RETHINKING THE CURVE NUMBER THROUGH CATCHMENT MODELING

The SCS curve-number estimates the maximum retention capacity of a watershed through the “curve-number” (CN), found as an empirical value characterized by the soil type and the land cover. This estimated maximum retention capacity is then used to find the event runoff. In this paper, hydrology is done backward to establish a storage discharge relationship that can be applied to all of the rain events to more accurately represent the maximum retention capacity for the specific watershed. The storage discharge relationship is found through the slope of the recession plot for the watershed. This relationship is used to define initial abstraction and the volume retained. Then, using multi-linear regression, the maximum retention capacity can be found. This is applied to 671 small to medium sized watersheds with minimal human impact across the United States.