Speculation on the resilience of karst aquifers using geophysical and GIS-based approaches (a case study of Iran)

摘要

Employing the "resilience" term to groundwater is a formidable challenge. The situation is even more intricate for the karst aquifers which may act as surface water with low resilience, alluvial groundwater with high resilience, and a combination of both. The objective of this study is to assess the groundwater resilience and hydrogeophysical characteristics of Asmari and Ilam-Sarvak formations at Susan karst, south-west Iran. Hence, 260 vertical electrical soundings (VESs) were carried out with the Schlumberger array. The VES curves were interpreted, scored, and interpolated to produce a groundwater potential map. Moreover, a geographic information system (GIS)-based approach was employed, including six layers, i.e. distance to springs, elevation difference from springs, slope, lithology, fracture density, and fracture length density. The GIS criterial maps were generated, reclassified, weighted, and overlaid, such that a supplementary groundwater potential map was produced. The electrical resistivity values and degrees of smoothness of the VES curves depicted considerable groundwater potential for the Asmari formation. However, the groundwater potential of the Ilam-Sarvak formation may be attributed to the superficial fractured zones. On the other hand, the geospatial technology which is based on the surface indices represented enormous groundwater potential for both formations, especially for the Ilam-Sarvak formation. Finally, regarding the groundwater resilience, various hydrological characteristics occur for two karst formations in a small-scale region. The Ilam-Sarvak formation primarily behaves like the surface water with low resilience (conduit flow, low storage), and the Asmari formation portrays the features of the alluvial aquifers with high resilience (diffuse flow, large storage).