陕北子洲县典型淤地坝淤积过程和降雨关系的研究

淤地坝作为黄土丘陵沟壑区水土流失治理的重要工程措施之一,其坝系优化布局、相对稳定性及坝地效益等受到广泛关注,但对其淤积过程研究甚少。该文通过对黄土高原淤地坝进行调查,典型坝淤积过程剖面的观测及取样分析,结合库容曲线和每个淤积层的淤积厚度求出分层淤积量。根据暴雨产沙过程原理及淤积过程降雨资料,反演淤地坝各淤积层所对应的次侵蚀性降雨,建立层淤积量与相应次侵蚀性降雨指标的相关方程。研究结果表明：坝地淤积物中层淤积量和次侵蚀性降雨的降雨侵蚀力呈幂函数关系,层淤积量和次侵蚀性降雨的最大30 min降雨强度呈指数函数关系,经检验结果良好。     

黄土高原淤地坝坝地淤积物两个重要物理特性指标研究

淤地坝淤积过程机理的研究是个薄弱环节，坝地淤积物的主要物理特性指标的研究能为淤积过程机理的研究提供重要依据。在调查典型淤地坝挖取剖面采集土样的基础上，通过室外试验与室内分析计算相结合的方法，研究了坝地各层淤积物的干容重和粒径级配两个物理特性。结果表明：淤积程度相似（淤积年限相近．淤积层数相当），淤积物的干容重的变化规律类似；对于同一座坝，淤积层厚度相近的各个淤积层，其干容重从上到下有增大的趋势；坝地各层淤积物的粒径主要集中在0．025～0．1mm之间。该结果可为进一步求解淤积沙量，建立各淤积层淤积量与次侵蚀性降雨的相关关系提供重要参数。     

基于坝地泥沙淤积信息的流域侵蚀产沙特征研究

以淤积年限53年、淤积厚度为10.58 m的王茂沟流域背塔沟闷葫芦坝为研究对象,利用2012年洪水冲刷成的深沟,通过剖面辨识将泥沙沉积层分为86个淤积巡回,结合1959-2012年间降雨资料以及流域侵蚀产沙沉积剖面的物理特征,建立了淤地坝沉积序列的时间坐标。在此基础上,依据泥沙沉积量计算了坝控范围不同时期的土壤侵蚀模数,分析了土壤侵蚀模数变化与当时对应农村经济政策和土地利用的密切关联。研究结果表明:对于无泄洪设施的淤地坝,层淤积泥沙量与次侵蚀性降雨最大30 min降雨强度(I30)具有极强的相关性;研究方法可为无水文资料地区水沙资料的反演提供新的可行途径;水土流失治理必须以生态经济学为指导,才能符合客观规律。     

运用主成分分析法确定时段最大降雨强度

本文通过南安市水土保持试验站1987－1989年自然坡面径流小区122场侵蚀性降雨资料，选择七个不同时段的最大雨强指标（It)，运用主成分分析法，借助电算技术进行变量筛选，对降雨侵蚀力R因子的参数指标作了客观的选择，结果表明：80分钟最大降雨强度（I60）可作我省热带，亚热带丘地区降雨侵蚀力R因子的最优参数指标，同时指出，对于I10，I30和I60三个主分量的进一步研究，有助于不同降雨侵蚀力类型区的研究。     

太行山土石山区侵蚀性降雨对典型植物措施产流产沙的影响

通过对山西省长治市白马小流域的1个标准小区和4个植物措施小区近5a(2006—2010年)的降雨和径流泥沙观测,研究太行山土石山区的降雨特征以及不同类型降雨对典型植物措施小区径流泥沙的影响。结果表明:(1)太行山土石山区侵蚀性降雨主要集中于5—8月份,7—8月份侵蚀性降雨次数占侵蚀性降雨总次数的54.55%,侵蚀性降雨量占侵蚀性降雨总量的61.19%,故该时期是防治水土流失的关键时期;(2)径流量R与降雨量P、最大30min降雨强度I30、降雨量和最大30min降雨强度的乘积PI30呈正相关且在0.01水平上显著;侵蚀产沙量E与最大30min降雨强度I30、径流量R、降雨量和最大30min降雨强度的乘积PI30之间呈正相关且在0.01水平上显著;(3)在不同类型降雨条件下,4种典型植物措施的减流效益在17.18%~91.86%之间,差异明显;在B类型降雨条件下各措施的减流效益最低,分别是乔木43.38%、灌木24.44%、人工种草26.59%、自然荒坡17.18%,在E类型降雨条件下各措施的减流效益最大,分别是乔木89.29%、灌木91.86%、人工种草75.56%、自然荒坡66.22%;(4)在不同类型降雨条件下,减沙效益:乔木林灌木林人工种草自然荒坡;降雨量最大的A类型降雨和最大30min降雨强度最大的B类型降雨对植物措施减沙效益影响显著。研究表明,在该地区不同类型降雨条件下4种植物措施的减流减沙效益明显,能够有效防治水土流失。     

