Research into the quality and supply of groundwater

Groundwater is an important source of water for the provision of drinking water, agriculture, industry and nature. The quality and supply of groundwater is a function of natural processes, such as precipitation, evaporation and ground passage, and of human activities at ground level and in the subsurface. Our experts research the behaviour of both natural compounds and of contaminants, like pesticides, and develop tools to calculate whether and/or when they will reach an abstraction well. We develop tracers to determine the groundwater residence and travel times. Using comprehensive time-series analysis, we show the effects on groundwater levels of interventions in the water system.
Over the past few years, the subsurface has been increasingly used for aquifer thermal energy storage (ATES). We study the effects of these systems on groundwater quality and flows, and contribute to the thinking about the sustainable use of the subsurface.

Development of subsurface techniques for the provision of water and heat

River bank and dune infiltration of surface water have been used for decades as a treatment step in drinking water production. Besides these, we also work on techniques for the subsurface removal of iron, manganese and compounds, like pharmaceuticals and pesticides.
The subsurface offers the time and space for the storage of freshwater, heat and cold. Horticulturalists in the western Netherlands use the KWR-developed ASR Coastal and Freshmaker methods to store fresh rainwater in the brackish subsurface, so that it is available for irrigation in the summer. We also make the residual waters of industry available in this manner for use by farmers in dry agricultural areas. In cities, we make use of subsurface water storage to prevent surface flooding.
As far as energy is concerned, we develop methods which optimise the storage efficiency of heat and cold in individual or clustered ATES systems. We also research methods for the storage and recovery of high-temperature (80-90o C) water. This makes possible the reuse of (residual) heat, for example, from industrial and geothermal sources, and its integration into heat networks.

Research into well technology and management

Wells provide access to the subsurface. In close collaboration with drilling companies, water companies and horticulturalists, we work on improving wells and well systems. We study the chemical, biological and physical processes that cause well clogging. And we translate this knowledge into practical guidelines and tools (Well Clogging Index) for the design, installation and efficient exploitation of water abstraction and infiltration wells. Horizontal Directional Drilled Wells (HDDWs) and Expanded Diameter Gravel Wells (EDGWs) are examples of new well designs that make the efficient use of thin of moderately permeable aquifers also possible. Our research into the management of corrosion, scaling and injectivity contributes to the development of geothermal energy as a sustainable source of heat.