The Influence of Seasonal Changes and Headwaters on Physico-chemical Dynamics of Temengor Reservoir, Malaysia     

Zarul Hazrin Hashim  Asmah Patiroi  Mashhor Mansor  Shahrul Anuar Md. Sah  Donald C. Jackson 《湿地科学》2011,9(4):314-321

A study on physico-chemical dynamics of Temengor Reservoir was conducted to determine whether headwaters and seasonal changes play a major role in regulating physico-chemical dynamics of Temengor Reservoir. Temengor Reservoir receives water from its surrounding water catchments and headwaters. Then, the water flows into a series of hydroelectric dams, namely the Bersia, Kenering and Chenderoh dams. Generally, water quality in Temengor Reservoir can be classified as Class I. Physico-chemical trends showed that water quality in euphotic zone of Temengor Reservoir is stable and consistent. Two-way ANOVA analyses showed that seasonal variations only affected water temperature, Secchi disc’s depth and nitrate-nitrogen. Based on Tukey’s post-hoc test, all three headwaters in this study exert no influence to the reservoir’s water quality. These insignificant differences were probably due to water temperature and the size of the headwaters and the reservoir itself. In situ parameters profiling showed that the epilimnion zone in Temengor Reservoir is from the surface to 6 m depth, the metalimnion zone is from 6 m to 12 m depth and the hypolimnion zone is from 12 m depth onwards to the bottom of the reservoir. Thus, continuous water profiling monitoring that covers high and low water levels need to be conducted to determine characteristics of the physico-chemical dynamics in the water column and also to analyse changes in reservoir layers. Through these studies, discontinuity trends in the Perak River could be determined and suggestions to the respective agencies could be made to conserve and to sustain downstream biodiversity.  相似文献   

塔里木河三源流区气候变化对径流量的影响   总被引：6，自引：4，他引：2  

傅丽昕  陈亚宁  李卫红  徐长春  何斌 《干旱区地理》2008,31(2):237-242

结合对近50年塔里木河源流区气象、水文资料的分析,探讨了过去半个世纪塔里木河源流区气候变化及其对河川径流的影响。研究结果显示,在过去50年里,塔里木河三源流径流流量总体呈现增加的趋势,期间有波动过程;对影响径流变化的气温、降水和蒸发等因子分析发现,降水量变化对塔里木河径流量变化影响最为显著,而温度的升高,加速了山区冰雪资源的消融,加大了冰雪融水对径流量的补给,但同时导致蒸发量增大,增加了地表淡水资源的消耗,对山区来水量的增大起到一定的削弱作用。  相似文献   

Fish persistence and fluvial geomorphology in central Australia     

Peter J. Unmack 《Journal of Arid Environments》2001,49(4):653

The purposes of this paper are to document the composition and distribution of fishes in the Alice Springs region of Australia, and discuss constraints on fish persistence in this arid region. Nine native and six exotic species were recorded; most exotics no longer exist. Except in Finke River, only one or no native species were found. Fish survival in the area is ameliorated by the exceptionally broad environmental tolerances and migratory abilities of many species, but ultimately depends upon the effects of geology, geomorphology, and the vagaries in pattern of sediment transport on water persistence.  相似文献   

侵蚀沉积模型在嘉陵江流域的应用     

村上正吾  林诚二  渡边正孝 《地理学报》2004,59(1):136-142

从20世纪50年代到80年代长江宜昌水文站观测的泥沙输送量逐年增加,但是到了90年代却出现了逐渐减少的趋势。泥沙量增加的原因主要是乱伐森林和土地利用方式的快速改变,而减少的原因则可能是采取了一系列防止水土流失的对策和在上游修建了许多大坝而造成的。嘉陵江流域是长江泥沙的主要源区之一,90年代每年从嘉陵江流域到长江的输沙量减少到1988年前的约36%。因此,分析该流域每年泥沙输送动态及其变化原因,对制定减小水土流失的森林规划,防止三峡水库的淤积以及保护长江流域的生存环境和生态系统等具有重大意义。本研究开发并改进了一个流域集水坡面上的侵蚀模型,并将它应用到1987年的嘉陵江流域,以对其适用性进行了研究。结果表明,该模式可被用于月度泥沙生产量的评估中。  相似文献   

Hydrological impacts of flow regulation associated with the Upper Nepean water supply scheme,NSW     

