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1.
基于概率加权FDC法的河流生态需水量计算 总被引：2，自引：0，他引：2
基于河流流量过程的年内和年际变化特性,提出了一种计算河道内生态需水量的概率加权FDC(流量历时曲线)方法。该方法基于年均流量系列和逐月月均流量系列的特定频率,将年均流量系列和逐月月均流量系列划分为丰、平、枯组,通过建立年月丰枯遭遇的Copula联合分布函数,求得不同典型年下各月丰平枯的条件概率,将其作为概率权重,得到不同典型年生态需水过程的计算公式,改进了FDC法,计算出了丰、平、枯典型年的年内生态需水过程。以屏山站为例,将计算结果与Tennant法、逐月最小生态径流法、年内展布法和改进FDC法进行了对比分析。计算结果表明:由此方法得到的生态流量在Tennant法评价体系中,能很好的满足河道的生态需水要求,且较好地体现了河流径流的年内及年际变化过程,符合实际情况。 相似文献
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结合物理栖息地模拟模型的水力学与栖息地模型,以黄河干流兰州-石嘴山河段为研究样区及该河段的关键鱼种黄河鲤鱼为对象物种,以流速及水深二水力学因子进行研究,推求该研究样区兰州、安宁渡、下河沿、青铜峡和石嘴山五断面对象物种的流量与权重可使用面积的关系。通过对上述各断面1975-1985年汛前共11年生态、水文及断面资料的分析计算,归纳出研究断面汛前适合的生态流量分别为195、220、220、220、175 m3/s,计算结果在Tennant法界定的生态流量范围之内。 相似文献
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Introducing a new method to determine rivers’ ecological water requirement in comparison with hydrological and hydraulic methods 总被引：1，自引：1，他引：0
A. Shokoohi M. Amini 《International Journal of Environmental Science and Technology》2014,11(3):747-756
The absence of a rational, comprehensive, flexible and easy to use method with minimum data requirement to determine rivers’ environmental flow requirements is the main motivation for this research. Based on the microhabitat preferences of index species, hydrological (the Tennant and Q 95) and hydraulic methods for determining the environmental flow requirement (EFR) are compared. Using an ad hoc procedure, the important species of a river at the southern part of the Caspian Sea in Iran were distinguished, and the discharges to maintain the microhabitat (depth and velocity) in critical months were calculated. The observed differences between the index species’ required velocity and depth and those suggested by the Tennant method emphasize the importance of the rivers morphological properties for this method application. Allocating EFR by the Tennant and Q 95 methods would degrade the aquatic life. The EFR determined by the hydraulic method is equal to 95 % of the average annual discharge, which could maintain the ecological habitat in good situation, but may provoke a conflict in the region. The Tennant, Q 95 and hydraulic methods allocate EFR as 14, 36 and 79 % of the annual flow volume, respectively. Developing a new combined method based on using the hydraulic method’s discharge for critical months and the Tennant method suggestion for the excellent condition in other months allocates 50 % of the average annual discharge. This new method is a compromise between protecting environment and considering the water rights of rivers’ flow consumers and is suggested specially for dry regions of the world. 相似文献
4.
塔里木河流域气候与径流变化及生态修复 总被引：5，自引：2，他引：3
从20世纪90年代中期开始,塔里木河流域气温上升、降水增加,阿克苏河、开都河等主要河流几乎同步进入持续的丰水周期时段,为塔里木河流域生态修复创造了绝好的“天时”和历史性机遇.这种大区域的气候异常变化现象引起了国内外广大学者的广泛关注,区域气候异常变化是全球气温上升影响盆地气候向温湿转型,还是一个世纪性的水文周期变化现象,一时间成为了学术界的热点议题.系统分析了塔里木河流域山区水文气象站近50 a来的气温、降水、河川径流以及塔里木河来水量变化,并系统评价了利用开都河丰水期的有利时机,向塔里木河下游应急输水及其生态修复情况. 相似文献
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确定河流生态流量既是保护河流生态系统的根本举措,又是开展梯级水库生态调度的重要依据。基于逐月最小生态流量法、RVA法、DC法和逐月频率法,分别计算了清江水布垭和隔河岩水库坝址的生态流量过程,并采用Tennant法对结果进行合理性分析。结果表明:RVA法优于逐月最小生态流量法和DC法,计算得到的最小生态流量在一般用水期和产卵育肥期的评价结果分别为“好”、“中”等级;逐月频率法第3种情景计算的适宜生态流量,其评价结果均为“最佳”等级。研究成果为清江流域保护和梯级水库生态调度提供技术参考。 相似文献
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环境变化改变了河流水文情势,影响了河流的生态系统健康,亟需开展变化环境下河流水文健康演变定量归因方法研究。选取北方半干旱地区老哈河流域为研究区,依据流域内3个水文站、17个雨量站和6个气象站1964—2016年数据,基于可变下渗容量模型还原河流的天然流量序列;采用概率密度法计算河流生态流量,基于生态流量阈值推求河流水文健康等级;基于"观测-模拟"对比分析法,定量分离气候变化和人类活动对河流水文健康情势的影响。结果表明:人类活动是甸子和太平庄子流域自1980年以来河流水文健康情势退化的主要原因,其贡献率分别为86.9%和87.9%;大面积农业灌溉用水引起地表径流下降以及水利工程改变天然水文情势,影响了河流水文健康情势;90年代降水量较为充沛,研究流域受人类活动影响程度较小,河流水文健康等级维持在较高的水平。综合生态流量阈值和"观测-模拟"对比分析方法可定量识别河流水文健康情势演变原因,为适应环境变化的河流健康管理提供科学依据。 相似文献
