延河流域骨干坝拦沙量反推与未来可拦沙年限预测

定量研究延河流域淤地坝拦沙贡献率和未来可拦沙潜力,对流域淤地坝建设效益分析具有重要的参考价值。根据延河流域1952—2018年的径流输沙数据和2011年全国水利普查中的骨干坝建坝年限、控制面积、总库容和淤积库容等资料,构建了延河流域骨干坝拦沙量反推计算模型,计算了延河流域骨干坝逐年拦沙量与减沙贡献率,预测了骨干坝未来可拦沙年限。结果表明:不同年代延河流域骨干坝年均拦沙量持续增加,2000—2011年多年平均拦沙量为401万t/a,达到最大值;人类活动是延河流域年输沙量减少的主要因素,1997—2005年和2006—2011年人类活动对延河流域减沙量的贡献率分别为63.44%和84.98%;骨干坝拦沙量在人类活动减沙量中的占比呈减小趋势,1997—2005年占比24.67%,2006—2011年占比7.46%;截止2019年,延河流域62%的骨干坝未来拦沙年限为30年以内,并且北部骨干坝未来可拦沙能力大于南部骨干坝。研究结果可为延河流域水土流失防治与效益评价、水土保持措施规划与布局以及流域综合管理等提供参考依据。     

大理河流域淤地坝拦沙贡献率分析

为提高淤地坝拦沙贡献率的计算精度,揭示淤地坝拦沙量对流域输沙量减少的作用。以大理河流域为研究对象,提出一种基于GIS和土壤侵蚀模数的淤地坝逐年拦沙量计算方法,分析大理河流域淤地坝拦沙量对流域出口输沙量减少的贡献率。结果表明:(1)1954—2011年,大理河流域淤地坝逐年拦沙量呈波动式增加,多年平均拦沙量为0.12亿t,累积拦沙量为7.17亿t,其中1980—1989年年均拦沙量最高,为0.19亿t。(2)1960—2015年,大理河流域输沙量呈显著减少趋势,且在1971年和2002年均发生显著突变(P<0.05)。(3)人类活动是大理河流域输沙量减少的主要原因,1971—2001年淤地坝拦沙量占人类活动减少输沙量的贡献率为47.42%;随着流域植被恢复,2002—2011年淤地坝拦沙量占人类活动减少输沙量的贡献率降至31.04%。该方法对评价大理河流域淤地坝拦沙贡献率有一定的指导意义。2000年以后,由于植被恢复,大理河流域淤地坝拦沙贡献率下降。     

黄河中上游地区水利水保措施蓄水拦沙作用分析评价

对黄河中上游地区水利水保措施的蓄水拦沙作用分析的结果表明,现阶段水保措施年均蓄水量为10亿m~3,年均拦沙量3亿t,支流水库和淤地坝的拦沙量占水保措施拦沙量的77.8％。这种蓄水拦沙作用是在80、90年代降雨量减少的情况下得出的,由于前期积累、隐蔽、潜伏着许多泥沙问题,某些支流遇到较大暴雨产沙量激增,这对黄河下游可能会造成一定影响。当前应当把更多的精力和投资放在沟道的整治和利用上,大力修建控制性的大型骨干水库或淤地坝。     

黄河流域泥沙配置状况及其资源化

 通过分析黄河流域水沙运动过程和水沙分布特点,给出了流域泥沙配置单元,指出流域泥沙配置单元的配置量随着流域治理工程实施、径流条件等不断变化;1950—1999年,流域水土保持滞沙、水库拦沙、河道滞沙、两岸引沙用沙、河口淤积与入海泥沙等配置单元年均配置沙量占流域产沙量(17.63亿t)的14.24%、14.05%、12.19%、10.56%和50.77%;阐述了水库拦沙多、河道淤积严重是黄河流域泥沙配置现状不合理的主要原因,指出流域水沙资源优化配置和泥沙资源化是维护黄河健康的重要途径;结合黄河下游长期泥沙处理与利用的经验和教训,总结了黄河下游泥沙资源化的主要途径,包括淤临淤背、河道治理与河槽维护、引洪淤灌与土壤改良、灌区堆沙高地农田化、建筑材料转化、河口泥沙造地和疏浚泥沙利用、湿地塑造等。     

