北洛河上游水沙变化及影响因素分析

以北洛河上游刘家河水文站1959—2006年的水文观测数据为依据,应用Mann-Kendall非参数检验法和逐步回归分析法,对刘家河站以上区域的水沙变化及影响因素进行了分析。结果表明:①刘家河以上流域降水量、径流量、输沙量的年内分配不均、年际变化大,1959—2006年均呈下降趋势,且在20世纪80年代初均发生了突变;②降水量是引起1959—1979年水、沙变化的根本原因;③1980—2006年间,径流量主要受降水量的影响,而输沙量受人类活动的影响较大。     

近60 a河南省河川径流演变特征研究

河南省地跨海河、黄河、长江、淮河四大流域,水资源问题突出,深入分析河川径流演变规律对河南省水资源管理具有重要意义。选取河南省主要流域的6个代表水文站实测流量数据,利用Mann-Kendall秩次相关检验分析了各代表站年平均流量、月平均流量演变规律。结果表明：近60 a河南省实测流量呈下降趋势,2000年后流量略有回升。自西向东,流量下降速率越来越大。全省径流突变后年平均流量减小,各站减小幅度均大于15%,北部流域突变年份较早,南部流域变化幅度较大。月平均流量总体呈减小态势,海河流域河南段、黄河流域河南段下降显著,达到5%显著性水平。除长江流域河南段外,全省月平均流量年内分配变化不大,从全省范围来看,月径流量占年径流量比例呈枯增丰减态势。     

平江流域水土保持综合治理水沙调配效益评价

以位于南方典型水土流失区的平江流域为研究对象,以长序列历史观测数据为基础,应用径流调控理论,对流域水土保持综合治理措施体系水沙调配效益进行了定性和定量的对比分析,结果表明：通过30多年的水土保持综合治理,平江流域径流洪枯比由治理前1958~1979年的年均3.51下降到治理后1980~2015年的年均2.45,枯季径流量占全年径流总量的比例总体呈上升趋势;流域年输沙量呈显著下降趋势,年均减少1.48豫,尤其是治理后期的2003~2015年,流域年均输沙量比治理前下降了61.4豫.体现了流域水土保持综合治理调控径流时空分配及减沙效益显著.     

变化环境下南渡江干流径流特征分析及变化趋势研究

根据南渡江干流福才、龙塘水文站1959—2018年共计60 a的月实测径流资料,运用统计学分析法、目估适线法、Mann-Kendall法及滑动t-检验对其径流特征、长期分布及变化趋势进行研究与分析。结果表明:南渡江干流径流年内分配相对集中,汛期(5—10月)径流量占全年径流总量约80%,流域汛期防洪任务重;南渡江流域在1986年后,流量呈现不显著的下降趋势;自1959年来,年均流量变化较为平缓,未出现突变点,受人类活动影响不大。     

基于数字滤波法的怒江流域基流时空分异

为明晰怒江流域基流时空分异特征,利用数字滤波法进行怒江干流和南汀河支流的基流研究。结果表明:1怒江干流3站基流指数IBF在0.71~0.74之间,南汀河支流2站的多年平均IBF在0.68左右,南汀河支流IBF明显低于怒江干流,干支流基流量和IBF自上游向下游递增;2各站基流量与径流量变化过程基本一致,两者相关系数均在0.9以上;3怒江干支流各站多年平均基流量和径流量年内分配均呈"尖廋"的单峰形,而多年平均基流指数年内分配均呈"V"字形,但两者变化过程不完全相反;4怒江干流代表站道街坝站和南汀河支流代表站姑老河站IBF均为丰水年平水年枯水年,这与基流相对于径流更为稳定有关。     

汤旺河流域河川基流量计算分析

河川基流量是指由地下水补给到地表径流中的径流量,是山丘区地下水资源的主要组成部分。山丘区河川基流量因观测条件限制还没有较好的直接计算方法,文章以山丘区流域为例,利用水文分割法中斜割法并结合代表站综合退水曲线,对流域河川基流量进行了分析计算,求出了流域多年平均和不同设计频率的基流量,提出了计算河川基流量的简化方法和使用条件。     

东山流域水土保持措施对地表径流和土壤侵蚀的影响

以太原市娄烦县东山流域为研究对象,通过在流域内设置不同水土保持措施配置的径流小区,观测各个小区的地表径流量和侵蚀量,分析研究不同水土保持措施配置对径流小区的径流量和侵蚀量的影响。试验表明：通过工程措施改变地表微地形可以明显降低地表径流量及侵蚀量,提高地表植被盖度可以降低径流量及侵蚀量。     

