Long-term hydrologic simulation using SCS-CN-based improved soil moisture accounting procedure

摘要

The Soil Conservation Service Curve Number (SCS-CN) method is widely used in determination of direct surface run-offnin long-term (continuous) hydrologic simulation models. Of late, Michel et al. (2005) reviewed the soil moisture accountingn(SMA) procedure that lies behind the original SCS-CN method and pointed out severe structural inconsistencies in the treatmentnof antecedent condition and, in turn, proposed a sounder methodology. However, this method still needs refinement in thendefinition of initial moisture level (V0) to make it usable in field. Thus, in the present study, the Michel et al. (2005) modelnis modified to avoid the unrealistic sudden jump in V0 by incorporating conceptual SMA procedure and variation of dailynCN based on antecedent moisture amount instead of antecedent moisture condition. When applied to 17 watersheds fromndifferent agro-climatic regions of India, the proposed model simulates daily stream flows better than those due to Michelnet al. model. The proposed model performed better in high run-off producing (wet) watersheds than in low run-off producingn(dry) watersheds, and the base flow was more and less significant in high and low run-off producing watersheds, respectively,nwhereas the evapotranspiration showed a reverse trend. Copyright  2010 John Wiley & Sons, Ltd.