Conveyance characteristics of the Nueces River, Cotulla to Simmons, Texas

Analysis of discharge hydrographs for streamflow-gaging stations on the Nueces River at Cotulla, Tilden, and Simmons indicate that significant water losses occur along the 108-mile reach from Cotulla to Simmon during storm-runoff periods. Computed losses along the 83-mile reach from Cotulla to Tilden for 15 storm periods range from 32 to 59 percent of the total runoff volume passing the Cotulla gage. For six storm periods that occurred while the gage at Simmons was in operation, computed losses from Cotulla to Simmons averaged 48 percent of the storm runoff passing the Cotulla gage. Estimates of total-annual losses were made with the aid of a regression model developed to relate monthly rainfall totals to monthly runoff. Total annual water losses, estimated with the aid of the regression model, ranged from 46,000 acre-feet during 1969 to 368,500 acre-feet during 1967, and averaged about 174,000 acre-feet for 1966-77. (USGS)