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The runoff curve number (also called a curve number or simply CN) is an empirical parameter used in hydrology for predicting direct runoff or infiltration from rainfall excess. [13] The curve number method was developed by the USDA Natural Resources Conservation Service , which was formerly called the Soil Conservation Service or SCS — the ...
A runoff models or rainfall-runoff model describes how rainfall is converted into runoff in a drainage basin (catchment area or watershed). More precisely, it produces a surface runoff hydrograph in response to a rainfall event, represented by and input as a hyetograph. Rainfall-runoff models need to be calibrated before they can be used.
A unit hydrograph (UH) is the hypothetical unit response of a watershed (in terms of runoff volume and timing) to a unit input of rainfall. It can be defined as the direct runoff hydrograph (DRH) resulting from one unit (e.g., one cm or one inch) of effective rainfall occurring uniformly over that watershed at a uniform rate over a unit period ...
[10] [15] The rain on land contains 107,000 km 3 (26,000 cu mi) of water per year and a snowing only 1,000 km 3 (240 cu mi). [15] 78% of global precipitation occurs over the ocean. [11] Runoff: The variety of ways by which water moves across the land. This includes both surface runoff and channel runoff. As it flows, the water may seep into the ...
The rainfall data can be either a user-defined time series or come from an external file. Several different popular rainfall file formats currently in use are supported, as well as a standard user-defined format. The principal input properties of rain gages include: rainfall data type (e.g., intensity, volume, or cumulative volume)
Runoff routing is a procedure to calculate a surface runoff hydrograph from rainfall. Losses are removed from rainfall to determine the rainfall excess which is then converted to a hydrograph and routed through conceptual storages that represent the storage discharge behaviour of overland and channel flow.
By 1892 M.E. Imbeau had conceived an event model to relate runoff to peak rainfall, again still with no chemistry. [2] Robert E. Horton’s seminal work [3] on surface runoff along with his coupling of quantitative treatment of erosion [4] laid the groundwork for modern chemical transport hydrology.
Agricultural runoff and other water pollution that flows to the outlet is the cause of the hypoxic, or dead zone in the Gulf of Mexico. A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth , or flows into another body of water , such as a lake or ocean .