Study On Water Environment Quality And Eco-environtal Water Requirement Of Baiyangdian

Baiyangdian Marsh is one of the few lakes in north China Plain, which has the vital significance to the region climate control, the biodiversity protection and the local economy development. However with the local economy development, more and more industrial and living pollution drain into the lake, which results in aquatic pollution worsening. And more badly the water volume is getting insufficient, because its supply rivers are seasonal and the reservoirs across the upper reaches of the perennial supplies also block the water's inflow. In order to maintain Baiyang Marsh's healthy development, we must realize its present environment condition and the foundation of its healthy development; therefore it is essential to carry on the quality synthetic evaluation of Baiyang Marsh's water environment. The detailed study is as follows:1. Apply the improved principal components analytic method to water quality appraisal. PCA which is traditional and widely used was improved aiming at the method's limitation, and then it was used to classify the 11 monitoring points of Baiyangdian Marsh. In order to check up the appraisal result, another method named probabilistic neural network was applied. The two method's appraisal result was consistent with each other. The analytic result demonstrated that the worsening of water pollution is more serious, and 45.46% of the monitoring points' water quality belongs to grade IV and V.2. Integrated state index method was applied to evaluate the state of eutrophication of Baiyangdian Marsh. And the dominated factors are predicted. The evaluation results show that Baiyangdian Marsh has turned into the stage of eutrophication, and element P element is the dominated factors.3. Geo-accumulation index method was applied to grade heavy metal pollution on the marsh sediment. The results showed that there has been a variety of heavy metal pollution, and element Cd is the major pollutants.4. Based on the integrated analysis of water quality index and heavy metal pollution index, the results indicate that there is linear correlation between them.5. Determine the threshold value of different water requirements. According to the calculation on the Baiyangdian Marsh's eco-environment water requirement, the minimum water amount to maintain its healthy development is 188.7 million m~3.6. Some feasible measures were proposed, which are about how to control water pollution and dispatch water from other area.7. In the last, the whole research was summarized and the prospects to the further research were put forward.