关键词: 城市化, 河流调整, 河流分类, 河流稳定性, 河流形态变化

Abstract: Urban river degradation under human impacts has aroused wide attention in the areas of geography science and hydrology. But in domestic academic field there is still a lack of systematic theory study on fluvial geomorphology and process which is the important work in river restoration design. Based on the study of river geomorphology and stabilization for nearly half a century, this paper reviews the research results from the content and method, summarizes the features and reasons about river changes in the process of urbanization, and analyzes the advantages and limitations of river classification. In conclusion, urbanization has transformed river landscapes across the Earth’s surface, caused great damage to fluvial equilibrium, and highly altered river natural progress. The main parameters include river enlargement, reductions in sinuosity, an overall increase in drainage densities, and a tendency for bed material to coarsen. The root cause of these changes is the change of hydrologic suystem and sediment discharge regiments in that urban construction can induce river aggradation due to soil erosion at the beginning of urbanization; and accompanied by the gradual completion of the construction, channel erosion has been the main source of river sediment; and that hydrological system is upset by a decrease in the perviousness of the catchment, driven by land-use changes. Therefore, scholars have been studying the classification of river evolution on form and stability. In this paper, a summary of existing urban stream classification systems can be classified primarily into three broad types by synthesizing literature methods: form-based method, process-based method and synthesis method. Form-based method is appropriate for concluding river morphological characteristics, but the classification scheme lacks significant explanation and has a limited basis in channel processes and stability. Process-based method can provide important information at the stage of evolution and the dominant channel processes that can help predict the future response to changing sediments and discharge inputs. However, it ignores the correlation between river degradation, adjustment time and different stages of urbanization. The synthesis method with form and process-based feature, which is currently widely used, avoids the lack in application of above two methods and emphasizes the theory period of river adjustment which include three phases“the onset of a morphological response-significant morphology change-a new equilibrium”, but still needs future quantitative research. Combing the existing experiences is beneficial to provide a scientific basis and practical references for watershed restoration and management in China.

Key words: channel adjustments, fluvial equilibrium, river classification, river form, urbanization