HR: 0800h
AN: H11C-1281    [Abstracts]
TI: A Comparison of Seasonal Patterns Observed in ERS 1 / 2 Differential InSAR, Groundwater Level Data, and Groundwater Production Data in Reno, Nevada, USA.
AU: * Oppliger, G L
EM: oppliger@mines.unr.edu
AF: University of Nevada, Reno, Dept. Geological Sciences and Engineering /MS172, Reno, NV 89557-0138 United States
AU: Goudy, C
EM: cheryl@cherylgoudy.com
AF: University of Nevada, Reno, Dept. Geological Sciences and Engineering /MS172, Reno, NV 89557-0138 United States
AU: Widmer, M
EM: MWidmer@MAIL.co.washoe.nv.us
AF: Washoe County Dept of Water Resources, 4930 Energy Way, Reno, NV 89502 United States
AB: We report on a comparison of repeating seasonal patterns observed in ERS 1 / 2 differential InSAR, (D-InSAR) groundwater level (GWL) data, and water production volume data in Reno, Nevada, USA. Over the 1992-2002 study period we found municipal groundwater utilization in the Reno study area was associated with centimeter and sub-centimeter surface elevation changes which are distributed over aquifer related zones several kilometers in width. In the central Reno area observations define two active anomaly areas which show cyclical surface deflation and inflation with elevation changes of 10 to 30 millimeters over one to nine years. Seasonal groundwater level change associated with these D-InSAR features ranged between 0.3 and 3 meters. Some D-InSAR pattern perimeters are localized by geologic structure while others are more mobile. Most surface deflation appears to be periodically restored by natural and managed aquifer recharge. The area's of active surface inflation-deflation nominally correspond with the area's most significantly utilized groundwater aquifers. To evaluate evidence for the direct relation between D-InSAR and groundwater production in the study area, comparisons between 1992-2002 groundwater levels, production rates and D-InSAR surface inflation-deflation features were developed. Groundwater level change maps showed good direct correlations with D-InSAR observations only in areas where the GWL changes were relatively large (~10 meters), spatially uniform and sustained over several years. Several factors probably contribute to the weak correlation of many GWL's and D-InSAR features including: incomplete GWL coverages, GWL monitoring data representing different aquifer horizons, proximity to production wells, delayed development of aquifer volume change when water levels are altered, and lateral change in aquifer composition. Consistency of the D-InSAR features suggests atmospheric artifacts were not the source of the discrepancies. Some of the spatial and temporal aliasing issues associated with estimating seasonal GWL dynamics from incomplete coverages were overcome by merging several years of seasonal groundwater level change data into a surface representing average seasonal GWL change. This average change surface proved significantly more robust than any of the individual GWL time differences, and showed the maximum zone of seasonal GWL change was offset 1 km and 2 km, from the groundwater production centroid and the maximum D-InSAR surface change, respectively. Although the spatial relations between these features are not one-to-one, the consistency of the results suggest that it may be possible to map D-InSAR observations to approximate changes in groundwater levels in the Reno study area.
DE: 1829 Groundwater hydrology
DE: 1855 Remote sensing (1640)
DE: 1880 Water management (6334)
SC: Hydrology [H]
MN: Fall Meeting 2005