The changes in the annual distribution of mountain runoff during the period of 1965-2018 in Hexi Corridor,Northwest China

The annual distribution characteristics of river runoff in arid regions have significant implications for water resource stability and management.Based on the mountain runoff data from 1965 to 2018,this study examines the annual change characteristics of monthly runoff of the Shiyang River Basin,Heihe River Basin,and Shule River Basin in the Hexi Corridor,Northwest China.Many indexes are used and analyzed,including the coefficient of variance,the complete regulation coefficient,the concentration degree and concentration period,the magnitude of change,the skewness coefficient,and the kurtosis coefficient of the annual distribution curves.The results reveal the following:(1)The inhomogeneity of annual runoff distribution in the Taolai River and the rivers to the west of it,except the Shiyou River,show an increasing trend.Conversely,the inhomogeneity of the rivers to the east of the Taolai River generally show a downward trend,but the coefficient of variance value is still very high.(2)In the Shiyang River Basin,the annual distribution of the concentration period is characterized by a relatively discrete pattern.Conversely,the Heihe River Basin exhibits a relatively concentrated pattern,and the distribution pattern of the Shule River Basin is quite different.Notably,all concentration periods in the three basins have shifted backward after the 2000s.(3)The Shiyang River Basin exhibits disordered annual distribution curves of runoff in different years.In contrast,the Heihe River Basin presents a typical‘single-peak’pattern with a prominent right-skewed.The Shule River Basin has regular distribution curves,with a gradually significant‘double-peak’pattern from east to west.Overall,there has been a slight change in runoff in the Shiyang River Basin,while the Heihe River Basin and Shule River Basin have experienced significant increases in runoff.The annual distribution curves of runoff in the Liyuan River and the rivers to the east of it exhibit a gentle peak pattern,and the appearance probability of extreme runoff during the year is low.Conversely,the rivers to the west of the Liyuan River,excluding the Danghe River,display a sharp peak and thick tail pattern,indicating that the appearance probability of extreme runoff during the year is high.These findings have practical implications for the planning and management of water resources in the Hexi Corridor.Moreover,they provide a solid foundation for predicting future changes in regional water resources.

Analysis on the Variations of Annual Runoff Distribution in the Weihe Basin

With the impact of climate change and the increasing intensity of human activities,the hydrological regime had changed,including annual runoff distribution,which was related with water resources management and ecological construction. Based on the monthly runoff data for more than 40 years of the Beidao,Xianyang,Huaxian station on Weihe Basin,the annual distribution characteristics of runoff were studied. Several indices related to attributes of uneven,concentrate degree and variation amplitude were calculated,and the results showed that there had obvious fresh and drought seasonal changes in 1990s. The annual runoff distribution had changed a lot,mainly because of runoff decrease in the wet season. The Huaxian station,which locates at the upper reaches,had a higher unevenness,concentration and relative variation rate than that of the Beidao and Xianyang station.

Quantitative research of annual runoff distribution characteristics in the Dagujia River basin,Yantai,China

Mann-Kendall method and minimum variance method are used in this study to analyze the mean value variable-point of the runoff data observed by Fushan Hydrological Station in the Dagujia River basin from 1966 to 2004. Based on the results, the runoff time is divided into four periods with the similar hydrological variation character. The annual runoff distribution characters in the Dagujia River basin are discussed by using the non-uniform coefficients, concentration degree and concentration period, variation range, etc. The results indicate that: (1) River runoff is very unevenly distributed throughout the year in Dagujia River. About 90% of runoff is in the period from June to October, while the runoff from November to April of the next year is lower. (2) The annual runoff distribution characters during 1966-1971 are very similar to that of 1982-1996, and the runoff of 1972-1981 is almost similar to that of 1997-2004. (3) The annual runoff distribution characters have changed obviously during 1997-2004 compared with the other periods, which makes it more difficult to exploit and use the water resource in the future.

