GPS DETERMINATION OF GROUNDWATER WITHDRAWAL SUBSIDENCE

GPS (Global Positioning Systems) surveys were performed in 1984 and 1985 along two level lines in southeast Arizona to evaluate the accuracy with which GPS could be used to determine subsidence by (1) comparing repeat GPS determinations of ellipsoidal heights; and (2) by comparing orthometric heights derived from GPS ellipsoid heights with orthometric heights obtained from leveling. The details of this study are described. The study showed that repeat GPS measurements can be used to monitor current and future vertical motions in subsiding areas at the plus or minus 2-3 accuracy level. The accuracy with which GPS, combined with existing leveling, can give information on past subsidence depends upon the accuracy of geoid heights available for converting GPS results to orthometric heights.

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  • Accession Number: 00485136
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 30 1989 12:00AM