Sakarya nehri’nde kum-çakıl madenciliği kaynaklı arazi kullanım değişimleri

Sakarya River total length is nearly 810 km, rising on the Anatolian plateau, northwest of Turkey. The Sakarya River has mild slopes with its sinuous and meandering shape extending from Black Sea, Karasu Region. Sand and gravel are important materials for construction and generally found in the floodplain and bed of rivers and streams. Sakarya River, which has changed various beds up until today, has a lot of sand-gravel mining fields on the sides and on the previous beds due to the fact that it is less sloping in especially Sakarya province. In the river, whose sand-gravel potential is 78500000m3, the activities such as opening new sand gravel mines and expanding, deepening the current ones have been increasing (Yüksel vd., 2007). These constructions negatively affect the morphology, hydrology and ecology of the river. It leads to losing fertile cultivated areas, causes the emergence of hollows in the river, deformation of ecosystem, and changes in stream bed and flow rate. Additionally, the constructions located on the streambed like regulator, bridge come under threat; surface and ground water are affected negatively in terms of amount and quality (Uslu vd., 2003). In this context, the purpose of this study is to identify the corrosions in riverbank of Sakarya River caused by sand and gravel mining, bed changes and changes in land use in the river coastal area. For this purpose, these changes have been determined with GIS software through satellite images of two different years and verified with actual land information. As 2006 and 2014 were compared, coast scouring and ponds emerged due to rising of phreatic groundwater because of intense sand intake, and the losses in agricultural and forestlands have been observed clearly. The results of the study will be a guideline to planners and policy-makers for choosing the land for and properly operating sand-gravel mines, so that there won’t be any negative changes in land use in agricultural and forest fields. The field of study is the part of Sakarya River that remains in Sakarya provincial borders. In the study, 2006 and 2014 satellite images and NETCAD software. The satelite images and data of sand and gravel mines have been received from Governorship of Sakarya. Within the borders of the province; there are 11 active sand gravel mines. There were marked on the satellite images, the situations in 2006 and 2014 were compared by overlapping the satellite images and the changes in river flood plain, flood bed and agricultural and forest lands on the coast of river through time have been identified. As seen from results of this study, choosing the wrong place and taking over materials lead to changes in land use and land losses. In determining the place of sand gravel mines, places which will not harm to the hydrology, the bed, river bank and agricultural areas should be selected.