Application of the SCS–CN Method to the Hancheon Basin on the Volcanic Jeju Island, Korea

Abstract

This study investigates three issues regarding the application of the SCS–CN (Soil Conservation Service–Curve Number) method to a basin on the volcanic Jeju Island, Korea. The first issue is the possible relation between the initial abstraction and the maximum potential retention. The second is the determination of the maximum potential retention, which is also closely related to the estimation of CN. The third issue is the effect of the antecedent soil moisture condition (AMC) on the initial abstraction, maximum potential retention and CN. All of these issues are dealt with based on the analysis of several rainfall events observed in the Hancheon basin, a typical basin on Jeju Island. In summary, the results are that, firstly, estimates of initial abstraction, ratio λ, maximum potential retention, and CN were all found to be consistent with the SCS–CN model structure. That is, CN and the maximum potential retention showed a strong negative correlation, and the ratio λ and the maximum potential retention also showed a rather weak negative correlation. On the other hand, a significant positive correlation was found between CN and the ratio λ. Second, in the case where the accumulated number of days is four or five, the effect of antecedent precipitation amount is clear. The antecedent five-day rainfall amount for the AMC-III condition is higher than 400 mm, compared to the AMC-I condition of less than 100 mm. Third, an inverse proportional relationship is found between the AMC and the maximum potential retention. On the other hand, a clear linear proportional relation is found between the AMC and CN. Finally, the maximum potential retention for the Hancheon basin is around 200 mm, with the corresponding CN being around 65. The ratio between the initial abstraction and the maximum potential retention is around 0.3. Even though these results are derived by analyzing a limited number of rainfall events, they are believed to properly consider the soil characteristics of Jeju Island.

Assessment of the Contribution of Rainwater Collection to Crop Production on Udo Island, Korea

“…The CN of 0 indicates that all the rainfall is infiltrated, while the CN of 100 indicates that there will be no infiltration to maximize the effective rainfall. This study considered Lee et al (2019) and Kang and Yoo (2020) in the application of the SCS-CN method [31,32]. In particular, Lee et al (2019) proposed a new hydrological soil group by considering the volcanic ash soils of Jeju Island [31].…”

“…In particular, Lee et al (2019) proposed a new hydrological soil group by considering the volcanic ash soils of Jeju Island [31]. Their new hydrological soil group was also proven to be very accurate by Kang and Yoo (2020) and Yoo and Kang (2021) [32,33]. Kang and Yoo (2020) additionally proposed the use of a somewhat different initial loss rate and antecedent soil moisture conditions (AMCs) in the application of the SCS-CN method [32].…”

“…Their new hydrological soil group was also proven to be very accurate by Kang and Yoo (2020) and Yoo and Kang (2021) [32,33]. Kang and Yoo (2020) additionally proposed the use of a somewhat different initial loss rate and antecedent soil moisture conditions (AMCs) in the application of the SCS-CN method [32]. Their results showed that the conventional values of initial loss rate and AMCs used in the inland area of the Korean Peninsula could produce a somewhat biased estimation of the effective rainfall on the volcanic Jeju Island.…”

Use of Nonofficial Intermittent Waterfall Occurrence Data for the Validation of an Infiltration Model for Volcanic Jeju Island, Korea

“…The SCS-CN method, developed by the U.S. Soil Conservation Service [1], has been widely used in Korea for estimating the volume of effective rainfall or direct runoff [2][3][4][5]. The main parameter of the SCS-CN method is the curve number (CN), which represents the hydrologic infiltration characteristics of a basin.…”

“…Recently, Kang and Yoo [2] proposed a somewhat different setup for the application of the Soil Conservation Service-Curve Number (SCS-CN) method to Jeju Island. Based on the analysis of rainfall events observed in the Hanchun basin, Jeju Island, they showed 2 of 17 that the application of the conventional approach outlined in the guidelines published by the Ministry of Environment [3] could lead to an overestimation of effective rainfall.…”