Assessment of spatial distribution of flood generation hotspots in the Ramian’s Ghoorchay watershed using KINEROS2 model

Considering the ability for spatial quantification of various hydrological components, the distributed modeling of rainfall-runoff processes across the watersheds plays a key role in terms of water resources management, river engineering, flood control, and storage facilities as well as simulation of different watershed management scenarios. To this end, the Kinematic Runoff and erosion model, KINEROS2, has been used to assess the spatial distribution of rainfall-runoff processes components for the identification of surface runoff and flood generation hotspots across the Ramian’s Goorchay watershed with an area of about 254 km2 in the east of the Golestan Province. For evaluation of the model performance, 6 recorded rainfall-runoff events in the watershed were selected and divided into two sets of 3 events. The first set was used to run and calibrate the model and the second set was used to validate the model results. The mainland use types of the watershed are the Hyrcanian lush forest and rainfed agriculture on sloping lands. The rainfall-runoff simulations were carried out on an hourly basis.  The results of the performance evaluation of the model indicated that the KINEROS2 model is good enough at simulating the hydrological components of peak discharge and time to peak of flood hydrographs. However, it rarely performs well at simulating flood volume. The spatially distributed simulated map of surface runoff depth shows that various locations of the watershed have different flood generation potential. Whereas, the middle section of the watershed, where extensive land use change from forest to agriculture has occurred, shows high flood generation hazard potential, while the upstream section of the watershed displays lower flood generation potential despite having steep slopes.