Investigation of the development and change of the Sakarya River floodplain between Arifiye-Boğazköy by using geographical information systems and remote sensing

The study area is located within the Sakarya River drainage area in the Northwestern part of Anatolia, in the Eastern Marmara region. Sakarya River drains most of NW Turkey (60.000 km2) with average annual discharge as 164.5 m3/s, carrying 23400 tons of suspended sediment load to the Black Sea. The focus of this study is the 15 km long floodplain of Sakarya River in Adapazarı Basin, between Arifiye and Boğazköy. The study consists of two main objectives. The first objective is to investigate the development of the Sakarya River deposits during the Holocene. Two terrace steps and the recent flood plain, are introduced with spatial and temporal relationships. The second objective of the study is to identify and monitor the sand-gravel mining activities in the study area, which in time cause the destruction of the recent floodplain and issued environmental and social problems in the area. The temporal expansion of the sand mines are investigated by using remotely sensed imagery from 1970 to the present and digitized to develop a geographic information system for the area. The collected data are used to define the surface area and volume of material exploited in time for the last 44 years. The results show that nearly all of the current flood plain (T0) and T1 terrace steps and a significant part of T2 terraces steps were operated by sand-gravel mining activities. The total amount material exploited is calculated as 41-52 million m3 in a total area of ~970 hectares. The gross total of the sand-gravel sediments operated is estimated as 107-137 million tons.