Abstract

Urbanization tends to increase runoff volumes, which might cause flooding and reduce groundwater recharge. Since the design of impermeable urban elements is based on the water flow volume before their construction, once they are erected the induced change to the local drainage pattern might generate flooding of the newly developed and previously developed areas. As such, precise modeling is essential to allow municipal watershed-sensitive hydrological design, which may prevent impervious urban surface expansion negative impacts. The digital elevation model that represents the watershed relief at any given location is the hydrological modeling base layer, which is necessary for describing urban landscapes and watersheds. The common notion is that the finer the elevation model resolution is, the more precise the hydrological model will be. Nevertheless, it is suggested that over-accuracy might be redundant. In the same manner, the land use classification resolution should be aligned with the modeling requirements. Such careful evaluation of the modeling resolution will reduce the computing resources needed for the modeling procedure and may be utilized as a sensitivity filter for insignificant tributaries of the hydrological network. This paper demonstrates a nominal procedure for urban watershed sub-basin analysis, which is the initial stage for detailed urban runoff modeling. It was found that the scale-optimized model performed very well and was found suitable for the prediction of runoff volume and discharge from a mainly urban, mountainous karstic watershed.