Linking geomorphology and hydrodynamics: a case study from Península Valdés, Patagonia, Argentina

A case study is presented to assess the relevance of geomorphology in hydrogeological phenomena in an arid coastal area in the Argentinean extra-Andean Patagonia (Península Valdés) with an average rainfall of 232 mm/year and a soil moisture deficit of about 472 mm/year. Various geomorphic units were identified by interpreting Landsat 7 satellite images processed with ER Mapper software and then surveyed in the field, as well as by geological characterization. The hydrodynamic analysis was based on a survey of 89 wells, the construction of equipotential maps, and the interpretation of pumping-test results by a non-equilibrium method. The hydrochemical characterization was based on chemical tests analyzed with the Easy_Quim 6.0 application. The combination of geomorphological, geological, hydrodynamic and hydrochemical elements allowed the definition of hydromorphological units that are typical of recharge, circulation and discharge areas, the latter both for coastal and inland areas in wetlands (salt pans) with elevations to −40 m relative to sea level. These units and the criteria used for their definition allow immediate recognition of hydrogeological phenomena in arid regions such as the extra-Andean Patagonia, with low information density but with near-optimal satellite imaging of landforms due to the lack of vegetation cover.