Hydraulic and Energy-Integrated Study of Reclaimed Wastewater in the Lower Mijares River Basin (Castelló)—Spain

Abstract

In Mediterranean regions, water resources suffer from important hydric stress which produces subsequent negative climate change effects. Such is the hereby presented case, taking place in the lower river basin of the Mijares River, in the eastern Spanish region of Castelló, in the Júcar River Basin District—Spain. This paper presents the case of integration and use of reclaimed waters coming from wastewater treatment plants (WWTPs) and the photovoltaic (PV) energy production, as a solution to a double problem in this region. The first problem deals with a water scarcity impact in the lower stretch of the Mijares River, where the environmental flows are not totally covered, making the river flow disappear and breaking the river course’s community. The second problem consists of marine intrusion in the coastal aquifers (Palancia-Mijares Interfluvial aquifer), caused by the overexploitation of groundwaters for irrigation purposes. This kind of solution requires a long-term study and planning process and necessitates an inter-users costs assumption transfer process, where the main users of water resources, are the main impact sources, too. Thus, irrigators, as well as water authorities and managers, must contribute jointly to give a solution to, both, an environmental problem, and a problem of water scarcity and unsustainable water usage. In this case study, we investigate an integrated water management solution which may lead to big investments in the establishment of the necessary facilities in the short term that will be offset and even turn advantageous in the long run as this solution reduces the operation costs; thus, making the current irrigation uses sustainable and economically worth over time.