A study and implementation of the watershed runoff extraction algorithm in the loess hilly-gully area

By means of discrete processing on the small watershed, the paper defined the elements of a watershed like the source point, confluence point, outlet point, single runoff and composite runoff based on the set theory, proposed an algorithm and implemented it. Based on the hydrologic simulation, the algorithm solved the problem of identifying the watershed outlet point and loop which made the runoff traced more realistic, simple, efficient, and practical. An application system was developed based on the algorithm, and was applied to the distributed prediction modeling for the watershed hydrology and erosion of the loess hilly-gully areas, and achieved appreciable results.