A Morphometric Approach to Bozkurt (Kastamonu-Türkiye) Flood

Abstract

This study aims to analyze the flood disaster that occurred in Kastamonu-Bozkurt in 2021 through the morphometric parameters of the basin. In the study, the Basin of Ezine Stream, which is the flood experienced most effectively, was analyzed together with the neighboring basins. Bozkurt flood is one of the most destructive floods in the history of Türkiye. As a result of the floods that occurred in Kastamonu and neighboring provinces on 10th - 12th August 2021, 82 people lost their lives. The Digital Elevation Model (DEM) of the study area was created with a cell size of 10*10 m using topography maps, and the boundaries of the basins to be analyzed with the ArcGIS-Archydro Module were determined. 30 indices were applied to these basins within the scope of shape (geometric), areal and relief morphometric features of the basins. The relationship between morphometric parameters was determined with the Pearson correlation coefficient. When the analysis results are evaluated for the Basin of Ezine Stream, it is the basin with the largest area, and the largest value of basin relief, relative relief and ruggedness. As a result, erosional activities and the risk of flood are high. When all basins are evaluated in general, it has been revealed that the shape of basins are more elongated, and the features of relief morphometry facilitate the formation of floods. Basin relief, relative relief, dissection degree, slope values, and average slope values are high for all basins; and both the amount of water added to the overland flow and the speed of the overland flow increased. This situation also increased the amount of material carried during the flood. Constructions built close to the stream bed increased the effect of the flood. Depending on the global climate change, the study area corresponds to the area where the change in daily maximum precipitation varies between 5-10%. Therefore, floods are likely to continue. For this reason, it is recommended to consider geometric, areal and relief morphometric features of the basins along with the climatic features of the basins while taking the necessary precautions. According to CORINE land cover data, urban areas in the Ezine Stream Basin increased by over 100% between 1990 and 2018, which is also affected by disastrous floods and overflows. Conservation and strengthening of natural vegetation in the study area will reduce the damage level of floods and overflows.