assigned to take responsibility for coordination and planning of individual components of each study.

Legislative Mandate

Texas Senate Bill 2 directs the TPWD, TCEQ, and TWDB, in cooperation with other appropriate governmental agencies, to “jointly establish and continuously maintain an instream flow data collection and evaluation program.” The agencies were further directed by Senate Bill 2 to “conduct studies and analyses to determine appropriate methodologies for determining flow conditions in the state’s rivers and streams necessary to support a sound ecological environment.” These study results “will be incorporated into future regional and state water plans, and will become essential data for conservation of fish and wildlife resources and consideration in the state water rights permitting process.”

Priority Instream Flow Studies

The PWP identifies six river subbasins for priority study, which will be addressed in the following order during 2003-2010: Guadalupe River (lower subbasin), Brazos River (lower subbasin), San Antonio River (lower subbasin), Trinity River (middle subbasin), Sabine River (lower subbasin), and Brazos River (middle subbasin). Four additional basins are identified as candidates for a second tier of studies in the event that priorities change or supplementary resources are made available: Guadalupe River (upper subbasin), Neches River, Red River, and Sabine River (upper subbasin). The exact process for selecting the priority and second tier studies is not described in detail in the PWP; however, potential water development projects and water rights permitting issues are identified as important factors.

Scope of Studies

The PWP specifies that studies will include hydrology, biology, geomorphology, water quality, and connectivity, and that studies will be conducted using an interdisciplinary approach. The PWP notes the challenges of an inter-disciplinary approach:

Recognizing the constraints of time and resources, it will not be possible to address each of these components in a systematic or



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