Water quality assessment and change detection in urban wetland using high spatial resolution satellite imagery

摘要

Wetland water quality is a critical issue in ecology and environment science, however to identify the quality and to detect the change of wetland are still knowledge gaps. In this paper, high spatial resolution IKONOS imagery was used to assess the water quality in a small urban wetland. A water-only image was created by masking out the terrestrial features from the image with unsupervised classification method. A three-class water quality map was created by a second unsupervised classification on the water-only image, and the relationship between water quality and spectral reflectance was examined. Based on the two classified water quality maps, the water quality changes from 2003 to 2006 were detected by map comparison and cross-tabulation analysis. It concluded that high spatial resolution satellite as IKONOS is essential for water research in a local scale. The unsupervised classification based on spectral reflectance of water surface is an effective and rapid way on mapping and assessing the general water quality.