季节性冻土地区衬砌渠道冻胀及防治措施

渠道冻胀及其防治问题是我国北方灌区渠道工程中的一个重要问题，文中从渠基土的冻胀性能、地下水位的埋深、渠道衬砌材料和结构及渠道走向等四个方面，较深入地分析了产生渠道冻胀破坏的机理，总结了各地近年来渠道冻胀的研究成果，提出了渠道冻胀防治的各种措施，对渠道防渗防冻胀工程建设具有参考价值，并指出今后应进一步开展研究的若干问题。     

开发渠道经济大有可为

如何充分利用渠道管理范围内的土地,并且管好用好工程,扩大效益,造福于民,是摆在我们水管单位面前的一个课题。桃曲坡管理局在下高埝南支渠上尝试开发渠道经济,栽植果林,收效明显,为水管单位搞好渠道维修养护,壮大自身经济实力,提供了一条新的途径。     

汾河二坝西干渠渠堰滑坡原因及对策

汾河二坝西干渠渠堰滑坡现象是由干渠从二坝向三坝送水过程中遇到的问题,分析其原因有渠道运行问题和渠道管理问题。本文提出相应的解决措施,以防止渠堰再次发生滑坡,保证渠道安全运行。     

渠道施工中应注意的问题

在整个防漏工程中,渠道施工工程是相当关键的环节,渠道施工工程的质量将在很大程度上影响到相应防漏工程的质量,并对百姓的日常生活产生一定的影响。渠道施工工程主要包括3个大的方面:一是渠道开挖;二是渠道的填筑;三是渠道的衬护。围绕渠道施工中常见的问题出发,对渠道施工中应注意的问题进行了相关的分析。     

衬砌渠道伸缩缝漏水原因分析及对策

运城地区截止１９９６年底，已建成各类固定渠道２７７９６ｋｍ，其中累计衬砌渠道长１７９５８ｋｍ，占到固定渠道的近２／３，这些衬砌防渗渠道都设置了不同形式的伸缩变形缝，为保护渠道起到了一定的积极作用。但由于部分灌区不注意伸缩缝的设计，施工和管理，以致造成了一定的不良后果。     

渠道防渗技术介绍

1　渠道防渗的优点[1](1)提高渠道的抗冲能力,保证渠道可以长时间使用;(2)减少渠道糙率,加大流速,增加输水能力;(3)减少渠道渗漏对地下水的补给,有利于地下水水位的控制,有利于盐碱化的防治;(4)减少渠道淤积,防止渠道生长杂草,节省维修费用和清淤劳力,降低灌水成本。2　渠道防渗的主要方法2 1　土料压实防渗[1,2]土料压实防渗就是在渠床表面建立一层压实的土料防渗层,主要是压实渠床土壤以减少渗漏,或利用粘土、砂粘土建立压实的防渗层等。在进行压实前,应清除渠底和渠坡的杂物。2 2　土料护面防渗[1,2]三合土可作为渠床表面的防渗材料,铺筑…     

用混凝土衬砌U形槽渠道的设计与施工

为了减少渠道的渗漏量，提高水的利用系数，辽宁省兴城市修建了一条１６．６ｋｍ的混凝土衬砌Ｕ形槽渠道。本文详谈了混凝土衬砌Ｕ形渠道的断面设计与施工，施工中应用了Ｕ－１６０型渠疲乏衬砌机。Ｕ型混凝土渠道为薄壳反拱结构，防渗效果好，输水能力强，占地面积比梯形渠道省１／３，且抗冻胀性能好。用混凝土衬砌的Ｕ形槽渠道减少了渠道渗漏，是一项重要的节水措施，应用衬机进行渠道施工，不令施工简单效率高，而且渠道断面尺寸     

渠道爆破开挖施工技术

水利工程施工中,渠道开挖施工是重要施工环节,其中合理采取爆破施工方案则是渠道开挖的一大难题,涉及爆破对周边环境的破坏、安全等考虑,需较为慎重。文章通过结合某渠道施工实例,渠道最大开挖高度为14 m,工程对渠道开挖爆破采取分层分段浅孔松动控制爆破,系统地探讨该爆破开挖的具体实施技术,为同类工程提供参考实例。     

现浇混凝土衬砌渠道爆破开挖施工技术探讨

水利工程施工中,渠道开挖施工是重要施工环节,其中合理采取爆破施工方案则是渠道开挖的一大难题。文章通过结合某渠道施工实例,渠道最大开挖高度为1 4m,渠道开挖爆破采取分层分段浅孔松动控制爆破,采用预裂爆破的方式进行爆破开挖施工,以保持边坡的稳定和完整,系统地探讨该爆破开挖的具体实施技术,为同类工程提供参考实例。     

