USGS2000
Water budgets were developed for the 14 hydrographic areas in the middle Humboldt River Basin of north-central Nevada. The water budgets include estimates of average annual precipitation, runoff, water yield, ground-water recharge and subsurface flow, and evapotranspiration (ET) determined from recently developed or revised methods. Ground-water pumping is not included in the budget estimates. The estimated budgets represent average annual volumes over a 30-year reference period ( 1961-90) and are compared to water budgets developed more than 30 years ago. Annual inflow to the middle Humboldt River basin is about 5 million acre-feet. An estimated 4.6 million is from precipitation in the 14 hydrographic areas and about 350,000 acre-feet is inflow from the Humboldt River. Annual outflow is about 5.1 million acre-feet, of which ET accounts for 4.8 million acre-feet, and outflow of the Humboldt River is about 300,000 acre-feet. Average annual precipitation in the hydrographic areas for 1961-90 ranged from 105 to 128 percent of that for the 1912-63 period. The annual volume ofET in the 14 areas was 102 to almost 134 percent of that previously estimated, although the percentage of annual precipitation lost to ET is similar. About 15 percent of the annual precipitation in mountain-block areas becomes water yield (either ground water or runoff) as compared to previous estimates of 11 percent. On the basis of mass-balance calculations, ground-water recharge on average is about 145 percent of previous estimates.