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1.
滩区居民基于自身需要对生产堤持强烈的维护态度,出于种种考虑,即使政府对其实施淹没补偿政策,仍有30%-50%左右的人不愿放弃对防洪大局不利的生产堤。生产堤的废除与否.实质上是滩区群众生存需要与政府维护防洪大局利益需要的矛盾,解决这一矛盾的关键在于政府越须科学、客观、公正地制定滩区洪水淹没补偿政策,并切实将洪水淹没补偿政策落实到位。  相似文献   

2.
左萍  黄淑阁  刘风景 《中国水利》2007,(9):15-16,27
调查结果显示,黄河下游滩区居民在遭受黄河水灾后所获得的实际救助金与他们的期望值相差很大;仅靠社会微薄的救助,不能解决滩区居民洪水淹没后的实际困难;滩区居民绝大多数对洪水淹没损失能够“如实申报”.对补偿的预期并不是集中于高比例范围,这种客观的、基本上符合实际的心理需要,为制定滩区洪水淹没补偿政策提供了一定的群众心理依据。  相似文献   

3.
黄河下游滩区居民因特殊自然环境而形成了特定的心理活动、心理需求,这既影响到他们的生产与生活.又对政府在滩区的有关政策产生或积极或消极的影响。国家制定和实施滩区政策时,应根据滩区居民的心理需要.树立“以人为本,,的观念,在洪水淹没补偿、村台建设与搬迁、基层组织建设、外迁政策的落实等方面切实解决滩区居民的具体困难,并采取一系列综合措施促进滩区社会经济健康发展及人与自然的和谐。  相似文献   

4.
提高三峡-葛洲坝两坝间通航能力试验研究   总被引:5,自引:0,他引:5  
三峡-葛洲坝两坝间河段是川江船舶航行最困难的航段之一.葛洲坝建成后,当川江流量小于2万 m 3/s,航行条件较好;当川江流量大于2万m 3/s,两坝间洪水急流滩相继出现,航行条件逐渐变差.各主要滩段均不能满足万吨级船队的通航要求.因此,提高两坝间河段通航流量,延长通航期具有重要意义.采用增加推轮推力,改善推轮操纵性能和减驳减载等改进措施,可将两坝间河段的通航流量级由上水的2万m 3/s提高到4.5万m 3/s.  相似文献   

5.
The development of large impoundments along the Paraná river, particularly on the Superior section, with fifteen large dams having a capacity over 25000 MW, has had important hydrological and ecological impacts on the lower reaches. The important retention of the suspended solids by the dams has caused a significant reduction of P concentrations. With river impoundment and water eutrophication, cyanophiceae currently dominate during spring and summer, with brief but dense blooms of Anabaena spiriodes and Microcystis aeruginosa. Many fishes of the Superior Paraná have been dispersed downstream as the Itaipú reservoir covered the Guayra falls, the natural barrier for these fishes. The most important effects of Superior Paraná dams are related to the changed hydrological regime in the alluvial Middle and Lower reaches. This floodplain plays an important role in the bioproductivity of the river. Fisheries production depends to a high degree on the relationship of the river and its alluvial valley, where the alevines and small fishes of migratory species develop after spawning. During falling river levels the waters carry large quantities of organic matter, floating vegetation, important amounts of plankton and fishes from the alluvial plain to the river. Before the dams, the river defined two subsystems which were joined for about six months during the flood season and effectively isolated during low water periods. Since the commencement of river impoundment and flow regulation, the river ecology has begun a sequence of changes especially within the alluvial reaches.  相似文献   

6.
周丰年  周才扬 《人民长江》2002,33(3):39-40,43
在长距离的航道带状地形测量中,利用全数字摄影测量技术,具有速度快、周期短、效率高、精度好、现势性强、自动化程度高、使用方便等优点。在全数字摄影测量实施过程中,首先建立了基本控制网,首级控制采用E级GPS控制网,在它的控制下,沿航道布设平均边长为500m的一级光电测距导线。航摄像片是全数字摄影测量的重要依据,直接影响成图质量,必须认真进行航摄资料的检查验收工作。像控点平面及高程以航道沿线的E级GPS点、一级导线点为起算点,采用GPS快速定位法施测。数字化测图作业中内业测图是用全野外的像控点进行定向,根据工作站上模型参照野外调绘进行测图,然后在计算机中进行编辑成图。实践证明,全数字摄影测量技术与传统的摄影测量相比,具有明显的经济效益和社会效益。  相似文献   

