Istanbul faced several floods in different districts after the heavy rainfall dated 11 August 2004 which affected the whole Marmara Region. These floods caused 3 deaths and huge economical losses. One of these floods occurred on the Kozdere River flowing into the middle Bosporus in Istanbul. The aid amount to suffering losses made by different governmental and non governmental bodies is around 350.000 $. Climatic and physiographic factors are the main factors of floods. Rainfall type, rainfall intensity etc. are some of the climatic factors. Basin shape, elevation information etc. and land use changes are some of the physiographic factors. According to land use classification, lands classified as forest area must not be used as settlement or agriculture. This kind of miss land uses encourages flood formation. In this connection, it should be investigated whether forest area is used as settlement or agriculture or are there any land use changes against forest area.