Long-term surface water mapping in the Pearl River Delta based on multiple satellite images

Research on surface water (SW) dynamics is important for understanding climate change and the impacts of human activities on water resources. This article assesses the extent and direction of SW changes in the Pearl River Delta (PRD). Landsat images were used to determine the area of SW based on the modified normalized difference water index (MNDWI); the center of gravity was used to map the shifting distribution of SW dynamics; and landscape indices and potential causes of the observed SW changes were explored. Although the PRD has experienced high-intensity economic development for 30 years, the total SW areas in 1988, 1998, 2008, and 2018 were 2,608, 3,154, 3,521, and 3,613 km(2), respectively. The center of gravity of SW was in Shunde, Foshan (FS), which exhibited a trend of westward expansion. Over time, the landscape pattern of SW in the PRD became increasingly fragmented, and its shape tended to be complex. The growth of fish ponds was the most obvious change, as illustrated by the increase in aquatic product production. These and other findings highlight the importance of patterns, structures, and policies in SW dynamic analyses. Wetland and agricultural policies will likely cause the maintenance or continued expansion of SW areas.