USGS: Groundwater Influences Key to Sustainable Water Supply

White Pine County, Nev., is a critical recharge area for several major regional flow systems that extend north to the Great Salt Lake and south to the Colorado River, according to the U.S. Geological Survey study, "Water resources of the Basin and Range carbonate-rock aquifer system, White Pine County, Nevada, and adjacent areas in Nevada and Utah."

The groundwater systems underlying many of the valleys in eastern Nevada and western Utah are not isolated but rather contribute or receive flow from adjoining basins. Some large-volume springs cannot be supported entirely by the local recharge from the adjacent mountains and depend on water from potentially hundreds of miles away. The imbalance between recharge and discharge within a basin is an important factor in making decisions that could affect water sustainability in surrounding areas.

This report is the final product of the Basin and Range carbonate-rock aquifer system study ordered by Congress in the Lincoln County Conservation, Recreation, and Development Act of 2004. The report was prepared in collaboration with the Desert Research Institute and the state of Utah, and in cooperation with the Bureau of Land Management.

The USGS study included a water-resources assessment that analyzed the geologic framework and hydrologic processes influencing the quantity and quality of groundwater resources. This information is critical for water-resource agencies to make informed decisions about future water-supply issues. Understanding the factors that influence flows from the aquifer system is necessary in evaluating how future groundwater development may affect discharge, ecosystems, and water supplies. Knowing what factors influence the quantity and quality of groundwater resources is essential when developing management plans for a sustainable water resource.

The study designates basin and regional groundwater "budgets," for 13 hydrographic areas and the entire study area in White Pine County, Nev. Water budgets enable an accounting of water as it moves through Earth's atmosphere, land surface, and subsurface. In order to do this, scientists from the USGS and the Desert Research Institute studied the hydrogeology, recharge and discharge, groundwater flow and geochemistry of the aquifer system.

The study-wide average annual groundwater recharge exceeded annual discharge by about 90,000 acre-feet. Most of this groundwater surplus exits the study area through Snake Valley to the northeast or White River Valley to the south. Annual recharge exceeded discharge in Steptoe Valley by 53,000 acre-feet, and a significant amount of groundwater flows from this valley to adjacent areas such as Jakes and White River Valleys to the west and Spring and Lake Valleys to the east. Annual discharge exceeded recharge in White River Valley by 41,000 acre-feet, and a significant amount of groundwater flows into this valley from adjacent areas, such as Jakes, Steptoe, and Cave valleys.

Groundwater flows through three types of aquifers in White Pine County: a shallow basin-fill aquifer, a deeper volcanic-rock aquifer, and an underlying carbonate-rock aquifer. The basin-fill aquifer is the principal source of domestic and agricultural water supply, which is safe for human consumption.



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