title: Operational resilience of reservoirs to climate change, agricultural demand, and tourism: A case study from Sardinia.
abstract: Many (semi-) arid locations globally, and particularly islands, rely heavily on reservoirs for water supply. Some reservoirs are particularly vulnerable to climate and development changes (e.g. population change, tourist growth, hydropower demands). Irregularities and uncertainties in the fluvial regime associated with climate change and the continuous increase in water demand by different sectors will add new challenges to the management and to the resilience of these reservoirs. The resilience of vulnerable reservoirs must be studied in detail to prepare for and mitigate potential impacts of these changes. In this paper, a reservoir balance model is developed and presented for the Pedra e' Othoni reservoir in Sardinia, Italy, to assess resilience to climate and development changes. The model was first calibrated and validated, then forced with extensive ensemble climate data for representative concentration pathways (RCPs) 4.5 and 8.5, agricultural data, and with four socio-economic development scenarios. Future projections show a reduction in annual reservoir inflow and an increase in demand, mainly in the agricultural sector. Under no scenario is reservoir resilience significantly affected, the reservoir always achieves refill. However, this occurs at the partial expenses of hydropower production with implications for the production of renewable energy. There is also the possibility of conflict between the agricultural sector and hydropower sector for diminishing water supply. Pedra e' Othoni reservoir shows good resilience to future change mostly because of the disproportionately large basin feeding it. However this is not the case of other Sardinian reservoirs and hence a detailed resilience assessment of all reservoirs is needed, where development plans should carefully account for the trade-offs and potential conflicts among sectors. For Sardinia, the option of physical connection between reservoirs is available, as are alternative water supply measures. Those reservoirs at risk to future change should be identified, and mitigating measures investigated.
authors.affiliation: Department of Science for Nature and Environmental Resources (DipNeT), University of Sassari, Italy; Euro-Mediterranean Center on Climate Changes, IAFES Division, Sassari, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Mereu
authors.affiliation: Centre for Water Systems, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK; UNESCO-IHE Institute for Water Education, Integrated Water Systems and Governance Department, PO Box 3015, 2601DA Delft, The Netherlands. Electronic address: j.susnik@unesco-ihe.org.
authors.forename: Janez
authors.initials: J
authors.lastname: Sušnik
authors.affiliation: Department of Science for Nature and Environmental Resources (DipNeT), University of Sassari, Italy; Euro-Mediterranean Center on Climate Changes, IAFES Division, Sassari, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Trabucco
authors.affiliation: Euro-Mediterranean Center on Climate Changes, IAFES Division, Sassari, Italy.
authors.forename: Andre
authors.initials: A
authors.lastname: Daccache
authors.affiliation: Centre for Water Systems, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK.
authors.forename: Lydia
authors.initials: L
authors.lastname: Vamvakeridou-Lyroudia
authors.affiliation: Center for North South Economic Research (CRENoS), Cagliari, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Renoldi
authors.affiliation: Water Resource Planning - Sardinian Regional Water Authority (ENAS), Cagliari, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Virdis
authors.affiliation: Centre for Water Systems, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK.
authors.forename: Dragan
authors.initials: D
authors.lastname: Savić
authors.affiliation: School of Chemical Engineering, National Technical University of Athens, Greece.
authors.forename: Dionysis
authors.initials: D
authors.lastname: Assimacopoulos
keywords: Hydropower; Irrigation; Reservoir resilience; System dynamics; Water resources