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The article presents results of long-term monitoring, detailed studies and numerical simulation of hydrological hazards at the mouths of the Northern Dvina and the Pechora rivers. The Northern Dvina River discharges into the White Sea and the Pechora River flows into the Barents Sea. They are major rivers in northern European Russia. The main hydrological hazards at the mouths of these rivers include dangerous ice phenomena, inundations from both pure maximum stream flow and peak discharges with ice jams, surge-induced flooding, wind-induced down-surges, low-water periods and seawater intrusion into the delta branches. These hazards repeatedly caused significant socioeconomic loss and environmental damage to the riparian areas. Causes and characteristics of hydrological hazards have been evaluated and considered with respect to features, pattern and factors of their long-term, seasonal and spatial variability using statistic methods, remote sensing data and numerical simulation. Furthermore, the impact of regional climate change and economic activities is discussed. As a result, detailed information about the Northern Dvina river mouth is presented. It included the structure and the efficiency of measure for preventing ice jam formation and protecting from river discharge, ice jam and surge-induced inundations. The article also included fundamental and updated data on the structure, parameters and hydrological regime of the Northern Dvina and the Pechora river mouths and specifics of their changes in the twentieth and early twenty-first centuries. 相似文献
8.
加强塔里木河阿拉尔生态系统综合监测 总被引：3，自引：0，他引：3
塔里木河流域是我国最大的内陆河流域,流域总面积102×104km2,水资源总量为429×108m3,水资源相对贫乏,生态环境十分脆弱.阿拉尔生态系统监测站位于阿克苏河、叶尔羌河、和田河三河和塔里木河交汇处的肖夹克,是平原区重要区域代表站,其生态环境直接关系着塔里木河干流上、中、下游生态和环境安全.查阅模清该区域的生态环境的基本特点、变化规律和演变趋势,对指导塔里木河综合治理,以及当地社会经济和谐发展极其重要.该站始建于1996年7月,监测项目有水文气象;地下水动态;乔、灌、草;土壤、水盐;沙漠化动态5类监测项目.野外监测设施有河道水文断面、气象观测场、第一监测剖面(长22 km).除水文气象监测项目在综合系统监测站附近外,其余4个监测项目均在第一剖面进行. 相似文献
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全球范围内干旱区河流正日益受到高强度人类活动的扰动,但较少研究报道这种扰动对河流地貌过程的影响。采用历史文献、水文数据和遥感影像相结合的方式,详细分析了人类活动影响下中国最大内陆河塔里木河（简称塔河）的河流地貌变化过程。结果表明:塔河流域人类活动的规模和强度日趋上升,对河流水沙过程和地貌形态等影响显著。近50年来,塔河干流低流量过程发生频率呈显著上升趋势,而中、高流量过程则呈降低趋势,河道径流和输沙量减少显著。塔河干流上游现为游荡河道,冲淤变化剧烈且总体处于淤积抬升状态, 但河道平均河宽呈减小趋势,可能是因为塔河两岸冲积平原的开垦和河岸加固。塔河中游弯曲河道蜿蜒系数在近几十年呈缓慢上升趋势,但明显低于废弃古河道。 相似文献
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M. R. Majdzadeh Tabatabai R. Mousavi Nadushan S. Hashemi 《International Journal of Environmental Science and Technology》2017,14(8):1757-1770
In recent decades, due to river regulations and their impact on river morphology, brown trout populations have been declining along Lar River downstream of Lar Dam located near Tehran, Iran. Considering the recent water scarcity in the country, development of river habitat assessment models seems necessary. Therefore, in this research, an analytically applied approach is adopted to evaluate brown trout habitat by creating a relation among the hydrologic, hydraulic, geomorphic and ecologic processes. After field survey, dimensionless shear stress of the stream flow thresholds including environmental flow, bankfull flow, surface and subsurface sediment flow thresholds was calculated for Lar, Dalichay and Sefidab Rivers using Shields formula. Then, by considering the dimensionless shear stress ranges of the stream flow thresholds, functional flows ranges and duration were calculated together with ecological efficiency of the cross sections. In addition, effects of annual water yield and entrenchment ratio of the cross sections on habitat functionality were also worked out as a result of which an exponential interaction was developed between the dimensionless shear stress and discharge. Results show that an increase in functional flows ranges and duration, together with rising of ecological efficiency, is directly proportional to an increase in median bed sediment size, entrenchment ratio and annual water yield. Therefore, flow regime, cross-sectional geometry, water-surface slope and bed sediment size could be effective on the ecological functions of the brown trout’s life cycle and functionality of river flow. 相似文献
13.
