Geological study for a wetland restoration: the case of the drained Mouria lake (W. Peloponnese)

Περίληψη

The Μouria Lake was drained for cultivation during late 1960's. A 0.5-ha large pilot- scale wetland is now constructed in order to study the sedimentological lakerestoration aspects. The uppermost horizons (up to 3 m thick) consist of fine sediments (mud, silt, clay) of fluvial origin, deposited in a lacustrine environment and constituting the lagoonal bottom material, which extents all over the area ever covered by the original Mouria Lake. A sand layer (3 m beneath the current surface) constitutes the substrate of the lagoonal bottom revealing a higher energy deposition environment in comparison to the overlying fine sediments. High pH and electric conductivity values reveal strong alkaline environment and high content of dissolved solids, respectively. The sediments reveal high CEC, as a result of high clay minerals content. Other main mineral phases that occur include quartz, feldspars and calcite. The weathering of marginal rocks is the major factor controlling the mineralogical-geochemical composition of the sediments. The strong alkaline features of the sediments inhibit trace element mobilization. Continuous monitoring of the chemical composition is necessary in order to predict and prevent a possible mobilization of hazardous trace elements and the subsequent release to the environment.