Combination of Hydrological Modelling and Gis for Runoff Hydrograph Prediction in Small Urban Catchment

Most of the catchments, especially in the developing world, lack the adequate discharge measurements necessary for model calibration. These facts lead hydrologists to the challenge of predictions in ungauged catchments. One possible approach to deal with the problem of predictions in ungauged catchments is to establish transfer functions which associate model parameters with relevant hydrological characteristics. Due to the relative scarse data in these areas, lumped parameters are used to simplify the hydrological processes. The most recent studies, which aimed to simulate the rainfall-runoff response of small catchments in semi-arid regions, used semi-distributed models. In this study the linear reservoir Model, parallel cascades model, the HEC-HMS and WBNM software and GIS were used to predict direct runoff hydrographs in of a small urbanized catchment located in Azzaba in the north-east Algeria. The prediction presented how the catchment responds to rainfall events of return period of 50-years obtained from the constructed IDF Curves, for current land use. The main result from this study is that it has demonstrated how modelling tools can be used to study the potential effects of actual urban development on storm runoff.