7.
三峡水电站船闸在山体中开挖修建,最大边坡高170 m,最高直立墙68 m.采用预应力锚索对边坡加固.本文介绍了预应力锚索在永久船闸高边坡加固处理中的应用,并结合监测资料就锚索应用中的几个相关问题进行了分析和探讨.  相似文献   

8.
Lacking substantial erosive and sedimentation forces, regulated rivers allow their floodplains to become overgrown with forest, increasing the flood risk of the hinterland. In the Netherlands, floodplains have therefore been subjected to interventions, like clear cutting, lowering and creation of side channels, and management, consisting of grazing and mowing. However, the comprehension of how those activities influence landcover dynamics is lacking. The aim of this study is therefore to investigate long‐term landcover dynamics of a regulated river system through the lens of remote sensing. What transitions between landcover classes can be observed? And how (if) do management and interventions impact succession and retrogression of landcover classes? The study area comprised the upstream part of the Dutch Rhine River, its three branches and five adjacent floodplains. Satellite data (LandSat 5 and 8), encompassing a 35‐year period (1984–2018), were used for studying landcover dynamics. Landcover classification was based on seven classes: water, built‐up area, bare substrate, grass, herbaceous vegetation, shrubs and forest. Retrogression was highest for the landcover classes obstructing water flow (shrubs, forest and herbaceous vegetation), succession was most frequent on bare substrate, and water and grass were the most stable landcover classes. The regulated nature of the system became apparent from the spatial and temporal cacophony of landcover dynamics which differ from those of natural meandering rivers. This study showed that satellite data are useful for analyzing the impact of human activities within floodplains of regulated rivers and may assist in floodplain management aimed at combining water safety and nature policies.  相似文献   

9.
为了研究芜申运河安徽段航道整治工程(包括青弋江线和水阳江两条线路)对流域河网水系防洪的影响,应用Mike11水动力学模型,模拟遇设计标准洪水和超标准洪水条件下,航道整治工程实施前后水阳江、青弋江、漳河流域关键控制站点的水位变化、水阳江干流中游分洪量变化以及航道整治对流场流态的影响情况。分析表明,航道整治工程实施后,控制站点水位降低或者保持不变,水阳江干流分洪量有所减少,并且航道整治工程对河道进行拓展底宽、疏浚挖深、撇弯切滩及局部河段裁弯、退堤等工程措施,扩大了河道行洪断面,增加了泄流能力,整体上有利于河道行洪,符合流域“上、中、下游兼顾,上游以蓄为主;中游蓄泄兼施;下游在充分利用湖泊调蓄作用的基础上,尽可能将洪水外排”的防洪治理原则,对水阳江、青弋江、漳河流域防洪是有利的。航道整治工程实施后,工程段内近岸流速普遍减小,对局部区域近岸流速增大的情况,建议加强观测,若影响堤防或岸坡稳定,应及时加强防护。  相似文献   

10.
介绍了三峡水利枢纽双线五级船闸人字闸门主要技术参数、技术特点和安装工艺,建立了闸门安装测量质量控制网点。该安装工艺可供其他水利水电工程借鉴。  相似文献   

11.
Length–length and length–weight relationships was estimated for 48 fish species collected in 30 neotropical reservoirs located in the State of Paraná, Brazil. Significant relations were found for all species. The values of the parameter slope (b) in the length–weight relationship ranged from 2.49 to 3.46 for grouped sexes, and from 2.66 to 3.15 for separated sexes. Differences between sexes (indication of sexual dimorphism) were verified for 20 species. Males exhibited greater lengths than females for Astyanax janeiroensis, Bryconamericus iheringii, Geophagus brasiliensis, Glanidium ribeiroi and Hypostomus derbyi, whereas females attained greater lengths than males for the other 15 species examined in this study.  相似文献   

