This study is designed to characterize baseline conditions of the hydrology within the BRNCA. Collecting baseline precipitation, spring flow, and water-level data is the initial step for determining how ecosystems in the BRNCA may respond to future hydrologic change. These baseline conditions will be the standard against which effects of climate change and potential groundwater development will be compared. Hydrologic data collected as part of characterizing baseline conditions will be used to support concurrent ecological studies of perennial springs within the BRNCA by DRI.

Research plan

The study will be completed over a 2 ½-year period and will collecte the following data:

• Precipitation: Measure type, timing and quantity of precipitation at precipitation gages near the ridgeline of the Calico Mountains.
• Springs: Conduct a field inventory of perennial springs to select springs suitable for DRI’s ecological studies. Make miscellaneous discharge measurements at as many of these springs as possible. Evaluate spring sites for installation of partial flumes and monitor springs on a bimonthly basis.
• Groundwater: Complete a well inventory and measure water levels at most of the 95 wells with data in NWIS. Measure a representative subset of wells on a quarterly basis. Measure wells influenced by nearby pumping in the spring and fall immediately before and after the irrigation season. Construct hydrographs to compare the spatial and temporal groundwater-level fluctuations to assess if they are influenced by regional of climatic influences or by groundwater withdrawals.

Background

The BRNCA lies within the center of the Black Rock Desert flow system (Harrill and others, 1988), a large hydrographic region of more than 9,000 square miles in northwest Nevada. NCAs are designated by Congress to conserve, protect, enhance, and manage public lands for the benefit and enjoyment of present and future generations. BLM has the responsibility of managing NCAs. The BRNCA consists largely of arid landscapes, including playas and rugged mountains that provide habitat for wildlife and native vegetation. A critical component of this habitat is the fauna and aquatic ecosystems that are sustained by groundwater discharge at perennial springs.

An important role for the USGS climate change science is the measuring of and describing the hydrologic changes that are currently underway. Unfortunately, minimal historical hydrologic data are available for the BRNCA; most data are from the 1960s-era reconnaissance reports. Therefore, is it critical to initiate a program designed to collect baseline precipitation, spring flow and groundwater-level data. Spring flows can fluctuate in response to climatic conditions and nearby groundwater pumping. Springs are points of focused discharge from groundwater systems thus an improved understanding of the groundwater-flow system is needed to determine what effects climate change and groundwater development may have on the water-dependent ecosystems in the BRNCA.