盘锦近岸海域无机氮污染因子削减与预测

通过盘锦海域的海水质量和水文分析,建立盘锦海域潮流场模型。在不同输入条件下,利用潮流场模型对近岸海域的无机氮污染物含量变化响应进行模拟,得出3条河流(辽河、大辽河和大凌河)无机氮削减值,在此条件下可实现近岸海域无机氮达标要求。     

北黄海北部海域潮余流的模拟研究

基于二维水动力模型,在仅考虑潮流作用条件下,通过计算欧拉余流和拉格朗日余流并结合粒子追踪方法研究了辽宁大连—朝鲜龙渊郡连线北侧的北黄海北部海域的潮余流结构和粒子运移的趋势。结果表明:欧拉余流和拉格朗日余流流速整体较小,呈现由南向北的流向,但在獐子岛及长山群岛的附近岛屿和朝鲜半岛沿岸的海域欧拉余流和拉格朗日余流流速较大。对比粒子追踪计算的结果与欧拉余流和拉格朗日余流的结果表明,流向与粒子运移路径基本一致。该海湾的余流及粒子运动规律特点对辽东半岛东岸及朝鲜半岛西侧海域的排污及污染控制有重要的借鉴意义。     

海口湾人工填海前后冲淤演变数值模拟

为了解近年南海明珠项目、葫芦岛、秀英港扩建工程等人工填海工程对海口湾冲淤变化的影响,基于FVCOM海洋数值模型,对研究区人工填海前后潮流场、波浪场及冲淤变化进行了数值模拟。人工填海后,综合各条件下的冲淤情况,海口湾受潮流和波浪共同作用大部分区域处于淤积状态,年淤积量预测值为0.1～1.0 m;白沙角等局部区域处于侵蚀状态,年冲刷量预测值为0.1～0.3 m;受海口湾人工填海工程的影响,秀英港航道的水动力条件减弱,对通航条件改善有利,需加强航道的水深监测和定时的清淤工作;在南海明珠人工岛南侧波影区泥沙堆积会形成向海的舌状的突出体,其两侧海岸形成侵蚀后退带,需人工补沙等措施以保证岸线稳定。     

关于污水管网淤积的技术研究

对某城市污水管网建立SWMM模型进行水力模拟,并对其运行后得到的流速、充满度等数据进行综合分析。研究表明,流速慢且充满度大的管段更容易产生淤积且较为严重。据此找出研究区域内容易发生淤积及淤积严重的管段,并确定管网的淤积风险级别。通过对找出的易发生淤积及淤积严重管段进行校核,验证了分析结果的正确性。通过建立模型并分析流量及充满度,可有效预测排水管网的易发生淤积及淤积严重管段。     

平流层冬季内纬向风十年际变化形势差异分析

使用ERA-Interim 1979—2000年冬季各月(12月、1月、2月)的风场再分析资料,分析研究了全球平流层冬季内纬向风场的分布特征及十年际变化形势。结果表明：北(冬)半球平流层与对流层均盛行西风,但平流层冬半球急流核比对流层急流核纬度偏高;南(夏)半球平流层与对流层盛行风向相反,且平流层夏半球急流核比对流层急流核纬度偏低。南半球中高纬地区自上层到下层平均纬向风变化均为正变化;赤道及北半球低纬地区在平流层中上层一直为正变化,在对流层为负变化;北半球中高纬及极区平流层纬向风变化较低纬度更为明显,其中极区最为明显。     

环境保护与移民安置和谐推进同步发展——嘉陵江亭子口水利枢纽移民安置区环境保护纪实

嘉陵江亭子口水利枢纽工程库区位于四川省北部边缘的广元市境内,地处秦巴山西段,水库淹没和移民安置区涉及广元市利州区、元坝区、剑阁县和苍溪县等35个乡(镇),迁建集镇13个。该区域的嘉陵江沿岸水土流失严重,生态环境遭到破坏;部分支流水污染严重、水质较差;自然灾害频繁。枢纽工程业主嘉陵江亭子口水利水电     

水系连通改善入海闸控河流水质效果评估——以练江流域为例

为科学评估水系连通与闸站调度对平原河网水质的改善效果，以典型重污染区域练江流域为例，构建练江水系一维河网水动力-水质耦合数学模型，模拟不同水系连通、闸站调度方式对练江水质的影响，采用NH₃-N浓度变化定量评估水系连通、闸站调度对练江流域水环境质量的改善效果。结果表明：增加引水天数可显著改善练江水系水质，且随着引水时长的增加，NH₃-N浓度改善率先下降后提高最终趋于稳定；多水源联合引水与闸站调度相结合对练江水质改善起到了一定的促进作用。可为改善练江流域水质状况及水环境长效管理与科学决策提供理论依据，同时也为我国平原河网闸控河流水系连通与闸站调度提供重要参考。     

