Watershed-Scale Water Resource Management: The U.S. Army Corps of Engineers’ Nueces River Basin Feasibility Study

摘要

The objective of the Nueces River Basin Feasibility Study is to investigate opportunities for flood damage reduction, ecosystem restoration, and multipurpose projects located in the Nueces River Basin that have a justified federal interest in being pursued for further study. Opportunities to develop an environmentally sustainable, holistic watershed approach to address the water resource problems of the Nueces River basin will be evaluated through a combination of unique alternatives using the U.S. Army Corps of Engineers (COE) planning process. The Edwards Aquifer recharge zone stretches across the upper portion of the basin in a series of exposed fractured limestone formations. The aquifer serves as the primary drinking water supply for the city of San Antonio, located in the Guadalupe-San Antonio River Basin. Alternatives include looking at developing recharge enhancement structures across the recharge zone. These structures provide additional recharge into the aquifer that in turn will be used to enhance the city of San Antonio’s water supply and increase spring flows associated with the aquifer, which are the only habitat of several endangered species. The Nueces River Basin is rather unique when compared to other basins in Texas as two large water supply reservoirs (Choke Canyon Reservoir and Lake Corpus Christi) serve as the primary water supply source for approximately 500,000 people surrounding and including the city of Corpus Christi. Since the completion of these reservoirs, historical flows into the Nueces Delta and Estuary have been reduced resulting in occasionally hyper-saline conditions in the delta. One goal of the study is to identify alternatives that could be developed to improve the habitat in the delta, either through increased freshwater inflow or by discharge of nutrient-rich water to strategic locations. The overall goal of the study is to provide for ecosystem restoration to two key ecosystems; the Nueces Estuary and the springs (associated with Edwards Aquifer) that serve as the habitat for several endangered species. The challenge is to identify and formulate alternatives that both provide benefit to these ecosystems while minimizing impacts from the new projects and producing additional water supplies and flood damage reduction benefits for the residents of the basin. The COE planning process is a new approach to addressing the concept of water resource management. A distinctive aspect of this study is that it is being performed on a basin-wide scale. This creates some issueswhen dealing with a basin this diverse with perennial flowing streams in the hill country, to the dry stream reaches of the Edwards outcrop, to the flat meandering reaches of the Nueces River down to the Nueces Estuary. The COE study addresses these issues and presents potential alternatives that have a strong probability of being able to provide simultaneously for man and nature’s need for water.