近50a来官厅水库上游流域泥沙输移平衡研究

近50 a来官厅水库上游流域侵蚀产沙总量为4.57×109t,其中水土保持措施拦沙量7.71×108t,占总产沙量的16.89%;水利工程拦沙量7.65×108t,占总产沙量的16.76%;引洪淤灌减沙量9.65×108t,占总产沙量的21.14%;河道淤积沙量8.16x 108t.占总产沙量的17.88%;官厅水库淤积量7.50× 108t,占总产沙量的18.02%;官厅水库下泄4.25×108t,占总产沙量的9.31%.20世纪的后20 a,流域内的水土保持措施拦沙量大幅度提升,和1950-1980年间相比,水土保持措施拦沙率提高了26.27%.     

关于淤地坝拦沙量计算方法的探讨

淤地坝是水土保持中拦沙效益最为显著的措施,但在大范围调查时,由于群众性建坝的原始资料不足,难以准确、简便地计算其拦沙量。本文作者通过数学推导,建立了拦沙量与淤地面积、坝前淤积高度和反映沟道形状的综合系数K的关系式,用这易调查得到的参数,可比较准确地计算已淤坝地的拦沙量。     

黄河中游粗泥沙集中来源区现有治理措施拦沙能力分析

黄河中游粗泥沙集中来源区现状治理措施年拦沙能力为1.03亿t,占区域年泥沙流失量4.08亿t的25.2%。其中:淤地坝(系)年拦沙能力为2757万t,占现状措施年拦沙能力的26.8%;水库年拦沙能力为2688万t,占现有措施年拦沙量的26.1%;治坡措施年拦沙能力为4842万t,占现状措施年拦沙量的47.0%。     

黄河上游内蒙古河段塑槽输沙需水量分析

为了解冲积性河流塑槽输沙需水量,合理调配水资源,以内蒙古河段为例,依据挟沙水流能量平衡方程,研究了冲积性河流挟沙水流的能量耗散原理及水流塑槽和输沙能量的分配模式,给出了反应冲积性河流冲淤状态的塑槽输沙需水量计算方法,由平滩流量、河道来沙量和冲淤量三者组成的关系确定塑槽输沙需水量。利用内蒙古河段1960-2013年实测资料,计算得到内蒙古河段塑槽输沙水量,汛期来沙量0.7～1.1亿t,塑造2 000～3 000 m~3/s的中水河槽、淤积水平控制30%以下,需要的汛期塑槽输沙水量为94.6～141.2亿m~3;分析了不同条件下汛期塑槽输沙水量变化规律:来沙量一定,同样的中水河槽规模,控制淤积水平越低,需要的塑槽输沙水量越大;来沙量一定,同样的淤积水平,塑造中水河槽规模越大,需要的塑槽输沙水量越大;控制同样淤积水平,塑造同样中水河槽规模,汛期来沙量越大,需要的塑槽输沙水量越大。内蒙古河段塑槽输沙需水量计算结果和结果变化规律可为黄河上游内蒙古河段水资源配置提供参考。     

谈谈汾河水库泥沙清理问题

汾河水库位于汾河上游娄烦县境内,总库容7.33亿m~3,是一座以防洪、灌溉、供水为主,兼顾发电、旅游等综合应用的大(2)型水利枢纽工程。1958年动工兴建,1961年正式投入运行。由于坝控范围内水土流失严重,造成大量泥沙淤积。至2016年底,淤积库容3.87亿m~3,占总库容52.8%。为排除水库淤积泥沙,保证供水安全,1967-1977年间,利用洪水进库实施异重流排沙,共进行了19次试验,总排沙量412.27万t,平均排沙比3.72%。从1988年开始,省委、省政府决定对库区上游的宁武、静乐、岚县、娄烦4县进行水土流失综合治理,经过一二期工程建设,至2008年底已治理水土流失面积1 900 km~2,起到了较显著的拦沙保库作用。根据国内外水库淤积清理技术,提出了宜选择机械运输清淤方法。     

