Sensitivity analysis and regional imperviousness in an urban basin

Abstract

The complexity of the initial determination of water imperviousness, commonly abbreviated as % imp., is partially due to the high spatial variability that characterizes an urban environment, which presents a variety of land covers within small portions of land, some of which may be less than 1 hectare. This article seeks to contribute to the methodology for
indirectly measuring imperviousness based on the number of inhabitants and residences per unit area, using as a case study two sub-basins located in the western sector of the city of Coro, Venezuela. First, sensitivity tests of imperviousness were performed and then the technique for automatic digital interpretation of satellite images with traditional classifiers was tested to determine its quantification, revealing considerable inconsistencies in the transition zones with mixed uses. Manual extraction of impermeable zones was chosen and regionalized curves were constructed. From a methodological perspective, the procedure was effective since the regionalized curves enabled saving a significant amount of time in the initial calculation of this parameter.