《The Australian geographer》1995,26(1):71-86

The upper Nepean River has been progressively regulated for water supply to Sydney and Wollongong since 1886 by the Upper Nepean Water Supply Scheme which consists of four large dams, two small dams and two diversion weirs. Secular rainfall changes produced periods of high rainfall and large floods (flood‐dominated regimes) between 1857 and 1900 and 1947 and the present, and an intervening period (1901–46) of low rainfall and small floods (drought‐dominated regime). Upstream impoundment and flow regulation significantly reduced flood magnitudes for most return periods during both types of flood regimes. The probability distribution of mean daily flows was also changed significantly by flow regulation such that during the drought‐dominated regime, the high and low frequency flows were reduced substantially but the moderate frequency flows were increased due to dam releases; the change from a regulated drought‐dominated regime to a regulated flood‐ dominated regime resulted in a substantial increase in discharge for most durations; and increased water diversions to Wollongong during the current flood‐dominated regime produced a marked downward shift in the whole flow duration curve. Nepean Dam reduced downstream suspended sediment yields by two orders of magnitude because it traps in excess of 99 per cent of the inflowing suspended sediment load. Streamflow releases are urgently required from the two diversion weirs to improve downstream water quality and to ensure the viability of the resident ‘potentially threatened’ eastern Macquarie perch (Macquaria nov. sp.).  相似文献   

蚌埠闸及上游闸坝对淮河自然水文情势的影响   总被引：3，自引：0，他引：3  

胡巍巍 《地理科学》2012,(8):1013-1019

淮河流域建设了许多闸坝,为揭示如此密集的闸坝对河流自然水文情势的影响,选取比较典型的淮河干流上的蚌埠闸作为控制节点,用成熟的IHA法和RVA法,研究蚌埠闸及其上游闸坝对水文情势的影响程度,同时通过蚌埠水文站水文情势变化的估算来分析闸坝对淮河河流生态水文条件的影响。结果显示,这些闸坝对河流水文情势的影响强烈,特别是在枯水季节。由此得出的淮河蚌埠段生态水文目标可为蚌埠闸开展生态系统管理、生态修复以及进行生态调控提供理论支持。  相似文献   

水电开发对河流水沙特性影响的综合评价方法   总被引：5，自引：1，他引：4  

刘新有  何大明 《地理学报》2011,66(7):953-960

选取已连续25 年大规模水电开发的澜沧江为研究对象,建立了河流水沙特性受影响程度评价指标体系及指标回归还原模型,并采用层次分析法和因子分析法相结合的赋权方法确定指标权重;借鉴“边际效益”原理,结合基于河流水沙自然变幅确立的指标评价标准,建立了各指标受影响程度定量评价模型。利用所建立的方法与模型,综合定量评价了澜沧江水沙特性的受影响程度,结果表明：澜沧江水电开发以来(1986-2007 年),河流水沙特性总体受影响程度等级为很小的年数占72.7%,为较小的年数占18.2%,为一般的年数占9.1%,输沙受影响程度远大于径流;水沙特性受影响的变化过程呈“U”形,其主要原因是在漫湾水电站运行与大朝山水电站建设并存期,库区拦沙作用与电站施工增沙作用使输沙趋于平衡。本研究,为后续相关研究提供方法借鉴,为评估水电开发对澜沧江水沙特性影响提供新的依据。  相似文献   

Evolution characteristics and drivers of the water level at an identical discharge in the Jingjiang reaches of the Yangtze River     

CHAI Yuanfang  YANG Yunping  DENG Jinyun  SUN Zhaohua  LI Yitian  ZHU Lingling 《地理学报(英文版)》2020,30(10):1633-1648

The operation of large-scale reservoirs have modified water and sediment transport processes, resulting in adjustments to the river topography and water levels. The polynomial fitting method was applied to analyze the variation characteristics of water levels under different water discharge values in the Jingjiang reach of the Yangtze River from 1991–2016. The segregation variable method was used to estimate the contributions of the varied riverbed evaluation, the downstream-controlled water level, and the comprehensive roughness on the altered water level at an identical flow. We find that low water levels in the Jingjiang reach of the Yangtze River from 1991–2016 are characterized by a significant downward trend, which has intensified since 2009. Riverbed scouring has been the dominate factor causing the reduced low water level while increased roughness alleviated this reduction. From 1991–2016, there was first a decrease followed by an increase in the high water level. The variation characteristic in terms of the "high flood discharge at a high water level" before 2003 transformed into a "middle flood discharge at a high water level" since 2009. The increased comprehensive roughness was the main reason for the increased high water level, where river scouring alleviated this rise. For navigation conditions and flood control, intensified riverbed scouring of the sandy reaches downstream from dams enhanced the effects that the downstream water level has on the upstream water level. This has led to an insufficient water depth in the reaches below the dams, which should receive immediate attention. The alteredvariation characteristics of the high water level have also increased the flood pressure in the middle reaches of the Yangtze River.  相似文献