Introduction Statement of the Problem Rapid population and economic growth in Texas is accompanied by increased needs for water supply and flood control. Depleting groundwater reserves are resulting in an increased reliance on surface water. The rising cost of fossil fuel during the 1970's has focused attention on increasing hydroelectric power generation. Instream flow needs for fish and wildlife habitat and maintenance of fresh water inflows to bays and estuaries have received increased attention in recent years. The climate of the state is characterized by extremes of floods and droughts.
Reservoirs are necessary to control and utilize the highly variable streamflow.
Due to a number of economic, environmental, institutional, and political factors, construction of additional new reservoir projects is much more difficult now than in the past. Consequently, optimizing the beneficial use of existing reservoirs is becoming increasingly more important. In addition to ever increasing water related needs, other factors affecting reservoir operation change over time as well. Watershed and flood plain conditions are dynamic. Construction of numerous small flood retarding dams by the Soil Conservation Service and other entities in the watersheds of major reservoirs have reduced flood inflows to the reservoirs.