tailieunhanh - WETLAND AND WATER RESOURCE MODELING AND ASSESSMENT: A Watershed Perspective - Chapter 11

Trong những năm gần đây, hiện tượng phú dưỡng đã trở thành một vấn đề trong môi trường ngày càng nghiêm trọng hệ thống hồ. Làm giàu chất dinh dưỡng quá mức là nguyên nhân gốc rễ của hiện tượng phú dưỡng. Mặc dù hồ tự nhiên nhận được nguyên liệu đầu vào chất dinh dưỡng từ lưu vực của họ và không khí, các hoạt động của con người như các dòng nước thải, nước thải từ các lĩnh vực nông nghiệp, và nước thải công nghiệp có rất nhiều đẩy nhanh quá trình hiện tượng phú dưỡng. Để. | 11 Simulating Historical Variations of Nitrogenous and Phosphorous Nutrients in Honghu Lake Basin China Feng Gui Ge Yu and Geying Lai INTRODUCTION In recent years eutrophication has become an increasingly serious environmental problem in lake systems. Excessive nutrient enrichment is the root cause of eutrophication. Although lakes naturally receive nutrient inputs from their catchments and the atmosphere many human activities such as sewage inflows runoff from agricultural fields and industrial effluents have greatly accelerated the eutrophication process. To assess the relative roles of natural climate-induced changes versus human-related activities such as the removal of vegetation it is important to evaluate the natural trajectory of nutrient transportation over the catchments and its contribution to a lake s eutrophication. The eutrophication of the lakes in the most developed region in China the mid-lower reaches of the Yangtze River has brought great attention from the public scholars and government. As there are many types of lakes in the Yangtze River basin and the causes of eutrophication are different for each type Honghu Lake basin which is located at the middle reach of the Yangtze River was chosen as the study area. Computational simulations with the SWAT Soil and Water Assessment Tool model were used to reflect the historical nutrient sedimentation and transportation processes. With the application of the SWAT model the principle of nutrient transportation in the natural agricultural environment the environment under which the nutrient sedimentation and transportation processes are only controlled by natural factors such as topography climate changes and natural vegetation cover etc. has been discussed in order to provide scientific basis for the mechanism research of lake water eutrophication. STUDY AREA Honghu Lake located at the middle reach of the Yangtze River 113 12 -113 26 E and 29 40 -29 58 N Figure is typical of a shallow .