1984年~2018年四卯酉河径流演变规律及归因分析

为揭示四卯酉河径流演规律及其影响因素,基于四卯酉闸水文站1984年~2018年的实测径流数据,采用Mann-Kendall检验法、Pettitt检验法、Morlet小波分析法分析四卯酉河年际变化规律,采用不均匀系数、集中度与集中期三个指标分析四卯酉河径流年内分配规律,采用双累积曲线定量分析四卯酉河径流演变原因。结果表明:四卯酉河径流量呈现显著上升趋势,并于2004年发生显著向上突变,径流主周期为28 a、18 a、13 a、9 a;四卯酉河径流年内分配较为均匀;降水因子和人类活动因子对四卯酉河径流变化贡献率分别为3.3%、96.7%,人类活动引起的不透水面的变化是导致四卯酉河径流变化的重要原因。

Sensitivity of runoff to climatic variability in the northern and southern slopes of the Middle Tianshan Mountains,China

Temperature and precipitation play an important role in the distribution of intra-annual runoff by influencing the timing and contribution of different water sources.In the northern and southern slopes of the Middle Tianshan Mountains in China,the water sources of rivers are similar;however,the proportion and dominance of water sources contributing to runoff are different.Using the Manas River watershed in the northern slope and the Kaidu River watershed in the southern slope of the Middle Tianshan Mountains as case studies,we investigated the changes in annual runoff under climate change.A modified hydrological model was used to simulate runoff in the Kaidu River and Manas River watersheds.The results indicated that runoff was sensitive to precipitation variation in the southern slope and to temperature variation in the northern slope of the Middle Tianshan Mountains.Variations in temperature and precipitation substantially influence annual and seasonal runoff.An increase in temperature did not influence the volume of spring runoff;but it resulted in earlier spring peaks with higher levels of peak flow.Damages caused by spring peak flow from both slopes of the Middle Tianshan Mountains should be given more attention in future studies.

THE COMPARISON OF CHINESE AND EUROPEAN STREAM RUNOFF

This paper compares stream stream runoff in China in terms of drainage basin, water balance, and regional distribution and regime of stream runoff with that in Europe. European stream runoff resources are more abundant than that of China. Europe has 28 rivers with runoff volume exceeding 10 km3, and China only has 19.But Europe has no rivers like those in China which are long andhave abundant waer volume such as Changiiang (Yangtze River) and Zhujiang. Heat conditions of the European water-abundant and water-sufficient zones are poor and their agiculture are not flourishing.In China these zones have very good heat conditions and are main farm production regions. The interannual and annual variation of stream runoff are the sane to the irrespective feedings in Europe and China.

麻街水文站年径流量频率密度和频率分布规律分析

利用频率密度和频率分布分析方法,对丹江上游麻街水文站实测径流系列进行频率密度和频率分布分析,得出该河段年径流量的概率分布规律在0.5 m^(3)/s~3.0 m^(3)/s之间占76%,特别大、特别小的年径流量出现的机会较少。

透水混凝土压缩试验及劈裂试验三维离散元分析

为研究透水混凝土细观力学参数与宏观力学性能的关系,通过PFC3D三维颗粒流建立平行粘结模型,对所建立方体透水混凝土进行单轴压缩试验模拟,得到砂浆粘结力提高倍数低于2.0时,两者呈y=x趋势增长,高于2.0时,呈y=1.54 ln(x)+0.90非线性趋势增长;三轴压缩试验模拟,得到围压从5 MPa~20 MPa,透水混凝土抗压强度提高了约2~3倍,表明结构可显著增强透水混凝土力学性能,并计算得透水混凝土的c、φ值分别为0.8 MPa、24°;压条劈裂试验模拟结果得透水混凝土劈裂抗拉强度为2.43 MPa,与试验结果相差0.08 MPa,提供了一种较为可靠的劈裂试验替代方法。

基于集中度与集中期的径流年内分配研究

借鉴年降水量年内分配的向量法,描述径流年内分配的径流集中度和集中期,尝试提出一种计算河川径流年内分配不均匀性的定量新方法。实例研究表明,用月径流量计算的集中度比径流年内不均匀系数有更高的分辨能力和敏感性,用月径流量计算的集中期对应的月份与月径流最大值出现的实际月份完全一致,径流集中度、集中期能够充分定量地表征径流在年内分配的非均匀性。

新疆和田河流域河川径流时序特征分析

根据新疆和田河流域3个测站的多年实测径流资料,从径流的年内分配和年际变化2个方面分析了和田河流域河川径流的变化特征。计算结果表明,在年内分配方面,由于径流补给来源的作用,流域径流绝大部分集中在夏季,这就使得径流年内分配不均匀系数和集中度普遍较高,而计算所得的集中期也与实测最大月径流出现的情况相吻合。在径流的年际变化方面,尽管和田河流域的年降雨量存在递增的趋势,但是由于源区高山的雪线高程上升、冰川退缩,再加上人类活动的影响越来越显著,从而导致流域的河川径流呈现微弱的下降趋势。经过周期图法分析得到,和田河流域的年径流量不存在明显的周期成分。