黄土高原地区淤地坝拦沙淤积监测中存在的问题及方法探讨

[目的] 探索研究科学成熟的淤地坝拦沙淤积监测方法，为精确获取淤地坝拦沙量，实现淤地坝安全运行和拦沙效益发挥提供实践支撑。 [方法] 以黄土高原为研究区，总结分析淤地坝拦沙淤积监测的重要性和存在问题，并提出黄土高原地区淤地坝拦沙淤积遥感监测方法。 [结果] 提出了基于遥感技术获取淤地坝拦沙淤积量的原理和关键影响因素；对比分析了无人机正射测量、无人机倾斜摄影、无人机载LiDAR等遥感方法的精度、工作量和可行性及在淤地坝拦沙淤积监测中的不同应用场景。 [结论] 相较传统人工调查方式，遥感监测技术在淤地坝拦沙淤积监测中具有较大优势，可满足不同的拦沙淤积监测需求，是未来淤地坝拦沙淤积测量监测的重要发展方向。     

好水川流域小型水库及淤地坝泥沙淤积量估算

建立了小型水库及淤地坝泥沙淤积体的概化模型。结合水库及淤地坝泥沙观测数据,采用以小型水库的特性征曲线为基础的泥沙淤积量测算方法,对好水川流域小型水库及淤地坝淤积量进行了估算。运用泥沙淤积体规则概化的测算方法对估算结果进行验证,并推求区域侵蚀模数。该方法计算简单,结论可靠,可为进一步研究该流域的水沙规律提供理论依据,并为宁夏南部山区的淤地坝淤积量估算提出一种简便的算法。     

天然降雨对红壤坡地侵蚀的影响

通过气象观测站与标准径流小区的试验观测,全面系统地分析了江西省红壤坡地的天然降雨特征。主要内容包括与土壤流失关系密切的降雨量(P)、降雨强度(I)等降雨特征参数的等级划分和时间分配规律;确定了江西红壤坡地侵蚀性降雨标准;确立了ΣE·I60 为红壤坡地降雨侵蚀力因子R的最佳计算组合,并分析了R值的季度分配、月分配特征以及雨量分配、雨强分配特征。这为探索控制江西红壤坡地水土流失的最佳时段,研究水土流失产生的动力来源以及发生演变的规律具有积极的借鉴意义     

南京市丘陵区不同农耕措施水土保持效益

利用南京市桥头小流域2015—2017年日降雨量、最大30 min降雨强度I30数据和4种植被措施下径流小区的产沙量、产流量等监测数据,分析不同植被措施在64场不同类型侵蚀性降雨条件下的水土保持效益.结果表明:(1)侵蚀性降雨主要集中在4—10月份,7月份发生频率和降雨总量都最高.(2)研究区侵蚀性降雨可分为5类,发生...     

从淤地坝淤积调查推算坡面侵蚀状况

对韭园沟流域沟掌淤地坝次暴雨淤积量的调查及结果分析，客观地评价了坡面水土保持措施的作用，并为大面积坡面在不同降雨和不同治理状况下水土流失量的科学估算提出了一种新方法。     

黄土丘陵区淤地坝建设后小流域泥沙拦蓄与输移特征

了解淤地坝建设后小流域泥沙拦蓄与输移的变化特征对正确认识和评价淤地坝的减蚀作用有重要意义.该文通过对黄土丘陵区王茂沟流域1953-2015年不同时段内淤地坝的拦沙量和流域出口输沙量的分析,研究了坝系建设后泥沙拦蓄、输移和侵蚀的变化过程与特征.研究表明,王茂沟流域年均拦沙模数呈减少-增加-再减少的波动变化趋势;流域年均输沙模数呈先增加后减少的变化趋势;1953-1986年期间,不同阶段的年均侵蚀模数变化不大,1987年后呈显著下降趋势.流域治理后期与初期相比,年均拦沙模数、输沙模数和侵蚀模数分别下降了79.3％、90.6％和83.9％.淤地坝建设初期,有效库容对流域拦沙模数和输沙模数的变化有重要影响,侵蚀性降雨频发和较低的水土流失治理度是侵蚀强烈的主要因素;流域治理后期,侵蚀性降雨及其发生频次的减少,水土流失治理度的提高与稳固,是流域拦沙、输沙和侵蚀产沙显著下降的主要原因.淤地坝在控制流域侵蚀产沙、减少泥沙输移方面作用显著,但要达到持续有效的作用,坡面治理不容忽视,两者兼顾是黄土丘陵区水土保持的必由之路.     

