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Abstract
Variable source areas of pollution can be mapped using topographic wetness indices (TWI) derived from digital elevation models. These maps come in an infinite number of resolutions, and affect the calculation of terrain attributes depending on the resolution used. The purpose of this project was to study the effects of DEM resolution on the calculation of TWI maps on a small Upper Coastal Plain watershed. The maps were then used to make predictions of soil attributes across the watershed. It was found that the optimal TWI resolution depended on the soil attribute. For example, the mineral soil horizons correlated best to the 30m TWI, while the organic soil horizon correlated best to the 5m TWI. Prediction maps were made of the soil attributes by themselves, and also cokriged with TWI. These maps and methods are potentially useful to forest managers and to researchers for future projects.