太湖底泥的生态疏浚工程

指出:①太湖底泥是湖体水生态系统的基本要素,也是重要的内污染源.②在湖泊外源污染得到一定控制后,以减少内源污染负荷为目的的生态疏浚是控制内源污染效果较为明显的工程措施.③太湖底泥疏浚属水生态整治工程,以最大可能取走污染物、改善水生态环境为控制目标,生态疏浚是局部的薄层精确疏浚.经采用生态调查方法,查明太湖底泥总蓄积量为19亿m3.主要疏浚范围是底泥厚且污染重的重点功能湖区,如梅梁湖、贡湖等.依据太湖底泥的污染特性,疏浚深度以40～50cm为宜,并应为后续生物修复技术介入创造必要的生态环境条件.密闭无扰动抽吸式头部掘进是关键,冬初至春末为最佳施工期.排泥场防渗、尾水处理达标后排放、淤泥安全处置和资源化利用是生态疏浚的环保要求.     

太湖底泥的生态疏浚工程──太湖水污染综合治理措施之一

底泥是太湖富营养化营养物质的内污染源。太湖淤泥沉积面积约占全湖的69．84％，其分布受湖泊水动力特点的制约，粒度组成与湖周围土壤粒度和污染物有关。底泥表层富含营养物质，总氮为0．022％～0．45％，总磷为0．039％～0．237％，是引起湖体富营养化和藻类爆发营养盐的重要来源之一。自80年代以来，底泥中营养盐含量呈上升趋势，同时受制约于湖水水质变化，呈同步急剧增长的趋势。在强化外源综合治理的同时，对水源地和重要保护水域实施府泥生态疏浚，对改善湖泊生态环境有很大作用。生态疏浚有别于工程清淤，其目的是为清除含高营养盐的表层沉积物，属生态环境工程范畴。实施的技术路线、方法、设备、作业方式、清除最佳作业期等都有特殊要求。疏浚淤泥处理应注意防止二次污染。     

对太湖疏浚底泥处置方式的思考

针对底泥疏浚工程传统排泥场处置方式存在的问题,结合太湖及周边区域自然地理环境和经济社会特点,以及太湖水环境综合治理的需求,提出了将太湖疏浚底泥用于湖滨带生态修复基底和排泥场淤泥循环利用的两种处置方式。     

不同污染类型底泥处理方式研究

对于不同污染类型底泥,其处理与处置方式存在差异,为使底泥处理与处置更加高效、合理,应对不同污染类型底泥的处理与处置方式进行分类、分区研究。通过对国内外关于高营养盐、重金属、有机物和复合污染等4类污染底泥的处理技术进行总结和梳理,并对工程中常用的原位覆盖、原位生物修复和异位化学修复技术应用效果和应用条件进行分析,提出了对于污染负荷大、污染物种类复杂的区域可采取底泥环保疏浚技术,并在疏浚后配合生态修复工程,建立强大的生态自净系统,其中疏浚淤泥需及时进行合理、安全的处置,对重金属单一污染淤泥采取"清淤干化+稳定化+资源化利用"处置模式,对有机物单一污染淤泥采取"清淤干化+化学氧化+资源化利用"处置模式,对复合污染淤泥采取"清淤干化+化学氧化+稳定化+资源化利用"处置模式;对于污染程度较轻的区域,可采取生态安全性高的原位控制技术,如原位覆盖技术,并辅以水生植被修复,其中辅助的生态修复工程需综合考虑水生动植物生长的水质、基质和外界条件,使其发挥最佳效果。     

太湖重污染底泥的生态疏浚

太湖湖盆沉积物(底泥)是湖体营养盐的储积库，是重要的污染源。在湖泊外源污染治理得到一定成效后，以减少内源污染负荷为目的疏浚是控制湖体内源污染效果较为明显的工程技术措施之一。太湖底泥疏浚有别于港口、河流疏浚，属生态工程范畴。其基本核心要解决；疏浚必要性，疏浚区域范围、疏浚适宜深度、疏浚技术工艺、二次污染防治，环境风险评估，底泥合理处置和基底修复等生态技术问题。     

