|The objective of the project is to develop and test a new cost efficient and environmental-friendly technology to reduce or prevent salt-water intrusion into fresh water aquifers. The technology will be based on a reduction of the permeability of porous rock formations by an artificially induced crystallisation of slightly soluble minerals from over saturated solutions. Grout development, geochemical characterisation of interactions with different soil materials and the description of the flow and sealing properties of over saturated solutions will be some of the main topics. Three field tests in different geological areas will prove the sealing properties of over saturated solutions. The result of the project will be a technology, tested in different field studies, allowing in combination with developed flow and mixing models a regulation of the permeability of porous horizons and thus a sustainable use of coastal fresh water aquifers.