How subsurface water technologies (SWT) can provide robust, effective and cost-efficient solutions for freshwater management in coastal zones

“Freshwater resources in coastal zones are limited while demands are high,
resulting in problems like seasonal water shortage, overexploitation of freshwater aquifers,
and seawater intrusion. Three subsurface water technologies (SWT) that can provide
robust, effective, and cost-efficient solutions to manage freshwater resources in the
subsurface are evaluated using groundwater modelling and validation at field-scale: (1)
ASR-coastal to store freshwater surpluses in confined brackish-saline aquifers for recovery
in times of demand, (2) the Freshkeeper to counteract salinization of well fields by
interception and desalination of upconing brackish groundwater, and (3) the Freshmaker
to combine ASR and Freshkeeper to enlarge the volume of natural freshwater lenses for
later abstraction. The evaluation indicates that SWT can be used in various
hydrogeological settings for various hydrogeological problems like seawater intrusion,
upconing, and bubble drift during ASR and have significant economic benefits. Although
only sporadically applied to date, we foresee that SWT will stimulate (cost-)efficient and
sustainable exploitation of various freshwater sources (like groundwater, rainwater,
treated waste water, surface water) in coastal zones. Prolonged SWT testing in the
current pilots, replication of SWT in other areas worldwide, and the development of
technical and non-technical support tools are required to facilitate potential end-users in
investment decision making and SWT implementation.”
(Citaat: Zuurbier, K.G., Raat, K.J., Paalman, M.A.A., Oosterhof, A.T., Stuyfzand, P.J. How subsurface water technologies (SWT) can provide robust, effective and cost-efficient solutions for freshwater management in coastal zones – Water Resources Management 31(2017)2, p.671-687 – Open Access)