catchmentsuch

Catchmentsuch is a term encountered in some German-language hydrological texts and software documentation to describe the process of identifying or extracting a drainage catchment, or watershed, associated with a given outlet or point on a landscape. It is not an official international standard term, but it is used informally to refer to catchment delineation within geographic information systems (GIS) and hydrological modeling.

The word combines the English word catchment with a German form suggesting search or identification. In practice, catchmentsuch refers to methods that delineate the upstream contributing area that drains to a specified outlet, using terrain data and flow-routing rules. It is commonly applied in the context of water resources and environmental planning.

Its typical workflow involves data preparation: a digital elevation model (DEM) is corrected for errors, flow direction and accumulation are calculated, and a pour point or outlet is defined. The GIS then identifies all cells upstream of the outlet that drain to that point, producing a catchment boundary. Some workflows additionally subdivide the catchment by streams, land cover, or political boundaries to obtain hydrologic units or sub-catchments. Software tools used include common GIS platforms and hydrological modules.

Applications of catchment delineation include water resources planning, flood risk assessment, environmental management, sediment routing studies, and ecological habitat analysis. It supports scenario analysis, such as the impact of land-use change or hydraulic structures on drainage areas.

Limitations arise from data quality, resolution, and projection; DEM imperfections can misplace boundaries, and human alterations to drainage networks can complicate delineation. Catchment boundaries are also dynamic with hydrological conditions and seasonal variations.

See also: drainage basin, watershed, catchment delineation, GIS, digital elevation model, hydrology.