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1.
应用EUROSEM模型对三峡库区陡坡地水力侵蚀的模拟研究 总被引：10，自引：3，他引：7
三峡库区坡地资源被广泛利用,但水土保持措施没有被很好地利用。坡地,尤其是陡坡地是库区主要泥沙来源,因此,有效评估土壤侵蚀风险、预测径流和侵蚀速率以及选择合理的水土保持措施在该地区显得非常必要。EUROSEM模型是动态分布式模型,可以在单独地块或小流域中预测水力侵蚀强度,其特点比较适合库区土壤侵蚀预测预报。本研究以在三峡库区秭归县王家桥小流域水土保持试验站的标准径流小区的人工降雨资料为基础,应用EUROSEM模型模拟陡坡地中的侵蚀状况。模拟结果表明,EUROSEM对人工降雨中径流模拟效果较好,但对土壤流失的模拟效果相对较差,更精确地模拟库区陡坡地的土壤侵蚀状况则需要作进一步的研究 相似文献
2.
利用高精度GPS动态监测沟蚀发育过程 总被引：4，自引：0，他引：4
基于5次连续模拟降雨试验对坡面沟蚀发育过程的模拟和ArcGis9.0空间分析功能,利用高精度GPS动态监测坡面沟蚀发育过程,估算沟蚀发育不同阶段的侵蚀量,分析误差产生的原因及提高精度的途径.结果表明,在高精度GPS测量生成的沟蚀发育不同阶段的5期图像上展现的侵蚀形态与实拍相片完全一一对应,完美反映了坡面侵蚀形态的空间分布及其变化.高精度GPS测量能很好地估算坡面侵蚀量,侵蚀量估算值与实测值之间的误差随沟蚀形态的发育而逐渐减少,5次测量估算的侵蚀量平均误差为7.38%.GPS测量过程中所产生的误差可以通过划分统一测量区域,适当增加测量点,特别是增加对沟壁和沟床的测量点及后期数据处理进行纠正. 相似文献
3.
大连市可建设用地的等级结构与分布 总被引：1，自引：0，他引：1
城市化过程的典型表现是非建设用地向建设用地的变化过程.区域可建设用地的预测,与人口、城市化、工业化、区域产业结构调整、外资、地价、政策等因素相互关联.在借鉴已有研究成果和研究方法的基础上,综合采用AHP指标层要素分析、GIS空间分析方法中的空间叠加分析等方法,测算和研究大连市可建设用地的等级结构与分布状况.结果表明:在大连可建设用地等级结构中,Ⅰ级可建设用地(丰富)占17.92%,Ⅱ级可建设用地(较丰富)占18.15%,Ⅲ级可建设用地(缺乏)占28.59%,Ⅳ级可建设用地(极缺乏)占35.34%.Ⅰ级、Ⅱ级可建设用地主要分布在濒临渤海、黄海一侧的沿海平原,其次多为零散分布的低地或丘陵谷地等;Ⅲ级、Ⅳ级可建设用地除北部山区的连片集中分布之外,则多呈带状或半环状分布. 相似文献
4.
半日花(Helianthemum soongoricum)是古地中海区系的残遗种,是国家二级珍稀保护植物,种群数量和规模已非常有限。为了揭示半日花种群的结构和发展的空间规律,运用大小结构分析法将半日花种群分为3个龄级(Ⅰ级,d≤3cm;Ⅱ级,3cmd≤9cm;Ⅲ级,d9cm,d为植株体积(高度×冠幅)的立方根),并采用空间点格局分析中的O-ring统计方法研究了分布于西鄂尔多斯砾石质和石质生境的半日花种群的结构和不同发育阶段个体的空间格局及空间关联性。结果表明:(1)半日花个体主要集中在龄级Ⅱ,龄级Ⅰ和龄级Ⅲ的个体都较少,种群的更新受到限制;(2)半日花种群的空间分布格局与不同龄级间的空间关联性受生境条件的影响较大,并且对空间尺度表现出很强的依赖性。砾石质生境中的半日花种群及其各龄级在小尺度范围内呈聚集分布,随着尺度增大逐渐趋向于均匀分布,不同龄级间主要表现为(或接近于)负关联;石质生境中半日花种群及其各龄级在中小尺度呈聚集分布,随着尺度增加表现为随机分布,龄级Ⅲ与Ⅱ和龄级Ⅱ与Ⅰ之间的空间正关联或不关联关系更明显。这种差别与两种生境下的环境条件和群落结构有关;(3)半日花幼龄个体(龄级Ⅰ)在一定程度上受到了来自成年个体(龄级Ⅱ与Ⅲ)的竞争压力。研究结果对半日花的保护与利用具有一定的参考价值。 相似文献
5.
