The Role of Land Use Changes on Runoff and Flood Properties in the Doab catchment

Deforestation and Pastures, invasion of privacy and riverbanks, flooding of the Doab catchment during recent years, especially the downstream flood of 2019, It raises the possibility of impacts of land use changes on flood characteristics.The purpose of this study was to evaluate the impact of land use changes on flooding in Doab catchment using HEC-HMS model. For this purpose, first land use map of Doab catchment was prepared for the years 1995 and 2019. SCS method was used to calculate initial rainfall and basin runoff height and Muskingum method was used for flood routing. In order to investigate the effect of land use changes on flood characteristics, precipitation data and discharge for the year 2019 were implemented in the model created with land use conditions of 1995. Evaluation of land use maps showed reduction of forest area and Pastures area to the 56.71 and 28.25 square kilometers equivalent to 7.39 and 3.68 Percentage of total basin area, Dryland, irrigated and residential areas respectively 58.30, 19.88, and 6.78 square kilometers increased equivalent to 7.60, 2.59, and 0.89 percent. The results of this comparison showed that the average runoff peak increased by an average of 15.46 percent and the volume of runoff by an average of 19.74 percent. This indicates a decrease in the initial amount of rainfall losses and an increase in runoff. Therefore, it can be said that land use changes in the Doab catchment have increased the peak and volume of runoff and ultimately increased flooding in this basin.