苏州河底泥疏浚关键技术研究

苏州河底泥疏浚有别于常规工程疏浚，故疏浚断面不能简单以排水断面确定。由于目前我国尚无河湖底泥污染物控制标准，设计只能根据底泥污染垂直分布特性、土壤质量标准、苏州河生物毒性指标、土壤背景值等情况，参考美国、加拿大以及欧州一些国家和我国香港、台湾地区的研究成果和实践经验，研究确定苏州河底泥污染物控制指标，确定期望疏浚泥面线，并综合考虑防汛墙稳定、景观水库、施工控制等要求，对65个典型断面逐个拟合确定了疏浚设计断面。其工程经验可为同类工程参考。     

苏州河底泥污染物控制指标的研究与应用

本文根据苏州河底泥污染特性、土壤环境质量标准、苏州河生物毒性指标、土壤背景值,参考国内外疏浚工程实践,大胆创新,提出底泥污染物控制指标,确定了期望疏浚深度与疏浚规模;本文以苏州河底泥疏浚为工程实例,初步探讨了河湖底泥污染物控制标准,其方法具有一定的科学性,值得同类工程推广应用。     

太湖疏浚底泥的脱水技术研究

太湖环保疏浚工程产生大量高含水率的疏浚底泥,处置不当就造成十分严重的二次污染。由于疏浚底泥重金属含量基本低于农用污染物控制标准,合理施用即可改良土壤、节约大量处置费用,不仅能够解决我国土壤退化的问题,还能带来良好的经济效益。为实现底泥的快速脱水,便于资源化利用,同时针对疏浚底泥渗水性差致使底部排水法困难的缺点,采用了絮凝剂、脱水剂与真空抽滤相结合的方法处理疏浚底泥。试验结果表明:加药实验组在520h内可将疏浚底泥的含水率从70%降至41.9%,而不加入药剂的空白组实验含水率只降至60.3%就无法继续脱水。所用脱水剂不与絮凝剂、淤泥和淤泥中的有机质等成分发生化学反应,且对出水水质无明显影响,出水的浊度、CODMn以及pH值在废水排放的规范之内。     

挖槽疏浚在太湖生态清淤中应用研究

太湖水环境综合治理作为国家工程已被提上议事日程,措施正在逐项落实。出于治理太湖局部内源需要,修复水生态的底泥清淤试点工作已经展开。太湖湖底大量的流泥应是清淤的重点,但是由于生态清淤技术的成本较高、规模较小、占用大量堆场、淤泥再次污染等问题,建议太湖清淤与挖槽疏浚并举的模式,以克服上述诸问题,并扩大内源治理的效果。     

一种新型淤泥脱水装置在太湖生态 清淤工程中的应用

针对太湖生态清淤工程中底泥产生量大、力学性质差和含水率高等处理难点,采用技术比较先进的美国IMS全机械淤泥脱水装置对太湖生态清淤泥浆快速处理,并增加深度脱水、尾水净化等技术措施优化淤泥处理工艺。实践表明：IMS淤泥脱水装置能即时分离淤泥中大量的沙砾等无机杂质,将清淤底泥分类处理为满足工程要求的土工材料。工艺优化后,淤泥中的有机悬浮污染物也被快速分离出来,脱水后干泥含固率达到62.2%,处理后的尾水满足排放要求。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

Serial discontinuities in a Rocky mountain river. II. Distribution and abundance of trichoptera