积雪资源深刻影响着滑雪旅游的发展与布局,刻画中国积雪资源时空特征,识别旅游开发关键区,对中国冰雪旅游高质量发展具有重要意义。本文通过Mann-Kendall突变检验、热点分析、重要-感知实绩分析（IPA）等方法刻画中国1979—2020年积雪资源时空演变特征,构建资源稳定性-旅游开发适宜性指标体系,识别中国滑雪旅游开发关键区。结果表明：(1)中国积雪资源过去40年变化可划为3个阶段,1980—1995年（Ⅰ）积雪资源下降,1995—2010年（Ⅱ）增加,2010—2020年（Ⅲ）下降。在空间上,变化面积呈现Ⅰ-Ⅱ（33.2%）>Ⅱ-Ⅲ（31.1%）>Ⅰ-Ⅲ（29.3%）的特征;(2)中国积雪资源在月尺度上,1—3月（Ⅰ）积雪资源基本维持稳定,3—10月（Ⅱ）显著下降,10—12月（Ⅲ）恢复。在空间上,变化面积呈Ⅰ-Ⅲ（30.3%）>Ⅱ-Ⅲ（28.3%）>Ⅰ-Ⅱ（26.8%）的变化规律;(3)中国境内滑雪旅游开发极关键区面积占比为4.90%、关键区为11.69%、一般区为31.57%、不关键区为25.73%、极不关键区为26.11%,总体来看中国境内85%的区域不... 相似文献
6.
水资源短缺是个全球性的问题,近年来,随着城市化的发展,城市水资源供需矛盾也日益突出,解决供需矛盾的根本途径,一是开源,另一是节流。由于开源有许多限制条件,使得节流在近期内成为主要的水资源对策。利用数据库技术对城市水资源进行系统管理正是出于上述考虑的。城市水资源管理系统是一个大系统。内部为层 次结构,即一个系统往往又是另一个更大系统的子系统(见图1)。将系统结构划分为三个层次,即Ⅰ,Ⅱ,Ⅲ三级,用水户、水源或水厂为Ⅲ级,用水系统和资源系统为Ⅱ级,城市总协调级为Ⅰ级,这三级的关系为金字塔式的(见图2)。Ⅰ级控制Ⅱ级,Ⅱ级控制Ⅲ级。同时,下级的信息可反馈给上级。 相似文献
7.
为准确刻画资料缺乏、地表水–地下水转换频繁的泽令沟盆地地表水?地下水不同时空尺度上的转换关系,利用河道径流数据、遥感蒸散发数据、地下水位观测数据等对SWAT-MODFLOW耦合模型进行率定和验证,在此基础上对泽令沟盆地水循环过程进行模拟分析。结果显示：① SWAT-MODFLOW耦合模型模拟效果较好,率定期和验证期月径流量的R2≥0.73,NSE≥0.67,PBIAS在?20%~20%。其各子流域实际蒸散发的R2均大于0.91,NSE均大于0.85,PBIAS在?10%~10%。此外,模拟地下水位与实测值误差在0.6 m以内,R2为0.94。② 地表水补给地下水的河道占整个河道长度90.31%,年平均补给量占年总交换水量的50.20%;季节尺度上,补给的最大值出现在7月,为331043.31 m3/d,最小值出现在12月份,为41208.33 m3/d。地下水对地表水的补给量较为稳定,季节性变幅在?2.5%~2.5%,年际变幅处于?6.5%~0.6%之间。 相似文献
8.
三峡库区共有高等陆生植物6088种，珍稀濒危植物56种，其中Ⅰ级保护物种4种，Ⅱ级保护物种23种，Ⅲ级保护物种29种，处于濒危状态的7种，渐危状态的27种，稀有状态的22种。在分析三峡库区珍稀濒危植物种类组成、地理成分、现状分布的基础上，探讨了库区珍稀濒危植物致危原因及目前所采取的保护措施中所存在的问题，并提出了相应的保护对策。 相似文献
9.
黄土丘陵小流域土地利用变化对水土流失的影响 总被引：80，自引：3，他引：80
在土壤侵蚀模型LISEM (Limburg Soil Erosion Model) 校正的基础上,模拟了陕北黄土丘陵沟壑区大南沟小流域5种土地利用方案的水土流失效应,旨在探讨土地利用变化对流域出口水土流失的影响。研究结果表明:流域出口的洪峰流速、径流总量和侵蚀总量的大小顺序为:1975年>1998年>25度退耕>20度退耕>15度退耕。1975年和1998年25度以上的陡坡耕地和休闲地均退耕还林还草,这2种土地利用格局的径流和侵蚀模拟值都显著大于3种退耕方案。在3种退耕方案中,20度和15度以上的陡坡耕地和休闲地逐步转变为果园/经济林地,3种退耕方案之间的水土流失差异不显著。相对于1975年土地利用来说,1998年土地利用能降低洪峰流速、径流量和侵蚀量约5%~10%;3种退耕方案的减流减沙效益更加显著,可以降低洪峰流速、径流量和侵蚀量约40%~50%。 相似文献
10.
采用像元二分模型,以1974-2014年间的10期Landsat 5/8影像和DEM数据,对抚仙湖流域植被覆盖动态变化进行监测,并结合基础地理信息数据、行政区划界资料、行业部门专题资料等,分析流域植被覆盖时空分异及其与坡度的关系.结果表明:(1)1974-2014年,抚仙湖流域裸地(Ⅰ级)面积波动极小,低植被覆盖(Ⅱ级)、中低植被覆盖(Ⅲ级)、中高植被覆盖(Ⅳ级)面积变化波动大,变化趋势线数次出现谷值和峰值,高植被覆盖(Ⅴ级)面积则呈增加趋势.(2)坡度较小、地势较平缓的区域(0°~15°)以裸地和低植被覆盖为主;中低植被覆盖度、中高植被覆盖和高植被覆盖度主要分布在地势比较陡峭的区域(>15°).(3)抚仙湖流域各年份植被覆盖度Ⅰ级面积最大,1974,1977,1989,1996年Ⅱ,Ⅲ级面积较大,而Ⅳ,Ⅴ级面积较小;2000年后的Ⅱ,Ⅲ,Ⅳ级面积变化较小;2006,2009,2012,2014年Ⅳ,Ⅴ级的面积较大,Ⅱ,Ⅲ级的面积较小. 相似文献
11.
Fluvial sediment transport and deposition following the 1991 eruption of Mount Pinatubo 总被引：1，自引：0，他引：1
The 1991 eruption of Mount Pinatubo generated extreme sediment yields from watersheds heavily impacted by pyroclastic flows. Bedload sampling in the Pasig–Potrero River, one of the most heavily impacted rivers, revealed negligible critical shear stress and very high transport rates that reflected an essentially unlimited sediment supply and the enhanced mobility of particles moving over a smooth, fine-grained bed. Dimensionless bedload transport rates in the Pasig–Potrero River differed substantially from those previously reported for rivers in temperate regions for the same dimensionless shear stress, but were similar to rates identified in rivers on other volcanoes and ephemeral streams in arid environments. The similarity between volcanically disturbed and arid rivers appears to arise from the lack of an armored bed surface due to very high relative sediment supply; in arid rivers, this is attributed to a flashy hydrograph, whereas volcanically disturbed rivers lack armoring due to sustained high rates of sediment delivery. This work suggests that the increases in sediment supply accompanying massive disturbance induce morphologic and hydrologic changes that temporarily enhance transport efficiency until the watershed recovers and sediment supply is reduced. 相似文献
12.
流域侵蚀产沙和物质转移* 总被引：3，自引：2，他引：1
联系当前全球土壤流失的现状,本文阐明研究侵蚀产沙和物质输移规律的重要性,从侵蚀产沙和物质输移的流域系统概念出发,并结合我国黄土高原的治理,扼要介绍国内外这一领域的研究概况. 相似文献
13.
