Climatic Adjustments of Natural ResourceConservation Service (NRCS) Runoff Curve Numbers

Abstract

For the purposes of this project, the term observed curve number (and CNobs) refers to the estimate of effective curve number for a watershed that is derived for paired observations of rainfall depth and runoff depth. Similarly, the term predicted curve number (also CNpred) refers to the standard estimate of the curve number for a watershed for the average antecedent moisture condition (AMC II). The standard curve number (CNpred) is derived from soil association (hydrologic soil group) and land use/land cover through a table look-up procedure.