River regulation in the headwaters and middle reaches of the Gunnison River, Colorado, significantly altered distributions and abundances of Trichoptera fauna. Twenty-five species were collected from mainstream samples, with the greatest species richness occurring at an unregulated, rhithron segment above the central reach dams. At sites immediately below the three hypolimnial-release dams and a reregulation dam, species richness was reduced 35–90 per cent and abundance > 95 per cent. Net-spinning caddisflies were the dominant trichopterans at unregulated sites; Arctopsyche grandis in the upper reaches (218 organisms, 586 mg dry mass m^?2) and Hydropsyche cockerelli, H. occidentalis and Cheumatopsyche pettiti in the lower river (9041 total organisms, 6621 mg m^?2), downstream from the last dam. The observed distributional pattern of low trichopteran densities in dam tailwaters and high hydropsychid densities at sites 60–80 km below the central reach dams is a classic expression of continuum resets and adjustments in response to stream regulation as predicted by the Serial Discontinuity Concept.     

Surveying for Water Resources

Abstract

A professional Land Surveyor (Geomatician) describes the Hydrogeologists' survey requirements of a major water resources assessment for the government of The Sultanate of Oman (1992 to 1996). The need for objective specifications is stated. Specialist terms like geoid, spheroid, Mean Sea Level are explained and how to relate spheroidal levels to the geoid. Methods like traditional survey, satellite survey, and photogrammetry are introduced. The paper encourages coordinated working for the benefit of water resource assessment and recommends employment of the professional land surveyor for major studies.     

库水波动下库岸边坡地下水浸润线解析解及误差分析

解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明：库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。     

Changes in Summer Irrigated Crop Area and Water Use in Southeastern Turkey from 1993 to 2002: Implications for Current and Future Water Resources

Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region.     

The Impact of Economic Development on Water Pollution: Trends and Policy Actions in Malaysia

The paper examines the impact of development activities on water pollution in Malaysia. Hence, the main objective of this paper is not just to examine the trends of development-induced water pollution around the region of the country but to know where the problems are and the policy measures taken by the government. It evaluates the probable causative relationship between problems introduced due to technology employed in water pollution control and governmental policy measures. It examines the relationship between development indicators as sources of pollution and polluted rivers over a period of 12 years. The findings of the paper have shown that despite the policy enforcement actions against the identified sources of water pollution, all the three development indicators (chosen based on those identified sources) still accounted for high percentage of river pollution in Malaysia. The findings of the paper were used to identify the central fact of the location of the problem. Some crucial conclusions of where the problems likely to be, as reflected in the findings, are: (a) the issue of interactive-effects between pollutants that many policy-makers are not aware of. This is when policy measures concentrate only on one source of water pollution; (b) the enforcement strength and/or effectiveness of policy measures themselves; (c) financial constraints to invest in appropriate technology especially sewerage systems for controlling human source of water pollution in the country; as well as those confronting small polluting industries (d) finally, lack of cooperation between government and private business firms to comply with regulatory policies for water pollution control.     

浅淡溢洪道改扩建方案与选择

溢洪道改扩建和进行溢洪道方案布置，要择优选取溢洪道进口型式、防冲消能工，以使其工程量省、施工快、运行管理方便     

Intangible Flood Damage Quantification

Flooding is a natural disaster that may cause tremendous tangibleand intangible damage to the national economy. The tangible damage assessment, i.e. the monetary value of all direct and indirect physical damages, has already been studied, whileintangible damages have not yet been taken into account. Thisarticle, therefore, is the first systematic attempt to assess bothtangible and intangible damages. The new proposed Anxiety-Productivity and Income Interrelationgship Approach (API) has been developed to quantify the intangible damage in monetary terms. The Bangkok area has been selected as the research area because several severe flood events have occurredthere over the last two decades. The 1983 Bangkok flood caused 6600 million baht in damage, according to estimates by the National Statistical Office (NSO). This article examines the totalflood damage (including the intangible damage) at different flood magnitudes. Case studies with and without flood mitigation projects are studied and compared. Furthermore, thisarticle also discusses the improvements over the conventional approach offered by the new API methodology.