This tool can be used to calculate the impoundment size index (ISI) from a digital elevation model (DEM). The ISI is a land-surface parameter related to the size of the impoundment that would result from inserting a dam of a user-specified maximum length (damlength) into each DEM grid cell. The tool requires the user to specify the name of one or more of the possible outputs, which include the mean flooded depth (out_mean), the maximum flooded depth (out_max), the flooded volume (out_volume), the flooded area (out_area), and the dam height (out_dam_height).
Please note that this tool performs an extremely complex and computationally intensive flow-accumulation operation. As such, it may take a substantial amount of processing time and may encounter issues (including memory issues) when applied to very large DEMs. It is not necessary to pre-process the input DEM (dem) to remove topographic depressions and flat areas. The internal flow-accumulation operation will not be confounded by the presence of these features.
Lindsay, JB (2015) Modelling the spatial pattern of potential impoundment size from DEMs. Online resource: Whitebox Blog
insert_dams, stochastic_depression_analysis
def impoundment_size_index(self, dem: Raster, max_dam_length: float, output_mean: bool = False, output_max: bool = False, output_volume: bool = False, output_area: bool = False, output_height: bool = False) -> Tuple[Union[Raster, None], Union[Raster, None], Union[Raster, None], Union[Raster, None], Union[Raster, None]]: ...