Impoundment Size Index (ISI): The use of potential impoundment size for the characterization of topographic incision in DEMs

Abstract

The purpose of this research is to present a novel land-surface parameter (LSP) of impoundment size, designated as the Impoundment Size Index (ISI), for mapping and quantifying the extent of topographic incision in DEMs. The ISI inserts a digital dam with a user-defined cross- sectional profile length for each cell in the DEM to calculate the size of the impoundment (area, volume, mean depth) that is created as a result of the “digital damming” operation. An analysis of computational performance of ISI was performed to assess the execution times of the algorithm. A bivariate correlation analysis was performed between ISI and six common LSPs used in incision mapping to determine the degree to which the ISI provides unique geomorphometric information. Finally, an assessment of agreement was performed between incised areas identified with the ISI and incised areas identified with visual inspection of the DEMs.