Study On Ecological Basis Regulation And Water Quality Improvement In The Lower Reaches Of Fen River

The natural conditions of China's natural resources and ecological environment are relatively poor,and the unreasonable exploitation and utilization of water and soil resources have aggravated the pressure of ecological environment for a long time,which has caused a series of ecological and environmental problems.Water pollution and deterioration of water quality and water ecological deterioration have become an important factor restricting the sustainable development of regional economy.In order to realize the sustainable utilization of water resources in the lower reaches of the Fen River value,it is necessary to study ecological base flow-and water quality improvement to control Water pollution and mitigation of water ecological deterioration.The conclusions and main results obtained through the study are as follows:(1)Through the use of water quality identification index method for the downstream of Fen River,Chaizhuang and Xin Jiang monitoring cross-section of the water quality evaluation in 2009-2013,the study founding that the Fen River downstream water quality is inferior V class of water,especially two factors,COD,ammonia,exceeded seriously.Fuzzy matter-element model was used to calculate the overall ecological safety of the lower reaches of the Fen River,the results show that ecological security level in 2014 was between Grade ?(less safe)and Grade V(no safety),indicating that human activities in the basin created enormous pressure on the water quality and aquatic ecosystems.Effective measures should be taken to ensure ecological water use and to improve the quality of the water environment in order to maintain the stability of the aquatic ecosystem.Therefore,the ecological base flow and water quality were discussed separately.(2)Based on the years of runoff data,the ecological basis flow in the lower reaches of the Fen River was calculated by the minimum monthly mean flow method and the Tennant method and the different frequency annual method.Comparing results of the basic flow calculation of different hydrological stations,the minimum value of the ecological base flow of Zhaocheng,Chaizhuang and Hejin hydrological stations in the lower reaches of Fen River was 2.00m3/s,3.67m3/s,3.99m3/s.Ecological base flow control model were established based on the principle of base flow protection,and water regulation and control scheme of different water supply departments under the dry water year were proposed,obtaining the water diversion under different ecological base flow guarantee.Finally,combined with the"water-saving emission reduction"comprehensive program,put forward the ecological base of the guarantee measures,which provided the theoretical basis and technical support for the reduction of water shortage and pollution in the downstream of Fen River.(3)Based on wetland ecological dynamics model,studied the migration and degradation of pollutants in existing constructed wetlands in Fen River basin.After the appropriate hydrodynamic and water quality model parameters were obtained,the corresponding degradation rate was determined according to different working conditions.Based on the wetland parameters of the optimal degradation rate,the artificial wetland was constructed.According to the wetland depth treatment technology,three wetlands were selected along the lower reaches of the Fen River.Through the one-dimensional water quality model,water quality of the section before and after the artificial wetland was calculated,COD could be reduced by about 33.7%and NH3-N was about 37.0%.The construction of the"Pearl Strand"shaped wetland project in the Fen-he area can greatly improve the water quality along the river,supplemented by sewage discharge standards and sewage reduction measures,which would greatly promote the improvement of the ecological environment of the basin.