12.
对河南、山东黄河下游部分滩区居民的调查结果显示:被调查对象的文盲率比全国农村文盲率平均水平高15.44个百分点;滩区居民81.87%从事的是粮食种植,职业结构单一;家庭类型以直系家庭或复合家庭居多,家庭平均人口、居住代数高于全国平均水平;人均耕地面积低于全国农村人均耕地面积;搬迁居民住房状况有所改善。针对滩区的人口数量与人口质量状况,应加强人口控制、教育与职业培训工作。  相似文献   

13.
Management at 27 low-head dams affects water surface elevations for a 1050km stretch of the Upper Mississippi River (UMR) between St Louis, Missouri and Minneapolis, Minnesota. A systemic overview is given of current operating plans at dams on the UMR and historical data are analysed to determine how well the operating plans are being met. Water level elevations at all 27 dams are regulated as a function of discharge, although plans are specific for each dam. The management objective is to maintain a target water level at specific locations (control point) in each impoundment over specific ranges of discharge. The target water level and control point may change as discharge changes in each impoundment. In some of the impoundments water regulation causes drawdowns below the elevation for which the dams were planned, and at other dams no drawdown occurs. During the navigation seasons of 1980 to 1990, water levels were within their target window for an average of 72·5% of the time for 25 dams analysed. Difficulties in meeting targets are caused by winds, local rainfall events, ice dams and rapidly fluctuating discharges from tributaries with upstream reservoirs used for peaking hydropower.  相似文献   

14.
Successful design and operation of fish passage systems are important to protect fish communities from impacts of hydroelectric dams in the Río de la Plata River basin. We evaluated the performance of an elevator lift system to pass adult fish through Yacyretá dam on the Paraná River between 1995 and 1998, both for mechanical reliability and performance. The elevator lift system was mechanically inoperative 30–38% of the time during the October–December period of greatest fish migration. Target species represented 30% of total fish number in gillnet samples in the tailwater, but constituted only 10% of the total number of fish transferred. Fish collected within the system were dominated by Pimelodus clarias (>69%), although this species represented less than 10% of captures in experimental gillnets set in the tailwater. Prochilodus lineatus, a key species, represented less than 5% of transferred fish, but constituted 22.1% of tailwater samples. Estimated number of fish transferred per year ranged between 1 210 000 (1995) and 3 610 000 (1996) with biomass ranging from 631 to 1989 tons, respectively. We estimated a fish passage efficiency of 1.88% for all species and 0.62% for target species. At this efficiency, transferred species would increase the total fish yield in the reservoir by as much as 4.9 kg/ha/year, but only 0.5 kg/ha/year for target species. We conclude that fish transfer efficiency is inadequate to maintain populations of target species in the Paraná River system. We identify critical research needs to improve the passage of fish at dams. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

15.
为分析降雨空间分布非一致性对城市内涝的影响,应用耦合了水文和水动力过程的数值模型,以陕西省西咸新区海绵城市部分核心试点区为研究区域,对不同重现期设计暴雨及离差系数Cv条件下的内涝过程进行模拟,并对内涝积水总量峰值、重度内涝积水总量峰值及其与均匀降雨情况下的内涝积水削减进行对比分析。结果表明:相比于空间均匀降雨,各重现期下空间分布不均匀的内涝积水量均会减少。各重现期下,Cv值越大,即降雨越不均匀,相比于均匀情况内涝积水削减量越大。当Cv值为0.07、0.11、0.15及0.2时,积水总量削减率分别为1.94%~2.05%,3.00%~3.17%,4.08%~4.23%,4.86%~5.15%。重度内涝情况下,同一Cv值,相比于均匀情况内涝积水削减量随设计降雨重现期变长而增多,当Cv=0.07、Cv=0.11、Cv=0.15、Cv=0.20时,削减率的范围分别为2.00%~2.51%、2.60%~3.82%、3.66%~4.98%、3.80%~5.83%。研究结果揭示了降雨空间分布非一致性对内涝的影响规律,为城市内涝防治工作提供了理论依据。  相似文献   

