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1.
土壤侵蚀现象是黄土高原的一个重大环境问题。土壤侵蚀的发生和发展有其自然的规律。黄土高原的土壤侵蚀可概括为三种类型:(1)水流侵蚀;(2)重力侵蚀;(3)风力侵蚀。控制黄土高原土壤侵蚀的自然因素为:降水、地形、植被和岩土性质。降水和地形两个因素称之为“侵蚀性因素”;植被和岩土性质两个因素称之为“可蚀性因素”。土壤侵蚀的发生与否,以及侵蚀的程度,最终取决于上述侵蚀性因素与可蚀性因素两者之间相互影响的结果。如果侵蚀性因素的效果大于可蚀性因素的效果,则发生侵蚀作用;反之,则侵蚀作用不显示。 相似文献
2.
WEPP模型(坡面版)在贵州石漠化地区土壤侵蚀模拟的适用性评价 总被引：6，自引：2，他引：4
文章以贵州花江喀斯特石漠化地区为研究区域,利用WEPP模型(坡面版)分别模拟2006年、2010年土壤侵蚀模数,并将实测数据与WEPP模型模拟值作比较,探讨WEPP软件在喀斯特石漠化地区的适用性。研究表明:WEPP模型对于模拟喀斯特石漠化地区土壤侵蚀有较大误差,对土壤侵蚀模数模拟的有效性系数均为负值,不适用于直接计算该区域土壤侵蚀模数。WEPP模型对微度侵蚀模拟精度不够,但能大体反映不同径流小区之间土壤侵蚀强弱的关系和生态修复过程土壤侵蚀的变化趋势。若要应用WEPP模型对喀斯特地区土壤侵蚀模数模拟计算,必须考虑水土的地下漏失、地表裸岩率、地形高度破碎等环境条件。裸岩率、土壤漏失、地形条件等都是WEPP模型修正所必须注意的内容。 相似文献
3.
黄土丘陵区堆积体边坡对上方来水的侵蚀响应 总被引：2，自引：0，他引：2
为探明上方来水类型对工程堆积体高陡边坡下部冲刷侵蚀的定量影响,以神府高速公路沿线典型工程堆积体陡坡坡面(36°)为例,设计4种上方来水类型,通过野外放水冲刷试验分析了不同上方来水类型下堆积体坡面的径流侵蚀输沙过程.结果表明:①上方来水类型对堆积体坡面下部的产流影响较小,却干扰了坡面侵蚀产沙过程,造成土壤流失量增加;②径流深、单宽径流侵蚀力和水流功率均可以较好地预测堆积体边坡下部输沙模数的变化;③单宽径流侵蚀功率可以作为表征坡面尺度次径流事件中径流侵蚀力变化的指标.研究结果可为工程堆积体土壤侵蚀强度评价、侵蚀模型建立及新增水土流失防治提供参考. 相似文献
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农业非点源污染具有广泛性、随机性和难监测性、难治理性等特点,应用模型描述农业非点源污染物输移过程、进行污染负荷计算、评价防控与治理效果成为水环境保护与治理领域的难点与热点。着重讨论农业非点源污染模型(AGNPS)系列模型的结构、机理以及国内外的研究与应用进展。国内外该模型研究结果表明,模拟结果可以接受,年模拟效果要好于次降雨模拟效果,径流量、泥沙侵蚀量、氮磷营养盐负荷模拟精度根据研究区域的不同有所差异,模型的管理措施效果评价、关键污染源区的判断与实际相符。AGNPS系列模型单元网格的划分、敏感性分析及参数的调整对模型的精度有重要影响,针对该模型的特点与研究现状,提出改进意见及研究展望。 相似文献
7.
