Anomalous Behavior of the Curve-Number Infiltration Model

Abstract

The curve-number (CN) infiltration model is widely used in translating rainfall hyetographs into runoff hydrographs. The model is anomalous in that it does not place any limit on the infiltration rate within a catchment, and therefore can be inconsistent with the infiltration characteristics of real soils. An alternative methodology is proposed that generates infiltration rates that are more consistent with conventional soil infiltration-capacity characteristics. It is shown that significant underprediction of peak runoff rates can occur as a result of using the anomalous CN infiltration model.