| Title |
Isotopenhydrologische Methoden (2H, 18O) zur Bestimmung der Grundwasserneubildung in Trockengebieten: Potenzial und Grenzen |
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| Author |
Beyer M, Gaj M, Koeniger P, Hamutoko JT, Wanke H, Wallner M & Himmelsbach T |
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| Abstract |
The estimation of groundwater recharge in water-limited environments is challenging due to climatic conditions, the occurrence of deep unsaturated zones, and specialized vegetation. We critically examined two methods based on stable isotopes of soil water: (i) the interpretation of natural isotope depth-profiles and subsequent approximation of recharge using empirical relationships and (ii) the use of deuterium-enriched water (2H2O) as tracer. Numerous depth-profiles were measured directly in the field in semiarid Namibia using a novel in-situ technique. Additionally, 2H2O was injected into the soil and its displacement over a complete rainy season monitored. Estimated recharge ranges between 0 and 29 mm/y for three rainy seasons experiencing seasonal rainfall of 660 mm (2013/14), 313 mm (2014/15) and 535 mm (2015/16). The results of this study fortify the suitability of water stable isotope-based approaches for recharge estimation and highlight enormous potential for future studies of water vapor transport and ecohydrological processes. |
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