Nitrogen （N） and phosphorus （P） released from the sediment to the surface water is a major source of water quality impairment. Therefore, inhibiting sediment nutrient release seems necessary. In this study, red so...Nitrogen （N） and phosphorus （P） released from the sediment to the surface water is a major source of water quality impairment. Therefore, inhibiting sediment nutrient release seems necessary. In this study, red soil （RS） was employed to control the nutrients released from a black-odorous river sediment under flow conditions. The N and P that were released were effectively controlled by RS capping. Continuous-flow incubations showed that the reduction efficiencies of total N （TN）, ammonium （NH4＋-N）, total P （TP） and soluble reactive P （SRP） of the overlying water by RS capping were 77%, 63%, 77% and 92%, respectively, and nitrification and denitrification occurred concurrently in the RS system. An increase in the water velocity coincided with a decrease in the nutrient release rate as a result of intensive water aeration.展开更多
Tarbela dam is one of the largest earth filled dam in the world. The sediments inflow in the Tarbela reservoir has resulted in reduction in water storage capacity. In addition damage to the tunnels, power generating u...Tarbela dam is one of the largest earth filled dam in the world. The sediments inflow in the Tarbela reservoir has resulted in reduction in water storage capacity. In addition damage to the tunnels, power generating units and ultimately to the plant equipment by the sediments particles carried by water is observed. To the authors knowledge, to-date no comprehensive simulation studies are performed for this dam reservoir and tunnels, especially at present when sediment delta and presence of sediment particles in the tunnels is observed to a reasonable extent. The aim of this study is to investigate the damage to the Tunnel 2 of the Tarbela Dam with and without considering the affect of sediment particles for one way and two way/full coupling during summer, winter and average seasons, using turbulent flows of water. Numerically calculated erosion results are compared with the experimental erosion results. Pressure, velocity and erosion rate density results are discussed in detail.展开更多
嘉陵江入汇流量的不同造成长江干流重庆主城河段相同流量情况下水位、比降、流速等水文特征差异较大,进而影响泥沙的输移特性,对研究河段航道条件造成影响。基于原型观测数据和二维水流数学模型,分析支流入汇特性及其对水位、流速、比...嘉陵江入汇流量的不同造成长江干流重庆主城河段相同流量情况下水位、比降、流速等水文特征差异较大,进而影响泥沙的输移特性,对研究河段航道条件造成影响。基于原型观测数据和二维水流数学模型,分析支流入汇特性及其对水位、流速、比降、输沙等的影响程度和范围。结果表明:长江干线朱沱站流量在3000~30000 m 3/s时,不同汇流比对入汇口上游长江段影响范围为20~75 km,在流量Q朱沱相同的情况下,汇流比R增大,重庆主城河段水流强度减小,输沙强度Φ减弱。三峡水库175 m蓄水后,在消落期和蓄水期,重庆主城河段水位抬升,水面比降放缓,而汛期重庆主城河段恢复天然河段特性,主城河段不受回水影响。在流量Q相同的情况下,蓄水后重庆主城河段水位抬升、坡降放缓,水流强度和输沙强度均呈减小趋势。研究成果可为重庆主城河段航道整治和维护提供技术支撑。展开更多
文摘Nitrogen （N） and phosphorus （P） released from the sediment to the surface water is a major source of water quality impairment. Therefore, inhibiting sediment nutrient release seems necessary. In this study, red soil （RS） was employed to control the nutrients released from a black-odorous river sediment under flow conditions. The N and P that were released were effectively controlled by RS capping. Continuous-flow incubations showed that the reduction efficiencies of total N （TN）, ammonium （NH4＋-N）, total P （TP） and soluble reactive P （SRP） of the overlying water by RS capping were 77%, 63%, 77% and 92%, respectively, and nitrification and denitrification occurred concurrently in the RS system. An increase in the water velocity coincided with a decrease in the nutrient release rate as a result of intensive water aeration.
文摘Tarbela dam is one of the largest earth filled dam in the world. The sediments inflow in the Tarbela reservoir has resulted in reduction in water storage capacity. In addition damage to the tunnels, power generating units and ultimately to the plant equipment by the sediments particles carried by water is observed. To the authors knowledge, to-date no comprehensive simulation studies are performed for this dam reservoir and tunnels, especially at present when sediment delta and presence of sediment particles in the tunnels is observed to a reasonable extent. The aim of this study is to investigate the damage to the Tunnel 2 of the Tarbela Dam with and without considering the affect of sediment particles for one way and two way/full coupling during summer, winter and average seasons, using turbulent flows of water. Numerically calculated erosion results are compared with the experimental erosion results. Pressure, velocity and erosion rate density results are discussed in detail.
文摘嘉陵江入汇流量的不同造成长江干流重庆主城河段相同流量情况下水位、比降、流速等水文特征差异较大,进而影响泥沙的输移特性,对研究河段航道条件造成影响。基于原型观测数据和二维水流数学模型,分析支流入汇特性及其对水位、流速、比降、输沙等的影响程度和范围。结果表明:长江干线朱沱站流量在3000~30000 m 3/s时,不同汇流比对入汇口上游长江段影响范围为20~75 km,在流量Q朱沱相同的情况下,汇流比R增大,重庆主城河段水流强度减小,输沙强度Φ减弱。三峡水库175 m蓄水后,在消落期和蓄水期,重庆主城河段水位抬升,水面比降放缓,而汛期重庆主城河段恢复天然河段特性,主城河段不受回水影响。在流量Q相同的情况下,蓄水后重庆主城河段水位抬升、坡降放缓,水流强度和输沙强度均呈减小趋势。研究成果可为重庆主城河段航道整治和维护提供技术支撑。
