Application of a GIS based distributed model for rainfall runoff simulations

In this research work, the development and application of a distributed rainfall – runoff model, to be used in flood related simulations was performed. The model utilizes the time–area diagram theory in order to calculate and route the runoff of each grid to the basin’s outlet. The selected study area is the upper part of the Alfeios river basin, the Karitaina basin, located in southern Greece, while historic rainfall data from regional rain gauges were used, which were interpolated through GIS tools into spatially gridded rainfall fields, with a one-hour temporal scale. The performance of the distributed model was evaluated through its comparison with two lumped models, one based on GIS techniques and the other one based on the unit hydrograph derived from historical rainfall-runoff events. Finally, the abovementioned models were also compared and evaluated with the observed hydrograph of the studied event. The results showed that the distributed model performed well considering that no calibration has been carried out regarding the hydrological losses.