Print PageIn Texas, prior to 1985, water rights permits for stream diversions or reservoir impoundment were granted, in perpetuity, with little regard for environmental flow considerations. After this date, most water rights contain instream flow conditions—limits on diversions or prescriptions for reservoir releases—usually based on desktop evaluations. In this century, two major water bills formed the basis of establishing environmental flow protection in Texas. In 2001, Senate Bill 2 (SB 2) established the Texas Instream Flow Program and set the stage for comprehensive sub-basin level studies to identify instream flow conditions needed to maintain a sound ecological environment in Texas rivers and streams. In 2007, SB 3 established a statewide scientific and stakeholder process for identifying environmental flow needs, including both instream flow needs and freshwater inflow needs for bays and estuaries. SB 3 established a clear distinction between science teams and stakeholders. Science teams are mandated to identify environmental flow needs using “all reasonably available science, without regard to the need for the water for other uses”. Conversely, stakeholders are charged with balancing these environmental needs with human needs. Science teams are given one year, with limited budget, to identify instream flow and freshwater inflow needs throughout large river basins. Accordingly, the potential for the collection of new data is severely limited. The science teams must find an appropriate middle ground between “desktop methodologies” and intensive site-specific studies.
Results/Conclusions
After scientific peer review, the Texas Instream Flow Program released a framework calling for multidisciplinary assessments of subsistence flows, base flows, high flow pulses, and overbanking flows. The disciplines include biology, hydrology, geomorphology, water quality, and connectivity. Information from these assessments is used to inform instream flow needs. This framework has also been used in the SB 3 process by the science teams preparing instream flow recommendations. To date, these two programs have advanced the science of environmental flows in Texas and represent a significant conceptual step forward in the management of water rights permits. However, considerable work remains to be done to bring the best science to the table and convey that science in meaningful ways to stakeholders and decision makers in order to ensure that environmental flows needs are truly and fairly considered in water resources management.
