Abstract
HK-curve method can rate water-discharge Q more accurately than conventional HQ-curve method by considering hydrological data not only water level H but also water-surface slope i. By the analysis using the actual measured hydrological data during flood, it was shown that the error of rated Q by HK-curve method for the measured value became less than almost 5%, although the error of rated Q by HQ-curve method sometimes exceeded 10%. In addition, it was shown that HK-curve almost same as considering whole measured data from the water-level increasing period to the decreasing period via the peak time during flood could be calculated even though only the data in the period of drawdown was used, and as the result, even when the data was measured only in the drawdown period of flood, HK-curve method could estimate highly accurate Q for the data missing period.
