The non-point source pollution arising from soil erosion is one of the main reasons for the deterioration of the water quality of the Taihu Lake Basin. Forest plays an important role in controlling soil erosion and re...The non-point source pollution arising from soil erosion is one of the main reasons for the deterioration of the water quality of the Taihu Lake Basin. Forest plays an important role in controlling soil erosion and reducing nutrient loss. Based on the survey data on forest resources in Anji County, we estimate the amount of soil erosion and nutrient loss of nitrogen and phosphorus reduced by forest, using soil erosion modulus method and soil nutrient content. In accordance with the degradation coefficient of pollutant and regional compensation standards of environmental resources, we assess the ecological benefits of forest function in reducing nutrient loss of nitrogen and phosphorus in Anji County. The results show that the forest in Anji County can reduce the soil erosion amount at 1.51 million t annually on the average, so as to control the nutrient loss of 1 409 t of total nitrogen and 577 t of total phosphorus in soil, equivalent to annually avoiding the flow of 824 t of total nitrogen and 410 t of total phosphorus into river water; this ecological service function can make forests in Anji County get 92.55 million yuan of ecological compensation funds (about 688 yuan/hm2·a), equivalent to 15 times of the current ecological compensation standard (47 yuan/hm2). The study reveals the importance of forest function in controlling soil erosion and nutrient loss in the upper reaches of Taihu Lake Basin to water environment protection in the basin, conducive to carrying out pollution control and protection work of the water environment in the basin.展开更多
Climate change and human activities have changed a number of characteristics of river flow in the Taihu Basin.Based on long-term time series of hydrological data from 1986 to 2015,we analyzed variability in precipitat...Climate change and human activities have changed a number of characteristics of river flow in the Taihu Basin.Based on long-term time series of hydrological data from 1986 to 2015,we analyzed variability in precipitation,water stage,water diversion from the Yangtze River,and net inflow into Taihu Lake with the Mann-Kendall test.The non-stationary relationship between precipitation and water stage was first analyzed for the Taihu Basin and the Wuchengxiyu(WCXY)sub-region.The optimized regional and urban regulation schemes were explored to tackle high water stage problems through the hydrodynamic model.The results showed the following:(1)The highest,lowest,and average Taihu Lake water stages of all months had increasing trends.The total net inflow into Taihu Lake from the Huxi(HX)sub-region and the Wangting Sluice increased significantly.(2)The Taihu Lake water stage decreased much more slowly after 2002;it was steadier and higher after 2002.After the construction of Wuxi urban flood control projects,the average water stage of the inner city was 0.16e0.40 m lower than that of suburbs in the flood season,leading to the transfer of flooding in inner cities to suburbs and increasing inflow from HX into Taihu Lake.(3)The regional optimized schemes were more satisfactory in not increasing the inner city flood control burden,thereby decreasing the average water stage by 0.04e0.13 m,and the highest water stage by 0.04e0.09 m for Taihu Lake and the sub-region in the flood season.Future flood control research should set the basin as the basic unit.Decreasing diversion and drainage lines along the Yangtze River can take an active role in flood control.展开更多
It is of great significance to study the encounter possibility of typhoon and plum rain in the Taihu Lake Basin in order to adjust the schemes of design storm and utilize flood resource and make the decision of real-t...It is of great significance to study the encounter possibility of typhoon and plum rain in the Taihu Lake Basin in order to adjust the schemes of design storm and utilize flood resource and make the decision of real-time scheduling for flood control in the Basin. Based upon the existing research findings of description of encounter phenomena of typhoon and plum rain, the initial time of typhoon affecting the Taihu Lake Basin, the start time of plum rain season and the end time of plum rain season were selected as the characteristic indices of typhoon and plum rain, respectively. According to their synchronous data from 1954 to 2009, the distribution functions of the above-mentioned three random variables were identified and a formula expressing the encounter possibility of typhoon and plum rain was derived. In view of the complexity and solution of this formula, joint distribution functions of typhoon and plum rain were constructed by the use of Gumbel Copula function on the basis of the adaptability comparison among three functions (Gumbel Copula, Clayton Copula and Frank Copula) in Archimedean functions. For the characteristics of the formula with the joint distribution functions based on Gumbel Copula function, two methods, i.e., numerical integration and Monte Carlo simulation, were selected to solve the encounter probability, and the validity of the computed results was analyzed finally.展开更多
