Supplementary water supplies are needed for a rapidly growing population in southern Nevada. Groundwater resources from basin-fill and consolidated rock aquifers in southern Spring and Snake valleys in eastern Nevada have been identified as a potential water supply source. These aquifers provide water to springs, streams, wetlands, limestone caves, and other biologically sensitive areas on Federal lands in eastern Nevada, which provide habitat for numerous species of plants and animals, including one species of Federally listed endangered fish. The USDOI National Park Service (NPS), Bureau of Land Management (BLM), Fish and Wildlife Service (FWS), and USDA Forest Service (USFS) need additional geologic, hydrologic, and chemical information to assess the hydraulic connection of basin-fill and carbonate-rock aquifers with surface-water resources and water-dependent ecological features. Understanding these connections is important because pumping of groundwater in Spring Valley or Snake Valley may result in unintended capture of water currently supplying streams, springs, and wetlands in southern Snake Valley.

Objectives

The Secretary of the Interior approved funding for research to improve understanding of hydrologic systems that sustain water-dependent ecosystems on Federal lands in southern Snake Valley. The specific research objectives are to:

• Characterize the distribution, geometry, and hydraulic properties of the Cenozoic sedimentary rocks and deposits.
• Characterize streambed hydraulic conductivity and quantify the volume of water exchanged between groundwater and surface water along Lehman, Baker, and Snake Creeks.
• Determine the source of water to (a) Rowland Spring, near Lehman Caves; and (b) Big Springs, the largest spring discharge in southern Snake Valley.
• Delineate the groundwater divides and estimate the quantity of groundwater flow across the Limestone Hills, a topographic divide between the southern Spring and Snake valleys.   

Strategy and Approach

The distribution, geometry, and hydraulic properties of the Cenozoic sedimentary rocks and deposits will be evaluated by drilling new test wells, compiling data from existing wells and oil test holes, using geologic maps correlated to geophysical surveys, and visual inspection of geologic outcrops. Streambed hydraulic conductivity will be quantified along selected reaches of the Lehman, Baker, and Snake Creeks using a combination of surface (on the streambed) and subsurface (1.5 and 3 ft below the streambed) temperature measurements, stage at temporary surface-water gages, synoptic streamflow measurements (seepage runs), temperature and water-level measurements in shallow piezometers installed in the streambed, and from multiple-well aquifer tests. The source of water to Rowland Spring and Big Springs will be determined by drilling test wells upgradient of each spring, analyzing the chemical composition of water from wells, rain gages, creeks, and springs, and determine the source water to springs using geochemical mixing models. Groundwater divides will be determined by contouring water levels measured in new and existing wells in southern Spring and Snake Valleys. The volume of subsurface flow beneath the Limestone Hills will be estimated using Darcy’s Law.

Down well video

Relevance and Benefits

Results of this study will benefit the Federal bureaus, as well as Nevada and Utah State agencies, by providing relevant hydrologic data to better quantify the current hydrologic condition such that knowledgeable assessments can be determined on potential effects of ground-water withdrawals on surface streams and springs.

Public Meetings

Held periodically to update the public on the progress of this study.

Upcoming meetings:

November 4, 2009 (6:00-8:00PM) - Bristlecone Convention Center, Ely

November 5, 2009 (6:00-8:00PM) - National Park Service Great Basin Visitor Center, Baker

Past meetings

May 28, 2009 - National Park Service Great Basin Visitor Center, Baker

May 27, 2009 - Bristlecone Convention Center, Ely

October 16, 2008 - Bristlecone Convention Center, Ely

October 14, 2008 - National Park Service Great Basin Visitor Center, Baker

Related Project - Basin and Range Carbonate Aquifer System Study