河流管理涵盖灌溉、防洪、河流生态、环境等众多内容,其目的在于保护和恢复河流生态系统的整体生态功能。植物是具有生态功能河流的重要特征,为动物提供了栖息地,是维持河流健康发展的重要因素。由于植物的存在改变了水流运动特性和泥沙及污染物输移规律,含植物水流问题引起了河流管理领域的广泛关注,并且成为河流动力学新的重要的研究课题。回顾了当前国内外河流管理中含植物水流问题研究的主要成果,归纳为水流阻力、紊流结构、泥沙运动和被动标量扩散输移四个方面的研究内容,详细介绍了重要的研究方法、结论和量测手段,讨论了含植物水流问题当前研究存在的不足,并指出今后的研究趋势。 相似文献
14.
根据枯水径流在流量过程曲线上的定义,绘制枯水径流流量过程曲线(Low Flow Duration Curve,LFDC),分析1973～2004年间东北地区育林沟流域夏季桔水径流对造林引起覆被变化的响应规律.结果表明,1983～2004年相对于1973～1982年,流域森林覆被增加了l5%,多年平均夏季枯水径流相对增加11.84%,各年夏季枯水径流增加值却随着森林覆被的增加整体呈现递减的趋势.其中,流域覆被的增加对LFDC曲线上0～50%频率的夏季枯水径流增加尤为显著.LFDC曲线能够更好地体现超过某一频率的枯水径流对覆被变化的响应规律,对于枯水季节水文水资源的利用管理具有重要的参考价值. 相似文献
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《Applied Geochemistry》2005,20(11):2138-2153
Recent geochemical and hydrological findings show that the water quality of the base flow of the Lower Jordan River, between the Sea of Galilee and the Dead Sea, is dependent upon the ratio between surface water flow and groundwater discharge. Using water quality data, mass-balance calculations, and actual flow-rate measurements, possible management scenarios for the Lower Jordan River and their potential affects on its salinity are investigated. The predicted scenarios reveal that implementation of some elements of the Israel–Jordan peace treaty will have negative effects on the Jordan River water salinity. It is predicted that removal of sewage effluents dumped into the river (∼13 MCM/a) will significantly reduce the river water’s flow and increase the relative proportion of the saline groundwater flux into the river. Under this scenario, the Cl content of the river at its southern point (Abdalla Bridge) will rise to almost 7000 mg/L during the summer. In contrast, removal of all the saline water (16.5 MCM/a) that is artificially discharged into the Lower Jordan River will significantly reduce its Cl concentration, to levels of 650–2600 and 3000–3500 mg/L in the northern and southern areas of the Lower Jordan River, respectively. However, because the removal of either the sewage effluents or the saline water will decrease the river’s discharge to a level that could potentially cause river desiccation during the summer months, other water sources must be allocated to preserve in-stream flow needs and hence the river’s ecosystem. 相似文献
16.
Xiaoyan Wang Tao Yang Bin Yong Valentina Krysanova Pengfei Shi Zhenya Li Xudong Zhou 《Environmental Earth Sciences》2018,77(12):465
Climate change is expected to have substantial impacts on flow regime in the Upper Yellow River (UYR) basin that is one of the most important biodiversity hotspots in the world. These impacts will most possibly exert negative effects on the habitat availability for riverine species. Thus, it is necessary to understand the alteration of river flow regime under climate scenarios. In this paper, we use the modified hydrological model HBV in conjunction with three general circulation models under three representative concentration pathways (RCP 2.6, 4.5, and 8.5) to address changes in flow regime under climate change for the UYR basin in the mid-term (2050s) and end-term (2080s) of the twenty-first century. Flow regime is quantified using the Indicators of hydrological alteration approach. Thereafter, the potential threats to riverine ecosystem in the UYR basin are identified based on the projected alterations of various flow characteristics and their ecological influences. The results showed that the magnitude of monthly flow would increase during the dry period. The date of the annual 1-day minimum streamflow will likely shift toward earlier time under different scenarios, and significant increases in magnitude of annual minimum flow of different durations were detected under both RCP 4.5 and 8.5 scenarios in the 2080s. In addition, assessments of the modification degree of the overall flow regime revealed that climate change would remarkably modify (medium level) the overall flow regime in the UYR basin, particularly by the end of the twenty-first century or under the high emission scenarios. Besides, destruction of habitat and reduced availability of food induced by substantially increased hydrological instability in the 2080s would make two endangered fishes more vulnerable in the UYR basin. These findings provide insights into potential adaptive countermeasures for water resource management and environmental system restoration in the Upper Yellow River. 相似文献
17.
