Karst development of an evaporitic system and its hydrogeological implications inferred from GIS-based analysis and tracing techniques

Abstract

Abstract:The geomorphological characteristics and hydrogeological functioning of a geologically heterogeneous evaporitic karst plateau in Southern Spain were studied. Land surface information (LiDAR data) was used to analyze the shape and distribution of closed depressions. An artificial tracer test and monitoring of the natural responses of the main spring have allowed to infer the karstic development of the studied system. Three dyes were injected in selected swallow holes to trace the main groundwater flowpaths and to estimate the dimension of the conduit network. Discharge, electrical conductivity and temperature were monitored in the groundwater that drains the evaporitic plateau during an individual and intense recharge pulse. Tracing techniques were adapted to high salinity environments by using specific calibration standards (NaCl + dye). The hydrological connection detected between two of the swallow holes and the outlet, and the deduced orientation pattern for closed areas, would suggest that the karst evolution (internal and external) is related to fault orientation. The rapid tracer detection (16-20 h) and high estimated maximum flow velocities (125-192 m/h), together with the fast impulsional response of the controlled physicalchemical parameters in spring waters (~15-16 h) demonstrate the existence of quick flows under recharge conditions with well-defined system drainage, indicating a high degree of internal karstification (estimated master conduit diameter ~1.5 m). However, flooding of the depressions feeding swallow holes and analysis of the spring response times from natural and artificial tracers point to a restriction of the system´s drainage, most likely due to the constrained morphology of the karst conduits. This results in sustained recharge periods and delayed spring responses of some parameters, highlighting the relevant role of concentrated recharge in the hydrogeological behavior of the studied evaporitic karst. Gil-Márquez J.M., Barberá J.A., Mudarra M., Andreo B., Prieto-Mera J., Sánchez D., RizoDecelis L.D., Argamasilla M., Nieto J.M. and de la Torre B., 2017. Karst development of an evaporitic system and its hydrogeological implications inferred from GIS-based analysis and tracing techniques.

Comparative Analysis of Runoff and Evaporation Assessment Methods to Evaluate Wetland–Groundwater Interaction in Mediterranean Evaporitic-Karst Aquatic Ecosystem

“…Though the gross groundwater inflow to the Amarga wetland was not computed, it could be higher than the net value, as the presence of discharge pointing toward lower altitudes would enable water infiltration downflow. Additionally, locals declare to have observed water infiltration through karst swallow holes formed in the wetland side, and the hydraulic connection between nearby endorheic areas and one of the springs was proven by dye tracer tests [36].…”

“…Dissolution and karstification processes promoted the subsidence and collapse of the terrain, giving rise to closed-depression landforms. Furthermore, based on the alignment of fractures and slopes, previous research suggests that tectonics could also play an essential role in the development of karst depression [29,36].…”

Structural control on epigenic gypsum caves: evidences from Messinian evaporites (Northern Apennines, Italy)

“…Gypsum karst is widespread in many areas of the world including the US, Italy, Eastern Europe, Germany, Great Britain, Spain, the Ural area, and the Baltic States (Klimchouk et al, 1996;Calaforra, 1998;Johnson, 2002;Klimchouk, 2012;De Waele et al, 2017). In these areas, gypsum karst aquifers are important as water resources for the local communities especially where located in arid climate (Klimchouk, 1996b;Johnson, 2002;Raeisi et al, 2013;Reitman et al, 2014;Gil-Márquez et al, 2017). Furthermore, evaporitic karst is often associated with sinkholes, slumped beds, and collapse structures that are sources of engineering and environmental problems (Klimchouk, 2005;Johnson, 2008;Gutiérrez et al, 2008Gutiérrez et al, , 2014.…”