16.
汉江河口段航道整治工程以疏浚、清障为主,辅以必要的护岸、护滩、填挖槽等工程措施,本文采用河道演变分析和一、二维水流数学模型计算,研究了该航道整治工程的效果及其对河道行洪的影响,并优化了工程方案.研究表明:(1)丹江口水库自1968年正式蓄水以来,汉江河口段河道总体冲刷下切,年内洪淤枯冲;影响河道演变的主要因素有:丹江口水库、长江与汉江顶托和天然节点与人工护岸等.(2)航道整治工程实施后.汉江河口段上段流速趋于减小,下段流速趋于增加;河道流速分布趋于均化.(3)航道整治工程对河道行洪的影响有限,最大洪水壅高9.4cm,优化方案的最大洪水壅高7.0cm.  相似文献   

17.
针对陆域保护区低于外江高水位的钱塘江河口地区,以1949年以来登陆我国沿海最强的"5612"号台风为典型超强台风控制条件,对河口北岸平原潮水淹没情况进行了数值模拟研究。首先对地形进行概化,将平原内的二线堤防及具有挡潮作用的道路单独处理;然后以海堤极限防御能力计算分析为依据,确定超强台风作用下海堤损毁程度;最后采用覆盖两侧区域的二维风暴潮模型对北岸平原的淹没情况进行计算分析。结果表明,在超强台风作用下,钱塘江河口淹没区可随时段累积沿后方二线堤防及道路逐步推进,此类线状建筑物具有较好的挡潮作用;现状条件下,钱塘江河口北岸遭遇超强台风后,其最大淹没水深可达2.87 m,淹没面积达到127.52 km2。  相似文献   

18.
Hydraulic and substratum conditions have been identified as two stream features which affect the benthic community composition, abundance and distribution. However, little attention has been given to the influence of hydraulic variables in large river beds. The aim of this study was to analyse the incidence of the near‐bottom hydraulic conditions and other environmental variables on the density of Narapa bonettoi (Oligochaeta, Narapidae), a typical and dominant species found in sandy bed rivers of diverse hierarchy of the Paraná River basin. A large amount of existing and available benthic data were used. The highest correlations among N. bonettoi densities and environmental variables were obtained with the hydraulic variables of friction Reynolds number (R*) and shear stress (τ0); the substratum type (sand, silt and clay) and organic matter content. The results show that N. bonettoi density would be related with the hydraulic variables following a ‘bell‐shaped’ tendency, e.g. with the friction Reynolds number, N. bonettoi would have a preference for transition values of turbulence (~40 < R* < ~50), which is equivalent to τ0 between ~0.6 and ~0.8 kg ?2. Densities show a slight decreasing tendency toward the maximum R* values, suggesting that the species does not support a completely developed turbulence (R* > ~70). Significant but negative correlations were reported in the literature between benthic macroinvertebrates typical of smaller and steeper streams and R* values far beyond the threshold 70 value. N. bonettoi shows a clear preference for a completely sandy substratum and for sand particles sizes around 300 µm. Finally, considering the important role played by the hydraulic variables on the benthic community studied herein, the contagious distribution pattern of N. bonettoi, reported by other authors, would be principally linked with the interactions between current and sediment near the bottom rather than with the mobility of these organisms. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

19.
水口坝下枢纽工程航运过坝采用一线通航船闸.工程建成后,要求新建船闸的通航能力与上游水口水电站双线通航建筑物的通航能力相匹配.根据坝址选定位置的河床地形条件及布置条件比选,船闸总体布置采用加长方案,船闸输水系统型式采用闸墙长廊道侧支孔分散输水系统,上下游引航道平面布置采用不对称型式.  相似文献   

20.
水电枢纽建设改善了库区航运条件,但电站泄流会对坝下游航道产生影响,需要对此研究以实现水电开发与航运建设的协调发展.在分析大量研究文献与资料的基础上,总结了电站下游流量、泥沙、水位在电站建设前后变化与沿程变化的特性,归纳了电站泄流对坝下游设计最低通航水位、通航水流条件(沿程流速、流向与比降)、河床演变的影响,以及提出了应对策略与措施等研究成果,最后指出了有待进一步研究的问题,以期推动本领域研究的深入开展.  相似文献   

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