The research explored growth and development, economic profits, and eco- logical benefits of released black carps on basis of 21 group ecological data on 52 365 fish within 6 months. The results indicated that the age...The research explored growth and development, economic profits, and eco- logical benefits of released black carps on basis of 21 group ecological data on 52 365 fish within 6 months. The results indicated that the age and growth index of released black carp were normal and body length and size were coordinated; 88.89% released black carps exceeded theoretical weight, with an average of 25.15%, which indicated that black carps are hardly to reproduct naturally. In 2013, 310 000 black carps were released in the Reservoir, and 123 tons black carps were obtained, with direct economic value of 2.46 million yuan and indirect econom- ic value of 3.84 million yuan. It can be concluded based on averages that 123 tons black carps can be produced in 2013 and 3 690 kg nitrogen and 740 kg phospho- rus can be removed. The releasing of fish has shown much more economic, ecological and social benefits in Yantan Reservoir, but the hidden dangers still exist on fishery environment. Therefore, it is necessary to further increase the number of re- leased black carps in the Reservoir.展开更多
In order to understand the effect of river impoundment on carbon dynamics, a large reservoir in a subtropical area, the Xinanjiang Reservoir, was investigated in detail. CO_2 emissions from the water–air interface wa...In order to understand the effect of river impoundment on carbon dynamics, a large reservoir in a subtropical area, the Xinanjiang Reservoir, was investigated in detail. CO_2 emissions from the water–air interface was studied, as was organic carbon burial in sediment. The results show a significant seasonal difference in CO_2 emissions. River impoundment led to the enhancement of aquatic photosynthesis, generating large amounts of authigenic organic carbon that was then buried in sediment.展开更多
The water and sediment discharge regulation （WSDR） project, which has been performed since 2002 before flood season every year, is of great significance to the river management in China. Until 2007, six experiments ...The water and sediment discharge regulation （WSDR） project, which has been performed since 2002 before flood season every year, is of great significance to the river management in China. Until 2007, six experiments have been fulfilled to evaluate the effect of the project on the natural environment. To fill the gap of investigations, a study on flood and suspended sediment transportation and channel changing along the distributary channel of the Huanghe （Yellow） River was conducted during the WSDR project period in 2007. The lower channel was scoured rapidly and the channel became unobstructed gradually several days after the flood peak water was discharged from the Xiaolangdi Reservoir. Within four days after the flood peak at 3 000 m3/s entered the distributary, the channel in the river mouth area was eroded quickly. Both the mean values of area and depth of the main channel were tripled, and the maximum flood carrying capacity increased to 5 500 m3/s or more. Then, the river channel was silted anew in a very short time after completion of the WSDR. Favored by the WSDR project, the fiver status in April 2008 became better than that of the year before. The adjustment ranges of main channel parameters were about 30%, 10%, and 10% at sections C2, Q4, and Q7, respectively. The process of rapid erosion-deposition was more active 15 km away in the channel from the fiver mouth due to the marine influence. It is reasonable for discharging sediment at concentration peak from Xiaolangdi Reservoir at the end of the flood peak. As a result, the sediment peak reached the river mouth about two days later than that of the water current. In addition, the WSDR project has improved the development of the estuarine wetland. Wetland vegetation planted along the river banks restrained the water flow as a strainer and improved the main channel stability. It is suggested to draw water at mean rate of 150 m3/s from the Huanghe River during flood periods, because at the rate the water in the wetland would be stored and replenished in balance. Moreover, we believe that cropland on the river shoal of the lower Huanghe River should be replaced by wetland. These activities should achieve the Huanghe River management strategy of ＂To concentrate flow to scour sediment, stabilize the main channel, and regulate water and sediment＂.展开更多
In both the construction and operation phases of a repository for high-level radioactive waste, it will be important to constrain groundwater inflow using grouting technology that will be effective under the high grou...In both the construction and operation phases of a repository for high-level radioactive waste, it will be important to constrain groundwater inflow using grouting technology that will be effective under the high groundwater pressure conditions deep underground. In this research, a review of existing grout penetration models in Japan and foreign countries and a trial analysis are conducted with a goal of describing the gout penetration with accuracy on site. Specifically, the applicability of the model developed by Gustafson ＆ Stille to the laboratory penetration tests was studied. The results show that the calculated values from the Gustafson ＆ Stille model agree well with values of laboratory penetration tests.展开更多
基金Supported by Guangxi Natural Science Foundation(2013GXNSFEA053003)Special Fund for Agro-scientific Research in the Public Interest(201303048)Germplasm Resource Protection Project of Ministry of Agriculture([2013]75)~~
文摘The research explored growth and development, economic profits, and eco- logical benefits of released black carps on basis of 21 group ecological data on 52 365 fish within 6 months. The results indicated that the age and growth index of released black carp were normal and body length and size were coordinated; 88.89% released black carps exceeded theoretical weight, with an average of 25.15%, which indicated that black carps are hardly to reproduct naturally. In 2013, 310 000 black carps were released in the Reservoir, and 123 tons black carps were obtained, with direct economic value of 2.46 million yuan and indirect econom- ic value of 3.84 million yuan. It can be concluded based on averages that 123 tons black carps can be produced in 2013 and 3 690 kg nitrogen and 740 kg phospho- rus can be removed. The releasing of fish has shown much more economic, ecological and social benefits in Yantan Reservoir, but the hidden dangers still exist on fishery environment. Therefore, it is necessary to further increase the number of re- leased black carps in the Reservoir.
