新疆托什干河沙里桂兰克至秋格尔渠首河段水电开发方案选择

通过对托什干河沙里桂兰克至秋格尔渠首河段水电开发方案的研究与综合比较,从梯级工程地质条件、水能指标、工程布置及施工条件等方面选择了推荐方案:分别是别迭里一级、别迭里二级及牙满苏引水式开发。     

湄江河湄潭县政府新区河段防洪堤设计

湄江河湄潭县政府新区河段,基本没有防洪排涝设施,每遇暴雨就产生峰高、量相对较小的洪水汇流,造成县城、大片农田及村寨发生洪涝灾害。结合工程区的地形地质、河段治理范围等条件,对防洪堤布置、防洪堤轴线选择、堤型等内容进行了详细的设计分析,尤其对堤防结构、岸坡稳定性、护坡稳定性、河道清淤进行了详细的论证研究。推荐采用技术上可行、经济上优越的浆砌石护脚、护坡结合卵石护坡+草皮护坡的防洪堤设计方案。     

上海地区防汛墙加固工程关键问题

针对上海地区防汛墙在历年除险加固工程建设中出险原因分析不明、设防水平不一致、规划标准与现状存在矛盾、设防标准与现实发展不相匹配、加固规模拟定不合理等关键问题,通过收集出险事例,剖析了造成防汛墙出险的主要因素和各因素之间的关系,对比了规划标准、设防标准中的矛盾,分析了除险加固规模拟定不合理的原因。结果表明:防汛墙出险原因主要包括边界条件的变化、船只违章运行、结构安全度不足、临近或穿河工程影响及地面沉降等,不同出险状况由一种或多种因素造成;设防标准应从整体防汛水平校验,采用实测水文资料修正,提高中、上游岸段安全等级;除险加固工程规模应综合考虑现状工情、水情、出险原因、规划和规范标准的变化等原则确定;对码头、船闸等特殊岸段需设置限制性要求。     

黎平双江水电站拱坝开孔应力计算

在水电站工程建设中,拱坝因为其特有的优势因而被广泛使用在水电站中。在对拱坝进行设计的过程中,其开孔应力计算是一项重要的组成部分,对于拱坝的合理设计具有重要的作用,因此必须采取有效的措施对拱坝的应力进行计算。文章采用ANSYS建模分析在黎平双江水电站拱坝上开孔后对坝体应力问题,并根据计算成果分析开孔对拱坝的影响。     

城区穿河隧道工程安全施工关键技术探究

随着城市地下空间的开发,盾构穿越已有河道的现象越来越普遍。如何合理地安排施工过程,确保河道上建筑物和施工安全尤为重要。以南京地铁四号线某区间盾构穿越秦淮河线路工程为例,总结克服施工过程中盾构隧道下穿河道和侧穿桥墩技术难题的经验,保证其安全、顺利地通过秦淮河河段。     

飞来峡水利枢纽对北江河流综合影响研究

综合分析飞来峡水利枢纽平面布置、运行管理等方面,对北江河流水流流态、河道变化、水质、水温、水生物等方面的影响。枢纽建设运行有不利的影响因素,对河流生态方面的影响提出改进的建议。     

城市近郊蓄滞洪区非洪水期调度运行管理研究--以治理深圳河第四期工程为例

针对城市近郊蓄滞洪区的功能和运行管理特点,以治理深圳河第四期滞洪区工程为例,从滞洪区地形和区域布置合理性着手,分析滞洪区与上下游河道水力高程特点,开展了非洪水期蓄水、泄水过程模型试验研究。建立了基于理想理论的湿地水体环境水体更换周期预测模型,研究多因素条件下的滞洪区湿地水体置换周期。为保障非汛期滞洪区生态湿地景观水位和良好水质状态,根据上游河道来水条件,制定了滞洪区进水闸、泄水闸调度备用运行方案。     

渭河流域水沙关系分析

本文以渭河流域为研究对象,对流域水沙关系进行了分析研究。选择咸阳以下四个水文站研究流域水沙关系的变化,结果表明:年径流量和输沙量呈正相关关系,在径流序列发生第一次变异之前,水沙关系优于第一次突变之后,即在1970年后,受人类活动的影响,水沙关系朝着不协调的方向发展。     

USE OF NATIVE AND NONNATIVE NEST PLANTS BY RIPARIAN‐NESTING BIRDS ALONG TWO STREAMS IN NEW MEXICO

Nonnative plant invasions are a management concern, particularly in riparian forests, but little is known about mechanisms through which they influence vertebrate communities. In the American Southwest, native trees such as cottonwood (Populus spp.) are thought to provide better habitat for breeding birds than nonnative plants, which are more tolerant of human‐altered conditions. To evaluate effects of riparian forest composition on riparian‐nesting birds, we examined nest plant use along two rivers in New Mexico that differed in abundance of nonnative vegetation. Of the nests we observed, 49% along the Middle Rio Grande were constructed in nonnative plants, compared with 4% along the Gila River. Birds in the canopy and cavity‐nesting guilds constructed less than 5% of their nests in nonnative plants along either river. At the Middle Rio Grande, birds in the subcanopy/shrub guild constructed 67% of their nests in nonnative plants. Despite the relatively low availability of cottonwoods, they were used by greater numbers of species than any other woody plant at either river. Riparian obligates and species of conservation concern in the canopy and cavity guilds were especially dependent on cottonwood and Arizona sycamore (Platanus wrightii). Our results show that, although nonnative trees and shrubs support large numbers of nests for certain birds, cottonwoods and other large native trees are disproportionately important to riparian bird communities. Copyright © 2013 John Wiley & Sons, Ltd.     

DAILY AVERAGED 2D WATER TEMPERATURE MODEL FOR THE ST. LAWRENCE RIVER

A daily averaged two‐dimensional water temperature model has been developed for the freshwater part of the St. Lawrence River, between Lake St. Louis and Trois‐Rivières (Québec, Canada). The model was first calibrated and validated for the area of Lake St. Pierre, a natural enlargement of the river subject to strong lateral and longitudinal thermal variations. Forecasts from the Global Environmental Multiscale model were used in preference to observations from meteorological stations for model inputs, both to increase the spatial resolution and ultimately to allow the water temperature model to be used in predictive mode. The resulting model provided daily water temperature estimates with an overall root mean square error (RMSE) of 1.18 °C and a Nash–Sutcliffe coefficient of 0.44. Comparisons between Landsat images and simulations demonstrated that the model not only simulated accurate water temperature values but also showed the adequacy of the model in general. It not only simulated local water temperature relatively accurately but also provided a good representation of the spatial water temperature patterns within the study area. The error varied between deep and shallow water areas. In deeper water, the overall RMSE is 0.41 °C, and the modified Nash coefficient rises up to 0.92. Because shallow water areas are subject to greater variations, longer, more spatially dense data sets will be needed to refine the hydrodynamic and thermal budget models for those specific areas. Copyright © 2013 John Wiley & Sons, Ltd.