黄土高原典型小流域道路特征及影响因素 总被引：5，自引：1，他引：4
通过GPS野外实测黄土高原纸坊沟小流域的道路特征,在GIS空间分析等方法支持下研究了流域内各级道路的分布规律。研究表明:黄土高原道路可分为4级,2级以下的土路是小流域的代表路型。各级别道路总长度都随级别增大而增加且累计总长度与道路级别线性相关,道路平均长度和密度则随级别增大而减小。道路网系和流域水系在结构规律上具有一定的相似性。不同级别道路分布范围受地形特征影响不同。爬坡道路坡度与地表坡度之间存在线性回归关系,且次级道路分布受主路控制;典型爬坡路在大于25°坡度范围内多呈"之"字形弯曲,随坡度的减小道路弯曲跨度和与等高线夹角增大。研究结果有助于定量模拟黄土高原地区道路分布特征,并为土壤侵蚀模型中道路影响因子的确定提供参考。 相似文献
14.
Fallout radionuclide tracers identify a switch in sediment sources and transport-limited sediment yield following wildfire in a eucalypt forest 总被引：2，自引：0，他引：2
S.N. Wilkinson P.J. Wallbrink G.J. Hancock W.H. Blake R.A. Shakesby S.H. Doerr 《Geomorphology》2009,110(3-4):140-151
Fire can alter sediment sources and transport rates in river basins, changing landforms and aquatic habitats and degrading downstream water quality. Variability in the response between environments, between fires, and with time since fire makes predicting the catchment-scale effect of individual fires difficult. This study applies the fallout radionuclides 137Cs and 210Pbxs to trace the sources and transport of fine sediment through a river network following a wildfire of moderate to extreme severity in the 629-km2 eucalypt-forested Nattai River water-supply catchment near Sydney, Australia. The tracer analysis showed that post-fire erosion caused a switch in fine (< 10 µm) sediment sources from 80% subsoil derived from gully and river bank erosion to 86% topsoil derived from hillslope surface erosion. The fine sediment phosphorus content increased 4–10 fold over pre-fire levels. Annual post-fire sediment yields estimated from suspended solids rating curves were 109–250 times higher than they would have been without fire. A large additional amount of sediment remained stored within the river network for at least four years, particularly in lower-gradient reaches. Analysis of a sediment core showed that surface erosion following a previous fire had supplied at least 29% of total catchment sediment yield over the past 36 years. It is concluded that wildfire can alter catchment sediment budgets in two ways. Firstly, a spatially-diffuse pulse of elevated erosion is associated with moderate or intense rainfall events in post-fire years. Secondly, pulses of elevated catchment sediment yield are driven by the timing and river sediment transport capacity of runoff events. Severe post-fire erosion and high interannual hydrologic variability can result in large sediment stores persisting within the river network for many years. Fallout radionuclide tracers are shown to be useful in quantifying fine sediment sources and transport dynamics following wildfire, and the contribution of wildfire to catchment sediment yield. 相似文献
15.
流域输沙过程是地貌学和地表动力学的重要研究内容,但传统的输沙过程监测方法仅能得到某个区域的总输沙率,无法推算其空间分布。论文以黄土高原绥德县窑家湾小流域为例,利用无人机摄影测量技术得到其2006年和2019年2期数字高程模型(DEM)并计算地形变化量;然后,根据质量守恒原理和多流向算法建立泥沙在空间上的输送模型,进而计算小流域输沙率的空间分布。实验结果表明,该模型能有效模拟泥沙在空间上的输送情况,输沙率出现质量不守恒的区域面积占比小于4%,且不守恒区域多为人类活动影响区。同时,论文讨论了DEM的选择和不同地形变化检测水平对模型结果的影响。当使用第一期DEM进行泥沙搬运路径推算时,质量不守恒区域的面积显著降低。使用误差空间分布图进行地形变化检测得到的输沙率结果鲁棒性更强。使用中误差进行地形检测得到的结果在不同置信度下变化较大。基于无人机地形变化检测的空间输沙模型能方便、快捷地提供详尽的输沙率空间分布,为地表过程研究带来了新的机遇。 相似文献
16.
