Evaluating the potential of quarry lakes for supplemental irrigation

Population growth coupled with industrialization, increasing effects of climate change, and increasingly stringent water management regulations regarding the conservation of aquatic life are resulting in previously unknown agricultural water shortages in Padana Valley, Italy. To mitigate water shortage, it was recently proposed to use the water stored into numerous quarries of gravel material. Because quarry lakes are mostly located in the proximity of watercourses, aquifer drawdown induced by pumping can affect flow in nearby streams. The evaluation of the potential of quarry lakes for supplemental irrigation has to face stream depletion that is crucial from the perspective of the legal rights of the downstream users and ecosystem sustainability. The work presented in this paper investigates the potential of a quarry lake in Padana Valley to sustain irrigated crop water requirement during shortage periods. A simple and quite inexpensive technique for assessing streambed conductance based on streambed temperature measurements is presented. The results show that quarry lakes may be a promising alternative resource for supplemental irrigation during shortage periods, even when a watercourse is present in the surrounding area