DEM分辨率对分布式水沙过程模拟具有重要影响,然而,产生影响的内部机制尚不明确。改进水沙物理模型CASC2D-SED的结构,将坡度由DEM在模型内部直接提取改为由模块单独计算,并将坡度设计为模型的独立输入参数,通过单独改变坡度参数来研究坡度对水沙模拟DEM尺度效应的影响。基于改进的CASC2D-SED模型,以内蒙古准格尔旗沙圪堵镇附近的一个小流域为研究对象,以无人机航测的1m分辨率DEM数据、野外实测与室内实验获得的土壤特性数据、土地利用数据和降雨数据为基础,采用3种水沙模拟方案进行多象元尺度的水沙过程模拟,进而探索水沙过程模拟的DEM尺度效应及发生机制。研究表明:⑴在4~20m GRID分辨率区间模拟的径流量位于323.18m3和411.43m3之间,波动不大;⑵2~20m GRID分辨率区间内,模拟的侵蚀流量在3.43m3和65.61m3间变化,波动很大;(3)坡度和径流路径是水文过程模拟DEM尺度效应的两个对立影响因子,是水文过程模拟DEM尺度效应不明显的主要原因;⑷DEM尺度效应对侵蚀输沙具有重要影响,地形坡度是侵蚀输沙DEM尺度效应的主要控制因子;⑸地形坡度随DEM分辨率降低而发生的空间上的波动变化是侵蚀输沙量随DEM分辨率降低而波动变化的原因。 相似文献
8.
由于地质体和矿体的形态非常复杂，使用长方体网格离散建立正演模型时可能和真实情况有很大差别，因此计算结果可靠性差。本文提出一种基于约束Delaunay网格剖分的方法对地质体进行离散并进行重力建模，在模型边界等复杂区域使用网格自适应加密技术，将三维地质体离散为有限个四面体；并详细推导出针对四面体网格的重力正演公式，实现了基于约束Delaunay网格剖分技术的三维重力数值模拟；最后，针对一个合成数据模型，将计算解与解析解对比。结果表明，细化网格的模拟结果比粗糙网格更好，满足数值模拟的精度要求。将该方法应用到金川矿区实际地质体建模中，根据局部需要，建立各处网格密度不均匀的三维模型，并计算该模型的地表重力场，而后对比模拟数据与实测数据，结果表明Delaunay网格建模方法具有很强的适用性，能够模拟复杂的地质体重力异常。 相似文献
9.
黄土高原草地植被对土壤侵蚀影响研究进展 总被引：4，自引：0，他引：4
《地球科学进展》2017,(10)
黄土高原土壤侵蚀严重,草地植被具有良好的水土保持作用,能很好地改善其生态环境。学者们对草地植被盖度与土壤侵蚀的关系、草地植被对水力学参数的影响、草地植被对土壤性质的影响、草地植被减水减沙效应以及草地坡面土壤侵蚀过程等几个方面开展了大量研究;但是关于草地覆盖诱发的侵蚀作用研究较少。将前人的研究成果进行归纳总结,并补充关于草地诱发侵蚀的一些研究结果,继而指出目前研究中存在的问题以及今后需要加强的方面,旨在减少黄土高原土壤侵蚀。 相似文献
10.
本研究在GIS技术支撑下选择RUSLE模型作为基础模型,估算乌江流域20世纪80年代和90年代年均土壤侵蚀量,结合ANN技术,预测2001—2010年乌江流域的土壤侵蚀量,分析了该流域近30年来土壤侵蚀动态变化规律,以期为研究区土壤侵蚀防治工作提供理论依据。研究结果表明:应用RUSLE模型计算乌江流域年均土壤侵蚀模数,计算结果和以往土壤侵蚀调查估计的结果比较吻合,但由于RUSLE模型不计算重力侵蚀,因此计算结果仍与实测输沙模数有所出入。90年代潜在土壤侵蚀模数比80年代高,流域潜在土壤侵蚀呈增加趋势,其中三岔河流域和马蹄河/印江河流域年均潜在土壤侵蚀模数最高。3种主要土地覆被类型中,林地的土壤保持量最大,耕地次之,草地最少,这与非喀斯特地区在水土保持效果上通常林地草地旱地的结论有所不同。通过构建BP神经网络,预测得到乌江流域2001—2010年土壤侵蚀模数,结果显示,21世纪前10年,流域土壤侵蚀模数大幅降低,流域年均土壤侵蚀模数由90年代的23.13 t/(hm2·a)降低为1.01 t/(hm2·a)。三岔河流域的水土流失得到了控制,黔西、金沙、息烽、修文、贵阳、平坝、思南、石阡、沿河和松桃等县市应是"十二五"期间的水土流失重点治理对象。 相似文献
11.