圆弧底渠道水力最佳断面及其实用经济断面

介绍了圆弧底渠道水力最佳断面计算公式、圆弧底渠道的外切梯形渠道水力最佳断面及圆弧底渠道的实用经济断面,对比了圆弧底渠道与外切梯形渠道水力最佳断面及梯形渠道实用经济断面的有关指标。结果表明:《渠道防渗工程技术规范》规定的U形渠道断面及弧底梯形渠道断面并不是水力最佳断面,且距水力最佳断面甚远,圆弧底渠道水力最佳断面水深通过圆心,而规范规定的U形渠道水深比半径大得多,弧底梯形渠道水深比半径小很多,这样便使圆弧底渠道的优势大打折扣。圆弧底渠道水力最佳断面比梯形水力最佳断面优越,规范规定的圆弧底渠道实用经济断面偏离水力最佳断面较远。     

小浪底水库拦沙初期调控流量分析论证

根据黄河下游河道冲淤特性，从减淤角度出发，分析了小浪底水库初期运用的上限及下限调控流量。对得出的调控流量从下游河产可势及工程险情，下游河这减淤效果、水库的淤积发展及综合效益４个方面作了进一步的论证，经综合比选，水库拦沙初期，调控下限流量采用８００ｍ＾３／ｓ调控上限流量采用２６００ｍ＾３／ｓ。以后随首下河道冲刷的发展、河势的调整及整治工程的建设，在条件适宜时，调控上限一可采用３７００ｍ＾３／ｓ，以适     

An evaluation of flood forecasting,warning and response systems in the European Union

This paper presents results from the EUROflood research project sponsored by the European Commission under the EPOCH programme. The paper evaluates levels of development of flood forecasting, warning and response systems (FFWRS) in the European Union with reference to riverine and tidal floods in The Netherlands, the United Kingdom, Germany, France and Portugal. An experimental evaluation methodology, comprising fourteen criteria and five development stages, is used to evaluated FFWRS. Flood forecasting is the starting point, but the research addresses entire FFWRS. Despite advances in flood forecasting, FFWRS often under-perform because warning dissemination and response are unsatisfactory.FFWRS have developed in response to different water resource management problems, varying flood characteristics and different historic, cultural and institutional factors. FFWRS for flood defence and flood emergency response are the main focus, but they are also important for navigation, bridge clearance, fishing, recreation and industry. France, parts of Germany, The Netherlands and England and Wales have relatively mature FFWRS. FFWRS are much less well developed in Scotland, Northern Ireland and Portugal, and important areas for enhancement are identified in all countries. Cross-country and within-country comparisons reveal the potential for knowledge transfer, although ultimately the unique circumstances of each country places limits upon this process.     

Auto CAD应用技术研究

Auto CAD是国际上流行在微机上运行的通用绘图工具软件包。利用这些工具可以开发出各种各样的微机辅助设计(CAD)软件。和大型CAD系统相比,它具有投资少、见效快、容易放在生产第一线等突出优点,因而在航空、造船、机械、电子、土木建筑、水利水电工程等等领域得到推广。本文总结了笔者多年来在开发应用Auto CAD方面的一些经验,主要讨论软件接口技术、图块技术、形文件技术、专用菜单设计技术等。     

水库清淤技术：吸头清淤装置系统的研究

吸头清淤装置系统是主要适用于中小型水库泥沙处理的水库清淤系统，安装置的结构主要包括顺次连接的吸头，水库内软管及水库外输沙管，库外输沙管末端设一阀站以控制流量，根据试验研究成果，着重探讨了该系统的基本组成部分即吸头的结构设计，也就是最优吸头参数选择问题，并就该装置系统的输沙管道长度，管径以及系统工作水头等因素对系统淤效率的影响进行了分析，通过分析，表明吸头清淤装置系统具有以下特点，如结构简单，操作灵     

The effect of rivers,streams, and canals on property values

Rivers, streams, and canals support a variety of critical agricultural, industrial, transportation, ecological, and household uses. They also provide important aesthetic, recreational, and sociocultural benefits. This review paper synthesizes the evidence to date regarding the value of these linear water features as aesthetic and recreational resources to adjacent and nearby residents. Specifically, it summarizes 25 studies that have used the hedonic pricing method to calculate the effects of views of and proximity to rivers, streams, and canals on surrounding residential property values. The majority of studies indicated that significant positive property price effects are associated with river, stream, and canal view and proximity, though these effects appear less definitive in rural than urban settings. Implications of the body of evidence for planning, management, and development are discussed, and potential effects of climate change and diversion policies are highlighted. Improvements in measurement facilitated by advanced geographic information systems and rigorous spatially explicit regression techniques are noted.     

