Hydrographic network and watershed delimitation
In this article I’ll show you how to extract hydrographic network? And how to determine watershed from digital elevation model (DEM)?
1. Extract hydrographic network from digital elevation model (DEM): Fill, Flow direction, Flow accumulation, Con, Stream order, Stream to features.
2. Determine watershed from digital elevation model (DEM).
The sum total of water bodies and streams on land (rivers, lakes, swamps, and water reservoirs). If only streams are considered, the term “river network” is employed, but often the terms “hydrographic network” and “river network” are used interchangeably.
The hydrographic network is characterized by the ratio density of river, lake, and swamp networks, that is, the relation of the area of the water table of a lake or of the surface of a swamp to the area of a given territory as expressed in percentages.
The structure of the hydrographie network its density and lake and swamp networks—is determined by a complex of physicogeographic conditions, especially by climate (the total annual precipitation and rate of evaporation), by the topography, and by the geological structure of the locality.
In the process of erosion new areas are added to the drainage system that previously had no runoff to the river system, and areas without drainage such as sinkholes are eliminated. A decrease in runoff leads to the separation of various parts of the hydrographie network.