Application of GIS and remote sensing for measuring and evaluating land-use change and its impact on water quality in the Pinang River watershed

Abstract

Human activities in the Pinang River watershed have dramatically changed landuse and land cover characteristics, and have subsequently altered hydrological and watershed processes. Pinang River water quality in downstream areas is badly polluted, based on the Malaysian Department of Environment-Water quality index (DOE-WQI) classification. In order to assess the past and present water quality and the possible uses of the Pinang River, a water quality index was applied to a data set collected for this study, which is based on the Malaysia DOE-WQI standards. This study investigated the land-use and land cover changes, which are the main contributors to the water quality and hydrological problems in this watershed. With some information derived from Landsat images, Geographic Information System (GIS) application and land-use/land cover map, we identified the land-use changes and landscape patterns in the Pinang River watershed. The results showed that forested and scrub areas decreased rapidly within the sub-watersheds as well as the entire watershed, in contrast to the urban or built-up areas. Statistical analysis indicates that impervious land parcels are increasing, which contribute to water pollution and watershed degradation. Based on land-use fragmentation and diversity indices, it was revealed that these indices are reliable tools for measuring and evaluating land-use and land cover changes for the general guideline for watershed management. This study revealed that integration of GIS and remote sensing (RS) data to quantify landscape structure is a feasible and efficient method for evaluating the temporal effect of land-use activities in the river basin for watershed planning and future development.