Sustainable surface-subsurface water use in Ergene River Basin Turkey

A methodology known as Multi-Objective Water Cycle Algorithm (MOWCA) was developed for sustainable use of water at the river basin scale. This novel metaheuristic technique is similar to a Genetic Algorithm that uses natural hydrologic cycle components i.e., rainfall, evaporation, flow routing, as elements of evolutionary optimization tools. This methodology has been applied to the Ergene River Basin that has an area of 11 020 km2 in northwestern Europe and part of Turkey near the Istanbul metropolitan area. In this basin, groundwater has been exploited densely by seven organized industrial zone centers since 1995. Their waste water is discharged into the Ergene River stream network together with some other upstream point and non-point sources of pollution. The groundwater level in some areas has been depleted more than 40 meters in recent years due to the immense use of groundwater for industrial consumption. Toward sustainable water management of limited resources in this region, various scenarios (consumption loss reduction, exchanging surface water use instead of groundwater in industry and change of irrigation methods for agriculture) were proposed. Under economic, ecologic and sociological considerations, the optimum water re-allocation from surface and groundwater resources for various use was presented by this optimization model for Ergene River Basin sustainable development. The results show that under limited water resources in the river basin and toward sustainable development of the region, water allocation for different sectors should be done by considering conjunctive water use of groundwater and surface water by means of water management models to reduce water loss and pollution.