黄土高原梯田和淤地坝坡沟治理措施对产流产沙的协同效应

黄土高原地区的梯田和淤地坝措施发挥了重要的水土保持功能,然而现有的研究主要关注单个措施的减水减沙效应,对坡沟治理措施综合配置协同调控水沙过程的作用一直认识不清。因此,该研究为解析梯田和淤地坝措施对水沙过程的协同调控效应,构建了10个坡沟系统物理模型,设置了对照组（CO）,单一措施组（梯田措施（T0）,4种因淤地坝淤积导致坡沟区域的坡长缩短（L1、L2、L3和L4））和组合措施组（梯田与4种因淤地坝淤积导致坡沟区域的坡长缩短的综合配置（T1、T2、T3和T4））,进行降雨强度为90 mm/h的室内模拟降雨试验,量化不同试验方案下坡沟系统的产流产沙过程。结果表明：1）梯田措施和淤地坝淤积导致坡沟区域坡长缩短均有效调控了坡沟系统的产流产沙过程,梯田能分别减少46.30%～83.59%的径流总量和25.82%～82.41%的泥沙总量,淤地坝导致坡沟区域坡长缩短能分别减少7.87%～33.42%的径流总量和10.20%～30.57%的泥沙总量。2）不同试验方案下坡沟系统的产沙率和产流率之间满足线性关系,而累计产沙量和累计产流量满足幂函数关系。3）综合措施配置发挥了“1+1> 2”的水土保持...     

A laboratory study on the relative stability of the check‐dam system in the Loess Plateau,China

The building of check‐dams is one of the most effective measures for the conservation of soil and water in the Loess Plateau of China, and the hydro‐sedimentologic balance is the most important factor influencing the relative stability of the check‐dam systems. This means that the soil and water in small watersheds controlled by the check‐dams will be absorbed internally, without the need for raising the height of the dams, if some given parameters have reached certain values. A runoff simulation experiment for a single check‐dam and a rainfall simulation experiment for the whole check‐dam system has been conducted, and the runoff/rainfall intensity and the parameter RV were determined through the annual erosion rate of the prototype watershed. The results indicated that the raising of the dam‐land altitude became slower, and the mean gradient of the gully was kept at a constant. The main reasons causing the check‐dam to show a good relative stability are the enlarging of the dam‐land area, the alleviating of erosion by the check‐dam, and the auto‐stabilizing mechanism of the gullies. This study presents a kind of scale‐down model experiment in which the ratio of the model geomorphological variable to the corresponding prototype variable keeps constant after the determinate runs of rainfalls, so that the soil and water erosion processes of the prototype could be monitored from the results of the model experiment. Four measures have been suggested for ensuring this ratio is a constant: (1) A bare‐land model with an appropriate erosion rate should be used in the experiment. (2) Dimensions of the landform, including the check‐dam, should normally be scaled down according to the prototype watershed. (3) Soil similar to those of the prototype should be used. (4) The antecedent water content before each rainfall simulation should be kept constant. Copyright © 2006 John Wiley & Sons, Ltd.     

砒砂岩区典型淤地坝沉积泥沙特征及来源分析

黄土高原地区的淤地坝是拦减入黄泥沙的关键措施,尤以对泥沙具有绝对控制的"闷葫芦"淤地坝为甚。为研究淤地坝对侵蚀泥沙的拦蓄作用,以砒砂岩区皇甫川流域园子沟淤地坝为研究对象,采集坝地淤积剖面及沟间地、沟谷地表层样品,对沉积旋回进行断代分析,计算泥沙贡献率,反演其淤积过程。结果表明:坝地沉积泥沙粒径分布以2~0.05 mm砂粒为主,其次为粉粒、黏粒,砂粒中以极细砂和细砂占比最多。园子沟坝控流域内侵蚀性降雨事件对应的最小日降雨量为22.8 mm;淤地坝运行可划分为2个阶段,前期主要依靠坝体拦蓄泥沙,后期随着拦蓄泥沙的增多,减蚀作用凸显。坝地沉积泥沙主要来源为沟谷地,贡献率达71.4%,沟间地为28.6%,其中沟间地侵蚀产沙并非受植被唯一影响,在降雨量>45.4 mm时,地形因素会限制侵蚀的加剧。     

Sediment Yield Deduction from Check–dams Deposition in the Weathered Sandstone Watershed on the North Loess Plateau,China

