Abstract
Mathematical simulation techniques have been used to study the subsurface water-lake system. The volume of the subsurface drain from the Syrdarya artesian basin (Kazakhstan) into the Aral Sea depression was computed subject to the geoinformation-mathematical model of its hydrogeological conditions. Since the surface and subsurface (underground) water are interconnected, their movement has been measured during the undisturbed period (1960), the epignostic (1961–2014) period, and for forecasting problems for 2044 under two water withdrawal options. The first forecast option assumes the same withdrawal volume of subsurface water level which existed at the end of 2014. The second forecast option envisages the model assignment (from the start of 2015) of the water withdrawal in the production volumes of the subsurface water approved by the National Reserves Committee of the Republic of Kazakhstan. The simulation results showed that the technogenic factors in the explored area have a significant impact on the movement of the subsurface and surface water. Reduction of the Syrdarya and Amudarya rivers flows, production of subsurface water with multiple water-intake and unowned self-flowing wellbores promoted the desiccation of the Aral Sea. The proposed mathematical simulation technique used to assess the subsurface drain proved its efficiency and can be used for surveying the similar subsurface water-lake systems.