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Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to channel runoff (or stream flow). It occurs when excess rainwater , stormwater , meltwater , or other sources, can no longer sufficiently rapidly infiltrate in the soil .
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.
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. [1] The curve number method was developed by the USDA Natural Resources Conservation Service , which was formerly called the Soil Conservation Service or SCS — the ...
Runoff is the flow of water across the earth, and is a major component in the hydrological cycle. Runoff that flows over land before reaching a watercourse is referred to as surface runoff or overland flow. Once in a watercourse, runoff is referred to as streamflow, channel runoff, or river runoff. Urban runoff is surface runoff created by ...
This equation uses the principles of conservation of mass in a closed system, whereby any water entering a system (via precipitation), must be transferred into either evaporation, transpiration, surface runoff (eventually reaching the channel and leaving in the form of river discharge), or stored in the ground. This equation requires the system ...
The one-dimensional (1-D) Saint-Venant equations were derived by Adhémar Jean Claude Barré de Saint-Venant, and are commonly used to model transient open-channel flow and surface runoff. They can be viewed as a contraction of the two-dimensional (2-D) shallow-water equations, which are also known as the two-dimensional Saint-Venant equations.
Surface-water hydrology is the sub-field of hydrology concerned with above-earth water (surface water), in contrast to groundwater hydrology that deals with water below the surface of the Earth. Its applications include rainfall and runoff , the routes that surface water takes (for example through rivers or reservoirs ), and the occurrence of ...
An example of these efforts was developed at the Southeast Water Laboratory, [19] one of the first attempts to calibrate a surface runoff model with field data for a variety of chemical contaminants. The attention given to surface runoff contaminant models has not matched the emphasis on pure hydrology models, in spite of their role in the ...