Tekirdağ-Süleymanpaşa Kayı Creek basin morphology and flood flow

Kayı Creek, located in Süleymanpaşa district of Tekirdağ Province, is an important river basin in the center of the district with an area of 49,53 km2 . Kayı Creek reaches the sea by passing through Değirmenaltı Neighborhood, which is a dense settlement in the center of the district. The stream, whose flow rate decreases a lot in summer, has a significant flood potential. For this reason, knowing the morphological characteristics of the stream, the water yield of the basin and the flood flows that various repeated torrential rains will create in the stream bed is of great importance in terms of preventing the loss of property and life to be experienced. The morphological characteristics of the basin, which are one of the important elements in determining the precipitation-flow relationships, were calculated using the QGIS computer software program within the Geographical Information Systems. From here, the average slope of the basin is 10,2% and the height is 45,4 m, the length of the main stream tributary is 15,1 km and the slope is 1.0%. The specific flow rate in the basin, whose direction is northeast- southwest, was 0,000003 m3/s (0,26 m3/day) and the coefficient of surface runoff for the average amount of precipitation for many years was 17,4%. The annual water yield of the basin has been calculated as 5.007.483 m3/year for the amount of surface flow of 101,1 mm. The maximum flood flow rates generated by various recurrent torrential rains in the grain bed in the basin determined as surface flow curve number 82 were 80,23 m3/s for 6-hour rainfall surplus repeated for 100 years, and 112,48 m3/s for 6-hour rainfall surplus repeated for 500 years.