GIS Based Urban Runoff Modeling

ABSTRACT The urban hydrological models are rather different from the rural ones, because of the complicated and irregularly developed urban land uses, which make the urban hydrological analysis being a tedious work, i.e. the difficulties in accuracyand time consuming. This paper presents a method to import the GIS hydrological analysis results to urban runoff model to make the work accurately and efficiently. The hydrological modeling of Arcview GIS has been applied in this paper to delineatethe catchments, the outflow points of catchments and surface streams at three levels, in order to treat the constructed model as lumped, or less distributed, or even more distributed. The major catchment geographic and topographic characteristics have been calculated automatically by the program, while the percentage of different land types, e.g. impervious area and pervious area, are calculated by GeoProcessing procedures. The Time/area method, one of the MOUSE runoff models, has been applied in this study. The delineated catchments together with their characteristics are imported to MOUSE runoff model after implementing a series of data converting procedures. The calibration of the constructed runoff model has been carried out in a Norwegian case. This study focuses on the connection between GIS and urban runoff model. The procedures and results indicate that GIS based approach is more flexible and optimized to meet the requirements of distributed urban hydrological models. The subcatchmentdelineation and characteristic calculation are superior to the conventional methods both in accuracy and efficiency.