Integrated cave drip monitoring for epikarst recharge estimation in a dry Mediterranean area,Sif Cave,Israel |
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Authors: | Nathan A Sheffer Moty Cohen Efrat Morin Tamir Grodek Alex Gimburg Einat Magal Haim Gvirtzman Manuela Nied Daniel Isele Amos Frumkin |
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Institution: | 1. The Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel;2. Bureau of Economic Geology, The University of Texas at Austin, Texas;3. Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel;4. The Department of Geography, The Hebrew University of Jerusalem, Jerusalem, Israel;5. Regional R&D Center, Science Park, Ariel, Israel;6. Geological Survey of Israel, 30 Malkhe Israel st., Jerusalem, 95501, Israel;7. Institute of Hydrology, University of Freiburg, Fahnenbergplatz 79098 Freiburg, Germany |
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Abstract: | Understanding recharge mechanisms and controls in karst regions is extremely important for managing water resources because of the dynamic nature of the system. The objective of this study was to evaluate water percolation through epikarst by monitoring water flow into a cave and conducting artificial irrigation and tracer experiments, at Sif Cave in Wadi Sussi, Israel from 2005 through 2007. The research is based on continuous high‐resolution direct measurements of both rainfall and water percolation in the cave chamber collected by three large PVC sheets which integrate drips from three different areas (17, 46, and 52 m2). Barrels equipped with pressure transducers record drip rate and volume for each of the three areas. The combined measured rainfall and cave data enables estimation of recharge into the epikarst and to better understand the relationship of rainfall‐recharge. Three distinct types of flow regimes were identified: (1) ‘Quick flow’ through preferential flow paths (large fractures and conduits); (2) ‘Intermediate flow’ through a secondary crack system; and (3) ‘Slow flow’ through the matrix. A threshold of ~100 mm of rain at the beginning of the rainy season is required to increase soil water content allowing later rainfall events to percolate deeper through the soil and to initiate dripping in the cave. During winter, as the soil water content rises, the lag time between a rain event and cave drip response decreases. Annual recharge (140–160 mm in different areas in the cave) measured represents 30–35% of annual rainfall (460 mm). Copyright © 2011 John Wiley & Sons, Ltd. |
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Keywords: | cave drips percolation recharge vadose karst artificial tracers epikarst |
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