中国大唐集团公司

中国大唐集团公司四川分公司于2006年12月22日在四川省成都市正式成立。在四川省委、省政府的大力支持下,按照中国大唐集团公司的战略部署,目前四川分公司负责嘉陵江亭子口水利枢纽工程、甘孜南部水电站群等水电工程项目的开发和建设工作。     

海底悬空管线动力响应分析及悬跨治理

针对海底连续悬空管道的动力响应分析,文章采用ADINA有限元分析软件建立管土耦合的非线性有限元模型。讨论了双跨管道中间土体长度的变化对管跨动力响应的影响规律;与单跨管道对比分析了双跨管道中相邻跨之间的影响。通过对某海域海底悬空管线振动响应的实测,结合仿真分析结果探讨了长度较大海底悬空管线的治理方法。     

塔里木河中游输水堤防外的地下水质变化分析

针对塔里木河中游输水堤防修建与生态保育的问题,结合对沙子河和阿其河两个断面地下水质的监测资料的分析,对输水堤防修建后堤防外地下水质的时空变化进行了探讨,揭示了在输水堤防影响下堤防外地下水质变化的初步规律.结果表明：沙子河断面和阿其河断面洪枯期地下水矿化度的变化规律由于堤防的修建而被改变,同样在堤防外侧,由于无地表水经过,沙子河断面地下水矿化度远高于在有生态闸定期放水的阿其河断面,因此,生态闸建设对抑制由于输水堤防影响而导致的水质修建具有积极作用.     

Sediment Flux to the Sea as Influenced by Changing Human Activities and Precipitation: Example of the Yellow River,China

Since the 1970s, the sediment flux of the Yellow River to the sea has shown a marked tendency to decrease, which is unfavorable for wetland protection and oil extraction in the Yellow River delta. Thus, an effort has been made to elucidate the relation between the sediment flux to the sea and the drainage basin factors including climate and human activities. The results show that the sediment flux to the sea responds to the changed precipitation in different ways for different runoff and sediment source areas in the drainage basin. If other factors are assumed to be constant, when the annual precipitation in the area between Longmen and Sanmenxia decreases by 10 mm, the sediment flux to the sea will decrease by 27.5 million t/yr; when the precipitation in the area between Hekouzhen and Longmen decreases by 10 mm, the sediment flux to the sea will decrease by 14.3 million t/yr; when the precipitation in the area above Lanzhou decreases by 10 mm, the sediment flux to the sea will decrease by 17.4 million t/yr. A multiple regression equation has been established between the sediment flux to the sea and the influencing factors, such as the area of land terracing and tree and grass planting, the area of the land created by the sediment trapped by check dams, the annual precipitation, and the annual quantity of water diversion by man. The equation may be used to estimate the change in the sediment flux to the sea when the influencing variables are further changed, to provide useful knowledge for the environmental planning of the Yellow River drainage basin and its delta.     

Worldwide Tidal Current Energy Developments and Opportunities for Canada's Pacific Coast

Recent rapid advances of tidal current energy extraction (TCEE) technologies and resource analyses suggest in excess of 20,000 GWh/annum of electricity may be realistically exploitable in the near term off Canada's West Coast. Moreover, because tidal currents have a semi-diurnal (or, in some locations, diurnal) periodicity, and can be predicted and quantified on a spatial and temporal basis, this resource confers a distinct advantage over most other renewables, and, therefore, may achieve supply security.

In this study, TCEE technologies are assessed on the basis of energy delivered, environmental intrusion and economic viability. As such, relevant issues including resource characteristics, site selection, conversion efficiencies, capacity factors, power densities, hydrodynamic feedbacks, and grid integration are addressed.     

沿海油田污染物入海通量及优化管理

胜利油田所在的黄河三角洲诸条河流按入海类型分为三种形式：设有防潮闸的感潮河；设有排涝站的入海河；直流入海的感潮河。按照各河流入海段面、流速、流量和水体污染物浓度，建立起各种感潮河污染物入海通量模式，计算结果说明沿海油田排放的石油类污染物入海通量为1456t／a，COD入海量为5720t／a。根据各条入海河流不同功能和污染物入海量，按照国家地表水质标准，制定出入海河流环境组合目标，用总量控制方法提出污染源削减要求，以保证黄河三角洲沿海滩涂环境质量。并以污染物入海通量、河流径流量、污染物自净系数和污染物削减量等因子建立各条河流优化管理模型，为保护环境提供对策。     

