Document Type

Presentation

Publication Date

8-1-2014

Abstract

In arid regions, groundwater is the most reliable source for freshwater. Thus, ensuring an aquifer’s long-term stability is one of the fundamental tasks for nowadays groundwater management. Especially in agriculturally used coastal regions, where water consumption exceeds annual recharge, water table drawdown and subsequent saline intrusion are problems that need to be addressed. Wihin the context of the government-funded research project „International Water ResearchAlliance Saxony“, groundwater quality for near-coastal, agriculturally used areas was investigated under the influence of marine saltwater intrusion. In the study region’s near-coastal areas, agricultural development increased tremendously during recent decades, while a steady lowering of the groundwater level was observed, which is primarily due to uncontrolled groundwater mining. Extracted water is mainly used for local irrigation. Intensively decreased groundwater levels, cause an inversion of the hydraulic gradient leading to intrusion of marine saltwater, endangering the productivity of farms. Utilizing the modeling software package OpenGeoSys, which is developed and enhanced by the Department of Environmental Informatics at UFZ Leipzig (Kolditz et al., 2012), a three-dimensional, density-dependent model including groundwater flow and mass transport was built up (Walther, et al., 2012a). The model comprises a heterogeneous hydro-geology (Walther et al., 2012b). A pre-development steady-state was calibrated successfully offering initial conditions for an adjacent transient calibration yielding acceptable results within apparent uncertainties of input parameters. The numerical model was used to investigate a best-case scenario assessing remediation potential of the salinized aquifer. The scenario considers ceasing groundwater abstraction and evaluates time scale and spatial distribution along the coast of the saltwater retreat. Using advanced visualization techniques in a virtual reality (Walther et al., 2013), results show a heterogeneous distribution of the saltwater withdrawal. Remediation actions will require a long-term strategy to retreive the already salinized regions of the aquifer. Results reveal valuable insight for future measurement campaings and management.

Comments

Session R18, Groundwater Flow Modeling II

 
 

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