Techniques for estimating monthly mean streamflow at gaged sites and monthly streamflow duration characteristics at ungaged sites in central Nevada

Abstract

Techniques for estimating monthly mean Streamflow at gaged sites and monthly Streamflow duration characteristics at ungaged sites in central Nevada were developed using Streamflow records at six gaged sites and basin physical and climatic characteristics. Streamflow data at gaged sites were related by regression techniques to concurrent flows at nearby gaging stations so that monthly mean streamflows for periods of missing or no record can be estimated for gaged sites in central Nevada. The standard error of estimate for relations at these sites ranged from 12 to 196 percent. Also, monthly Streamflow data for selected percent exceedence levels were used in regression analyses with basin and climatic variables to determine relations for ungaged basins for annual and monthly percent exceedence levels. Analyses indicate that the drainage area and percent of drainage area at altitudes greater than 10,000 feet are the most significant variables. For the annual percent exceedence, the standard error of estimate of the relations for ungaged sites ranged from 51 to 96 percent and standard error of prediction for ungaged sites ranged from 96 to 249 percent. For the monthly percent exceedence values, the standard error of estimate of the relations ranged from 31 to 168 percent, and the standard error of prediction ranged from 115 to 3,124 percent. Reliability and limitations of the estimating methods are described.

Updated techniques for estimating monthly streamflow-duration characteristics at ungaged and partial-record sites in central Nevada

“…For the specific monthly relations, the R 2 ranged from 0.10 to 0.94 (average 0.72), and the SEE ranged from 36 to 237 percent (average 78 percent; table 6). The accuracy of both types of regression equations developed in this study generally is comparable to those in the previous study by Hess and Bohman (1996). This study had a slight increase in SEE probably because of a wetter period of record (1995)(1996)(1997)(1998)(1999)(2000) used and a wider range in streamflow values.…”

“…Averages not available in Parrett and Cartier. In the study area, Hess and Bohman (1996) reported that for all months the R 2 for equations ranged from 0.73 to 0.92 (average 0.85) and the SEE ranged from 51 to 96 percent (average 69 percent); and for specific months the R 2 for equations ranged from 0.33 to 0.97 (average 0.83) and the SEE ranged from 31 to 168 percent (average 74 percent).…”

“…In a similar manner, mean basin altitude was determined by GIS methods using elevation data from a 1-degree digital elevation model (U.S. Geological Survey, 1995), digitally overlaying a transparent grid on the basin outline, determining the value at the grid intersections, and then averaging the readings. These methods of determining mean annual precipitation and mean basin altitude are different than those used in Hess and Bohman (1996), who used paper topographic maps and manual methods. The stream length was determined by measuring the distance in miles along the main channel from the gaging station to the basin divide.…”

“…Beginning in 1996, a need for this type of information for upland streams in central Nevada was identified and an investigation was undertaken by the U.S. Geological Survey (USGS) in cooperation with the U.S. Department of Agriculture, Forest Service (USFS), Toiyabe National Forest. An initial study was done by Hess and Bohman (1996) to determine methods for estimating monthly streamflow. Since then, an additional 4 years (1997)(1998)(1999)(2000) of streamflow data have been collected.…”

“…The purpose of these estimates was to aid in the comparison of different range management plans in the recovery of two overgrazed riparian habitats. Hess and Bohman (1996) developed techniques for estimating monthly mean streamflow at gaged sites and monthly streamflow-duration characteristics at ungaged sites in central Nevada. Streamflow records at six gaged sites for the period 1951-95 and basin physical and climatic characteristics were used to determine equations for each month and for the entire period of record.…”