You have already added 0 works in your ORCID record related to the merged Research product.
You have already added 0 works in your ORCID record related to the merged Research product.
Consequences and mitigation of saltwater intrusion induced by short-circuiting during aquifer storage and recovery in a coastal subsurface
Consequences and mitigation of saltwater intrusion induced by short-circuiting during aquifer storage and recovery in a coastal subsurface
Coastal aquifers and the deeper subsurface are increasingly exploited. The accompanying perforation of the subsurface for those purposes has increased the risk of short-circuiting of originally separated aquifers. This study shows how this short-circuiting negatively impacts the freshwater recovery efficiency (RE) during aquifer storage and recovery (ASR) in coastal aquifers. ASR was applied in a shallow saltwater aquifer overlying a deeper, confined saltwater aquifer, which was targeted for seasonal aquifer thermal energy storage (ATES). Although both aquifers were considered properly separated (i.e., a continuous clay layer prevented rapid groundwater flow between both aquifers), intrusion of deeper saltwater into the shallower aquifer quickly terminated the freshwater recovery. The presumable pathway was a nearby ATES borehole. This finding was supported by field measurements, hydrochemical analyses, and variable-density solute transport modeling (SEAWAT version 4; Langevin et al., 2007). The potentially rapid short-circuiting during storage and recovery can reduce the RE of ASR to null. When limited mixing with ambient groundwater is allowed, a linear RE decrease by short-circuiting with increasing distance from the ASR well within the radius of the injected ASR bubble was observed. Interception of deep short-circuiting water can mitigate the observed RE decrease, although complete compensation of the RE decrease will generally be unattainable. Brackish water upconing from the underlying aquitard towards the shallow recovery wells of the ASR system with multiple partially penetrating wells (MPPW-ASR) was observed. This leakage may lead to a lower recovery efficiency than based on current ASR performance estimations.
- Technical University Delft Netherlands
- KWR Watercycle Research Institute Netherlands
- KWR WATER B.V. Netherlands
4315
Bakker, M.: Radial Dupuit interface flow to assess the aquifer storage and recovery potential of saltwater aquifers, Hydrogeol. J., 18, 107-115, 2010.
Bakr, M., van Oostrom, N., and Sommer, W.: Efficiency of and interference among multiple Aquifer Thermal Energy Storage systems, A Dutch case study, Renew. Energ., 60, 53-62, 2013.
Bibby, R.: Mass transport of solutes in dual-porosity media, Water Resour. Res., 17, 1075-1081, 1981. [OpenAIRE]
Bonte, M., Stuyfzand, P. J., Hulsmann, A., and Van Beelen, P.: Underground Thermal Energy Storage: Environmental Risks and Policy Developments in the Netherlands and European Union, Ecology and Society, 16, 2011a. [OpenAIRE]
Bonte, M., Stuyfzand, P. J., Van den Berg, G. A., and Hijnen, W. A. M.: Effects of aquifer thermal energy storage on groundwater quality and the consequences for drinking water production: a case study from the Netherlands, Water Sci. Technol., 63, 1922- 1931, 2011b. [OpenAIRE]
Bonte, M., van Breukelen, B. M., and Stuyfzand, P. J.: Temperatureinduced impacts on groundwater quality and arsenic mobility in anoxic aquifer sediments used for both drinking water and shallow geothermal energy production, Water Res., 47, 5088-5100, 2013. [OpenAIRE]
CBS: Hernieuwbare energie in Nederland 2012, CBS, available at: www.cbs.nl, last access: 24 November 2013.
Chesnaux, R.: Uncontrolled Drilling: Exposing a Global Threat to Groundwater Sustainability, Journal of Water Resource and Protection, 4, 746-749, 2012. [OpenAIRE]
Chesnaux, R. and Chapuis, R.: Detecting and quantifying leakage through defective borehole seals: a new methodology and laboratory verification, Geotech. Test. J., 30, 1-7, 2007.
Chesnaux, R., Rafini, S., and Elliott, A.-P.: A numerical investigation to illustrate the consequences of hydraulic connections between granular and fractured-rock aquifers, Hydrogeol. J., 20, 1669-1680, 2012.
- Technical University Delft Netherlands
- KWR Watercycle Research Institute Netherlands
- KWR WATER B.V. Netherlands
Coastal aquifers and the deeper subsurface are increasingly exploited. The accompanying perforation of the subsurface for those purposes has increased the risk of short-circuiting of originally separated aquifers. This study shows how this short-circuiting negatively impacts the freshwater recovery efficiency (RE) during aquifer storage and recovery (ASR) in coastal aquifers. ASR was applied in a shallow saltwater aquifer overlying a deeper, confined saltwater aquifer, which was targeted for seasonal aquifer thermal energy storage (ATES). Although both aquifers were considered properly separated (i.e., a continuous clay layer prevented rapid groundwater flow between both aquifers), intrusion of deeper saltwater into the shallower aquifer quickly terminated the freshwater recovery. The presumable pathway was a nearby ATES borehole. This finding was supported by field measurements, hydrochemical analyses, and variable-density solute transport modeling (SEAWAT version 4; Langevin et al., 2007). The potentially rapid short-circuiting during storage and recovery can reduce the RE of ASR to null. When limited mixing with ambient groundwater is allowed, a linear RE decrease by short-circuiting with increasing distance from the ASR well within the radius of the injected ASR bubble was observed. Interception of deep short-circuiting water can mitigate the observed RE decrease, although complete compensation of the RE decrease will generally be unattainable. Brackish water upconing from the underlying aquitard towards the shallow recovery wells of the ASR system with multiple partially penetrating wells (MPPW-ASR) was observed. This leakage may lead to a lower recovery efficiency than based on current ASR performance estimations.