HR: 1330h
AN: G43A-08    [Abstracts]
TI: GPS geodetic measurements of subsidence from groundwater drawdown in central Arkansas
AU: * Jansma, P
EM: pjansma@uark.edu
AF: Department of Geosciences, University of Arkansas, Fayetteville, AR 72701 United States
AU: Mattioli, G
EM: mattioli@uark.edu
AF: Department of Geosciences, University of Arkansas, Fayetteville, AR 72701 United States
AU: Marshall, A
EM: ams06@uark.edu
AF: Department of Geosciences, University of Arkansas, Fayetteville, AR 72701 United States
AU: Czarnecki, J
EM: jczarnec@usgs.gov
AF: US Geological Survey, Water Resources Division, Little Rock, AR 72211 United States
AB: The state of Arkansas ranks fifth in the nation in ground water consumption, largely fueled by its robust rice and manufacturing industries. The region centered on Lonoke, Arkansas, Jefferson and Monroe counties in the center of the state has seen dramatic drawdown of its ground-water resources and development of significant cones of depression. Subsidence of 1.5 meters over a few decades was postulated for portions of Arkansas county on the basis of elevation changes of benchmarks. These results were preliminary and measurements were not made with geodetic grade equipment. Validation of these results is the primary goal of our on-going work. We are developing an extensive network of suitable benchmarks throughout central and eastern Arkansas, whose vertical position can be monitored using high-precision Global Positioning System geodesy. Campaign GPS measurements were first obtained in summer 2003. Second epoch observations were acquired throughout 2004. Although errors are high due to the limited temporal dataset, preliminary GPS geodetic results are consistent with subsidence of the ground surface above the cones of depression on the order of tens of millimeters per year.
DE: 1243 Space geodetic surveys
DE: 1829 Groundwater hydrology
SC: Geodesy [G]
MN: 2005 Joint Assembly