Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-28
Total Federal Funds: $23,965 Total Non-Federal Funds: $47,890
Principal Investigators: Rina Schumer
Abstract: In 2012, the Nevada state engineer approved annual withdrawals of 61,127 acre feet of groundwater from Spring Valley, 5,235 acre feet from Cave Valley, 11,584 acre feet from Dry Lake Valley and 6,042 acre feet from Delamar Valley in Lincoln and White Pine Counties for transfer to the Las Vegas water system. Changes in near-surface mass from groundwater withdrawal has affected fault motion and seismicity in other regions. What magnitude of groundwater withdrawal and reduction of pore pressure within large capture zones in eastern Nevada basins is sufficient to modify the crustal stress field, affect basin faults, and possibly induce seismicity? How does this compare with proposed withdrawal rates? An analytical model for two dimensional elastic deformation from a normal line load distributed over a finite-width strip on the surface of a half space will be used to relate vertical displacement of a fault to reduced groundwater volume. Data from regional geologic studies will be used to relate stress changes to fault failure in Eastern Nevada. Also, previous groundwater modelling studies will be used to estimate the order of magnitude of overburden mass loss in Spring Valley under a variety of pumping scenarios. These estimates will be compared with mass-unloading necessary to modulate seismicity in Spring Valley.