河南省淤地坝建设与运用情况调查与分析

淤地坝是豫西山地重要的水土保持工程措施。根据对河南省淤地坝情况的调查和统计,至2019年,河南省共有淤地坝821座,总库容11 895.51万m~3,控制流域面积1 392.47 km~2,设计拦沙总库容为5 570.09万m~3,已淤积库容2 777.52万m~3,总淤积比为49.87%。淤地坝的蓄水灌溉功能成为重要的应用方向,全省具有灌溉功能的淤地坝数量为100座。根据实际调查,分析了目前河南省淤地坝建设和管理方面存在的主要问题,提出了相应的意见和建议。     

Topographical surveying for improved assessment of sediment retention in check dams applied to a Mediterranean badlands restoration site (Central Spain)

Purpose

The effects of check dams used in restoration projects have been discussed in a number of papers in recent years. This paper studies the effectiveness of retaining sediments from check dams constructed in the badlands restoration site of Tórtoles, located in the Corneja River basin (Spain), using a new topographical method.

Materials and methods

In order to assess the sediment-retaining capacity of the check dams, we measured the volume of sediment trapped by 15 of the 123 check dams built in 1965. We carried out a detailed topographical survey using a Total Station, with an accuracy of ±1 cm, to measure cross sections of the sediment trapped by each check dam. The results were then compared with those of two simplified methods which consider the volume of retained sediment as a simple geometric figure.

Results and discussion

According to our results, 258 m³ of sediment has been retained by the check dams. These results show a significant discrepancy between the topographical method and the two other methods, whose values are consistently lower (14 to 20 %). According to our survey, the mean value for the volume of sediment retained by each check dam is 17.23 m³, versus 13.86 and 14.74 m³ when applying the other methods. Although there is a strong correlation between the volume of retained sediment computed by the topographical method and the other two methods (r ² from 0.96 to 0.94), the differences between them increase with the increasing size of the check dams. Therefore, total differences are expected to be more significant with larger check dams. The erosion rates, calculated on the basis of the retained sediment in the Tórtoles check dams, are 16–21 % lower when using the simpler methods. The bed slopes of the streams were reduced 12.44 % because of the presence of the check dams.

Conclusions

After having completed a more detailed topographical survey of the sediment trapped in the check dams, our results are more likely to estimate erosion rates and sediment yield correctly, thus leading to a better understanding of the effects of check dams on badlands restoration.     

Connectivity of sediment transport in a semiarid environment: a synthesis for the Upper Jaguaribe Basin,Brazil

Purpose

Hydrosedimentological studies conducted in the semiarid Upper Jaguaribe Basin, Brazil, enabled the identification of the key processes controlling sediment connectivity at different spatial scales (10⁰–10⁴ km²).

Materials and methods

Water and sediment fluxes were assessed from discharge, sediment concentrations and reservoir siltation measurements. Additionally, mathematical modelling (WASA-SED model) was used to quantify water and sediment transfer within the watershed.

Results and discussion

Rainfall erosivity in the study area was moderate (4600 MJ mm ha^?1 h^?1 year^?1), whereas runoff depths (16–60 mm year^?1), and therefore the sediment transport capacity, were low. Consequently, ～60 % of the eroded sediment was deposited along the landscape, regardless of the spatial scale. The existing high-density reservoir network (contributing area of 6 km² per reservoir) also limits sediment propagation, retaining up to 47 % of the sediment at the large basin scale. The sediment delivery ratio (SDR) decreased with the spatial scale; on average, 41 % of the eroded sediment was yielded from the hillslopes, while for the whole 24,600-km² basin, the SDR was reduced to 1 % downstream of a large reservoir (1940-hm³ capacity).

