Study On The Trend Of Eutrophication In Three Gorges

Chang Jiang Three Gorges engineering is trans-century big institute of water conservancy and hydroelectric power junction engineering. Although it produces enormous profits in flood control, power generating, shipping, aquaculture and water supply,it produces, the water environmental protection is in the crucible of it.The nutrient salts level of the major portion of the lakes and reservoirs in China reachs the concentration of eutrophication fundamentally. Eutrophication of water body is very serious in many lakes and reservoirs.In recent years, Plankton bloom has happen successively in many branches of Chang Jiang such as Wu jiang,Han jiang and Da-ning river.The trend of eutrophication of water body gets more and more noticeably. Whether Three Gorges,which is the biggest waterway type reservoirs,meets the same problems is a problem which is paid attention by every environmental protection staff.The main research contents and result of this thesis as follows. 1. Review and analysis the water quality monitoring historical data of Three Gorges reservoir.By analyzing the water quality indexes affecting eutrophication of waterbody and the correlation of these indexes,we can draw a conclusion: In the water body of Three Gorges reservoir, in the main,the nutrient salts is in a high assay level,which is induced by the contamination taken by sediment in the upper stream.2. the study of the sediment in Three Gorges reservoir region effecting on nutritious substance adsorptionAt the base of summarizing researches of ancestors,at at the problem in the lack of research of the sediment concentration,initial concentration of aqueous phase nutritional contamination and oparticle diameter of sediment effecting on sediment adsorpting or stripping nutritional contamination,combining adsorption isotherm of fine particles sediment to nutritional contamination(mainly include total phosphorus) andadsorption dynamicsn to experiment,analyze and determine the influence of sediment concentration,initial concentration of aqueous phase nutritional contamination and oparticle diameter of sediment on sediment adsorpting or stripping nutritional contamination. Test result shows Langmuir adsorption isotherm can describe the process of sediment adsorpting total phosphorus. Under the same test conditions,the greater the initial concentration of aqueous phase total phosphorus is,the longer of the time of sediment adsorpting total phosphorus to bring into equilibrium.In contrast,the influence of sediment concentration on sediment adsorption is very little,we may overlook it.3. Analysis the trend of the Nourishment index after after impoundmentThe change of water quality and hydrology after first impoundment by 135 meter is studied in the article.By analyzing the change of hydrology after first impoundment, we can draw a conclusion: (1) After the first impoundment the water quality indexes will decline steadily , the concentration of nutrient salts will be lower ,but the total content will be higher than before for Contaminative source being enhanced .The concentration of nutrient salts will not be the restrictive actor of water eutrophication.(2)After the impoundment, Hydrology factor will be changed greatly , there are hydrographical condition at some water bodies such as land bordering a body of water, tributary inlet of backwater and reserveoir resulted from water bodies regretssion. If condition is proper water eutrophication will happen there.4. the system of assessment of nutritional quality in reservoir regionAt the base of analyzing and comparing several systems of eutrophication assessment at home and abroad.Using correlation weighted nutrition status index method we estiment nutritional quality of water body. The result shows the system of assessment of nutritional quality in reservoir region can be estiment using correlation weighted nutrition status index method,and the result is comparatively close.The study showed the water quality will be not optimistic if Three Gorges becomes reservoir region.we must strengthen treatment of soil and...