Hydrological modelling of South Creek catchment

![CDATA[South Creek (SC) catchment, covering an area of 628 km2, begins its journey in Narrellan and joins the Hawkesbury-Nepean river system at Windsor. Argued as one of the most polluted creeks in New South Wales (NSW), SC has several inland Sewage Treatment Plants (STPs) that discharge treated effluents directly into the creek. Water quality is a major concern within the creek. The first step to address this issue is to calibrate a mathematical model that simulates catchment behaviour. As part of hydrological modelling of SC, a Digital Elevation Mode (DEM) of the catchment was created using a Geographical Information System (GIS) procedure. A total of 21 subcatchments and associated stream network were generated using HEC-GeoHMS, a pre-processor for a widely used hydrology software package developed by the US Army Corps of Engineers. The generated sub-catchments range from an area of size 0.39 km2 to 95.5 km2 . HEC-GeoHMS was also used to generate an input file necessary for HEC-HMS, the hydrological simulation program used in this study. Ten years of observed rainfall data from 11 raingauge stations were used to extract input to the hydrological model. Evaporation data from the Prospect Reservoir (8 nearby water body) was used to estimate soil moisture recovery within the catchment. The model was calibrated using observed flow data. Long-term simulation runs were made using thus calibrated model. This paper presents the results of the automated delineation procedure in generation of input data based on the digital elevation model of the catchment. The results of the long-term simulation are also presented. In addition, simplicity and reliability of generation of spatial parameters for HEC-HMS is demonstrated.]]