Eutrophication Statement Analisies And Nutrient Criteria Establisment Of Xinlicheng Reservoir

The problem of eutrophication of lakes and reservoirs has become one of the most prominent water environment problems in China and even the world.There are many kinds of lakes and reservoirs in our country,and the regional distribution is wide,and the climate difference between lakes is very different.There are obvious regional differences in the existing problems and governance programs.The nutrient of lakes in our country is mainly problem due to the large input of nitrogen and phosphorus nutrients.If we want to limit the eutrophication of lacustrine lakes fundamentally,we should limit the discharge of nutrients and formulate the standard of the corresponding indicators is one of the most fundamental solutions.In this paper,taking an important drinking water source area in Changchun City for instance,water temperature(WT),pH,Secchi depth(SD),dissolved oxygen(DO)total nitrogen(TN),total phosphorus(TP),permanganate index(PMI)and chlorophyll a(Chl-a)were used to analyze Xinlicheng Reservoir,The eutrophication level and the relationship between chlorophyll a concentration and physicochemical factors was discussed by using correlation analysis and multiple stepwise regression.Based on the international chlorophyll a concentration grading method and the nutrient reference method,the Xinlicheng reservoir was established in spring,summer and Autumn nutrition standards;Finally,through the experiment to develop the standard to verify,the main results of this paper are as follows:(1)The range of TN in Xinlicheng Reservoir is between 0.47 and 3.76 mg/L in the period of 2011-2015,with an average value of 1.61 mg/L and 68% of the exceeding rate.The seasonal distribution is spring> summer> autumn;The range of TP is 0.02 ~ 0.09 mg/L,with an average value of 0.04 mg/L and 35% of the exceeding rate,there is no obvious seasonal changes in the law,mainly due to animal husbandry on the TP contribution rate of the largest peak in 2015,it might be the TN/TP range is between 6.0 and 193.0,and the TN/TP value can be seen as that the P nutrient is the limited parameter of Xinlicheng Reservoir.The variation range of Chl-a is between 2.55 ~ 26.54 μg/L,which is the seasonal distribution,that is,autumn> summer> spring.The comprehensive nutrition status index method is used to evaluate the reservoir.The results show that the whole reservoir is basically degree of light-eutrophic.(2)Correlation analysis and multivariate stepwise regression analysis showed that the temperature and TP were the main environmental factors affecting the growth of phytoplankton in spring.Therefore,the land should be planned reasonably,and the agricultural surface pollution caused by surface runoff should be controlled to the maximum extent.The control of the TP emission and the construction of the lake bank purification zone;the PMI is the main environmental factor of the summer phytoplankton growth model,so the summer should strictly control the organic matter,The main source of the TP is farmland and village farming living pollutants into the reservoir,the need to strictly control the TP into the water,if necessary,the reservoir should be sedimentation and other methods for eutrophication control.In general,the main environmental factors influencing the chlorophyll a concentration in Xinlicheng Reservoir are: temperature,total phosphorus and permanganate index.(3)Based on the international chlorophyll a grading method,the standard values of total phosphorus control were 0.044 mg/L,0.030 mg/L and 0.052 mg/L in spring,summer and autumn eutrophication evaluation criteria respectively.Based on the nutrient reference to lake method,The standard values of total phosphorus control in spring,summer and autumn were 0.038 mg/L,0.047 mg/L and 0.032 mg/L,respectively.In general,the two methods have their own advantages and disadvantages,the international Chl-a classification method is more suitable for the development of one lake nutrient standards,and when the criteria to be developed to guide the region eutrophication management,Basis to develop nutrient standards is suitable.(4)After the laboratory simulation of Xinlicheng reservoir in spring,summer and autumn water environment,the results showed that the nutrient standards of spring,summer and autumn were 0.38 mg/L,0.030 mg/L and 0.052 mg/L,respectively.From the results of this experiment,it can be seen that the standard developed by the international Chl-a classification method is more suitable for summer and autumn than the nutrient standards based on the nutrient reference method.The nutrient standard based on the nutrient reference method is suitable for spring.However,the spring TP standard developed by the two methods is relatively close to each other.Therefore,the international Chl-a classification method based on the nutrient reference is more suitable for the study of the nutrient standard applied in the lake.In the future research and development of the lake library nutrient standards should be as much as possible to collect effective data to improve the accuracy of standard setting.At the same time,in the process of experimental verification in the field to field experiments,consistent with the local climate conditions,in order to more scientific to the development of the standard to verify.