北江流域径流序列年内分配特征及其趋势分析

以石角站45 a的实测月径流资料为基础,研究了北江流域径流年内分配变化规律。通过计算径流年内分配不均匀性、集中程度、变化幅度等指标发现,北江径流量具有显著的洪枯季节变化,20世纪50、60年代的径流年内分配较不均匀,而70年代以来,径流年内分配较为缓和。选用db3小波函数,对各指标进行3层分解,以尺度水平3下的低频系数单支重构序列观察各指标的变化趋势,发现北江流域年内分配不均匀性指标显示为缓慢下降的趋势,尤其是70年代以后,这很可能是流域内人工水利设施对径流调节力度加大的缘故。对降雨序列的年内分配指标进行类似的分析后认为,径流不均匀系数等指标在趋势上变化的原因是流域内人工水利设施对径流的调节力度加大了。

松花江干流中游段径流年内分配变化规律

为了研究松花江干流中游段的径流年内分配变化规律,以哈尔滨站和佳木斯站1954—1987年、2001—2007年的逐日流量资料为基础,对径流年内分配的不均匀性、集中程度和变化幅度等指标进行了分析计算.结果表明:(a)松花江干流中游段在20世纪70年代径流年内分配较为均匀,80年代最不均匀;哈尔滨站的径流年内分配不均匀性和集中度通常要小于佳木斯站;最大径流出现的时间哈尔滨站滞后于佳木斯站.(b)2个站径流年内分配不均匀系数、完全调节系数、集中度和集中期的变化过程是同步的,且前3个指标之间具有较大的相关关系.

白龙江流域上游径流年内分配变化规律分析

在气候变化与人类活动双重影响下。河川径流的年内分配特征随着发生变化。本文根据白龙江上游4个站点的实测月径流量资料，分析了年内分配不均匀性，集中程度与变化幅度等指标。结果表明：在1965～1969年、1971～1984年和2002～2006年，径流年内分配不均匀性较强：白龙江上游集中度较小。集中度随时间的增加均呈现降低趋势。流域自上游向下游，在不同年代集中期均表现为逐渐缩短的变化趋势。Cm、Cm-max和AR随时间增加而减小，Cm-man刊。随时间增加而增大。总体上看，随着时间的推移，白龙江上游径流年内分配不均匀性越来越低，逐渐由不均匀向相对均匀转变。

近50年来淮河干流径流演变规律分析

基于淮河干流1956-2008年的实测径流资料,从不均匀性和集中程度等方面分析了径流年内分配的时空变化特征,并采用Mann-Kendall非参数检验和距平累积等方法对径流年际变化的趋势性与阶段性进行定性和定量分析。结果表明:(1)淮河干流径流年内分配极不均衡,年际变化较为剧烈。汛期径流量约占年径流量的63%,而最小年径流量仅占多年平均径流量的14.0%～18.2%。1980年以后,径流年内分配不均匀性与集中程度进一步加剧,空间差异有所减小,而集中期则延迟于7月份。(2)年径流量总体表现出递减的变化趋势,且中游递减趋势较上游明显,但均不显著。四季径流量变化趋势与变化幅度不尽相同,息县站和王家坝站仅在春季呈现递减趋势,而鲁台子站与吴家渡站在春、秋季均呈现递减趋势。总体而言,枯水期径流量的进一步减少将加剧流域水资源的供需矛盾。(3)年径流量序列中存在2个持续丰水时段和3个持续枯水时段,且持续枯水时段较持续丰水时段要长。在1996-2008年间,年径流量丰枯交替变化频繁,这主要与该时段流域内降水量年际变化大、旱涝交替出现有关。

沂河流域天然径流变化规律分析

根据沂河主要控制站-临沂站1958-2000年共43a的天然径流资料,采用线性倾向估计法、Mann-Kendall法和小波分析法等方法分析了临沂站天然径流年际变化的趋势性和周期性。选取天然径流年内分配的不均匀系数、完全调节系数、集中度、集中期和绝对变化幅度等指标分析了径流年内分配特征。最终获得了临沂站天然径流年际变化规律、年内分配特征,可为沂河流域水资源的合理开发、利用、优化配置和可持续发展提供一定的参考依据。