Conclusions

Hydrological behaviour in the Upper Jaguaribe Basin represents a constraint on sediment propagation; low runoff depth is the main feature breaking sediment connectivity, which limits sediment transference from the hillslopes to the drainage system. Surface reservoirs are also important barriers, but their relative importance to sediment retention increases with scale, since larger contributing areas are more suitable for the construction of dams due to higher hydrological potential.     

甘肃省长江流域水土保持综合治理效益分析

[目的]揭示甘肃省长江流域调水保土效益、经济效益和生态效益,为实现水土流失区社会经济的可持续发展提供依据。[方法]运用甘肃省长江流域水土保持综合治理评价体系以及水土保持综合治理效益计算方法(GB/T15774-2008)计算分析了甘肃省长江河流域水土保持综合治理效益。[结果]甘肃省长江流域各措施累计调水2.01×1010 m3,其中坡面措施减水2.01×1010 m3,占总调水量的99.99%,累计保土3.59×108 t,其中坡面措施减蚀2.96×108 t,占总保土效益的82.45%;梯田、水保林、经济林、人工种草经济效益分别为58.08,180.02,29.69和15.20亿元,合计279.99亿元。[结论]通过水土保持措施对降雨径流的拦蓄,有效缓解了甘肃长江流域以及各类型区干旱、洪涝灾害及下游防洪压力,减轻了下游河道的泥沙淤积,同时改善了土壤肥力,增强土壤抗侵蚀能力。植被覆盖度由1980年的1.47%增长到2011年的29.83%,增长了28.36%,植被覆盖度增长幅度较大。     

威胁三峡库区安全的大型特大型滑坡崩塌

从拟建三峡大坝坝址三斗坪到重庆,长约600公里的长江河谷两岸,计有滑坡崩塌214处,占据面积100余平方公里,总方量达13.52亿立方米;河谷平均每公里有滑坡崩塌0.36处,土石方量225.32万立方米。在214处滑坡崩塌中,有1,000万立方米以上的大型特大型滑坡崩塌36处。它们集中分布于构造急剧转弯部位,背斜倾没端,向斜翘起端,几组构造线交叉复合地段,构造盆地的边缘和新构造活动相对强烈的上升区。整个河谷岸坡的破坏方式,以基岩顺层滑坡为主,基岩切层滑坡不多;其次是第四系松散堆积层滑坡,约占总滑崩方量的17.73%;崩塌仅占8%左右。这些滑坡崩塌,尤其是大型和特大型滑坡,集中分布在库区的要害部位,对大坝库区的安全有影响。     

甘肃省淤地坝水资源的利用潜力

[目的] 分析淤地坝拦泥蓄水及其水资源利用潜力,为淤地坝水资源利用及管理提供依据。[方法] 本文通过调查法对甘肃省多沙粗沙区淤地坝建设现状、拦沙数量及空间分布、水资源利用效益和利用潜力进行分析。[结果] 截至2019年底甘肃省共建成淤地坝1 600座,其中大、中、小型坝各为559,452,589座;坝控面积4 101 km²,总库容4.82×10⁸ m³,其中设计拦泥库容2.29×10⁸ m³。目前拦泥库容1.43×10⁸ m³,占设计拦泥库容的62.37%;拦泥库容中,大、中、小型坝各占80.86%,13.21%和5.93%;泾河流域、黄河干流、渭河流域、洮河流域各占71.46%,13.91%,12.72%,1.91%。由于流域产沙量减少,大型坝平均淤积17 a后（平均设计淤积年限15 a）剩余拦泥库容占设计拦泥库容的43.88%;中型坝平均淤积后（平均设计淤积年限10 a）剩余拦泥库容占设计拦泥库容的38.81%。全省淤地坝剩余拦泥库容8.62×10⁷ m³,可作为今后蓄水利用的潜在库容。目前,淤地坝蓄水主要用于应急抗旱、农业及果园高效节水灌溉、土地多种经营及经济综合开发、畜禽养殖、淤地坝田园综合开发利用等。庆阳、平凉、天水和定西市安定区今后可开发用于人饮备用水源地、提灌补灌工程水源地、水体养殖（鱼塘）的淤地坝数量共147座。[结论] 为满足当地乡村振兴与高质量发展对淤地坝的社会需求,对有蓄水用水需求的区域,应提高新建坝的设计标准,建设可长期蓄水的高标准淤地坝;对已建成的大中型淤地坝进行提质改造,保证淤地坝坝体、防洪及水资源利用的安全性,同时建立淤地坝风险管控预警机制,有效化解缺水地区淤地坝蓄水用水与防汛管理的矛盾。     

