Department of Hydrogeology Methods of streamflow depletion estimation caused by cyclic groundwater pumping Filimonova E.A.1, Shtengelov R. S. 1, Maslov A.A. 1, Maximova E.S. 1 Lomonosov MSU Department of Hydrogeology Abstract n°2152 1. Conceptual model of seasonal pumping 4. Numerical modeling The availability of fresh water in sufficient quality and quantity is a major factor in the development of every society. Increasing scarcity and contamination of water resources is especially significant for megalopolises . Compensation groundwater pumping can be used to alleviate deficiencies in streamflow discharge during dry seasons. This approach has been practiced in many parts of the world predominantly for irrigation. Several investigations have been undertaken with a view to managing drinking water demands or processing-water supplies The source for the compensation well is the aquifer storage. Short-term groundwater pumping allows the use of aquifer storage instead of stream flow until drawdowns of the groundwater levels reach the edge of the stream. The stream flow depletion is delayed and it occurs after pumping during high water level periods. Groundwater - surface water interaction and stream depletion are at the core of seasonal compensation pumping. Estimation of streamflow depletion may be examined by different approaches. 3. Regression dependencies 2. Analytical solutions Two typical hydraulic conditions were classified depending on the relationship between SW and GW: alluvial aquifer and confined aquifer separated from the alluvial aquifer by an aquitard. The ‘capacitance’ C is a complex, dimensionless parameter of an aquifer system that defines the delayed effect on steam flow of groundwater pumping. Regression power dependencies between unit stream depletion Y created by cyclic pumping and capacitance were obtained for the estimation of stream reduction created by cyclic pumping. Theis model Wallace et al. (1990) gave analytical solution for cyclic pumping of wells Hantush model Darama (2001) obtained analytical solutions for cyclic pumping Baldenkov M. G., Shtengelov R. S. The formation of streamflow depletion during the periodic operation of riverine groundwater pumping. Moscow University Geology Bulletin. 2015. Vol. 70, no. 3. P. 262–269. Filimonova E., Baldenkov M. A combined-water-system approach for tackling water scarcity: application to the permilovo groundwater basin, Russia. Hydrogeology Journal. 2015. Vol. 24, no. 2. P. 489–502. Filimonova E. A., Shtengelov R. S. The dependence of stream depletion by seasonal pumping on various hydraulic characteristics and engineering factors. Hydrogeology Journal. 2013. Vol. 21, no. 8. P. 1821–1832.  References Hunt model Filimonova (2010) obtained analytical solutions for cyclic pumping 1 Lomonosov Moscow State University, Moscow, Russia, ea.filimonova@yandex.ru