Dozens of references recognizing pediment landforms in widely varying lithologic, climatic, and tectonic settings suggest a ubiquity in pediment forming processes on mountain piedmonts worldwide. Previous modeling work illustrates the development of a unique range in arid/semiarid piedmont slope (< 0.2 or 11.3°) and regolith thickness (2–4 m) that defines pediments, despite varying the initial conditions and domain characteristics (initial regolith thickness, slope, distance from basin to crest, topographic perturbations, and boundary conditions) and process rates (fluvial sediment transport efficiency and weathering rates). This paper expands upon the sensitivity analysis through numerical simulation of pediment development in the presence of spatially varying rock type, various base level histories, various styles of sediment transport, and various rainfall rates to determine how pediment development might be restricted in certain environments. This work suggests that in landscapes characterized by soil and vegetation types that favor incisive fluvial sediment transport styles coupled with incisive base level conditions, pediment development will be disrupted by the roughening of sediment mantled surfaces, thereby creating spatial variability in topography, regolith thickness, and bedrock weathering rates. Base level incision rates that exceed the integrated sediment flux along a hillslope derived from upslope weathering and sediment transport on the order of 10− 3 m y− 1 restrict pediment development by fostering piedmont incision and/or wholesale removal (stripping) of regolith mantles prior to footslope pediment development. Simulations illustrate an insensitivity to alternating layers of sandstone and shale 3–15 m thick oriented in various geometric configurations (vertical, horizontal, and dip-slope) and generating different regolith hydrologic properties and exhibiting weathering rate variations up to 3-fold. Higher fluxes and residence times of subsurface groundwater in more humid environments, as well as dissolution-type weathering, lead to a thickening of regolith mantles on erosional piedmonts on the order of 101 m and an elimination of pediment morphology. An initial test of the model sensitivity analysis in arid/semiarid environments, for which field reconnaissance and detailed geomorphic mapping indicate the presence of pediments controlled by climatic conditions (soil hydrologic properties, vegetation characteristics, and bedrock weathering style) that are known and constant, supports our modeling results that pediments are more prevalent in hydrologically-open basins. 相似文献
17.
黄河内蒙古段异源水沙输移特性 总被引：1，自引：1，他引：0
河流悬移质泥沙的输移方式按照水沙来源可以分为水沙同源与水沙异源两大类。黄河内蒙古段水沙来自不同的区域,冲泻质泥沙主要来源于陇西黄土高原区,而径流则主要来自唐乃亥以上的山区,呈现异源特性。通过分析内蒙古河段石嘴山与巴彦高勒水文站1951-2003年的水文数据,发现期间共发生了13次大流量和29次高含沙事件且大流量、高含沙量同时出现现象很少,多呈现大流量、低含沙量,或者小流量、高含沙量的态式。同时,通过改变传统流量-含沙量幂函数公式Ci=aQb(Ci为悬移质浓度,Q为流量)的参数项,建立了2种水沙异源情况下流量-含沙量的公式。 相似文献
18.
试论城市地貌环境与城市道路系统的关系*——以四川省几个城市为例 总被引：5，自引：0，他引：5
本文分析了城市地貌环境对城市道路系统的影响,认为地貌过程不仅影响了城市道路的建设和管理,而且是城市道路系统布局和发展的重要控制因素。以四川省几个城市为例,分析了山地城市、丘陵城市和平原城市道路系统的不同特点。 相似文献
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Erosion and sediment transport in High Arctic rivers, Svalbard 总被引：2，自引：0，他引：2
This paper discusses sediment yield, sediment delivery and processes of erosion in rivers subject to High Arctic conditions in Svalbard. Long-term measurements reveal large variations between rivers and from year to year in each individual river. In the unglacierized catchment of Londonelva, annual sediment transport varied between 28 and 93 t/yr, with a mean sediment yield of 82.5 t/km2 /yr. In the glacier-fed rivers Bayelva and Endalselva, the suspended sediment transport varied in the range of 5126 t/yr to 22797 t/yr during a 12-year period. A mean of 11 104 t/yr gave rise to a mean sediment yield of 359 t/km2 /yr for the whole Bayelva catchment area. The sediment yield of the glacier and the moraine area was estimated at 586 t/km2 /yr. A conceptual model used to interpret the long- and short-term patterns of sediment concentration in the meltwater from the glacier and erosion of the neoglacial moraines is proposed. Evidence is found that a proportion of the sediments are delivered by a network of englacial and subglacial channels that exist even in cold ice. Regression analyses of water discharge versus suspended sediment concentration gave significant correlations found to be associated with the stability of ice tunnels in cold ice. Large floods have been found to flush the waterways and exhaust the sediment sources. A long-term change in the exponent of regression lines is attributed to changes in sediment availability caused by flushing and expansion of tunnels and waterways by large floods and a subsequent slow deformation of them caused by the ice overburden and the glacier movement. A comparison of sediment yields from a number of polythermal and temperate glaciers in various areas showed large differences that were attributed primarily to bedrock susceptibility to erosion and, secondarily, to glaciological parameters. 相似文献