崇明岛地下水资源的利用现状及保护措施

未来地下水资源短缺,特别是由于地面沉降、地表退化、海平面上升等引起的地下水位下降,将对沿海地区的地质环境及人类的生存发展产生极大的影响。通过对崇明地区地下水资源利用现状以及影响地下水位下降的影响因素分析,提出了改善传统的灌溉系统来减少地下水资源的使用、海岸沿线修建人工湖泊防止海水入侵、鼓励农民大面积种植水稻、制定管理措施严格控制地下水的开采总量、进一步加强崇明岛地面沉降动态监测与研究等相应的防范措施。强调控制地下水位的下降,以减轻淡水资源短缺所造成的危害,具有特殊而重要的意义。     

Irrigation development and its environmental consequences in arid regions of India

The present paper examines the nature and dimensions of environmental transformation induced by canal irrigation in the arid region of India. The case study pertains to the Indira Gandhi Canal comand area in Rajasthan where the density and area of vegetation cover have increased due to afforestation, and the cultivated area has expanded due to irrigation. Consequently, there has been a perceptible improvement in the structure and fertility of sandy soils, but it would require a herculean effort on the part of the canal authority and local people to reduce soil erosion and siltation in the lower parts of stage I and the entire command area of stage II. Moreover, the water table has been rising rapidly throughout the command area of stage I. About half of the command area and adjoining Ghaggar basin in Ganganagar District will be facing the danger of waterlogging by the turn of the century. The incidence of irrigation-induced alkalization is higher in the lower parts of stage I. Soil alkalinity has appeared within five years of the introduction of irrigation in the interdunal basins and is manifested as a strong salt regime or calcareous pans near surface. This calls for immediate reclamation of the affected area and prevention of its expansion by altering the strategy of irrigation development, by changing cropping patterns, and by providing soil drainage.     

A港区海上溢油事故数值模拟预测

为研究A港区溢油事故的影响,通过MIKE21软件建模、并综合考虑风向、风速和潮流等因素设定6种不同情景进行模拟预测。结果显示,在不利风条件下,72 h油膜扩散距离为0.7~39.50 km,扫海面积可达0.03~142.97 km²,风场对油粒子的漂移和扩散起决定性作用,潮流场次之。通过模拟预测,为加强区域溢油应急联动、充分利用周边溢油应急资源,做好溢油应急防范提供参考。     

Tidal wetlands natural and human-made changes from 1973 to 1979 in Delaware: Mapping techniques and results

Coastal wetlands are dynamic ecosystems subject to the manipulative powers of both humans and sea. Areal changes in the tidal wetlands of Delaware were monitored over a six year period with color and color infrared aerial photography. Wetland changes were interpreted directly from the photography and were classified according to natural and legal categories of change. Human activities in tidal wetlands destroyed an average 8.1 ha of wetlands annually from 1973 to 1979. During the same period 3.9 ha of wetlands were eroded and 2.8 ha of wetlands were formed annually by natural processes. A total net loss of 55.1 ha of wetlands was estimated for the six year period. The enactment of state and federal legislation protecting wetlands in 1972–1973 resulted in a decrease of wetlands loss in Delaware from an average of 179.7 ha yr^?1 from 1954 to 1971 to the 8.1 ha yr^?1 determined by this study. The dynamic nature of these wetlands exemplifies the need for frequent monitoring and remapping, if an effective and accurate management program is to remain in operation     

DYNAMICS OF WETLAND DEVELOPMENT AND RESOURCE MANAGEMENT IN LAS VEGAS WASH,NEVADA1

ABSTRACT: This paper examines the co‐evolution of the Las Vegas, Nevada metropolitan area, Las Vegas Wash ecosystem‐a downstream riparian wetland‐and Wash management as a case of urban‐environment dynamics. Since Las Vegas Wash provides the primary drainage for Las Vegas, changes in the urban system lead to changes in the Wash and its ecosystem. The population of the drainage area has grown from approximately 1,000 people in 1900 to more than 1.3 million in 2000. This phenomenal population growth led to increased Wash flow, from less than .03 m³/sec (1 ft³/sec) to over 7.4 m³/sec (260 ft³/sec), and consequent ecological changes from a nearly dry wash to a rich wetland, and now to an eroded system. As the Wash ecosystem changed, valuation of Wash characteristics by residents and resource managers also changed, shifting the focus of management and use, which ultimately led to further ecosystem changes. Reciprocal relationships among human activity, environmental change, and management in this urban area highlight the need for a comprehensive and dynamic systems perspective and adaptive approaches in urban environmental management and make this a particularly compelling case study. This paper describes a conceptual systems framework for adaptive urban‐environment management derived from this case.