Fingerprinting sediment sources in the outlet reservoir of a hilly cultivated catchment in Tunisia

Purpose

Approximately 74 % of agricultural soils in Tunisia are affected by water erosion, leading to the siltation of numerous human-made reservoirs and therefore a loss of water storage capacity. The objective of this study was to propose a methodology for estimating the relative contributions of gully/channel bank erosion and surface topsoil erosion to the sediment accumulated in small reservoirs.

Materials and methods

We tested an approach based on the sediment fingerprinting technique for sediments collected from a reservoir (which has been in operation since 1994) at the outlet of a catchment (Kamech, 2.63 km²). Sampling concentrated on the soil surface (in both cropland and grassland), gullies and channel banks. A total of 17 sediment cores were collected along a longitudinal transect of the Kamech reservoir to investigate the origin of the sediment throughout the reservoir. Radionuclides (particularly caesium-137, ¹³⁷Cs) and nutrients (total phosphorus, total nitrogen and total organic carbon (TOC)) were analysed as potential tracers.

Results and discussion

The applications of a mixing model with ¹³⁷Cs alone or ¹³⁷Cs and TOC provided very similar results: The dominant source of sediment was surface erosion, which was responsible for 80 % of the total erosion within the Kamech catchment. Additionally, we showed that the analysis of a single composite core provided information on the sediment origin that was consistent with the analysis of all sediment layers in the core. We demonstrated the importance of the core sampling location within the reservoir for obtaining reliable information regarding sediment sources and the dominant erosion processes.

Conclusions

The dominance of surface erosion processes indicates that conservation farming practices are required to mitigate erosion in the agricultural Kamech catchment. Based on the results from 17 sediment cores, guidelines regarding the number and location of sampling cores to be collected for sediment fingerprinting are proposed. We showed that the collection of two cores limited the sediment source apportionment uncertainty due to the core sampling scheme to <10 %.     

唐山市沙流河镇水资源供需平衡优化分析

运用系统论和线性目标规划法,结合唐山市沙流河镇实证研究,构建小城镇水资源供需平衡优化数学模型,剖析该镇水资源供需矛盾,提出水资源供需平衡优化方案。结果显示,沙流河镇水资源补给总量为1490.55万m³·a^-1,若对水资源利用量不加约束,2001、2005和2010年沙流河镇用水总量分别达到2352.73万m³、2429.73万m³和2491.72万m³;水资源超采量分别达到862.18万m³、939.18万m³和1001.17万m³;其中农业用水量最大,占90%以上。鉴于农业用水比重大、利用效率低,提出沙流河镇实施、推广节水灌溉技术和积极退耕还林等节水措施。经过逐年逼近平衡的办法,到2010年沙流河镇水资源量可以节余63.32万m³,基本实现全镇水资源供需平衡。     

USE OF RESERVOIR DEPOSITS AND CAESIUM-137 MEASUREMENTS TO INVESTIGATE THE EROSIONAL RESPONSE OF A SMALL DRAINAGE BASIN IN THE ROLLING LOESS PLATEAU REGION OF CHINA

