The main stream of the Yangtze River, Dongting Lake, and the river network in the Jingjiang reach of the Yangtze River constitute a complex water system. This paper develops a one-dimensional （l-D） mathematical mode...The main stream of the Yangtze River, Dongting Lake, and the river network in the Jingjiang reach of the Yangtze River constitute a complex water system. This paper develops a one-dimensional （l-D） mathematical model for flood routing in the river network Of the Jingjiang River and Dongting Lake using the explicit finite volume method. Based on observed data during the flood periods in 1996 and 1998, the model was calibrated and validated, and the results show that the model is effective and has high accuracy. In addition, the one-dimensional mathematical model for the river network and the horizontal two-dimensional （2-D） mathematical model for the Jingjiang flood diversion area were coupled to simulate the flood process in the Jingjiang River, Dongting Lake, and the Jingjiang flood diversion area. The calculated results of the coupled model are consistent with the practical processes. Meanwhile, the results show that the flood diversion has significant effects on the decrease of the peak water level at the Shashi and Chenjiawan hydrological stations near the flood diversion gates, and the effect is more obvious in the downstream than in the upstream.展开更多
River cutoff works have been implemented on Lower Jingjiang section for 30 years. Engineering practices have shown that channel straightening has been the river regulation measure for the permanent control of the mean...River cutoff works have been implemented on Lower Jingjiang section for 30 years. Engineering practices have shown that channel straightening has been the river regulation measure for the permanent control of the meandering Lower Jingjiang section. River cutoff have been carried out in accordance with the evolution property of meandering rivers and these works have brought about expected benefits. It has also been noted that certain aspects in river cutoff had not been fully understood. River cutoff is a dynamic engineering. River channel evolution properties shall be fully understood so as to adroitly guide actions according to circumstances in cutoff works. In addition, river channel evolution observation and engineering effectiveness monitoring should be strengthened with a view to update the designs. The diversion canals for channel shortening are of great importance that will account for the success or failure of river cutoff works. The newly formed river channels and the river regime control works on the adjacent upper and lower reaches are guarantees for river cutoff works to be brought into play in the long run.展开更多
By using the meteorological data in the pollution boundary layer which was observed in two ground observation sites:coast and land in the river outlet area of Grand Liao River during January-February in 2007,the daily...By using the meteorological data in the pollution boundary layer which was observed in two ground observation sites:coast and land in the river outlet area of Grand Liao River during January-February in 2007,the daily change characteristics of pollute boundary layer in winter in the area were discussed. The results showed that the pollute boundary layer in the river outlet area of Grand Liao River was affected by the sea and land. In the certain weather condition,maybe the sea-land breeze appeared in the low altitude which was below 200 m in the coastal zone. The stability change in the different height in the coastal zone was more stable than in the land zone,and the wind field change in the area was mainly in 300 m low altitude. At night,the temperature inversion often appears in the area,and the thickness of temperature inversion layer is stably during 200-300 m. The thermal internal boundary layer penetrated deeply into the land about 10 km,and the height could reach 800 m. The atmospheric diffusion ability in the coastal area was weaker and stronger in the land area.展开更多
Based on a coupled hydrodynamic–ecological model for regional and shelf seas (COHERENS), a three-dimensional baroclinic model for the Changjiang (Yangtze) River estuary and the adjacent sea area was established using...Based on a coupled hydrodynamic–ecological model for regional and shelf seas (COHERENS), a three-dimensional baroclinic model for the Changjiang (Yangtze) River estuary and the adjacent sea area was established using the sigma-coordinate in the vertical direction and spherical coordinate in the horizontal direction. In the study, changing-grid technology and the "dry-wet" method were designed to deal with the moving boundary. The minimum water depth limit condition was introduced for numerical simulation stability and to