Preliminary Results, Helicopter ic and ic….doc

i In Cooperation with the Edwards Aquifer Authority Helicopter ic and ic Survey Data and Maps, Seco Creek Area, Medina and Uvalde Counties, Texas By Bruce D. Smith, David V. Smith, Patricia L. Hill, and Victor F. Labson This report is preliminary and has not been reviewed for conformity with . Geological Survey editorial standards or with North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not constitute endorsement by the . Government. Open-File Report 03-226 . DEPARTMENT OF THE INTERIOR . GEOLOGICAL SURVEY ii Table of Contents Abstract..........................................................................................................................ii Introduction....................................................................................................................1 Geologic Setting.............................................................................................................3 Hydrologic Setting..........................................................................................................6 Helicopter Geophysical Survey......................................................................................6 Apparent Resistivity Maps.................................................................................7 Digital Data.........................................................................................................9 Conclusions...................................................................................................................10 Appendix ……………………………………………………………………………...12 ii Abstract A helicopter ic and ic (HEM) survey pleted ofa 209 square kilometer (81 square miles) area of the central Edwards aquifer. This open-file report isa release of the airborne geophysical data and a summary of the hydrologic application. The survey area was centered on the Valdina Farms sinkhole along the Seco Creek drainage in western Medina