小浪底水库运用方式研究的回顾与进展

回顾了小浪底水利枢纽工程初步设计以来水库减淤运用的研究情况，总结以往的经验，结合当前的实际，对水库减淤作用、水库运用方式与分阶段运用、主汛期调水及运用方式的动态研究等问题提出了一些新的认识。分析论证了调水调沙与拦粗排细、近期调度与长远分析、小浪底工程与其他治黄工程建设等问题的辩证关系。提出水库初期运用应以调水为主，其后逐步抬高运用应与适时降低水位冲刷相结合。要及时总结经验，不断跟踪研究，及时合理调整运用方案。     

引黄灌区水沙综合利用及渠首治理

本文总结了引黄水沙综合利用的技术特点，其中包括淤改、稻改、淤临床淤背浑水灌溉和建筑材料的转化：指出各种泥沙利用技术在不同时期的作用是不同的，比如淤改和稻改是６０和７０年代泥沙利用的重要形式，军水灌溉测是８０和９０年代泥沙利用的重要组成部分。渠首地区一般是受害者，结合灌区的实际情况进行渠首综合８治理是十分必要的；本文进一步论述了渠首治理的主要内容，其中包括淤灌、发展经济林、沙化治理等。     

Comparison of AMC-dependent CN-conversion Formulae

The available antecedent moisture condition (AMC)-dependent runoff curve number (CN) (SCS, National Engineering Handbook, Supplement A, Section 4, Chapter 10, Soil Conservation Service, USDA, Washington, DC, 1956) conversion formulae due to Sobhani (M.S. Thesis, Utah State University, Logan, UT, 1975), Hawkins et al. (J Irrig Drain Eng, ASCE 111:330–340, 1985), Chow et al. (McGraw-Hill, New York, 1988), and Neitsch et al. (Texas Water Resources Institute, College Station, TX, TWRI Report TR-191, 2002) were compared utilizing the NEH-4 CN-values (SCS, National Engineering Handbook, Supplement A, Section 4, Chapter 10, Soil Conservation Service, USDA, Washington, DC, 1972) as target values. The Sobhani formula was found to perform the best in CN_I-conversion, and the Hawkins formula in CN_III-conversion. When evaluated on a large set of Agriculture Research Service (United States) data, a newly proposed formula performed the best of all, and the Neitsch formula the poorest, and therefore, the former was recommended for field use. The poorest performance of the latter is largely attributed to the occurrence of unreasonable negative CN_I-values at low CN_II-values.     

Short communication. Pipelines as a refuge for freshwater snails

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.     

The past,present, and future Aral Sea

The Aral Sea, a once vast brackish terminal lake in the heart of Central Asia, has been rapidly drying since the 1960s. It had separated into four separate waterbodies by September 2009. The maximum water level decline was more than 26 m, whereas the lake surface area decreased 88% and the water volume 92%. The lake salinity increased by more than 20‐fold. Prior to the modern recession, the Aral Sea experienced a number of water level declines and subsequent recoveries over the last 10 millennia. The main causative factor until the 1960s was the periodic westward diversion of the Amu Dar’ya, the main influent river, towards the Caspian Sea by both natural and human forces. The post‐1960 recession, however, was overwhelmingly the result of unsustainable irrigation development. The lake’s modern recession has caused a broad range of severe negative ecological, economic and human welfare problems. To restore the Aral Sea to its 1960s’ size and ecological condition would be very difficult, if not impossible, in the foreseeable future. The plight of the Aral Sea, however, is far from hopeless. Partial restoration of portions of the lake is still feasible. A project to raise the Small (northern) Sea was completed in Fall 2005, raising its water level by 2 m, and lowering its salinity to a level not much higher than the early 1960 levels. Its ecological recovery has been dramatic, and a new project to improve further the Small Aral was recently announced. Improving the Large (southern) lake would be much more difficult and expensive. A project to save the deep Western Basin partially is technically feasible, however, and should be given careful evaluation. It is important to repair and preserve what is left of the deltas of the two tributary rivers, Syr Dar’ya and Amu Dar’ya, as these two rivers are of great ecological and economic value, and act as biological refugia for endemic species of the Aral Sea.