Gis-based Hydrological Modeling: a Comparative Study of Hec-hms and the Xinanjiang Model

The last few years have witnessed an enormous study in the area of integrated hydrological modeling with GIS application. In this research, attempt was made to critically look at the application of HEC-GeoHMS which is an extension of ArcView in HEC-HMS; an HEC package which is a new generation of software being developed for rainfall-runoff simulation. The main role of HEC-GeoHMS is to formulate a watershed data structure under the platform of GIS that can be imported directly to HEC-HMS. With the topographic information supplied by HEC-GeoHMS, HEC-HMS works more readily and exactly. The performance of HEC-HMS was compared with that of the Xinanjiang conceptual model using historical flood data from the Wanjiabu catchment in China. The results obtained in the course of this study indicate that HEC-HMS is more convenient for flood stimulation especially in optimizing parameters but not quite accurate as compared with Xinanjiang model. The plausible reason for this could be due to the fact that the Xinanjiang model has more parameters thereby making it flexible to fit a flood event. Based on the results obtained as stated, it is thus suggested that with improvement in data conditions, runoff yield could be calculated on grid format and results for both models appropriately enhanced.