秃尾河1967—2007年径流变化特性分析

利用秃尾河高家堡站1967—2007年径流数据,对秃尾河径流年内、年际的变化进行了分析,并对年、月径流序列进行了Mann-Kendall检验,结果表明:①1967—2007年年径流量呈显著下降趋势;②径流量的年内分配呈双峰型,1967—2007年各月径流量均呈减少趋势,汛期径流量占全年径流量的比例逐渐下降,非汛期径流量占全年径流量的比例上升,1970年后径流年内分配的不均匀系数和集中度较之前明显减小;③秃尾河径流减少和年内分配均匀化是气温上升、水土保持措施以及水利工程建设等共同作用的结果。     

水电开发对下游河川径流及输沙特性的影响研究

以澜沧江流域为研究对象,建立了表征河川径流及输沙特性的系列回归还原模型,对澜沧江允景洪站的水沙特性进行了还原模拟,并以漫湾、大朝山两座电站的建设期与运行期为界,系统分析了澜沧江流域梯级电站建设对下游允景洪站水文特性的影响。水电站建成后,1993～2007年下游允景洪站年径流量、枯水期径流量分别年均减少5.79%,3.44%,而最小月平均流量年均增加4.38%,最大月平均流量年均减少13.4%,电站削峰作用明显。在水电站施工期间,电站对河道扰动明显,输沙强度大,而在运行期间,水库具有一定的拦沙效应。2001～2007年两座水电站共同运行期间,澜沧江径流年内分配均匀度年均升高1.47%,输沙年内分配均匀度年均降低0.42%,说明水电工程运行使河流中水沙关系发生了变化,但变化幅度均较小。因此澜沧江现有的水电开发对下游径流及输沙特性所产生的影响均较小。     

北洛河天然年径流特性分析

运用相关分析方法和基于小波的多时间尺度变换,对北洛河上、下游及其主要支流葫芦河的年径流量进行了时序相关性和多时间尺度变化特性的分析,认为:①在北洛河上游刘家河站和下游交口河站天然年径流长期变化中,序列自身都存在一定的弱自相关性;②互相关性分析方面,交口河站t时刻与刘家河站t时刻具有一定的互相关性,支流葫芦河与北洛河下游任何时刻都独立;③北洛河年径流量存在2年、9～11年和20年左右的变化周期;④该流域年径流量在21世纪初将逐渐由枯变丰.     

1975－2015年洪泽湖水沙变化趋势及成因分析

淮河流域洪涝灾害频繁,洪泽湖对其防洪除涝起关键性作用。掌握洪泽湖水沙变化趋势及突变点对流域水资源管理、水沙调节有重要的现实意义。利用入、出洪泽湖各支流代表水文站1975-2015年实测年径流量和年输沙量数据,分析入、出洪泽湖水量和沙量分布特征。通过Mann-Kendall(M-K)秩相关检验法和Pettitt突变点识别法研究入湖、出湖水沙量年际变化趋势和突变点。在此基础上,从流域降雨、水资源开发利用和水库滞沙三个方面分析了洪泽湖水沙变化的主要影响因素。研究表明:洪泽湖入湖、出湖水量年际变化趋势一致,无明显减小趋势,且无显著突变点。入湖沙量有小幅减小趋势,出湖沙量M-K统计值超过95%显著性水平,有明显减小趋势。入湖、出湖沙量发生突变的年份为1991年。对影响因素的分析得到:降雨量变化是水量变化的重要影响因素。1993-2015年,入湖水量呈不明显减小趋势则与流域用水量明显增加、水资源开发利用程度不断提高有关。上游水库建设是导致洪泽湖沙量有明显减小趋势的主要原因,1991年治淮工程的实施,水库复建和水土保持等措施是沙量突变的主要原因。     

金沙江上游河段水温变化规律及其影响因素探讨

金沙江上游作为长江的源头地区,具有特殊的生态环境功能,河流水温对水生生物的生长及周边生态环境具有重要意义。采用金沙江上游干流岗拖、巴塘、石鼓水文站实测水温数据,以河段天然水温作为研究对象,对其年内、年际变化及沿程分布规律进行了研究,并探讨了影响水温的主要水文、气象因素。结果表明,金沙江上游岗拖、巴塘、石鼓3个水文站月均水温最高值一般出现在7—8月份,最低值一般出现在1月份。1961—2018年3个水文站年水温总体上呈现出显著的上升趋势,并分别于1998年、1992年、2003年出现突变点。气温对3站月平均水温的影响最为紧密,其次是降水和径流,相对湿度、蒸发和风速也对该河段水温变化产生一定影响,日照与水温之间的关系最弱。从水温变化的沿程分布来看,从上游至下游,水温与径流、风速、水面蒸发相关系数沿程减小,与降水、气温、相对湿度相关系数沿程增加,其主要原因与金沙江上游流域水文气象特征关系密切。同时通过主成分分析,进一步验证了影响水温的主要因素。     

