Estimating the sediment trap efficiency of intermittently dry reservoirs: lessons from the Kruger National Park,South Africa          下载免费PDF全文

Bastian Reinwarth  Edward S. Riddell  Christoph Glotzbach  Jussi Baade 《地球表面变化过程与地形》2018,43(2):463-481

The assessment of sediment yield from reservoir siltation requires knowledge of the reservoir's sediment trap efficiency (TE). Widely used approaches for the estimation of the long‐term mean TE rely on the ratio of the reservoir's storage capacity (C) to its catchment size (A) or mean annual inflow (I). These approaches have been developed from a limited number of reservoirs (N ≤ 40), most of them located in temperate climate regions. Their general applicability to reservoirs receiving highly variable runoff such as in semi‐arid areas has been questioned. Here, we examine the effect of ephemeral inflow on the TE of 10 small (≤ 280 × 10³ m³), intermittently dry reservoirs located in the Kruger National Park. Fieldwork was conducted to determine the storage capacity of the reservoir basins. The frequency and magnitude of spillage events was simulated with the daily time step Pitman rainfall–runoff model. Different runoff scenarios were established to cope with uncertainties arising from the lack of runoff records and imperfect input data. Scenarios for the relationship between water and sediment discharge were created based on sediment rating curves. Taking into account uncertainties in hydrological modelling, uncertainties of mean TE estimates, calculated from all scenarios (N = 9), are moderate, ranging from ±6 to ±11% at the 95% confidence level. By comparison, estimating TE from the storage capacity to catchment area (C/A) ratio induces high uncertainty (ranges of 35 to 65%), but this uncertainty can be confined (15 to 33%) when the latter approach is combined with hydrological modelling. Established methods relying on the storage capacity to mean annual inflow (C/I) ratio most probably lead to an overestimation of the TE for the investigated reservoirs. The approach presented here may be used instead to estimate the TE of small, intermittently dry reservoirs in semi‐arid climate regions. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

三眼峪特大泥石流沟流域分区特征   总被引：2，自引：0，他引：2  

黎志恒  朱立峰  胡向德  于国强  贾贵义  李瑞冬 《西北地质》2011,44(3):38-43

三眼峪“8．8”特大泥石流属典型的沟谷型泥石流,整个沟域具有明显的形成区、流通区及堆积区。通过野外调查,竹塔沟-桥子沟以上的大、小眼峪上游沟脑为雨洪产流汇流区域,产流区与罐子坪-峪支沟一线之间为主要的固体物源区,大、小眼峪口至三眼峪口之间以过流为主,峪口至白龙江之间为堆积区。通过分析三眼峪流域分区特征和泥石流在不同分区的沿程冲淤变化,以期为建立三眼峪泥石流监测预警体系提供依据。  相似文献   

曹妃甸填海工程阻断浅滩潮道初期老龙沟深槽的地形变化     

尹延鸿  褚宏宪  李绍全  胡刚  毕世普  袁红明 《海洋地质前沿》2011,(5):1-6

通过研究1992、1997、2006年的测深资料,对比分析了横切老龙沟深槽口门处的地形横剖面和大致沿老龙沟深槽轴线的地形纵剖面,可知在此期间深槽内的水深有变浅和淤积的趋势.总体看来,老龙沟深槽的淤积厚度在0.61～4.8 m之间,并且老龙沟深槽轴线也有自东向西迁移的趋势.自2004年曹妃甸填海工程的通岛公路阻断浅滩潮道...  相似文献   

舟山凉潭岛填海工程对水动力及海床演变影响的模拟预测分析     

吴仁豪  童元正  张旭锋  赵晟  孙健  娄建富  王海平 《热带海洋学报》2011,(4)

用一个三维(ECOMSED)模式对舟山凉潭岛填海工程前后的潮流场变化进行模拟,做出预测。潮流场模拟结果与实测基本吻合。经分析可知,工程对潮流的影响主要在围堤的东南角小范围内:工程后流速明显减小,造成淤积现象,但淤积程度不大,1年后的淤积为13cm左右,5年后的淤积为0.8—1.2m左右。工程对较深水层的潮流运动影响很小。通过对施工期间产生的悬浮物在涨落潮时的分布模拟可知,涨潮时,悬浮物从工程区域的一个悬浮物源不断排出,主要对工程附近及其上游地区造成一定的影响;落潮时,悬浮物主要影响工程外围及其下游地区,整个落潮期间悬浮物能影响的范围比涨潮期间要大。总体上工程对该附近海域的潮流场及冲淤影响很小。  相似文献   

Siltation analysis in the Neyyar reservoir and forest degradation in its catchment: a study from Kerala state, India     

