Identifying control factors of hydrological behavior through catchment classification in Mainland of China

Catchment classification based on hydrological similarity helps to understand the control factors of hydrological behavior. However, the relationship between hydrological behavior and its influencing factors has been unclear in Mainland of China because long-term and widely-distributed flow data is unavailable. Thus, this study intends to identify control factors of hydrological behavior in China’s basins by using classification. Gauged basins are clustered into several classes using the fuzzy c-means method based on flow signatures, which quantify catchment hydrological behavior. The classification and regression tree is employed to learn from cluster results and then obtain classes of basins without observed flow. Correlation methods are used to analyze the influence of basin signatures on flow signatures, while the difference significance test is applied to the hydrological behavior diversity between clusters from classification and regression tree. Results show that China’s basins are divided into five clusters, with low flow signatures more distinguishing classes than high flow signatures. It confirms that climate factors dominate hydrological behavior. However, soil is also an important control factor found in this study, which is rare in others. These findings help to understand hydrological behavior in China and reveal its control factors.