General Catchment Delineation Method and its Application into the Middle Route Project of China’s South-to-North Water Diversion

A general catchment delineation method is proposed in this paper, which is suitable for either watershed or regional scales, and the method is successfully applied to two areas belonging to the Middle Route Project of China’s South-to-North Water Diversion. While traditional catchment delineation methods only function on a whole watershed scale, the new method introduces inlet points to ensure its suitability for regional simulations. Furthermore, in order to overcome uncertainties in producing long and narrow sub-catchments with traditional methods, a reach and subbasin refining method is proposed. This new method allows for the positions of hydrologic gauge stations and reservoirs to be accurately considered.