Trinity-San Jacinto estuary: a study of the influence on freshwater inflows. Draft report.

The provision of sufficient freshwater inflow to Texas bays and estuaries is an important factor in sustaining estuarine productivity, and a factor contributing to the near-shore fisheries productivity of the Gulf of Mexico. This report analyzes the interrelationships between freshwater inflows and estuarine productivity, and establishes the seasonal and monthly freshwater inflow needs, for a range of alternative management policies, for the Trinity- San Jacinto estuary of Texas. Simplifying assumptions must be made in order to estimate freshwater inflow requirements necessary to sustain Texas estuarine ecosystems. A basic premise described in this report is that freshwater inflow and estuarine productivity can be examined through analysis of certain key indicators. The key physical and chemical indicators include freshwater inflows, circulation and salinity patterns, and nutrients. Biological indicators of estuarine productivity include certain commercially important species. Useful species are generally chosen on the basis of their wide distribution throughout each estuarine system, a sensitivity to change in the system, and a sufficiently short life cycle to facilitate association of the organism with estuarine productivity.