Impervious surface estimation model for housing estates / subdivision

Abstract

It has long been established that urbanisation carries with it a series of environmental problems such as water pollution, heat pollution and flash floods. One indicator that has widely been used both to represent the extent of urbanisation and to link the effects of urbanisation to these environmental degradations is the amount of impervious surface or ‘imperviousness’. Quantifying the level of imperviousness, however, has proven to be a challenge and lately remote sensing images have been successfully used for this purpose. It is one thing to know accurately the amount of impervious surface but it is yet another thing to know the relationship between the amount and the variables of urbanisation – density, design, land use components, etc. This research was carried out with two objectives in mind: 1) to quantify the amount of impervious surface within residential areas using high-resolution remote sensing images; and 2) to establish a regression model linking the amount of impervious surface to the density of these residential areas. A sample of 11 housing estates around Skudai, Johor were selected for this research before the amount of impervious surface was measured using the high-resolution Quickbird remote sensing images. Different types of housing development with varying densities were represented in the 28 samples used for developing the regression model linking imperviousness to density. The results of the study confirm the positive relationship between them. The percentage of impervious surface measured in the study area ranged from 40 – 95%, well above the values indicated from similar studies overseas. The regression model obtained from this research could potentially be used in estimating the amount of impervious surface of a residential area, given the density. This could be useful in modelling of runoff hydrology as well as other environmental modelling. The study concludes with some guidelines on how to reduce the high level of impervious surface in future development.