共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
该文介绍福鼎市桐山溪河道整治工程中橡胶坝的设计与施工情况,指出该坝型在低水头、小流域的河道清水工程中的应用前景。 相似文献
3.
李双艳 《河北水利水电技术》2013,(6):52-54
组装式连拱闸适用于低水头山区河道,具有结构简单,闸顶可溢流,景观效果好,施工及维修方便,使用寿命长,造价低等特点。橡胶坝适用于低水头平原河道,具有结构较简单,坝顶溢流,使用寿命短,充塌坝时间较长,冬季冰冻问题严峻,运行管理复杂等特点。文章结合工程实际应用,讨论比较了两个建筑物的特点及适用范围。 相似文献
4.
通过对山口水电站泄洪底孔和溢流表孔的泄流能力及消能方式分析计算与水工模型实验相互验证,表明该工程底孔和表孔泄流能力和流态设计计算与水工模型试验基本一致;但由于对河道覆盖层和基岩抗冲能力估计不足,消能工和下游防护都有较大的变化,最终通过水工模型试验调整。结果表明山口水电站工程消能方式研究为今后大流量、低水头、低抗冲流速河道修建消能工提供了经验和设计依据。 相似文献
5.
该文介绍福鼎市桐山溪河道整治工程中橡胶坝的设计与施工情况,指出该坝型在低水头、小流域的河道清水工程中的应用前景。 相似文献
6.
乌斯满枢纽工程位于塔里木河中游的乌斯满河口附近,地处新疆巴音郭楞蒙古自治州尉犁县境内,距尉犁县96km,距库尔勒市148km,工程的主要任务是保证乌斯满河下游灌区农业生产及两岸生态用水,合理利用和调配塔河水资源,保证安全泄洪,加强河道的统一管理。本文深入分析了该枢纽的布置,为以后低水头多泥沙河流的类似工程提供设计经验。 相似文献
7.
8.
广东省境内河流多为宽浅式河床,所修建的电站大都是低水头河床式电站。低水头河床式电站一般具有水头低、流量大、水库淹没问题敏感、施工期要求尽量减少断航及河床覆盖层一般较厚等特点。通过分析低水头河床式电站的特点,对清远水利枢纽工程的枢纽布置方案进行了比较和选择,为同类型工程的设计提供参考。 相似文献
9.
低水头引水枢纽防沙布置研究 总被引:1,自引:0,他引:1
随着低水头引水枢纽的广泛应用,国内外在枢纽引水防沙布置方面积累了许多成功经验。论述了不同类型的低水头枢纽布置型式、适用条件以及枢纽河势规划及河道整治。 相似文献
10.
水能资源是水资源的重要组成部分,中小河流水能开发是积极响应开发利用清洁、可再生能源战略的重要组成部分.通过分析已建水库下游低水头梯级开发,结合灌溉渠道工程、大型闸坝工程和河道景观湿地改造工程等进行水能开发利用的特点,对中小河流如何构建生态友好的水能开发利用、体现对社会环境的关注、兼顾河流生态系统健康和可持续性需求的水能资源开发利用方式进行了探讨. 相似文献
11.
《给水排水》2014,(9)
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. 相似文献
12.
根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。 相似文献
13.
The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects. 相似文献
14.
15.
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。 相似文献
16.
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. 相似文献
17.
Mutlu Ozdogan Curtis E. Woodcock Guido D. Salvucci Hüseyin Demir 《Water Resources Management》2006,20(3):467-488
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. 相似文献
18.
19.
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. 相似文献
20.
In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment. 相似文献