The Trend Of Water Environment Changes And Ecological Security In The Huaihe River Basin

At present, the ecological security cannot be ensured, owing to the instability of the water quality and the seriousness of the water pollution in the Huaihe River basin. It resulted in a disadvantageous impact on the development of the regional economy. This paper specifically focused on the ecosystem in the cities along the Huaihe River, by applying the current theories of urban ecology and the combining approaches of theoretical and case study, dynamic and static, as well as quantitative and qualitative analyses. Bengbu City was selected as a case city owing to its typical regional position, economical, ecological and environmental problems in Huaihe River Basin.On the basis of the characteristic in urban social and economical development, the features of urban water ecosystem, the following aspects were carried out in this paper. â‘ The relationship between urban water quality and social economical development was studied by the approach of Grey Correlation Coefficient Analysis in order to find the main factors influencing the deterioration of water quality; â‘¡ The total value of ecosystem services of the case city was evaluated, which directly reflected the supporting impacts of the urban ecosystem on the urban sustainable development;â‘¢ The comprehensive evaluation of urban water ecological security was valued by means of Factor Analysis (FA) to reflected it's temporal and spatial change trend; â‘£ A system, which is scientifically reasonable, of sustainable management of urban ecosystem is established to maintain and conserve the urban water ecosystem.Some empirical and methodological approaches were first used in this paper. The findings of the research were believed to be not only an important practical significance in the protection of natural ecological resources, the maintenance of the sound ecological environment and the realization of the city's sustainable development, but also provide scientific evidences for the management of the ecosystem and had a great reference value for the relevant studies in other city. It also enriched the contents of ecosystem studies in the Huaihe River Basin. The main conclusions in this paper were made as follows.1. At present the characteristic of the pollution sources in the case city was changing from the industrial pollution source to a multiple pollution sources containing industrial, agricultural and domestic pollution, which was proved by the fact that the total amount of urban industrial waste water and its pollutants is lower than that of the domestic pollution source, at the same time, the non-point pollution was rather serious.2. The temporal dynamic changes of the urban water environment showed that the water pollution was characterized by organic pollutants and the change in water quality can be divided into three periods, namely, the period of gradual deterioration in water quality (1983 to 1988), accelerating deterioration (1989 to 1996) and gradual improvement (1997 to 2003). And that trend was obviously under the influence of the macro-control actions of the nationwide water quality prevention.3. The relationship between the long-term water quality and social economic development demonstrated that industrial pollution was the most important factor worsening the water quality. The ratio of the third industry in GDP was also of great prominence to the water quality.4. The total value of Bengbu's water ecosystem services was $0.634 billion in 2003. Among the different ecological service categories, the shipping function and the function of flood control and water resource storage of the urban water ecosystem were of great value. Though the purification value of the ecosystem accounts for only 0.24% of the services, its normal functioning was of extreme importance to the ecosystem health and the normal function of other services, and was therefore of special significance to the restoration of the urban ecosystem.5. The water ecological security of Bengbu mainly included the security of drinking water, the security of ecological water demand, and the maxim capaci...