This report presents an analysis of data uses and funding for the streamgaging program operated by the U.S. Geological Survey in Texas. Presently (1984), 39i continuous surface-water stations are operated in Texas. Selected hydro!ogic data, data uses, and funding sources are presented for each of the 391 stations. This study is a part of a larger project to determine the cost-effectiveness of the stream-gaging program in Texas. All stations have sufficient uses to justify their continued operation. History of Stream-Gaging in Texas The stream-gaging program in Texas has evolved through the years in response to changing Federal, State, and local needs for surface-water data. The first gaging station in Texas was established on the Rio Grande near El Paso in 1889. A systematic collection of streamflow records in Texas did not begin, however, until 1897 when four additional stations were established. Formal cooperation between the Geological Survey and the State of Texas was started in 1915. In that year the program increased from 12 to 31 stations. The rapid expansion of the streamflow data-collection program continued through 1925 when 132 gaging stations were in operation, 36 of which were equipped with recorders. Because of reduced cooperative funds, the Texas program began to decline in 1926. By 1929, only 94 stations were in operation. The program remained near this level through the mid-1930's. A significant feature of the Geological Survey operations during the 1930's was the study of the recordshattering floods of 1932, 1935, 1936, 1938, and 1939. As a result of these floods, the U.S. Army Corps of Engineers provided funds for the operation of an additional 55 stations. With these stations, the Texas program increased to 172 stations in 1939 and remained near that level through 1945. The end of World War II accompanied another rapid expansion of the streamgaging program. The 1957 compilation of surface-water records (Texas Board of Water Engineers, 1958) presented stream-discharge and reservoir-content records for 436 gaging stations in Texas, 297 of which were in operation on September 30, 1957. Of these, 247 were continuous-record stream-gaging stations.

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Catastrophic floods, which resulted in millions of dollars in property damages and the loss of 33 lives, occurred in Central Texas during August 1-4, 1978, as a result of intense rainfall produced by the remnants of tropical storm Amelia. Rainfall in excess of 30 inches was unofficially reported at several locations, while the highest 24-hour amount recorded by the National•Weather Service was 29.05 inches at Albany in Shackelford County.Major flooding occurred on the Medina River and triputaries above Medina Lake and on the Guadalupe River and tributaries above Canyon Lake. Minor to severe flooding occurred on the tributaries of the Nueces River, on the Clear Fork Brazos River and tributaries, and on the Llano and Pedernales Rivers, which are tributaries of the Colorado River.Peak discharges at several streamflow stations exceeded the historic peaks, and the flood magnitude and frequency data for the Guadalupe River above Canyon Lake, the Medina River near Pipe Creek, and Clear Fork Brazos River indicate that the August 1978 flood had a recurrence interval in excess of 100 years. The highest unit discharge observed during this flood was 3,010 cubic feet per second from a 14.1-square-mil.e drainage area of Spring Creek, which is tributary to the Pedernales River.

Acre-foot (acre-ft). The volume of water required to cover 1 acreto a depth of 1 foot. It equals 43,560 cubic feet, 325,851 gallons, or 1,233 cubic meters. Contents. The volume of water in a reservoir or lake. Content is computed on the basis of a level pool or reservoir backwater profile and does not include bank storage. Convection cloud. A cloud which owes its vertical development, and possibly its origin, to convection. Cubic foot per second (ft3/s). A rate of discharge. One cubic foot per second is equal to the discharge of a stream of rectangular cross section, 1 foot wide and 1 foot deep, flowing at an average velocity of 1 foot per second. It equals 28.32 liters per second or 0.02832 cubic meters per second. Cubic foot per second per square mile [(ft3/s)/mi2]. The average number of cubic feet per second flowing from each square mile of area drained by a stream, assuming that the runoff is distributed uniformly in time and area. One cubic foot per second per square mile is equivalent to 0.01093 cubic meter per second per square kilometer. Dew point (or dew temperature). The temperature to which a given parcel of air must be cooled at constant pressure and constant water-vapor content in order for saturation to occur. Drainage area of a stream at a specific location. The contributing area of a stream, measured in a horizontal plane, bounded by topographic divides. Drainage area is given in square miles. One square mile is equivalent to 2.590 square kilometers. Flash flood. A local and sudden flood which usually follows brief heavy precipitation. Flood. Any high streamflow that overtops natural or artificial banks of a stream and overflows onto land not usually underwater and causes or threatens damage. Flood peak. The highest value of the stage or discharge attained by a flood. Flood profile. A graph of the elevation of water surface of a river in flood, plotted as ordinate, against distance, plotted as abscissa. Flood stage. The approximate elevation of the stream when overbank-flooding begins. Front. The interface or transition zone between two airmasses of different density.

oxygen demand, dissolved solids, total phosphorus, total organic carbon, total nitrogen, and fecal-coliform bacteria. The water-quality data simulated by the STORM model will be used by the Texas Department of Water Resources to refine and verify a model of the Calveston Bay estuarine system. Discharge and precipitation data for the 1975 water year and all available waterquality analyses were used to calibrate the model for the Buffalo, Whiteoak, Brays, Sims, Hunting, Greens, and Vince Bayous. Data for the 1974 water year were used to verify the model for discharge. After verification, the calibrations were adjusted to balance the difference between the 1974 and 1975 error predictions for discharge. The adjusted model was used with records of precipitation and evaporation to simulate a 20-vear record of the quantity and quality of runoff from the modeled area._________