Utilizing Landsat TM and OLI in Predicting \u3ci\u3eOncomelania Hupensis\u3c/i\u3e Habitats Around Poyang Lake Before and After Three Gorges Dam Completion
Schistosomiasis is a parasitic disease caused by the Schistomsoma japonicum flatworm that utilizes the Oncomelania hupensis snail as an intermediate agent. In the People’s Republic of China, these amphibious snails contaminate freshwater systems infecting humans, bovines, and other mammals and have caused significant morbidity for over two thousand years (Wertheim, et al. 2012; Zhang, et al. 2012.) The gravity of this disease prompted the national government to initiate sizable public health programs, such as the World Bank Loan Project (WBLP.) In spite of WBLP\u27s achievements, in 2004, after this program ended, a national survey acknowledged a resurgence of schistosomiasis in various regions including the Poyang Lake area in the Jiangxi Province (Zhang, et al. 2012.) Poyang Lake, since the completion of the Three Gorges Dam in 2009, has experienced significant changes in the lake’s depth and water extent exposing increased land surface, which possesses the potential to alter snail habitats (McManus, et al. 2010.) In analyzing these changes, this project sought to apply remote sensing techniques using multispectral imagery from Landsat 7 and 8 in conjunction with spatial analysis tools offered by Geographic Information Systems (GIS.) Because snail habitats rely heavily on ecological factors, including location of water bodies, submersion periods, and vegetation coverage, this analysis observed these attributes using Modified Difference Water Index (MDWI) and Normalized Difference Vegetation Index (NDVI) calculations. These computations derived from images taken during 2000-2001 and 2013-2014 to observe Poyang Lake before and after Three Gorges Dam completion (Hui, et al. 2008.) Though the examination observed a drastic increase in potential O. hupensis habitats, further analysis that incorporates data unavailable during this project would establish a more complete suitability model (Chen & Lin 2004.
