Curve Number Hydrology State of the Practice

The curve number (CN) method for estimating direct runoff response from rainstorms was developed to fill a technological niche in the 1950s. Since then, use of the CN method has extended to other applications, and user experience and analysis have redefined numerous features of the original technology. In ""Curve Number Hydrology: State of the Practice"", an ASCE/EWRI Task Committee investigates the origin, development, role, application, and current status of the CN method. Topics in this report include: an introduction to curve number hydrology; the curve number method; findings and developments; structure of the basic equation; soil moisture modeling; calibration methods; current usage and professional practice; and recommendations. One of the Committee's recommendations is assigning a keeper to serve as the central source for responsible information and updates. An appendix provides solutions to the curve number equation. This publication will be valuable to water and environmental engineers involved in hydrology, especially the analysis of rainwater runoff problems.