Zhang Zonghu 《GeoJournal》1991,24(2):195-200
The soil erosion processes in the Loess Plateau may be divided into three types: namely, waterflow erosion; gravitational erosion; wind erosion. The waterflow erosion is most widely distributed and is the main erosion action in the Loess Plateau. The main factors dominating the occurrence and development of the soil erosion in the Loess Plateau are: 1. rainfall; 2. topography; 3. vegetation; 4. soil character. The energy of erosion action depends upon the rainfall and topography, but erodiblity depends upon the vegetation and soil properties. The degree of soil erosion in the Loess Plateau changes with variations of interaction of erosion and anti-erosion measures. 相似文献
12.
Suitability of transport equations in modelling soil erosion for a small Loess Plateau catchment 总被引：2，自引：0，他引：2
Rudi Hessel 《Engineering Geology》2007,91(1):56-71
Erosion models have not often been applied to very steep terrain such as the gully catchments of the Chinese Loess Plateau. The purpose of this research was to evaluate the suitability of a number of transport equations for use in erosion modelling under Loess Plateau conditions. To do this the equations were programmed into the LISEM model, which was applied to the 3.5 km2 Danangou catchment in the rolling hills region of the Loess Plateau. Previous evaluations of transport equations used either flume tests or river sections, and did no spatial modelling. The results show that some equations predicted physically impossible concentrations (defined as above 1060 g/l). The results were evaluated by using two methods: 1) by comparing predicted and measured sedigraphs and sediment yield at the catchment outlet, and 2) by comparing the fraction of the catchment in which physically impossible transport capacities occurred. The results indicated that for the small grain sizes, high density flows and steep slopes of the gully catchments on the Loess Plateau the Shields parameter attained very high values. Furthermore, the transport threshold can usually be neglected in the equations. Most of the resulting equations were too sensitive to slope angle (Abrahams, Schoklitsch, Yalin, Bagnold, Low and Rickenmann), so that transport rates were overpredicted for steep slopes and underpredicted for gentle slopes. The Yang equation appeared to be too sensitive to grainsize. The Govers equation performed best, mainly because of its low slope dependency, and is therefore recommended for erosion models that simulate sediment transport by flowing water in conditions with small grain sizes and steep slopes. 相似文献
13.
Application of a distributed erosion model for the assessment of spatial erosion patterns in the Lushi catchment,China 总被引：2，自引：2，他引：0
Guoqiang Wang Jingshan Yu S. Shrestha H. Ishidaira K. Takeuchi 《Environmental Earth Sciences》2010,61(4):787-797
A grid-based erosion model is developed by integrating the distributed hydrological model, BTOPMC, with the modified USLE
to estimate soil erosion and sediment outflow during single storms. The possible sheet, rill, channel erosion types, and sediment
transport processes are considered within each grid under the model structure. Instead of representing the sheet erosion and
rill erosion separately, the classic USLE method is modified to simulate the lumped sheet–rill erosion during storms. In the
modification, the runoff ratio and a relevant correction coefficient are brought into the R-factor which improves the model’s applicability in predicting erosion during single storms. Instead of representing a grid
with a unique erosion type, a channel component is assumed to exist in each grid, and its width varies with the upstream contributing
area of the grid. This assumption avoids the problems that are caused by the difference between the channel widths in the
upstream area and the downstream area if the grid is simply recognized as a channel grid. It also enables the model to be
applicable in simulating soil erosion and sediment outflow from a large catchment. Through a case study in the Lushi catchment,
China, the results show an overall satisfactory accuracy for the selected events. Moreover, by analyzing the spatial distribution
of soil erosion or deposition, the erosion-prone areas are identified for the prioritization purpose. 相似文献
14.
