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The runoff curve number was developed from an empirical analysis of runoff from small catchments and hillslope plots monitored by the USDA. It is widely used and is an efficient method for determining the approximate amount of direct runoff from a rainfall event in a particular area.
This approach is adopted from the NRCS (SCS) curve number method for estimating runoff. It assumes that the total infiltration capacity of a soil can be found from the soil's tabulated curve number. During a rain event this capacity is depleted as a function of cumulative rainfall and remaining capacity.
Otherwise, the factor A can be determined from a data record of rainfall and runoff using the method explained below under non-linear reservoir. With this method the reservoir can be used as a black box model. Conversions 1 mm/day corresponds to 10 m 3 /day per ha of the watershed 1 L/s per ha corresponds to 8.64 mm/day or 86.4 m 3 /day per ha
The Flood Estimation Handbook was published in 1999 and replaces the FSR. [3] It is based on the percentage runoff equation: P R = 0.829 P I M P + 25 S O I L + 0.078 U C W I − 20.7 {\displaystyle PR=0.829PIMP+25SOIL+0.078UCWI-20.7}
Regarding stormwater runoff in Washoe County, the specific elements within a new xeriscape ordinance were analyzed for efficacy using the model. For the varied agricultural uses in the watershed, the model was run to understand the principal sources of impact, and management practices were developed to reduce in-river pollution.
Observed and modelled runoff using the non-linear reservoir model. [38] Physical models use parameters to characterize the unique aspects of the system being studied. These parameters can be obtained using laboratory and field studies, or estimated by finding the best correspondence between observed and modelled behavior.
The simplest methods involve using a runoff coefficient, which according to the State Water Resources Control Board of California is "a dimensionless coefficient relating the amount of runoff to the amount of precipitation received. It is a larger value for areas with low infiltration and high runoff (pavement, steep gradient), and lower for ...
The runoff curve number was developed from an empirical analysis of runoff from small catchments and hillslope plots monitored by the USDA. It is widely used and is an efficient method for determining the approximate amount of direct runoff from a rainfall event in a particular area.