This paper reports the results of an investigation of the erosional response of the 3·86 km² Zhaojia Gully catchment in the rolling loess plateau region of Zichan County, Shaanxi Province, China. In the absence of direct measurements, information derived from reservoir deposits and from caesium-137 measurements on both the catchment soils and reservoir deposits was used to obtain a retrospective assessment of the longer-term (ca. 30 year) erosional response of the catchment and of the relative contributions of the rolling plateau surface and the gully areas to the sediment output from the basin. Net erosion rates on cultivated land occupying the gentle crest slopes and steeper lower slopes of the rolling plateau and the steep gully slopes were estimated to be 4500 t km⁻² year⁻¹, 8584 t km⁻² year⁻¹ and 15851 t km⁻² year⁻¹, respectively. Estimates of annual sediment yield from the study catchment based on analysis of sediment deposits in the two sediment-trap reservoirs ranged between 4627 and 32472 t km⁻² year⁻¹. Almost all the sediment transported from the catchment was contributed by 2–4 large floods each year. Measurements of the caesium-137 content of recent sediment deposits in a sediment-trap reservoir allowed the relative contributions of the total sediment yield derived from the rolling plateau and gully areas of the catchment to be estimated at 23 and 77 per cent, respectively. Analysis of the sediment deposits dating from 1973–1977 in another sediment trap reservoir allowed individual flood event couplets to be identified and indicated that the sediment associated with the first one or two floods in a season, when the soils of the plateau area were relatively dry, was derived primarily from the gully areas. The cultivated soils of the rolling plateau contributed an increased proportion of the total sediment yield during the latter stages of the flood season when the soils were wetter, and surface runoff and erosion were more widespread. Based on analysis of the caesium-137 content of the sediment deposited in this sediment-trap reservoir, the relative contributions of sediment from the rolling plateau and gully areas over the period 1973–1977 were estimated to be 21 and 79 per cent, respectively. The results obtained demonstrate the potential for using caesium-137 measurements and analysis of reservoir deposits to document the erosional response of a drainage basin. © 1997 John Wiley & Sons, Ltd.     

Sediment Budget Analysis for River Reservoirs

The sediment, budget of a reservoir on the Neckar River, Germany, was investigated by means of experimental and numerical methods. Field measurements of channel bathymetry show that. sedimentation and erosion occur primarily in the lower backwater-influenced section of the reservoir, which stores approximately 350,000 m³ of fine-grained deposits. Sediment load balances for two major storm events in Dec. 1993 and Apr. 1994 showed net erosion of 32,000 ±10,000 tonnes and 24,000 ± 5,000 tonnes of sediment, respectively. A balanced sediment budget, was found for a minor flood in Jan. 1995. In agreement with the field data, numerical simulation of sediment transport. over a period of 45 years demonstrates that the river reservoir served initially as a sediment trap from 1950 to 1978, and since then as a temporary storage basin for sediment.     

近50年沂蒙山区两个不同岩性小流域塘库的拦沙效应

在沂蒙山区选取代表性花岗岩与石灰岩小流域各一处,即分别为姜庄和泉安子小流域,对比分析了两个不同岩性小流域塘库近50年的拦沙效应。沿主沟道方向于两个塘库中央位置各取3孔沉积物样芯,参照流域人类活动和环境演变历史,探明了各孔137 Cs、210 Pbex、黏粒和容重深度分布变化特征。以137 Cs和210Pbex示踪法进行沉积物断代,参照塘库原始库容曲线,计算建坝以来塘库不同时段的年均淤沙量,以表征拦沙效应。姜庄和泉安子塘库各孔、各时段拦沙效应的计算结果分别为(394±142)~(121±43)t/a和(22±7)~(59±21)t/a,平均值分别为(208±75),(41±15)t/a,建库以来的总拦沙量分别为10 475,2 097t。姜庄塘库拦沙效应明显大于泉安子塘库,这是此两座塘库分别控制的花岗岩与石灰岩小流域在人类扰动作用下产沙强度的差异所致。近50年两个塘库拦沙效应的变化趋势反映了不同岩性小流域人类活动及其产沙强度响应的近期特征和规律。