Figure 8. Rating curve of runoff and SY.
3.2 Potential Maximum Retention and Sediment Yield
Potential maximum retention was an essential parameter in the calculation of CN values. These calculations considered rainfall, runoff, and initial loss and were widely applied to estimate runoff from rainfall data. If the potential maximum retention could be used to estimate SY, then the relationship between the two parameters could serve as a reference for management strategies. Therefore, this study analyzed typhoon events during 1999–2009 to investigate the relationship between potential maximum retentions and SY.
Based on a study of rainfall events (Gajbhiye, Mishra, & Pandey, 2014), the relationship between the two parameters could be expressed by a power function. The two curves in Figure 9 exhibit similar trends; however, this study found that different cumulative rainfall conditions should be classified and investigated individually. The two functions in Figure 9 were suitable for high cumulative rainfall (SY=13764S–1.133) and low cumulative rainfall (SY = 473.64S–0.866), and the correlation coefficients were 0.92 and 0.71, respectively.