respective BBEST. There are several issues related to the implementation of the BBEST instream environmental flow regime. The SAC has prepared the attached Discussion Paper to assist the stakeholders in their consideration of the BBEST analyses. As noted, the SAC westward across the state. As always, your feedback would be welcome.