HR: 1340h
AN: H23A-1107    [Abstracts]
TI: Gravity Monitoring of the Weber River Aquifer Storage Project
AU: * Gettings, P
EM: gettings@mines.utah.edu
AF: University of Utah, 135 South 1460 East, Salt Lake City, UT 84112 United States
AU: Hurlow, H
EM: hughhurlow@utah.gov
AF: Utah Geological Survey, 1594 West North Temple, Salt Lake City, UT 84114 United States
AU: Chapman, D S
EM: dchapman@mines.utah.edu
AF: University of Utah, 135 South 1460 East, Salt Lake City, UT 84112 United States
AU: Harris, R N
EM: rnharris@mines.utah.edu
AF: University of Utah, 135 South 1460 East, Salt Lake City, UT 84112 United States
AB: Repeated precision gravity measurements provide an economical way to track aquifer storage changes through time. In early 2004, the Weber River Water Conservancy District in northern Utah began an aquifer storage and recovery pilot project by infiltrating river water into a depleted aquifer. We are tracking the infiltrated water by measuring gravity changes over the aquifer through time. A network of 28 stations around the infiltration location was established, with an additional station in the nearby mountains for a stable reference. Gravity surveys are conducted at approximately two week intervals; monthly rapid-static GPS campaigns monitor ground deformation across the network. Gravity monitoring commenced in Feburary 2004, to establish a baseline before infiltration and investigate the magnitudes of natural signals and measurment noise. Infiltration commenced six weeks after the start of monitoring and by early July 2004, nearly 750 000 m$^3$ of water were infiltrated; gravity changes at the infiltration site reached a peak of $\sim$100 $\mu$Gal. Gaussian integration of the peak gravity signal is consistent with the total volume of infiltrated water. Continued monitoring during infiltration tracked the horizontal migration of infiltration water south and west of the site, consistent with known hydraulic gradients. Infiltration ended in July 2004 and gravity measurements show a declining recharge mound, with the peak decreasing to $\sim$60 $\mu$Gal one month later. The spatial and temporal changes in gravity will be used to refine and enhance reservoir modeling around the infiltration site.
UR: http://thermal.gg.utah.edu/$\sim$gettings
DE: 1803 Anthropogenic effects
DE: 1829 Groundwater hydrology
DE: 1894 Instruments and techniques
DE: 1294 Instruments and techniques
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting