Addressing uncertainties in the environmental sustainability of limno‐reservoirs: insights from the synthesis of multidisciplinary research

Abstract

AbstractLarge reservoirs in the Mediterranean area exhibit a variety of negative impacts resulting from exploitation of their water, many a result of large water‐level fluctuations. Water managers in Spain have implemented various mitigation measures to reduce these negative impacts. One such measure is construction of small dams in the riverine zone of large reservoirs to create a small waterbody with a constant water level (i.e. a ‘limno‐reservoir’) to provide the environmental and recreational services that the main reservoir cannot provide due to water‐level variations. To this end, the Pareja Limno‐reservoir was built in 2006 in a sidearm of the Entrepeñas Reservoir (Guadalajara, central Spain). As its environmental sustainability was not assessed prior to construction, however, there are some uncertainties about the ability of the limno‐reservoir to provide the expected environmental and recreational services. Accordingly, a multidisciplinary study was conducted on the Pareja Limno‐reservoir to shed on its environmental sustainability. This study addressed three relevant issues associated with the limno‐reservoir, focusing on water availability, water quality and the risk of sediment filling. This study reviews the research conducted to date, including an integrative discussion that endeavours to address these issues. The Pareja Limno‐reservoir is currently a successful tourist and recreational aquatic resource. The results of this study, however, reveal its recreational and environmental value may be reduced, especially as a constant water level at the maximum capacity of the limno‐reservoir cannot be guaranteed. The conclusions of this study may be useful for reservoir managers by providing guidelines for assessing the environmental sustainability of limno‐reservoirs.