D. S. Suresh Babu  V. Nandakumar  B. John  B. K. Jayaprasad  S. V. Pramod 《Environmental Geology》2000,39(3-4):390-397

 Impact of catchment erosion and the resultant reservoir siltation from a tropical environment is reported here to discuss the effect of a reservoir in the natural degradation of an evergreen-forested segment. While an area of 8.01 km² has been affected by direct inundation at the full reservoir level, another 2.6 km² area once under thick forest cover, had also lost its identity over the last 38 years by indirect degradation. This zone mainly falls in the confluence of tributaries, namely Neyyar and Mullayar, with the reservoir. The capacity of the reservoir was found to be reduced by 28.8 Mm³ during this period and the annual average loss is calculated as 0.75 Mm³ (0.71%), indicating the intensity of erosion from the catchment zone. In case the proposed upper dam in the reservoir comes into existence, an additional area of 2.4 km² from the virgin forest would be submerged and more area would face degradation around the inundated zone. Received: 29 July 1998 · Accepted: 16 November 1998  相似文献   

Reservoir rehabilitation: The new methodological approach of Economic Environmental Defence     

Annamaria De Vincenzo  Antonio Jacopo Molino  Bruno Molino  Vittoria Scorpio 《国际泥沙研究》2017,32(2)

This paper proposes a new methodological approach to silted reservoir management and defence, which combines the reservoir rehabilitation process and the utilization of the recovered water volumes and sediments. This approach, strategic from both the economical and environmental points of view, is here defined as Economic Environmental Defence (EED) of a reservoir. The EED approach is applied to the case study of Guardialfiera reservoir, where the available experimental data allowed the estimation of silta-tion up to date, the analysis of the distribution of sediment particle size along the reservoir bottom and the possibility to propose a feasible utilization of water and sediments resulting from the reservoir rehabilitation.  相似文献   

Grey Prediction of Siltation in North Channel of Yangtze Estuary     

Yu Cimei Shanghai Waterways Design & Research Institute  Shanghai 《中国海洋工程》1994,(2)

-The North Channel in the Yangtze Estuary is one of sea-leading waterways of Shanghai Harbour, in which yearly dredging volume reaches over ten million cubic meters, and it tends to increase year by year. Based on the channel regime similarity and through the relational grade, a GM (2, 1) is set up. It reveals the course of development of channel regime similarity under the action of various factors, and predicts the siltation volume in the nearest future which is the basis of dredging planning for relevant dredging departments.  相似文献   

浙江省海岸侵蚀及防治概述     

谢钦春  李全兴 《海洋学研究》1992,10(3):46-52

浙江海岸侵蚀现象普遍存在。基岩海岸海蚀地貌发育,因其组成物质抗冲蚀能力强,岸线后退不明显;砂砾质海岸普遍发生侵蚀,尤其是无计划的人工挖沙,造成沙滩减小或消失;淤泥质海岸大多处于缓慢的淤涨状态,但由于自然条件的改变和人为作用的影响,某些岸段发生侵蚀,特别是受到台风暴潮的影响,岸线在短时间内出现大规模后退和滩面下蚀。侵蚀岸段主要见于杭州湾北岸澉浦至金丝娘桥岸段,杭州湾南岸临山至西三岸段及瓯江口北岸盘石至黄华岸段。淤泥质海岸后缘为滨海平原,组成物质为粘土质粉砂,抗冲蚀能力弱,为防止和减轻海岸侵蚀,沿岸建造各类海岸工程(海塘、丁坝、导堤等),提高防潮抗浪能力,在朝滩种植大米草,互花米草,消浪促淤明显。另外,在海岸开发活动中,应加强海岸侵蚀监测和综合管理。  相似文献   

辽东湾绥中海岸侵蚀研究   总被引：1，自引：0，他引：1  

王玉广  张宪文  贾凯  王权明 《海岸工程》2007,26(1):1-5

通过不同时期海图对比、分析遥感图像和多年现场监测资料,分析了辽东湾绥中沙质海岸侵蚀的特点,认为海岸组成物质松散与海岸动力作用强烈是本区现代海岸侵蚀的基本条件;陆源物质入海量减少、海动力作用、沿岸工程建筑和海上采砂是其海岸蚀退的主要影响因素。  相似文献   

上游建库引水对健跳港冲淤影响的经验预测     

于传见  黄世昌  姚炎明  唐子文 《海洋学研究》2008,26(3):53-61

从分析健跳港水文和泥沙特性出发,探讨了健跳港水动力和河床演变的基本特征,结果表明,尽管健跳港内落潮最大流速大于涨潮最大流速,但该港泥沙净输沙方向还是朝向港内;流域径流对健跳港海床稳定起着重要作用,维护健跳港冲淤平衡的主要动力来自洪水期的径流.利用水沙关系和河相关系模型预测了健跳港上游引水后对该港海床淤积的影响.  相似文献