Statistical Assessment of the Impact of Conservation Measures on Streamflow Responses in a Watershed of the Loess Plateau, China

The objective of this study was to examine the trends of changes in streamflow in a watershed of the Loess Plateau, where a series of soil conservation measures were implemented since the late 1950s. Both parametric and non-parametric Mann–Kendall test were used to identify the trends in hydrologic variables over the last 50 years, and it showed significant downward trends in annual runoff, surface runoff and baseflow. The Pettitt’s test was used to detect the change points of runoff, which occurred in 1973, and the whole 50-year records could be divided into contrast (from 1957 to 1973) and treated (from 1974 to 2006) periods. It was observed that the average annual runoff during treated period reduced by 60%, surface runoff and baseflow reduced by 65% and 55%, respectively in comparing with the contrast period. But the proportion of baseflow to total runoff showed a significant increasing from 0.57 to 0.63. Seasonal runoff also showed decreased trend with the highest reduction occurring in summer and lowest in winter. Annual precipitation in whole period showed no significant trend, so the changes in hydrologic variables were induced by conservation measures. Comparison of the flow duration curves for the two periods showed that reductions in high and low flows varied greatly. Results showed that conservation measures have resulted obvious changes in the hydrologic variables in a watershed of Loess Plateau.     

青藏高原东南部径流特征的空间规律及控制因子研究

采用青藏高原东南部的水文气象资料,对比分析了该地区23个(区间)流域的年径流深、集中度与集中期、基流系数、退水系数等径流特征及其空间分布规律,并进一步研究了这些径流特征的控制因子。结果表明:该地区径流特征的空间分布规律为年径流深从东南(700~1 300 mm)向西北(<400 mm)递减,而集中度则呈相反的空间格局(从<0.44增加到>0.59);退水系数及基流系数,在低海拔地区随高程增大而增大(分别为0.55~0.69、0.51~0.73),但在高海拔地区则随高程增大而减小(0.74~0.42、0.79~0.63)。本研究发现,青藏东南径流特征空间规律的控制因子,具有显著的区域分异:在低海拔流域(平均高程<3 000 m),降水是径流特征的主要影响因子;而在高海拔流域(平均高程>3 000 m),仅径流深和集中度受降水控制,其他特征则主要受温度、冻土、地形等条件的共同影响。可见,由于青藏高原东南部降水和冻土对气候变化敏感,该地区水资源时空分布格局将面临很大的不确定性,对此应予以充分重视。     

1956-2016年黄河流域河川径流演变规律

黄河流域水资源短缺问题突出,深入分析河川径流的演变规律对于流域水资源管理具有重要的指导意义。基于黄河干流上、中、下游不同位置的代表性水文站实测径流,利用Mann-Kendall非参数趋势检验方法分析了1956-2016年期间黄河流域年、月径流的历史演变规律。结果表明:1956-2016年,除源头区年径流变化不显著以外,黄河流域径流呈现出显著的下降趋势,达到了1%的显著性水平。从上游到下游,河川径流下降幅度越来越大,趋势越来越显著。1980-2000和2001-2016年的多年平均入海径流比1956-1979年分别减少了50. 07%和59. 67%。径流演变呈现出3阶段特征,20世纪50、60年代属于丰水期;随后在70至90年代径流持续下降;在2000年以后径流有所回升。除源头区以外,黄河流域的月径流总体呈现减少趋势;上游和中游地区的月径流占年径流的比例枯增丰减;下游地区月径流占年径流的比例在冬季、夏季增大,春季、秋季减小。     

Detection of Streamflow Change in the Susquehanna River Basin

Streamflow statistics are commonly used for purposes of planning and managing water resources in the Susquehanna River Basin. For accurately estimating streamflow statistics, it is important to identify whether there are increasing or decreasing changes during the period of records and whether the change is gradual or abrupt. This study employs repeated monotonic trend tests with varying beginning and ending time for detecting changes in streamflow in tributaries within the Susquehanna River Basin. The method is employed to analyze long-term streamflow trends and detect change for annual minimum, median, and maximum daily streamflow for eight unregulated watersheds within the basin. Monthly baseflow and storm runoff are investigated. The results show a considerable increase in annual minimum flow for most of the examined watersheds and a noticeable increase in annual median flow for about half of the examined watersheds. Both these streamflow increases were abrupt, with only a few years of transition centered around 1970. The abrupt change in annual minimum and median flows appears to occur in the summer and fall seasons. The abrupt change in annual minimum and median flows is due to increased flows in the summer and fall seasons. The results also indicate there is no long-term significant increasing or decreasing change in annual maximum flow in the examined watersheds.     

