Estimating freshwater inflow needs for Texas estuaries by mathematical programming

Abstract

As mandated by the Texas State Legislature, the Texas Department of Water Resources conducted studies of the effect of freshwater inflows upon the bays and estuaries of Texas. Developed as part of these studies, a mathematical programming model is described for computing estimates of the monthly and seasonal freshwater inflows necessary to meet specified environmental conditions in each of the major estuaries of the Texas Gulf Coast. The optimization model relates freshwater inflow to the key estuarine indicators of salinity, marsh inundation, and commercial fisheries harvests. Three management proposals are formulated for each estuary, corresponding to ecosystem subsistence, maintenance of fisheries harvests, and fisheries harvest enhancement. Linear and nonlinear mathematical programming techniques are used to determine the optimal inflows for each of these three management alternatives in all but one of the seven major estuaries, where only one of the management proposals could be solved.