avoid producing negative depths in the shallow water areas. Using the Eulerian transport approaches included in COHERENS for the advection and dispersion of dissolved pollutants, numerical simulation of dissolved pollutant transport and diffusion in the Changjiang River estuary were carried out. The mass centre track of dissolved pollutants released from outlets in the south branch of the Changjiang River estuary water course has the characteristic of reverse current motion in the inner water course and clockwise motion offshore. In the transition area, water transport is a combination of the two types of motion. In a sewage-discharge numerical experiment, it is found that there are mainly two kinds of pollution distribution forms: one is a single nuclear structure and the other is a double nuclear (dinuclear) structure in the turbid zone of the Changjiang River estuary. The rate of expansion of the dissolved pollutant distribution decreased gradually. The results of the numerical experiment indicate that the maximum turbid zone of the Changjiang River estuary is also the zone enriched with pollutants. Backward pollutant flow occurs in the north branch of the estuary, which is similar to the backward salt water flow, and the backward flow of pollutants released upstream is more obvious.展开更多
南盘江是珠江源头、云南曲靖人民的母亲河,其综合系统治理关系到曲靖的生态环境改善和经济社会的可持续发展。为精准掌握南盘江流域水污染问题,本研究详细分析了水质时空变化,降雨时城区管网溢流情况,沿岸排污口分布及污染物排放、合流...南盘江是珠江源头、云南曲靖人民的母亲河,其综合系统治理关系到曲靖的生态环境改善和经济社会的可持续发展。为精准掌握南盘江流域水污染问题,本研究详细分析了水质时空变化,降雨时城区管网溢流情况,沿岸排污口分布及污染物排放、合流制截污管网覆盖及漏损情况,南盘江干流闸坝运行调度情况。结果表明:南盘江流域水质劣Ⅴ类,重度污染,水质旱季劣于雨季,支流劣于干流,下游劣于上游,主要超标因子为NH 3-N和TP;当城区降雨量高于约10 mm时,部分支流白石江等雨水口大量生活污水溢流,雨污合流制难以应对降雨天气;干支流共有排口225个,抽检50个排口水质达标率约24%,超标排放情况普遍;曲靖城区城市建设落后,建成区约30 km 2采用雨污合流制,仍有约40%区域未覆盖截污管网;城区人均水资源量760 m 3,仅为云南人均的15.6%,全国的36%,沿岸闸坝蓄水满足农业灌溉用水需求,闸坝运行调度混乱,河道生态流量无法保障。建议以河长制为抓手,加强工业及城镇生活点源污染治理,优化区域水资源配置,推进河道综合治理、理顺管理机制体制,构建快处高效的治理执行体系,形成全社会参与的南盘江治理局面,方能促进南盘江水生态环境质量持续改善,惠及民生,还河于民。展开更多
松滋河是连通长江与洞庭湖的主要通道。自1950s以来,随着下荆江系统裁弯及葛洲坝、三峡等水利工程相继建成,松滋河分流量呈现阶段性减少。基于系列水文和河道原型观测资料,分析了三峡水库蓄水后松滋口分流变化特征及其影响因素。结果表...松滋河是连通长江与洞庭湖的主要通道。自1950s以来,随着下荆江系统裁弯及葛洲坝、三峡等水利工程相继建成,松滋河分流量呈现阶段性减少。基于系列水文和河道原型观测资料,分析了三峡水库蓄水后松滋口分流变化特征及其影响因素。结果表明:①三峡水库蓄水后,松滋口年分流比基本稳定在7%左右,没有明显趋势性变化;②当枝城站出现>25000 m 3/s流量时,蓄水后松滋口分流能力明显提升,特别是蓄水后前10 a;③三峡水库主汛期洪水调度影响较小,而汛末蓄水对口门分流产生消极影响;④荆江干流河床冲刷降低了口门处中枯水位,对松滋口分流产生不利影响;⑤芦家河浅滩航道整治工程实施在一定程度上对维持口门段中枯水位发挥了关键作用,口门河段河道采砂在一定时段改善了口门进流条件。展开更多
基金supported by the National Key Technologies Research and Development Program (Grant No. 2006BAB05B02)
文摘The main stream of the Yangtze River, Dongting Lake, and the river network in the Jingjiang reach of the Yangtze River constitute a complex water system. This paper develops a one-dimensional （l-D） mathematical model for flood routing in the river network Of the Jingjiang River and Dongting Lake using the explicit finite volume method. Based on observed data during the flood periods in 1996 and 1998, the model was calibrated and validated, and the results show that the model is effective and has high accuracy. In addition, the one-dimensional mathematical model for the river network and the horizontal two-dimensional （2-D） mathematical model for the Jingjiang flood diversion area were coupled to simulate the flood process in the Jingjiang River, Dongting Lake, and the Jingjiang flood diversion area. The calculated results of the coupled model are consistent with the practical processes. Meanwhile, the results show that the flood diversion has significant effects on the decrease of the peak water level at the Shashi and Chenjiawan hydrological stations near the flood diversion gates, and the effect is more obvious in the downstream than in the upstream.
文摘River cutoff works have been implemented on Lower Jingjiang section for 30 years. Engineering practices have shown that channel straightening has been the river regulation measure for the permanent control of the meandering Lower Jingjiang section. River cutoff have been carried out in accordance with the evolution property of meandering rivers and these works have brought about expected benefits. It has also been noted that certain aspects in river cutoff had not been fully understood. River cutoff is a dynamic engineering. River channel evolution properties shall be fully understood so as to adroitly guide actions according to circumstances in cutoff works. In addition, river channel evolution observation and engineering effectiveness monitoring should be strengthened with a view to update the designs. The diversion canals for channel shortening are of great importance that will account for the success or failure of river cutoff works. The newly formed river channels and the river regime control works on the adjacent upper and lower reaches are guarantees for river cutoff works to be brought into play in the long run.
