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Thermographic Data Analyses for Karst WatershedsAerial thermography is an emerging technology unsurpassed for locating groundwater discharges. Thermography can be used to locate submerged discharges that are extremely difficult to find by other means. In two large projects, thermography was used to identify almost every significant spring at sites underlain by karst aquifers. This technology effectively converts Brown's Type 5 topology to types 1 or 2 (all discharges known), which has a significant impact on dye tracing. At a north Alabama site, springs located by thermography quadrupled the known groundwater discharge in and around the site. For submerged discharges, thermographic temperatures can be measured down the center of the groundwater plume that rises to the surface in the winter. Using the Cornell Mixing (CORMIX) model, flow rate for one submerged spring was estimated. Once identified, estimates of spring recharge area were desired. The size of the area of recharge was estimated by hydrograph separation of flow data from nearby, unregulated surface streams. Monthly recharge estimates were also made and used to show that in north Alabama the mean annual recharge/discharge occurs during May and December. Spring flow measurements for the same county of north Alabama were averaged to obtain mean flows. Then measurements for May only, were averaged. The two averages usually agreed to within 20 percent. This provides evidence that hydrograph separation determinations of recharge are valid.
Document ID
20000110581
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Campbell, C. Warren
(Alabama Univ. Huntsville, AL United States)
McCaleb, Rebecca C.
Date Acquired
August 19, 2013
Publication Date
January 1, 2001
Subject Category
Earth Resources And Remote Sensing
Meeting Information
Meeting: Sinkholes and Engine Environmental Impact of karst
Location: Louisville, KY
Country: United States
Start Date: April 1, 2001
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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