Research On Land Use Zoning For Controlling Of The Total Amount Water Pollutants In Wuxi City

In recent years, the water pollution in China is getting more and more serious, and incidents related to it occurred frequently. The harm caused by water pollution has become an important factor that will influence people’s life and restrict the social and economic development of China. Wuxi city, lies on the verge of Taihu Lake, is one of the most important cities in Taihu basin. It has entered into a high speed development in social and economic since the reform and opening up, especially since the90s. The change of land use pattern is strong drived by the constant development of industrialization and urbanization, and the emissions of industrial waste water and sewage are growing. In addition, the lack of consciousness on the water environmental protection then lead to a variety of pollutants and nutrients entered into the Taihu Lake by rivers. The booming increase of the pollutants and nutrients has caused very serious water environmental pollution consequences, which tremendously destroyed the health of ecosystem in Taihu lake basin. Although the water pollution treatment technology projects which have been developed, such as centralized management, rehabilitation of canal system and river diversion dredging have played a certain role in the process of local prevention and control of water pollution, it is difficult to prevent the water pollution from happening at root. The reason lies in that all these "end-treatment" which mainly aiming at the water environment itself can’t relieve the water environment pressure fundamentally.Land is the carrier of all human economic activity, it will ultimately change the way of land use in order to achieve the human economic and social goals.If these activities exceed the carrying capacity of natural ecosystems(including land), will result in the occurrence of environmental problems, in this respect, unreasonable land use change is the the ultimate "source" of environmental problems. Water pollution is also true for this, in the case of "end-treatment" controlling technology was limited,"The source of emission reduction"will play an important role for these, that is it can relieve the regional water environment pressure from the source. One of the research hotspots of LUCC-the development of the research on land use/cover change of water environment effect in hydrology, as well as the proposal of water environment management mode and concept "by region, by type, by grade and by term" established the theoretical basis for the research in this paper. This paper will try to treat the land use as the root of water pollution issues, and control the water pollution by way of land use zoning in wuxi city. The main content and the main conclusions of this study include:1. The allocation of allowed water pollutants load in Wuxi city:In order to ensure water pollution control responsibilities clear, this study select towns as the basic unit of evaluation, total amount water pollution was allocated in accordance with the City-County-township administrative level. According to the fairness as the primary criteria, established a analytic hierarchy process model from pollution sources view to distribute the county level total amount water pollutants, the Calculation results are:In2012, Jiangyin City,the allocation of allowed emissions TN and TP pollutants are4428.63tons and387.74tons, in2020, the allocation are2382.30tons,211.49tons; In2012, Wuxi City,the allocation of allowed emissions TN and TP pollutants are4963.17tons,349.80tons, in2020, the allocation are2669.84tons,190.80tons; In2012, Yixing City,the allocation of allowed emissions TN and TP pollutants are5108.20tons,362.46tons, in2020, the allocation are2747.86tons,197.71tons.Using the objective function of the entropy method to distribute the township level total amount water pollutants, select the demographic, economic, land area, and from the Taihu Lake distance as the indicators, to evaluate the differences load weighted allocated pollutants,building a objective function and setting constraints to solve the problem.to ensure that smallest difference by the unit population, per unit of GDP, per unit of land area, and the unit distance indicators, the specific result of allocation shown in Table4-6.2. Land use zoning for contrlling water pollution:Relying on the "source" and "sink" landscape ecology theory.distinguish the water pollution environmental effects in different land use types (landscape).For the "source" land use type,using export coefficient to estimate the evaluation unit’s water pollution export qutity by land use,for the "sink" land use type, the water purification service functions calculate method was adopted, then consider the ecological protection of the different regions to Taihu Lake. Developed the zoning standards and naming conventions, Wuxi City was divided into seven land use control zones by exceeded proportion of water pollutants, water purification service functions value, and the Taihu buffer classification of protected areas.The zoning included: Wuxi north zone for TP slight control,Wuxi south zone for TP moderate control,Wuxi central and south zone for TN and TP moderate control,Wuxi east zone for TN and TP severe control, Yixing north zone for TP severe control, Yixing west zone for TP moderate control,and Yixing south zone for TN and TP slight control.3. Based on the land use landscape pattern index calculations of land use zones,and according to General land use planning of Wuxi city(2006-2020), Regional planning of important ecological function protected areas in Jiangsu province, Technical report of important ecological function zoning in Wuxi city, proposed land use control measures to guide land use conversion direction and rational distribution, making a variety of land use types suitable location, and play the biggest role, reducing the regional water pollution stress to Taihu ecosystem.