基金Supported by The Special Project of Public Welfare Industry(Meteorology)of Science and Technology Ministry(GYHY200806020)The National Natural Science Fund(40975084)The Science Research Fund of Liaoning Meteorological Bureau(2008008)
文摘By using the meteorological data in the pollution boundary layer which was observed in two ground observation sites:coast and land in the river outlet area of Grand Liao River during January-February in 2007,the daily change characteristics of pollute boundary layer in winter in the area were discussed. The results showed that the pollute boundary layer in the river outlet area of Grand Liao River was affected by the sea and land. In the certain weather condition,maybe the sea-land breeze appeared in the low altitude which was below 200 m in the coastal zone. The stability change in the different height in the coastal zone was more stable than in the land zone,and the wind field change in the area was mainly in 300 m low altitude. At night,the temperature inversion often appears in the area,and the thickness of temperature inversion layer is stably during 200-300 m. The thermal internal boundary layer penetrated deeply into the land about 10 km,and the height could reach 800 m. The atmospheric diffusion ability in the coastal area was weaker and stronger in the land area.
基金Supported by the Public Welfare Special Scientific Research Project funded by the Ministry of Water Resources of China (No. 200701026)National Natural Science Foundation of China (No. 50709007)the Startup Fund of Hohai University (No. 2084/40801107)
文摘Based on a coupled hydrodynamic–ecological model for regional and shelf seas (COHERENS), a three-dimensional baroclinic model for the Changjiang (Yangtze) River estuary and the adjacent sea area was established using the sigma-coordinate in the vertical direction and spherical coordinate in the horizontal direction. In the study, changing-grid technology and the "dry-wet" method were designed to deal with the moving boundary. The minimum water depth limit condition was introduced for numerical simulation stability and to avoid producing negative depths in the shallow water areas. Using the Eulerian transport approaches included in COHERENS for the advection and dispersion of dissolved pollutants, numerical simulation of dissolved pollutant transport and diffusion in the Changjiang River estuary were carried out. The mass centre track of dissolved pollutants released from outlets in the south branch of the Changjiang River estuary water course has the characteristic of reverse current motion in the inner water course and clockwise motion offshore. In the transition area, water transport is a combination of the two types of motion. In a sewage-discharge numerical experiment, it is found that there are mainly two kinds of pollution distribution forms: one is a single nuclear structure and the other is a double nuclear (dinuclear) structure in the turbid zone of the Changjiang River estuary. The rate of expansion of the dissolved pollutant distribution decreased gradually. The results of the numerical experiment indicate that the maximum turbid zone of the Changjiang River estuary is also the zone enriched with pollutants. Backward pollutant flow occurs in the north branch of the estuary, which is similar to the backward salt water flow, and the backward flow of pollutants released upstream is more obvious.
文摘南盘江是珠江源头、云南曲靖人民的母亲河,其综合系统治理关系到曲靖的生态环境改善和经济社会的可持续发展。为精准掌握南盘江流域水污染问题,本研究详细分析了水质时空变化,降雨时城区管网溢流情况,沿岸排污口分布及污染物排放、合流制截污管网覆盖及漏损情况,南盘江干流闸坝运行调度情况。结果表明:南盘江流域水质劣Ⅴ类,重度污染,水质旱季劣于雨季,支流劣于干流,下游劣于上游,主要超标因子为NH 3-N和TP;当城区降雨量高于约10 mm时,部分支流白石江等雨水口大量生活污水溢流,雨污合流制难以应对降雨天气;干支流共有排口225个,抽检50个排口水质达标率约24%,超标排放情况普遍;曲靖城区城市建设落后,建成区约30 km 2采用雨污合流制,仍有约40%区域未覆盖截污管网;城区人均水资源量760 m 3,仅为云南人均的15.6%,全国的36%,沿岸闸坝蓄水满足农业灌溉用水需求,闸坝运行调度混乱,河道生态流量无法保障。建议以河长制为抓手,加强工业及城镇生活点源污染治理,优化区域水资源配置,推进河道综合治理、理顺管理机制体制,构建快处高效的治理执行体系,形成全社会参与的南盘江治理局面,方能促进南盘江水生态环境质量持续改善,惠及民生,还河于民。
文摘松滋河是连通长江与洞庭湖的主要通道。自1950s以来,随着下荆江系统裁弯及葛洲坝、三峡等水利工程相继建成,松滋河分流量呈现阶段性减少。基于系列水文和河道原型观测资料,分析了三峡水库蓄水后松滋口分流变化特征及其影响因素。结果表明:①三峡水库蓄水后,松滋口年分流比基本稳定在7%左右,没有明显趋势性变化;②当枝城站出现>25000 m 3/s流量时,蓄水后松滋口分流能力明显提升,特别是蓄水后前10 a;③三峡水库主汛期洪水调度影响较小,而汛末蓄水对口门分流产生消极影响;④荆江干流河床冲刷降低了口门处中枯水位,对松滋口分流产生不利影响;⑤芦家河浅滩航道整治工程实施在一定程度上对维持口门段中枯水位发挥了关键作用,口门河段河道采砂在一定时段改善了口门进流条件。
