Deriving optimal operational policies for off-stream man-made reservoir considering conjunctive use of surface- and groundwater at the Bar dam reservoir (Iran)

• Published in: Journal of hydrology. Regional studies Vol. 31; p. 100725
• Main Authors: Joodavi, Ata, Izady, Azizallah, Karbasi Maroof, Mohammad Taghi, Majidi, Maysam, Rossetto, Rudy
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2020; Elsevier
• Subjects: aquifers; Conjunctive use of surface water and groundwater; groundwater; Groundwater flow numerical modelling; hydrologic models; Iran; lakes; Managed aquifer recharge; MODFLOW; Reservoir management optimization model; rivers; seepage; Surface water-groundwater interactions; Water resources management; water security; water supply; Iran; Groundwater flow numerical modelling; Water resources management; Managed aquifer recharge; Reservoir management optimization model; Conjunctive use of surface water and groundwater; Surface water-groundwater interactions; MODFLOW
• ISSN: 2214-5818; 2214-5818
• DOI: 10.1016/j.ejrh.2020.100725

•Numerical groundwater/optimization models are integrated for artificial reservoir management.•Surface water reservoirs may be used to increase groundwater recharge.•Reservoir seepage losses mostly depends on regulated outflow and changing stages.•In semi-arid areas joint use of surface-and ground-water may satisfy water demand. The off-stream artificial Bar lake, built in 2015 to store the flood flows of the Bar river for domestic and industrial needs and with the objective to intentionally recharge the aquifer, is situated in the Razavi Khorasan province (Iran). We present a methodology, based on the combination of a MODFLOW groundwater flow model for estimating seepage rates, and an optimization model, for the management and operation of an artificial reservoir considering surface/groundwater interactions for satisfying 12 Mm3/year of water demand. We simulated the reliable amount of water that can be supplied from the reservoir, considering reservoir seepage, maximizing water supply yields subject to the water supply reliability requirements, and the additional intentional volume of groundwater recharge. Our results demonstrate the reliability of conjunctive use of surface-and ground-water in water scarce areas by exploiting reservoir infrastructures with relevant leakage losses, also for creating additional aquifer storage. In such systems, man-induced changes of lake stages can significantly affect the volume of water that seeps through the lakebed. The aquifer, under managed aquifer recharge operations, may then provide the resource not satisfied by the reservoir release, fulfilling 100 % reliability of water supply. The conjunctive use of surface- and ground-water, by improving water security, may open new sustainability views for leaking reservoirs, even if they were not initially designed for increasing aquifer recharge, in many areas worldwide.