As the basic unit of erosion and sediment yield, it was critical to determine the amount of soil erosion and sediment yield in the small watersheds for sustaining a reasonable water resource and sediment regulation system. In this study, we determined the sediment yield from the dams‐controlled watershed on the North Loess Plateau. Three check dams in the watershed were investigated by drilling ten‐hole sedimentation cores. The corresponding flood couplets were dated according to thickness of deposition layers, distribution of sediment particle size and historical erosive rainfall events. On the basis of the check dams capacity curve, the soil bulk density and the thickness of couplets, the deposit mass of check dams, and then the sediment yield of watershed at different temporal and spatial scale were deducted. In total of the 33, 60 and 55 couplets were corresponded to individual flood events in the dam MH1# from 1976 to 1984, the dam MH2# from 1985 to 2007, and the dam MH4# from 1981 to 2009, respectively. The specific sediment yield for flood events was 1,188.5–11,527.9 Mg km⁻², 1,278.6–17,136.7 Mg km⁻², and 3,395.9–33,698.5 Mg km⁻², and the annual average sediment yield was 10,728.6 Mg (km² · a)⁻¹, 12,662.9 Mg (km² · a)⁻¹, and 16,753.3 Mg (km² · a)⁻¹ in dam MH1#, MH2# and MH4# controlled watershed, respectively. The sediment yields were inversely proportional to the dams – controlled areas. For the whole watershed, the annual average sediment yield was 14,011.1 Mg (km² · a)⁻¹ from 1976 to 2009. There were large amounts of sediments (42.3–50.5%) were intercepted gradually along the way from small watersheds to the river channel. And the minimum rainfall for sediment deposited in the dams was greater than 20 mm in this watershed. The results of this study suggested that the sediments retained behind check dams were helpful to quantifying the amount of erosion sediment yield and understanding the soil erosion evolution in the small and ungauged watersheds. Copyright © 2016 John Wiley & Sons, Ltd.     

淤地坝淤积高度对斜坡稳定性影响的定量评估

为了评估淤地坝建设对流域斜坡稳定性的影响,该文基于地理信息系统(GIS)的斜坡稳定性模型(SINMAP),根据实测的土力学参数和野外滑坡与崩塌分布点调查,分析了淤地坝淤积至不同高度时的斜坡稳定性。研究发现,随着流域淤地坝系淤积高度的增加,流域极不稳定区域逐渐减少,而极稳定性区域逐渐增加。随着淤积高度的增加,陡坡区域(坡度>45°)所占比例逐步减少,且与极不稳定性区域的减少呈线性相关。该文总结了淤地坝淤积过程中的"淹没效应",泥沙的淤积,不仅改变了流域坡度组成、缩短了坡长,而且改变了流域的土地利用等因子。该研究可为淤地坝建设提供参考。     

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.     

延河流域2013年7月连续暴雨下淤地坝毁坏情况调查与评价

[目的]查明2013年7月延河流域连续出现的5次范围广,历时长,量级大的强降雨条件下淤地坝的运行及毁坏情况。[方法]对延河流域3县区15个小流域45座淤地坝进行实地考察。[结果]被调查淤地坝中35座经受住了暴雨洪水的袭击。遭毁坏的10座淤地坝中9座为已淤满变为耕地的"闷葫芦"坝(一大件)及1座新建坝。而尚未淤满正在发挥作用的淤地坝以及新旧结合的坝系大多数都正常运行。[结论]延河流域该次淤地坝毁坏的直接原因是高强度和持续集中降雨造成的超标准暴雨洪水,同时淤地坝在建设、运行和管理方面也存在诸多问题。     

降雨特性和覆盖方式对麦田土壤水分的影响

为探明不同降雨特性和覆盖方式对冬小麦土壤水分的影响,利用人工模拟降雨器,模拟40和60mm/h2种降雨强度,在大田设置地膜覆盖(PM)、秸秆覆盖(覆盖量分别为1500、4500、7500和10500kg/hm2,即SM15、SM45、SM75和SM105),同时设置无覆盖处理作为对照(CK),研究不同降雨强度和覆盖方式对雨后冬小麦0～60cm土层土壤水分分布和降雨土壤蓄积量的影响。结果表明:模拟降雨前各覆盖处理土壤含水率均比CK高,其中0～20cm土层土壤含水率差异显著(P<0.05),而20cm以下各处理土壤水分相差较小,除SM105与CK差异显著外(P<0.05),其他处理与CK差异不显著;同一覆盖处理,60mm/h降雨强度条件下降雨入渗深度和入渗量明显高于40mm/h。在相同雨强条件下,不同覆盖处理可以不同程度的增加耕层土壤含水率,其中秸秆覆盖量越大,效果越明显,而PM效果最差;2种雨强条件下各处理0～60cm土层降雨土壤蓄积量规律表现一致,即SM105>SM75>SM45>SM15>CK>PM,其中SM105和SM75均显著高于CK(P<0.05),PM则显著低于CK(P<0.05);受植株冠层降雨截留的影响,同等降雨条件下,同一覆盖处理拔节前降雨土壤蓄积量大于拔节后的;相比60mm/h降雨强度,40mm/h降雨强度下各处理拔节前、后降雨土壤蓄积量变化幅度较大。