The GWE Program's Water Resource Sustainability work includes two cooperative studies with the U.S. Geological Survey (USGS) Nevada Water Science Center:   

 

Evapotranspiration (ET) Study

• ET definition

• Perennial yield in the Amargosa Desert hydrographic area may have been underestimated by as much as 28,000 acre-feet in previous USGS studies

• Evaluate ET rate over bare soils where depth to water is less than 50 feet

• Study will be 3-5 years, depending on ET rates determined in the first year of data collection

Southern Amargosa eMbedded Model (SAMM)    

• "Daughter model" to Death Valley Regional Flow System Model will allow evaluation of pumping scenarios at fine scale in the Amargosa / Ash Meadows area

• Grid size in the Death Valley regional flow system model is 1,500 x 1,500 meters; grid size in SAMM is 500 x 500 meters

• In the figure (upper right), the Death Valley regional flow system model boundary (green line) and boundary for SAMM (black line) are shown.  Proposed renewable energy developments, as of April 2009, are shown in magenta. [Figure from Belcher and Bright, 2009].

BACKGROUND

 

 

Evapotranspiration (ET) Study: Numerous studies by the USGS have been conducted to estimate groundwater recharge and discharge in the Death Valley regional groundwater flow system.  These estimates assume that springs and seeps contribute only minimally to groundwater discharge, and that the ET rate from unclassified areas and non-vegetated areas are negligible.  Nye County contends that significant discharge does occur in these areas where the depth to water is less than 50 feet (these areas total approximately 90,000 acres).  Depending on the groundwater discharge rate applied, as much as 28,000 acre-feet of discharge may have been overlooked in the previous studies.  To address Nye County's concerns, a 5-year study has been proposed by the USGS to characterize groundwater discharge in the areas identified by Nye County as having significant groundwater discharge.

 

SAMM: The SAMM is a groundwater flow model constructed by the USGS that is a "daughter model" of the much larger Death Valley regional groundwater flow system model developed cooperatively by the Yucca Mountain Project and National Nuclear Security Administration 9NNSA).  The SAMM will rely on inputs from the regional model and refines the geologic and hydrologic grids (over a small area) to simulate groundwater flow and the effects of geologic structures more accurately than possible with the regional model.  Funding for the SAMM, as well as the data used to construct the model is derived from multiple sources, including the USGS, Nye County, the USF&WS, NPS, DOE and BLM.  The model will serve as a common tool for these agencies, and others, to simulate the potential effects of pumping groundwater under various scenarios.

 

 

 

 SPECIFIC TASKS

 

• Recharge Evaluation.  This study will consist of 1 - 3 years of direct measurement of ET losses from areas of shallow groundwater.  After the initial year of data collection the study may be terminated if the ET rates are found to be very low (implying very limited groundwater discharge).
   

• Perennial Yield Evaluation. This task is complete. Results are documented in Parks, 2010 thesis titled: "Analysis of Electromagnetic and Seismic Geophysical Methods for Investigating Shallow Sub-surface Hydrogeology" 
   

• Impact Evaluation.  Development of a finer-scale model domain for the embedded model, including Ash Meadows, Amargosa Farms area, Devils Hole, and Stewart Valley; linking the embedded and regional models; and tandem calibration of the shared model domains.