Jing Liu Siliang Li Jun Zhong Xuetao Zhu Qingjun Guo Yunchao Lang Xiaokun Han 《中国地球化学学报》2017,36(4):611-618
While it is critical to accurately understand the sources and transformation of sulfate based on time-series analysis, there are limited studies on temporal variation of sulfate in rivers and on rock weathering by sulfuric acids. We conducted a monthly sampling campaign in the Beipan, Nanpan, and Hongshui Rivers over the course of one hydrological year. This study examined seasonal variations in riverine sulfate impacted by the monsoon climate in the upper reaches of the Xijiang River basin. In general, the SO4 2? contents in these rivers dropped from relatively high levels to low values during the high-flow season, in response to increasing discharge. The sulfate was generally enriched in heavy isotopes during the low-flow season compared to the high-flow season. The calculated results indicate that the riverine sulfate was mainly derived from sulfide oxidation, but that evaporite dissolution could be an important source during the low-flow season, based on isotopic evidence. Mine drainage is likely an important source of sulfate to these rivers during the high-flow season due to contributions from fast surface flow, which responds to frequent heavy rain in monsoonal climate regions. A relatively high proportion of HCO3 ? was found to be derived from rock weathering by sulfuric acid during the high-flow season when compared to that observed during the low-flow season. The results suggest that approximately one quarter of the HCO3 ? in the Hongshui River originated from carbonate weathering by sulfuric acid derived from the oxidation of sulfide. Such information on the specific dual isotopic characteristics of riverine sulfate throughout a hydrological year can provide unique evidence for understanding the temporal variability of sulfate concentrations and weathering processes in rivers. 相似文献
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新疆阿尔泰山区克兰河上游水文过程对气候变暖的响应 总被引：17，自引：7，他引：10
额尔齐斯河支流克兰河上游发源于西风带水汽影响的阿尔泰山南坡,主要由融雪径流补给,年内积雪融水可占年径流量的45%.年最大月径流一般出现在6月份,融雪季节4~6月径流量占65%.流域自20世纪60年代开始明显升温,年平均温度从50年代的1.4℃上升到90年代的5.2℃;年降水总量也呈增加趋势,尤其是冬季和初春增加最多.随着气候变暖,河流年内水文过程发生了很大的变化,主要表现在最大月径流由6月提前到5月,月径流总量增加约15%,4~6月融雪径流量也由占年流量的60%增加到近70%.在多年变化趋势上,气温上升主要发生在冬季,降水也以冬季增加明显,而夏季降水呈下降趋势;水文过程主要表现在5月径流呈增加趋势,而6月径流为下降趋势;夏季径流减少而春季径流增加明显.冬春季积雪增加和气温上升,导致融雪洪水增多且洪峰流量增大,使洪水灾害破坏性加大.近些年来气候变暖引起的年内水文过程变化,已经对河流下游的城市供水和农牧业生产产生了影响. 相似文献
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Human has always modified its surroundings for better adaptation which include the building of urban landscapes, dams, and engineering constructions like bridges and other infrastructures. It has been unveiled from the study of River Chel that when the rail bridge was constructed before 1913, the natural width of the river was nevertheless maintained but the problem was initiated and after the road bridge construction in 1970s when the river width was minimized,the morphological changes started in a large scale. Such modifications have affected nature as well as human communities both positively and negatively. This paper will try to portray the evolution of channel shifting and changes of sediment size regime that the River Chel is experiencing due to the construction of bridges across the middle part of its course. So, this study is concerned about the changes in channel pathway since last 100 years and field-based hydrological parameters and sediment size analysis reveals some distinct changes in the channel planform with alteration of sediment size regime. Simulation of the hydraulic modeling in HEC-RAS specifies the probable affected area with bridges and without bridges in both upstream and downstream of the river course. Hence, the study unveils the alteration of the river hydrology and sediment size caused due to anthropogenic effects and impact of such flow analysis has been evaluated through the bridge scour calculation by CUS method. The discussion concludes that the Odlabari road bridge construction (after 1970) has modified the normal hydrological behavior of the river with a higher probability of bank erosion in downstream and floods in upstream resulting river bottleneck condition. 相似文献