基金Supported by the National Environmental Protection Public Welfare Industry Targeted Research(201209027)
文摘The non-point source pollution arising from soil erosion is one of the main reasons for the deterioration of the water quality of the Taihu Lake Basin. Forest plays an important role in controlling soil erosion and reducing nutrient loss. Based on the survey data on forest resources in Anji County, we estimate the amount of soil erosion and nutrient loss of nitrogen and phosphorus reduced by forest, using soil erosion modulus method and soil nutrient content. In accordance with the degradation coefficient of pollutant and regional compensation standards of environmental resources, we assess the ecological benefits of forest function in reducing nutrient loss of nitrogen and phosphorus in Anji County. The results show that the forest in Anji County can reduce the soil erosion amount at 1.51 million t annually on the average, so as to control the nutrient loss of 1 409 t of total nitrogen and 577 t of total phosphorus in soil, equivalent to annually avoiding the flow of 824 t of total nitrogen and 410 t of total phosphorus into river water; this ecological service function can make forests in Anji County get 92.55 million yuan of ecological compensation funds (about 688 yuan/hm2·a), equivalent to 15 times of the current ecological compensation standard (47 yuan/hm2). The study reveals the importance of forest function in controlling soil erosion and nutrient loss in the upper reaches of Taihu Lake Basin to water environment protection in the basin, conducive to carrying out pollution control and protection work of the water environment in the basin.
基金supported by the National Key Research and Development Project(Grants No.2018YFC0407900 and 2017YFC1502403)the Special Public Sector Research Program of the Ministry of Water Resources of China(Grant No.201501014)the National Natural Science Foundation of China(Grants No.51779071 and 51579065).
文摘Climate change and human activities have changed a number of characteristics of river flow in the Taihu Basin.Based on long-term time series of hydrological data from 1986 to 2015,we analyzed variability in precipitation,water stage,water diversion from the Yangtze River,and net inflow into Taihu Lake with the Mann-Kendall test.The non-stationary relationship between precipitation and water stage was first analyzed for the Taihu Basin and the Wuchengxiyu(WCXY)sub-region.The optimized regional and urban regulation schemes were explored to tackle high water stage problems through the hydrodynamic model.The results showed the following:(1)The highest,lowest,and average Taihu Lake water stages of all months had increasing trends.The total net inflow into Taihu Lake from the Huxi(HX)sub-region and the Wangting Sluice increased significantly.(2)The Taihu Lake water stage decreased much more slowly after 2002;it was steadier and higher after 2002.After the construction of Wuxi urban flood control projects,the average water stage of the inner city was 0.16e0.40 m lower than that of suburbs in the flood season,leading to the transfer of flooding in inner cities to suburbs and increasing inflow from HX into Taihu Lake.(3)The regional optimized schemes were more satisfactory in not increasing the inner city flood control burden,thereby decreasing the average water stage by 0.04e0.13 m,and the highest water stage by 0.04e0.09 m for Taihu Lake and the sub-region in the flood season.Future flood control research should set the basin as the basic unit.Decreasing diversion and drainage lines along the Yangtze River can take an active role in flood control.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50909063 and 51079037)Modern Water Science and Technology Innovation Project (Grant No. XDS2007-04)Non-Profit Special Industry Research Project both funded by the Ministry Water Resources of China (Grant Nos. 200901044 and 200901030)
文摘It is of great significance to study the encounter possibility of typhoon and plum rain in the Taihu Lake Basin in order to adjust the schemes of design storm and utilize flood resource and make the decision of real-time scheduling for flood control in the Basin. Based upon the existing research findings of description of encounter phenomena of typhoon and plum rain, the initial time of typhoon affecting the Taihu Lake Basin, the start time of plum rain season and the end time of plum rain season were selected as the characteristic indices of typhoon and plum rain, respectively. According to their synchronous data from 1954 to 2009, the distribution functions of the above-mentioned three random variables were identified and a formula expressing the encounter possibility of typhoon and plum rain was derived. In view of the complexity and solution of this formula, joint distribution functions of typhoon and plum rain were constructed by the use of Gumbel Copula function on the basis of the adaptability comparison among three functions (Gumbel Copula, Clayton Copula and Frank Copula) in Archimedean functions. For the characteristics of the formula with the joint distribution functions based on Gumbel Copula function, two methods, i.e., numerical integration and Monte Carlo simulation, were selected to solve the encounter probability, and the validity of the computed results was analyzed finally.
