The settlement of Kozlu in Zonguldak province located in the Western Black Sea Region of Turkey has experienced flood disasters since 1955 which has caused life losses and property damages. The study area comprises, order of age from the oldest to the youngest, Kozlu, Karadon and Inalti formations, Incigez Detritic member and alluvium. The fact that the Kozlu and Karadon formations are hydrogeologically impermeable units is an important factor that causes flooding. Construction on soil bearing the permeable Inalti formation and alluvium has a decreasing effect on soil infiltration. Water surplus constitutes 22.7% of the total precipitation that the study area receives. In the period from October to April, the area experiences heavy precipitation and therefore has large surplus water reserves. During the months between November and March, surplus water runs off. The study area experiences more flooding in the period from November and March than in the other months. During the months between April and October, when there is scarce or no water reserves, short-lived and heavy precipitation may result in flooding. The geological structure, hydrogeological and hydrological properties, slope gradient as well as damage to the vegetation cover and uncontrolled constructions cause the study area to suffer major floods.

Key words: Flooding, Kozlu, sediment, hydrology.