Development of the brackish karstic spring Almyros in Greece

Abstract

In karstic massifs of anisotropic permeability groundvvater circulates practically, only through zones of high permeability called veins. Coastal springs are contaminated by sea-water either at the mouth of a submarine spring or inside the karstic massif in a branching of veins. The methods to desalinate brackish karstic spring are: - isolation of the karstic aquifer from sea-water intrusion by a dam at the spring or by a grout-curtain that seals the lower vein with sea-water; - interception of fresh-water by boreholes, wells or drainage galleries within the karstic massif, inland of the sea-water influence; - rise of the spring level by a dam. In that case, fresh-water accumulates in the karstic massif and prevents the intrusion of sea-water. There are already numerous cases of successful development of brackish springs. A more detailed analysis discusses the development possibilities of the important brackish spring Almyros with a mean discharge of 7 m3/s on Crete island in Greece.