Environmental issues connected to the quarry lakes and chance to reuse fine materials deriving from aggregate treatments

Abstract

Nowadays the number of quarries below water table is increasing due to the raising demand of aggregates. This kind of quarry implies an irreversible change of land use, since it forms artificial lakes which remain also when the activity is over. Quarry lakes are particularly numerous in alluvial plains, as we can find in Northern Italy, along the main streams of the Po plain. A quarry lake alters the pre-existent piezometric water table morphology and there is the possibility of a mixing between shallow aquifer and deep aquifers. Furthermore, a quarry lake creates an area of high vulnerability, especially because potential contaminants could reach the aquifer. The presence of a quarry lake can affect the local hydrological balance due to a high evaporation in the quarry. At last, the working activities connected to aggregate exploitation cause the production of fine materials (silt and clay) potentially employable in quarry rehabilitation. Most of time, these materials are used in quarry lake backfilling with a consequent hydrogeological alteration. This research deals with a study and an analysis of problems concerning quarry lakes in plain areas, their relationship with the hydrogeological setting and the issues connected to the production of fine waste. These problems are examined both from a theoretical point of view and from the analysis of real contexts, focusing on the legislation in force in Italy. .