Completion Report on Techniques for Evaluating the Effects of Water Resources Development on Estuarine Environments

The research project was designed to provide a set of analytical techniques for use by water resources planners and decision-makers to assist in measuring and evaluating the effects of water resources development on estuarine environments. The techniques are designed to be sufficiently flexible to analyze many types of water development and management policies. This report describes: (1) the techniques developed by the Texas Water Development Board to measure the environmental impact of water resources development on estuarine environments, and (2) the application of these techniques to a prototype Texas River basin - estuarine system to demonstrate the methodology. At this time, results are not definitive but serve as valuable learning tool. Environmental effects of water development and management are examined by simulation models of stream, reservoir, and estuarine environments, and placed within a flexible analytical framework for evaluating a wide range of alternatives. An estuarine ecological model (ESTECO) and an estuarine model (MOM) for migratory organisms (Gulf shrimp) were developed for use with existing Board models that were designed to simulate stream, reservoir, and river basin conditions as water use demands increase on projected scales. The test case was executed on the Guadalupe Estuary and its major contributing drainages, the San Antonio and Guadalupe River Basins. Year 2000 simulations indicate water use projections would increase frequency of low flow events with varying environmental effects.