Polyak et al. (Reports, 7 March 2008, p. 1377) reported speleothem data leading to their inference that the western Grand Canyon incised much earlier than previously thought. This contradicts several lines of published geological knowledge in the region, hinges upon unjustified hydrogeological assumptions, and is based on two anomalous data points for which we offer alternative explanations.

The primary objective of the current study is to produce karstification potentiality maps in northeast of Khuzestan province, Iran, using both fuzzy logic and AHP models as an additional tool in hydrogeological research. Geographic Information Systems (GIS) and Remote Sensing (RS) are used to create two maps depicting the development of the karstification, consisting of five classes, showing th...

Groundwater resources from karst aquifers play a major role in the water supply in karst areas in the world, such as in Switzerland. Defining groundwater protection zones in karst environment is frequently not founded on a solid hydrogeological basis. Protection zones are often inadequate and as a result they may be ineffective. In order to improve this situation, the Federal Office for Environ...

Modeling an aquifer provides significant advantages when evaluating and estimating the water resource for its sustainable use. This study focuses on rural parish Manglaralto, a semi-arid area with shortage of water, without supply service by public network. Still, it has great demand local floating population (tourism). caused coastal aquifer, which supplies area’s to show signs overexploitatio...

Similarities in both water and electric current flows allow the relation of hydraulic geoelectric parameters porous aquifers. Based on this assumption importance for groundwater analyses, study aimed to estimate conductivity (K) transmissivity (T) with vertical electrical sounding (VES) aquifer at experimental farm University Brasilia, Brazil. VES is a geophysical technique that provides resist...

Deep porous reservoirs are subject to charge and discharge of fluids (oil, gas or water), either naturally or induced by human exploitation. This leads to a variation in pressure inside the reservoir and consequently to a deformation of the overlying material. The knowledge of the ground surface displacements allows inferring the fluid migrations and the hydromechanical properties in the porous...

Based on geophysical, geological and geochemical investigations carried out in the last decade, we reviewed three major geothermal plays that well represent different structural, volcanological hydrogeological realms can be encountered East African Rift System (EARS). Alalobeda (Ethiopia) Menengai (Kenya) are examples of typical Eastern Branch EARS. The former is a fault-leakage-controlled play...

The relevance of research, diagnostics and study natural technical objects belonging to I–II hazard classes is shown. Methodological approaches the application interdisciplinary methods for a complex observations observation such are proposed: visual photodocumentation, geophysical survey, hydrological measurements, geomechanics methods, satellite geodesy, digital photography using UAVs, remote...

Little Kinyasungwe River Catchment, central semi-arid Tanzania. The structure and hydraulic properties of superficial geology can play a crucial role in controlling groundwater recharge drylands. However, the pathways by which occurs their sensitivity to environmental change remain poorly resolved. Geophysical surveys using Electrical Resistivity Tomography (ERT) were conducted study region use...