고려대학교

초록/요약

In this study, the conceptual foundation and development process of the Antecedent soil Moisture Condition(AMC) in SCS runoff curve number method are reviewed. Although the runoff volume is very sensitive with AMC condition, the AMC class limits developed in SCS(1972) are used in rainfall-runoff analysis without careful consideration. In this study, following the SCS curve number development process, rainfall-runoff characteristics of the Jang-Pyung subbasin subject to the Pyung-Chang River basin are analyzed to evaluate the reasonability of the AMC class limits at present. As a result of this analysis, the lowest runoff potential condition (AMC-I) has the maximum number of events, and the highest runoff potential condition(AMC-III) has the second, whereas the average runoff condition(AMC-II) has the minimum value when applying the current AMC class limits. This results show that the current AMC class limits by the antecedent 5-day rainfall amounts is unreasonable. Therefore, the New AMC class limits are proposed by the sensitive analysis of the antecedent rainfall - curve number value. As a result, the classification value of AMC-I with II is 22mm of antecedent 5-day rainfall amount, and the classification of AMC-II with III is 117mm in growing season. When the New AMC class limits are applied to Jang-Pyung subbasin, AMC probability distribution shows that the AMC-II has increased remarkably even though the AMC-I has a little higher value. But the AMC-III has the smallest one. According to the conceptual basis of the curve number method, the AMC probability distribution, the New AMC class limits adopted, gives reasonable results. In addition to the New AMC class limits, the variation of AMC, based on the climate change(scenarios from several General Circulation Model predictions), is also analyzed. As a result, we can find that the occurrence of AMC-I is reduced, and AMC-II & III is increased.