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.

## Reference

Lindsay, JB (2015) Modelling the spatial pattern of potential impoundment size from DEMs. Online resource: Whitebox Blog

## See Also

insert_dams, stochastic_depression_analysis

## Function Signature

`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]]: ...`

## Project Links

WbW Homepage User Manual Support WbW