COMPARISON OF GROUNDWATER RECHARGE OF THE SAPANCA LAKE IN NORTHERN TURKEY WITH REMOTE SENSING

H. Gonca Coskun* ,  Levent Yilmaz**, Ugur Alganci*
*ITU, Istanbul Technical University, Faculty of Civil Engineering, Department of Remote Sensing, 80626 Maslak, Istanbul, Turkey
**ITU, Istanbul Technical University, Faculty of Civil Engineering, Department of  Hydraulics, 80626 Maslak, Istanbul, Turkey

In this study, remote sensing (RS)  techniques are used as a tool to verify the groundwater recharge of the Sapanca Lake in northern Turkey. It is necessary to work with recent data and with recent Pinder’s theory of Groundwater recharge to be able to compare the groundwater recharge with RS method. Sapanca Lake basin area is a polluted catchment because of heavy urbanization and industrial development around it. RS is an important tool to monitor groundwater quality and to compare the pollution area of the lake surface and the Izmit Bay area at Marmara Sea which is not far from Sapanca Lake. There is a seepage recharge between the lake and the bay. For this aim, a project has been initiated at the Technical University Hydraulic Laboratory and at the Remote Sensing Laboratory. The study uses LISS-III satellite data of 1996 for water quality analysis at Part of Sapanca Lake and Izmit Bay. The RS data was converted into the UTM coordinate system and image enhancement and classification techniques are used. As a result of disporsion of the seepage from Sapanca Lake to Izmit Bay recommendations are made for planning and management of the polluted environment of the Sapanca Lake basin. Measuring the groundwater recharge is a very important issue for preventing the pollution sources of the basin and for controlling the future development of the catchment, RS technique is performed and results are compared with theoretical considerations of the groundwater pollution.