The antecedent soil moisture condition of the curve number procedure

Estimation of direct runoff, peak discharge or hydrographs is often necessa ry in small to medium-sized ungauged basins. Different models are used in p ractice for these purposes, depending on the type of problem, the available data and the prevailing runoff mechanisms in the study basin. This paper d iscusses the applicability of the curve number procedure developed by the U S Soil Conservation Service (SCS) to estimate direct runoff in basins chara cterized by small to gentle undulating slopes mainly covered with natural g rasslands. Rainfall and runoff data measured in the Canada de Los Chanchos basin in Uruguay is used to fit the curve numbers and to analyse the antece dent soil moisture condition proposed by the SCS.