Application of Remote Sensing and Geoelectric Methods in Groundwater Exploration in Karst Areas of Southern Kuhdasht, Lorestan

Document Type : Research paper

Authors

1 MSc of Hydrogeology, Shahid Beheshti University

2 Assistant Professor of Earth Sciences, Shahid Beheshti University,

3 Professor of Earth Sciences, Shahid Beheshti University

Abstract

Remote sensing and GIS were used to map karstic groundwater potential (GWP) in the south of Kuhdasht, Lorestan Province, by integration of twelve factors affecting groundwater potential.The required layers were prepared using the satellite imagery Bing Map, the Digital Elevation Modeland the digitized maps. These layers were reclassified as criterion maps based on the contribution of each factor on the groundwater potential. Then the criterion maps were integrated using the Analytical Hierarchy Process (AHP) in a GIS environment. The groundwater potential maps of the region were prepared using a weighted overlay index method. The resulting thematic map was validated using the yield and specific discharge of the karst water wells in the area of the discharge and, then, 178 vertical geoelectrical soundings (VES) of Schlumberger array with AB = 1000 m, in Zaruni and Parian, were used to verify the GWP map. Based on the results of one -two dimensional inverse modeling of resistivity data, a high potential karst reservoir was detected in direction of the axis of Zaruni syncline in Asmari formation, so by greater distance from the axis to the limbs the water storage in the karst was decreased. The results showed that the circulation of infiltrated water through the dense joints and fractures in the syncline axis produced preferential groundwater flow in the joints, followed by karst development and formation of cavities and dissolution channels in the karst aquifer of Asmari formation. The results of this study also showed that the syncline axis factor had the greatest impact on the GWP of karst aquifer. Coincidence of high GWP areas by resistivity sounding data and water yield of wells indicated that the thematic map had a good accuracy.

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