Classification Of River Habitat And Establishment Of Assessment System In Hun River Valley

River is the indispensable environment for aquatic organisms living and its stability determines the species diversity and community structure integrity. It not only provides important living environment for human, but also has the service function of commerce, transportation, entertainment, etc. In the past few decades, rivers from all over the world have been disturbed and destroyed in varying degrees along with the rapid developing of industrialization and urbanization.The river health and river ecosystem have been badly affected by a series of environmental problems such as water pollution, habitat destruction and reduce,river natural function lose, biological species extinction,etc. River habitat is the essential condition of river ecosystem integrity and river health maintenance. It has been one of the most important bases for river health assessment and river management as the important component of river ecological system. So, the river habitat assessment method is established and Hun River Valley is chosen as the study area to supply some reference for developing the river habitat assessment system, river ecological protection and river recovery projects.Based on the extensive research on literatures, the meaning and characteristics of the river habitat are explored, and the river habitat assessment methods are summarized. On this basis, a river habitat assessment system based on habitat classification is established. Chose elevation, slope, sinuosity and channel order as the habitat classification indexes, and discussed the river habitat classification method. With consideration of the river habitat influencing factors and the domestic and international relevant research results, the river habitat assessment framework is established with8sub indices (such as riparian areas stability, riparian areas width, riparian vegetation condition, riparian areas human interference, aquatic plants condition, channel form integrity, channel connectivity and channel human interference) and11indicators from two aspects of river habitat natural condition and human interference.Hun River Valley was selected as study area. According to the data collection and riverecological investigation in2011, the river habitat classification and assessment is applied for practice.39valley habitats are put forward in the study area and divided into3types by cluster analysis. On the basis of river ecological investigation, the relevant research and the habitat classification result, the assessment criteria of each river habitat type and weight coefficient of each indicator are made and the river habitat quality is assessed in study area. The assessment result revealed the river habitat quality index (RHQI) distributed in1.97～8.38in the60monitoring sites, among which, the sites belonged to moderate level were most and had32sites,21sites achieved preferable level or better,7sites were poor or worse.The habitat quality of different habitat types and the influencing factors of habitat quality were analysed. The results showed the quality among the habitat types had no significant differences and the human interference was consistent. The main problems of river habitat are unstable bank, narrow riparian areas, poor riparian vegetation condition, landuse developing intensively in flooded area, human interference intensively in channel and poor quatic plants condition, etc. The habitat quality of different channel levels were analysed, the result showed that there quality were significant differences among the different channel levels, the higher level, the worse quality and the more human interference. The results of correlation analysis of river habitat indicators, river water quality index and aquatic organism index showed that river habitat was correlative with several water quality indexes, and correlative with the most aquatic organism indexes. It suggests that river habitat has smaller effect to river water quality, but it’s the important factor of aquatic organisms and its quality affects the survival and distribution of aquatic organisms.In view of the research about the river habitat assessment is still at the elementary stage, this research established a river habitat assessment system based on habitat classification tentatively. The classification indicators, assessment indicators, assessment criteria, weight coefficient of indicators are subject to further expand the river ecological investigation to improve the assessment system and the reliability of the results. This research classed habitat in macro-scale, assessed habitat in medium-scale and didn’t study the micro-scale. So, multi-scale research should been taken to know the influence mechanism of each indicator and assess the river habitat more accurately.