Final Report on Public Utilities Board of Brownsville/Texas A&M Research Foundation Contract RF-89-792 "Rio Grande Valley Water Conservation Project - Fisheries/Benthos Sampling Program"

Texas A&M University at Galveston (TAMUG) was contracted by the Public Utilities Board of Brownsville to conduct a field sampling program yielding biological and hydrological data pertinent to assessing environmental impact from channel dam operation on the Rio Grande. The TAMUG sampling program was designed to provide qualitative information on nekton (finfishes and macroinvertebrates) and benthos communities utilizing the: 1) Rio Grande riverine corridor between Falcon Dam and the Brownsville Gauging Station, with emphasis on the Brownville and Anzalduas backwater areas; 2) Rio Grande estuary between the Brownsville weir and the Gulf of Mexico; and 3) Lower Arroyo Colordao and adjacent Laguna Madre. Specific objectives of the TAMUG sampling program were to: 1) define the temporal and spatial utilization of the Lower Rio Grande Valley by nekton and benthos, with particular attention given to stream segments and/or adjacent drainages impacted by channel dam operation; 2) generate data prerequisite to assessing impact of the Brownsville channel dam operation on freshwater inflow and estuarine-dependent nekton and benthos of the Rio Grande estuary and adjacent drainages; and 3) generate data prerequisite to assessing impact of pooled riverine environments created by Brownsville and Anzalduas channel dams on freshwater nekton and benthos between Brownsville and Falcon Dams.