Classification and Identification of Severity Degree of the No-flow Events in the Yellow River
黄河断流严重程度分级与判别方法

Based on a review of the characteristic factors used for no-flow behavior analysis in previous studies, this paper proposed an additional comprehensive index which could remedy some deficiencies of other factors and thereby constitute a basis for classification of the severity degree of the Yellow River no-flow events. According to the cluster analysis of the measured data since 1972 when the no-flow phenomena occurred in the Yellow River first time, five severity levels could be classified for no-flow events in the Yellow River. Furthermore, the severity level is closely related to the incoming runoff as well as its fluctuation within a year expressed in terms of a deviation coefficient. A BP-typed ANN model was developed for identifying the complex response of the severity level to flow characteristics such as the incoming runoff and its fluctuation. The proposed method is of significance to the quantitative assessment of the severity level of the no-flow events in the Yellow River, and its applicability was proved through the comparison between the predicted and the measured results.