USGS SIR 2005-5247 Hydrogeology and Water Resources of Ruby Valley, Northeastern Nevada

Hydrogeology and Water Resources of Ruby Valley, Northeastern Nevada

By David L. Berger

Report availability: Portable Document Format (PDF).

Abstract

Ruby Valley is a topographically closed, relatively undeveloped basin in northeastern Nevada that is experiencing slow but steady rural development. In 1999 the U.S. Geological Survey, in cooperation with the Nevada Division of Water Resources and the U.S. Fish and Wildlife Service, began a phased evaluation of the water resources in Ruby Valley. Phase 1 was completed in 2001 and provides evapotranspiration data from wetland habitats within the Ruby Lake National Wildlife Refuge. Phase 2 of the evaluation, presented in this report, was designed to provide information on the water resources of the entire Ruby Valley Hydrographic Area, including an updated water budget.

The distribution of precipitation in Ruby Valley, derived from four estimates, range from 700,000 acre-ft/yr (acre-feet per year) developed from the Hardman precipitation map of Nevada to 910,000 acre-ft/yr based on a relation among annual precipitation, altitude, and location developed for this study. Predictions based on the Hardman precipitation map estimates about 25 to 31 percent less precipitation than the other estimates. Most of the differences in total precipitation are related to differences in climatic conditions during the period of estimated precipitation. Annual runoff generated in the mountain blocks that border Ruby Valley ranges from about 82,000 to 100,000 acre-ft/yr. The Ruby Mountains and East Humboldt Range generate about 80 percent of the total runoff.

The depth to ground water in basin-fill deposits during the spring of 2003 ranged from less than 5 feet along the margins of Ruby Lake to more than 200 ft beneath the alluvial slope in the northeast part of the valley. During the 4-year period from 2000 to 2003 water levels generally declined over much of the study area due to below average precipitation. Average ground-water recharge from precipitation is about 100,000 acre-ft/yr, based on basin-scale reconnaissance level methods. Water samples were collected from 16 wells and 11 springs in and near Ruby Valley and analyzed for major ions, nutrients, and stable-isotopic composition. No primary drinking-water standards were exceeded for any of the constituents that were analyzed. Secondary drinking-water standards were exceeded for manganese, sulfate, iron, dissolved solids, and pH at three wells. Most of the water sampled is a calcium-bicarbonate type.

Total annual inflow to Ruby Valley ranges from about 710,000 to 930,000 acre-ft/yr. Precipitation makes up the largest inflow component. Subsurface inflow, from Huntington and Northern Butte Valleys, represent less than 2 percent of the total inflow. Estimates of total annual outflow range from 780,000 to 870,000 acre-ft/yr. Evapotranspiration (ET) represents the largest outflow and is subdivided into areas of the mountain block, alluvial slope, and valley floor. ET from mountain-block areas that border Ruby Valley is about 270,000 acre-ft/yr based on mass-balance calculations. Estimates of ET on alluvial slopes, where the only source of water is soil moisture from precipitation and infiltrated streamflow, is about 180,000 acre-ft/yr. Total ET on the Ruby Valley floor in 2001 ranges from about 330,000 to 420,000 acre-ft/yr and is comprised from five different land-cover types. Subsurface outflow represents less than 1 percent of the outflow from Ruby Valley and takes place northeastward toward Clover Valley and possibly southwestward toward Long Valley.

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