鄱阳湖流域抚河径流特征及变化趋势分析

抚河是鄱阳湖流域第二大河流。其径流变化研究对揭示鄱阳湖水文情势演变规律和鄱阳湖生态环境保护具有重要的科学意义。本文采用鄱阳湖流域抚河上、中、下游8个主要水文站的实测资料．分析了抚河径流年内分配特征及变化规律；应用Mann—Kendall非参数检验与回归分析等方法，研究了近几十年内抚河年、月径流变化规律及与降雨的关系。结果表明：（1）抚河径流年内分配不均，但不均匀性在流域内空间差异较小；（2）受水利工程调蓄影响，径流年内分配越来越均匀；（3）不同年代年径流特性存在差异，20世纪70年代至90年代初，径流相对稳定，90年代中期到2002年，呈较明显上升趋势，2002年后，表现为下降趋势；（4）月径流变化有增有减，基本规律为枯水期（11月一次年3月）月径流量基本呈上升趋势，洪水期（4～6月）月径流基本呈下降趋势；（5）抚河的年降水量在2002年附近发生突变减少，与年径流量突变时间基本吻合，说明气候变化降雨量减少对近10年鄱阳湖流域抚河入湖径流的减少影响显著。

从潮白河年径流频率分布变化看北京市水资源安全问题

密云水库是北京市生活供水的唯一地表水源,而潮白河流域又是密云水库的径流形成区,因此,潮白河流域年径流量的变化直接关系到北京市的水资源安全。根据变化环境下非一致性年径流序列的水文频率计算原理,对潮白河水资源分区年径流序列的确定性成分和随机性成分进行分解,并分别对确定性成分进行拟合计算,对随机性成分进行频率计算;将确定性的预测值和随机性的设计值进行合成,得到潮白河水资源分区在过去、现在和未来年径流量的频率分布;从年径流量的频率分布变化上,分析了北京市所面临的水资源安全问题。分析结果表明潮白河流域年径流量变化的总体趋势是逐年减小,密云水库在平水年和枯水年的入库径流量也将随之减小,因此密云水库不能成为北京21世纪可持续发展的水资源保障。

黑龙江哈巴罗夫斯克站径流变化规律

以黑龙江哈巴罗夫斯克站1897—2005年共109a年径流时间序列和1897—1985年共89a月径流时间序列为基础,应用累积距平法和Mann-Kendall法等,分析计算哈巴罗夫斯克站年径流丰枯特征及其阶段性、径流年内分配不均匀性、集中度。结果表明:哈巴罗夫斯克站径流连丰年、连枯年交替出现,径流年际变化阶段性明显;哈巴罗夫斯克站径流量年内分配不均匀,主要集中在夏秋两季,占全年的76.01%;20世纪60年代径流年内分配最为均匀,10年代最不均匀。

北部湾经济区径流、降雨分配特点及其变化分析

基于1970-2008年南流江常乐水文站、钦江陆屋水文站月均实测径流、降雨资料,采用年内分配不均匀系数、变差系数、绝对变化比率、年际不均匀系数、距平百分率等指标分析北部湾经济区径流、降雨的年内分配、年际变化特点,采用线性趋势线法、双累积曲线法分析径流、降雨的变化趋势。结果表明,南流江、钦江实测径流量与降雨量年内分配呈单峰型,径流、降雨年内分配不均系数呈上升趋势,径流的多年变化大于降雨,径流量的年际变化均匀度较差。降雨旱涝等级变化波动小,而径流丰枯等级变化波动频繁。实测径流系数呈下降趋势,降雨径流关系存在减小的规律。

黄河源区径流年内分配变化规律分析

河川径流的年内分配特征与特定的径流补给条件关系密切。在气候变化以及人类活动的影响下,河川径流的年内分配特征也发生着相应的变化,直接影响水资源的开发利用以及生态系统的健康。本文根据黄河源区主要测站1952～1997年的月天然径流资料,分析了年内分配不均匀系数、集中度和集中期、变化幅度等特性。结果表明:1)黄河源区径流的年内分配特征20世纪90年代和70年代较为接近,而80年代则与60年代较为接近。2)90年代的径流年内分配特征出现了较大的变化,突出表现在汛期径流量的减少;3)玛曲水文站径流年内分配的不均匀性、集中度以及相对变化幅度都略高于唐乃亥,而绝对变化幅度则较小。