Research On Eutrophication Effect Of Storing Water In Three Gorges On Jialing River Downstream And Estuary Section

The Three Gorges project is one water conservancy project,which has great strategic significance to our country.After reservoir impounding,the separately water power in fundamental has a fundamental change. For example velocity lowdown,water self-purification decline.Chongqing is the largest commercial and economic center of Three Gorges southwest industrial.The jialing river basin is in the biggest tributaries of the Yangtze river system,which inflows from the western Chongqing urban and flows through the industrial,commercial,densely populated areas of Chongqing .The Jialing river water environment condition directly relates to Chongqing even whether the whole Three Gorges reservoir area water is safe or dangerous . Therefore to study chongqing urban sections eutrophication impact of the Jialing river has very important strategic significance to the Jialing river and the Changjiang river ecological harmony.By researching the different storage solutions of the Three Gorges reservoir area, water level influences water temperature,flow velocity,dissolved oxygen,PH value, turbidity,total nitrogen,total phosphorus,chlorophyll a,than come to this following conclusions:(1)When the Three Gorges water level between 159.32m to162.99m, because the jialing river downstream and estuary section continuous drought in February March April of 2010,according to the Three Gorges reservoir water requirements functioned from late April, reservoir reduce water to post-flight capacity, water level gradually reduces. The jialing river downstream and estuary section velocity increased gradually, the jialing river downstream and estuary section dissolved oxygen reduces gradually with water levels fall, PH increase gradually with water levels fall. By precipitation and runoff influence, turbidity increases gradually. The jialing river downstream and estuary section total nitrogen, phosphorus, chlorophyll-a, water eutrophication level development gradually from the state for eutrophication in 2010 mid-march - the end of may.(2)When the Three Gorges water level between 164.94m to171.55m, the reservoir gradually changes from the flood season to Initial impoundment , water level rises and the jialing river downstream and estuary section velocity slowdown gradually. Due to the September summer drought. The jialing river downstream and estuary section dissolved oxygen present first decreases then Increases and PH value after first decline rise. Turbidity Increases after first decline and total nitrogen experiences increases - reduce - increase process. Total phosphorus firstly rise then decline.Chlorophyll-a content after rising short first subsequently decline, total phosphorus and algae content are basically linear correlation. It shows the total phosphorus on algae growing importance and this water belongs to the eutrophication status.(3)When the Three Gorges water level is around 175m,water levels rises sharply, the jialing river downstream and estuary section velocity declines greatly, dissolved oxygen increases. PH value first rise then drop and turbidity dramatically reduces. Total nitrogen first decline then rise, total phosphorus first rise then decline. The jialing river downstream and estuary section belongs to rich nutrition. This stage total nitrogen influences largely, nitrogen, phosphor nutrient are relative enrichment and Chlorophyll-a reduces. But because of many factors such as entering winter temperatures drops significantly, Illumination inadequate, fog heavier, continuous overcast and rainy,which makes algae growth controlled effectively.