Climate change impact on the Almiros brackish karst spring at Heraklion Crete Greece

Abstract

The climate change due to global warming will undoubtedly affect the quantity and the quality of the available water resources. In this work the influence of the climate change in the coastal karst spring of Almiros at Heraklion of Crete in Greece was quantitatively investigated with the MODKARST deterministic mathematical model. The influence of the change of the parameters that affect the above-mentioned water resource (precipitation quantity and intensity, wet day number over year, mean sea level), based on the last predictions of the scientific community for the climate change at the end of 21th century, was examined separately, and in combination with two scenarios. The most important conclusions about the operation of the spring and the planning of the exploitation works under the predicted climate conditions are as follows: 1) the spring is mainly affected by the annual precipitation height and less, by the precipitation intensity, by the wet day number over the year and by the mean sea level rise, 2) it will not give fresh water during the whole year and sometimes, it will be dried in the summer, 3) due to fractal structure of the limestone porosity, the chloride concentration of the spring water will decrease during the depletion period, when the discharge becomes less than 2.80m3/sec, although there is not any precipitation during this period. From the MODKARST model simulation under the today’s climate situation, it has been proved that an 18 meters upraising of the water outlet point of the spring, through the construction of a dam, will prevent seawater entering into the spring reservoir and the salinization of the spring water. Under the predicted climate changes, the necessary upraising must be 2 meters higher than the upraising under the today’s climate situation that is it must be 20 meters.