A study on eutrophication assessment in typical bay of Danjiangkou reservoir

The South-to-North Water Transfer Project is an optimal allocation and scheduling of water resources major project, the Danjiangkou reservoir as the important water source, the protection of water and water quality security is critical, determines the success of diversion project. This paper selected a typical bay of the Danjiangkou reservoir as the research area, and 16 sampling points were surveyed on the summer and autumn. Water eutrophication status was assessed combining the eutrophication evaluation method and classification technology regulation by water sampling testing. The results showed that the spatial distribution of TN (total nitrogen) on each sampling point was not obvious, but the spatial distribution of TP (total phosphorus) was difference, TN and TP concentration in summer water was overall higher than that in autumn. The eutrophication assessment showed that the status of the study area was generally good water quality. Water situation of eutrophication in autumn was better than in summer. A little part of water resource appeared mild eutrophication, others in nutrition state in summer, and the water quality in whole study area in autumn were under the level of eutrophication. Eutrophication was mainly due to the uncontrolled discharge of urban sewage, agricultural non-point pollution caused by the cropping systems and operations, the water dynamics condition caused by the reservoir operation scheduling, and the release of nutrients caused by fishery breeding.