基金funded by the National Natural Science Foundation of China(No.41573064)the National Key Research and Development Program of China(No.2016YFA0601003)
文摘In order to understand the effect of river impoundment on carbon dynamics, a large reservoir in a subtropical area, the Xinanjiang Reservoir, was investigated in detail. CO_2 emissions from the water–air interface was studied, as was organic carbon burial in sediment. The results show a significant seasonal difference in CO_2 emissions. River impoundment led to the enhancement of aquatic photosynthesis, generating large amounts of authigenic organic carbon that was then buried in sediment.
基金Supported by National Key Basic Research Program of China (No. 2005CB422304)National Natural Science Foundation of China (No.40872167)
文摘The water and sediment discharge regulation （WSDR） project, which has been performed since 2002 before flood season every year, is of great significance to the river management in China. Until 2007, six experiments have been fulfilled to evaluate the effect of the project on the natural environment. To fill the gap of investigations, a study on flood and suspended sediment transportation and channel changing along the distributary channel of the Huanghe （Yellow） River was conducted during the WSDR project period in 2007. The lower channel was scoured rapidly and the channel became unobstructed gradually several days after the flood peak water was discharged from the Xiaolangdi Reservoir. Within four days after the flood peak at 3 000 m3/s entered the distributary, the channel in the river mouth area was eroded quickly. Both the mean values of area and depth of the main channel were tripled, and the maximum flood carrying capacity increased to 5 500 m3/s or more. Then, the river channel was silted anew in a very short time after completion of the WSDR. Favored by the WSDR project, the fiver status in April 2008 became better than that of the year before. The adjustment ranges of main channel parameters were about 30%, 10%, and 10% at sections C2, Q4, and Q7, respectively. The process of rapid erosion-deposition was more active 15 km away in the channel from the fiver mouth due to the marine influence. It is reasonable for discharging sediment at concentration peak from Xiaolangdi Reservoir at the end of the flood peak. As a result, the sediment peak reached the river mouth about two days later than that of the water current. In addition, the WSDR project has improved the development of the estuarine wetland. Wetland vegetation planted along the river banks restrained the water flow as a strainer and improved the main channel stability. It is suggested to draw water at mean rate of 150 m3/s from the Huanghe River during flood periods, because at the rate the water in the wetland would be stored and replenished in balance. Moreover, we believe that cropland on the river shoal of the lower Huanghe River should be replaced by wetland. These activities should achieve the Huanghe River management strategy of ＂To concentrate flow to scour sediment, stabilize the main channel, and regulate water and sediment＂.
文摘In both the construction and operation phases of a repository for high-level radioactive waste, it will be important to constrain groundwater inflow using grouting technology that will be effective under the high groundwater pressure conditions deep underground. In this research, a review of existing grout penetration models in Japan and foreign countries and a trial analysis are conducted with a goal of describing the gout penetration with accuracy on site. Specifically, the applicability of the model developed by Gustafson ＆ Stille to the laboratory penetration tests was studied. The results show that the calculated values from the Gustafson ＆ Stille model agree well with values of laboratory penetration tests.