Extreme value analysis of streamflow time series in Poyang Lake Basin, China

Extreme meteorological and hydrological events may cause major disasters and heavy social and economic losses.Therefore,more and more studies have focused on extreme hydro-meteorological events in various climates and geographic regions.Based on nearly 50 years of observed records of the Poyang Lake Basin,the occurrence and changing trends of extreme streamflow indices,including the annual maximum flow,annual peak-over-threshold flows,and low flows,were analyzed for ten hydrological stations.The results indicate that most annual maximum flows occurred from April to July,highly attributed to the Southeast Asian summer monsoons,whereas the annual minimum flows were concentrated between January and February.As for the low flow indices (the annual minimum flow,annual minimum 7-d flow,and annual minimum 30-d flow),a significant increasing trend was detected in most parts of the Poyang Lake Basin.The trends illustrate the potential effects of climate change and human activities on the hydrological cycle over the Poyang Lake Basin.     

Identification of Streamflow Response to Climate Change and Human Activities in the Wei River Basin,China

In this study, the calibration and validation period with stable underlying surface conditions was determined by using a statistically significant change point of the annual streamflow in several catchments of the Wei River basin (WRB). The effects of climate changes and human activities on streamflow were estimated by using the sensitivity-based method and the dynamic water balance model, respectively. The contributions of climate effects and human activities effects on streamflow were also investigated. The results showed that almost all the catchments exhibited significant decreasing trend of streamflow in the early 1990s. The streamflow was more sensitive to changes in precipitation than changes in potential evapotranspiration (PET). Effects of climate due to changes in precipitation and PET are weak in Linjiacun, Weijiabao and Xianyang catchments, while it is strong in the catchments controlled by other hydrological stations, accounting for more than 40 % of streamflow reduction. Effects of human activities on streamflow in Linjiacun, Weijiabao, Xianyang and Zhangjiashan catchments accounted for more than 50 % of the streamflow reduction. The study provides scientific foundation to understand the causes of water resources scarcity and useful information for the planning and management of water resources in the ecological fragile arid area.     

How much groundwater can we pump and protect environmental flows through time? Presumptive standards for conjunctive management of aquifers and rivers

Groundwater is a critically important source of water for river, wetland, lake, and terrestrial ecosystems, yet most frameworks for assessing environmental flows have ignored or not explicitly included the potential impacts of groundwater pumping on environmental flows. After assessing the processes and existing policies for protecting streamflow depletion from groundwater pumping, we argue that a new groundwater presumptive standard is critical as a placeholder to protect environmental flows in rivers lacking detailed assessments. We thus extend the previous presumptive standard to groundwater pumping, a different and important driver of changes to streamflow. We suggest that “high levels of ecological protection will be provided if groundwater pumping decreases monthly natural baseflow by less than 10% through time.” The presumptive standard is intended to be a critical placeholder only where detailed scientific assessments of environmental flow needs cannot be undertaken in the near term. We also suggest a new metric, the environmental flow response time, that allows water managers to quantify the timescales of the impacts of groundwater pumping on the loss or gain of environmental flows.     

Wavelet transform‐based analysis of periodicities and trends of Sakarya basin (Turkey) streamflow data

In this study, the wavelet transform and the Mann–Kendall test are used to determine possible trends in annual streamflow series. The wavelet analysis provides detailed information about the time‐frequency contents of the data. Using wavelet components of the original data, it was aimed to find which periodicities are mainly responsible for a trend in the original data. Also, the global wavelet spectra and the continuous wavelet transform (CWT) were used for the analysis of the streamflow data, in order to explain its time‐frequency characteristics. Annual streamflow series across Turkey were used for the detection of trends for the original data and the periodic wavelet components (obtained by discrete wavelet transform). It was found that some periodic events clearly affect the trend in the streamflow series. The DW4 component (16‐yearly periodic component) at the stations of the Sakarya basin is the effective periodic component and is responsible for producing a real trend in the data. The effects of regional differences on the wavelet‐trend analysis are studied using records of the stations located in different climate areas. DW2 (4‐yearly component) and DW3 (8‐yearly component) are the dominant periodic components of this data. This study aims to explain the trend structure in the data. Copyright © 2009 John Wiley & Sons, Ltd.