title: Small-Scale ASR Between Flow Barriers in a Saline Aquifer.
abstract: Regular aquifer storage recovery, ASR, is often not feasible for small-scale storage in brackish or saline aquifers because fresh water floats to the top of the aquifer where it is unrecoverable. Flow barriers that partially penetrate a brackish or saline aquifer prevent a stored volume of fresh water from expanding sideways, thus increasing the recovery efficiency. In this paper, the groundwater flow and mixing is studied during injection, storage, and recovery of fresh water in a brackish or saline aquifer in a flow-tank experiment and by numerical modeling to investigate the effect of density difference, hydraulic conductivity, pumping rate, cyclic operation, and flow barrier settings. Two injection and recovery methods are investigated: constant flux and constant head. Fresh water recovery rates on the order of 65% in the first cycle climbing to as much as 90% in the following cycles were achievable for the studied configurations with constant flux whereas the recovery efficiency was somewhat lower for constant head. The spatial variation in flow velocity over the width of the storage zone influences the recovery efficiency, because it induces leakage of fresh water underneath the barriers during injection and upconing of salt water during recovery.
authors.affiliation: Royal Haskoning DHV, P.O. Box 8520, 3009 AM Rotterdam, the Netherlands.
authors.forename: Marloes
authors.initials: M
authors.lastname: van Ginkel
authors.affiliation: Faculty of Civil Engineering and Geosciences, Water Resources Section, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, the Netherlands.
authors.forename: Bas
authors.initials: B
authors.lastname: des Tombe
authors.affiliation: Faculty of Civil Engineering and Geosciences, Water Resources Section, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, the Netherlands.|Waternet, P.O. Box 94370, 1090 GJ Amsterdam, the Netherlands.
authors.forename: Theo
authors.initials: T
authors.lastname: Olsthoorn
authors.affiliation: Faculty of Civil Engineering and Geosciences, Water Resources Section, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, the Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: Bakker
mesh_terms: D005618:Fresh Water; D060587:Groundwater; D014872:Water Movements; D014881:Water Supply