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Assessment and Model Application of Water Body Eutrophication in Qiandaohu Lake

Author: QuanWeiMin
Tutor: YanLiZuo
School: Zhejiang University
Course: Ecology
Keywords: Qiandao Lake Eutrophication Limiting factors Zoning Model
CLC: X524
Type: Master's thesis
Year: 2002
Downloads: 1053
Quote: 15
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Abstract

Water eutrophication problem has become today's world-wide problem of water pollution, is one of the global environmental problems. Europe and North America most of inland freshwater bodies have been in or will be in the eutrophication. Currently, our lakes caused by water pollution, eutrophication problem is very prominent, is one of the major environmental problems that plagued China's economic development. Put Taihu, Dianchi and Chaohu three lakes water pollution as the most important governance project to attach great importance to the \Qiandao Lake is located in the west of Zhejiang Province, is an artificial lake formed in the Xin'an River dam was built in 1959 after the impoundment. Watershed area above the dam site 10442km ~ 2, where 60% of the watershed area in Anhui Province. Qiandao Lake is a large variety of functions of power generation, flood control, drinking, farming, shipping, tourism, and industrial and agricultural water reservoirs, as Zhejiang Province, Hangzhou, the lifeline of the Qiantang River, an important water source, water resources accounts for about Qiantang 30% of the river's total water resources, so it has a significant impact on the ecological environment and sustainable socio-economic development in Zhejiang Province. Qiandao Lake has always been known for excellent water quality, but in recent years, Qiandao Lake has obvious signs of accelerated eutrophication. Provinces, municipalities and the Environmental Protection Agency and the National Environmental Protection Agency has caused serious concern, and launched a series of investigations and emergency action. In this study, based on the 1998-2000 continuous monitoring data on Qiandao Lake Water Quality Assessment and Biological Evaluation; limiting factor Eutrophication; pollution at the same time according to the individual sampling points in Qiandao Lake, the Lake the water quality of the environment division; previous experience in statistical models to predict the amount of pollutant load reductions needed for the existing level of phosphorus concentration in Qiandao Lake and governance; formation of multiple regression statistical model, the use of these models to predict the Qiandao Lake water concentration of total phosphorus in the body; Finally, based on years of water quality, sediment and biological monitoring data, and Qiandao Lake watershed meteorological and socio-economic status of the data set up machine rational Qiandao Lake eutrophication simulation model. In this study, the following results: (1) water quality evaluation results show that Qiandaohu overall quality of water, mostly in poor levels of nutrition the entrance blocks in the only Xinanjiang Qiandao Lake - eutrophic. Biological evaluation results, Lake planktonic algae average density than similar nutrient levels in freshwater bodies, all sampling point average density of phytoplankton> 10 to 6 per L, at home and abroad is generally believed that when the average density of phytoplankton> 10 to 6 a ╱ L has reached the eutrophication level single from phytoplankton density can think Qiandao Lake has reached eutrophication. Obviously that results Qiandaohu nutrients and a variety of water quality indicators are relatively low, basically at the level of oligotrophic, while the relatively high density of phytoplankton, which may be characteristic of deep-water lakes. (2) the determination of the limiting factors for lake eutrophication crucial. 1999 and 2000 Qiandao Lake total nitrogen (TN), total phosphorus (TP), the ratio of the mean mass concentration was 34 TN / TP minimum 14, maximum reach 59,1999 and 2000 TN / TP trend basic consistent. Usually considered, TN / TP> 14 lakes, phosphorus is the limiting factor of eutrophication. That phosphorus is the limiting factor Lake planktonic algae growth. In addition, analysis of the water temperature, light Chinese Abstract according PH planktonic algae growth correlation, but these factors are not enough to become a limiting factor to affect the growth of planktonic algae. (3) the quality of the water environment zoning also has a very important significance for the comprehensive utilization and protection of water bodies. Lake Pollution Situation similarity, the Qiandao Lake generally divided into three regions, heavy upstream pollution downstream clean water protection zone and the middle reaches of middle-contaminated areas, simultaneously application of FUZZY cluster analysis method for each sampling point pollution the status of cluster analysis, the results also verify that the above-mentioned principles of classification. (4) the water environment forecasting has become a hot research at home and abroad. Use the the generic multiple empirical statistical model to predict the phosphorus concentration levels in Qiandao Lake, six of which model is best suited for the Qiandao Lake forecasting. The model predicts that the phosphorus load decreased by 1/4, 1/2, 3/4, Qiandaohu concentration of total phosphorus in water response. Lake nutrient levels control the short and long-term goals, the use of the model to calculate the the allowed total phosphorus load into the lake phosphorus concentration. (5) monitoring data for each sampling point stepwise regression using stepwise linear regression, regression statistical model of sampling sites, basically consistent with the predicted and measured values ??obtained from the use of these models, indicating that these models can The forecast for Lake nutrient levels. (6) In accordance with the existing master years water, sediment and biological monitoring data, the formation of the Qiandao Lake phosphorus - phytoplankton ecology model, the model is relatively simple, considering only two state variables, that is, the total phosphorus concentration and phytoplankton biomass, due to the lack of data, while the basic parameters from the previous data, the predicted results of the model: biomass forecast and the actual level of agreement, but the total phosphorus predict large deviations, therefore remains to be further studied and perfect . Qiandao Lake is still in the low-level, periodic sampling monitoring, and monitoring of surface water body. As a unique deep-water lakes, which future research should strengthen the structure and characteristics of the vertical stratification of water, the the exogenous nutrient load and the spatial and temporal distribution, the entire lake lake current law the lakes ecosystem structure and lakes comprehensive development and utilization of other aspects of the study, resulting in a great deal of information and data on the basis of the formation of a mechanistic the Qiandaohu forecasting model, so as to guide the comprehensive utilization of the entire lake and water pollution control.

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CLC: > Environmental science, safety science > Environmental pollution and its prevention > Water pollution and its control > Lakes and reservoirs
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