Investigation of SCS-CN and its inspired modified models for runoff estimation in South Korean watersheds

Spatial identification of conservation priority areas for urban ecological land: An approach based on water ecosystem services

“…The U.S. Soil Conservation Service (SCS) hydrological model was used to calculate the runoff load (Ajmal, Moon, Ahn, & Kim, ). The model can reflect a wide range of underlying factors, such as land use, soil type and presoil wetting conditions, and the impact of human activities on rainfall runoff.…”

“…Finally, based on the spatial location of the regulation control point and the demand size of service land, the service land of runoff reduction was spatially identified.The U.S. Soil Conservation Service (SCS) hydrological model was used to calculate the runoff load(Ajmal, Moon, Ahn, & Kim, 2015).…”

Assessment of the flood hazard arising from land use change in a forested catchment in northern Iran

“…In the original CN method, I a = 0.2 S (i.e., λ = 0.2) but many studies have shown this to be too high, leading to runoff from large events being underestimated (Shi et al, ). Ajmal et al () redefined this critical parameter as I a = 0.02 P for several catchments across South Korea, but many studies have found that using λ = 0.05 produces satisfactory runoff estimates (Papathanasiou et al, ; Shi et al, ; Woodward et al, ). On the other hand, McColl and Aggett () found through calibration that they needed λ = 0.30–0.45 to account for additional abstractions such as interception and surface detention from forest‐dominated subcatchments.…”

“…“Direct runoff” incorporates overland flow, subsurface stormflow (i.e., excluding base flow) and direct channel precipitation and not simply infiltration excess overland flow as is commonly assumed (Garen & Moore, ). The low data requirements, simplicity of the method, and more recently its integration with GIS giving it a distributed capability, make the CN method a powerful tool for estimating runoff volumes from catchments (Shadeed & Almasri, ) and, as a result, possibly the most popular and widely applied runoff models (Ajmal, Moon, Ahn, & Kim, ). Caution is needed because the method was developed in, and for, “humid rain‐fed agricultural areas” of the United States, using rainfall and runoff data from catchments with a single soil and (vegetation) cover type (Woodward, Hawkins, Hjelmfelt, Van Mullem, & Quan, ).…”

“…Caution is needed because the method was developed in, and for, “humid rain‐fed agricultural areas” of the United States, using rainfall and runoff data from catchments with a single soil and (vegetation) cover type (Woodward, Hawkins, Hjelmfelt, Van Mullem, & Quan, ). However, although its application for water quality and pollution modelling has been found to be highly problematic (Garen & Moore, ), the CN method has been applied to runoff studies with reasonable success in many other parts of the world (e.g., southern China—Shi, Chen, Fang, Qin, & Cai, ; Palestine—Shadeed & Almasri, ), though sometimes with modification to the “initial abstraction” parameter (e.g., central E. China—Shi et al, ; South Korea—Ajmal et al, ). Hawkins (1984, cited in Woodward et al, ) noted that the CN method works better for non‐forested lands than forested areas, but Woodward et al () suggest that even CN values derived for degrees of urbanisation seem to work reasonably well.…”