Spatial distribution of soil erosion and suspended sediment transport rate for Chou-Shui river basin
Chin-Ping Lin Ching-Nuo Chen Yu-Min Wang Chih-Heng Tsai Chang-Tai Tsai 《Journal of Earth System Science》2014,123(7):1517-1539
In this study, a Physiographic Soil Erosion–Deposition Model (PSED) is applied for better management of a watershed. The PSED model can effectively evaluate the key parameters of watershed management: surface runoff discharge, suspended sediment transport rate, quantity of soil erosion, and spatial distribution of soil erosion and deposition. A basin usually contains multiple watersheds. These watersheds may have complex topography and heterogeneous physiographic properties. The PSED model, containing a physiographic rainfall-runoff model and a basin scale erosion–deposition model, can simulate the physical mechanism of the entire erosion process based on a detailed calculation of bed-load transportation, surface soil entrainment, and the deposition mechanism. With the assistance of Geographic Information Systems (GIS), the PSED model can handle and analyze extremely large hydrologic and physiographic datasets and simulate the physical erosion process without the need for simplification. We verified the PSED model using three typhoon events and 40 rainfall events. The application of PSED to Chou-Shui River basin shows that the PSED model can accurately estimate discharge hydrographs, suspended sediment transport rates, and sediment yield. Additionally, we obtained reasonable quantities of soil erosion as well as the spatial distribution of soil erosion and deposition. The results show that the PSED model is capable of calculating spatially distributed soil erosion and suspended sediment transport rates for a basin with multiple watersheds even if these watersheds have complex topography and heterogeneous physiographic properties. 相似文献
15.
Catchment-scale soil erosion and sediment yield simulation using a spatially distributed erosion model 总被引：1，自引：1，他引：0
Increasing rainfall intensity and frequency due to extreme climate change and haphazard land development are aggravating soil erosion problems in Korea. A quantitative estimate of the amount of sediment from the catchment is essential for soil and water conservation planning and management. Essential to catchment-scale soil erosion modeling is the ability to represent the fluvial transport system associated with the processes of detachment, transport, and deposition of soil particles due to rainfall and surface flow. This study applied a spatially distributed hydrologic model of rainfall–runoff–sediment yield simulation for flood events due to typhoons and then assessed the impact of topographic and climatic factors on erosion and deposition at a catchment scale. Measured versus predicted values of runoff and sediment discharge were acceptable in terms of applied model performance measures despite underestimation of simulated sediment loads near peak concentrations. Erosion occurred widely throughout the catchment, whereas deposition appeared near the channel network grid cells with a short hillslope flow path distance and gentle slope; the critical values of both topographic factors, providing only deposition, were observed at 3.5 (km) (hillslope flow path distance) and 0.2 (m/m) (local slope), respectively. In addition, spatially heterogeneous rainfall intensity, dependent on Thiessen polygons, led to spatially distinct net-erosion patterns; erosion increased gradually as rainfall amount increased, whereas deposition responded irregularly to variations in rainfall. 相似文献
16.
Soil erosion is a serious global environmental problem which limits the survival and development of human beings. In our country, due to the special physical geography and socio-economic conditions, soil erosion intensity is great, which is particularly prominent in Loess Plateau region. Therefore, preventing and controlling soil erosion, as well as reducing soil erosion in Loess Plateau have become the key to solving environmental problems in the region. Soil erosion on Loess Plateau is serious, and grassland vegetation has good effects on soil and water conservation, which can improve ecological environment well. After the implementation of the project about returning farmland to grassland on Loess Plateau, the ecological benefits mainly focused on soil and water conservation benefits, soil improvement benefits, water conservation benefits and species diversity benefits, etc. Grassland vegetation has an irreplaceable role in the construction of the ecological environment on Loess Plateau. Therefore, the role of grassland in preventing soil erosion has received more and more attention. Scholars have done lots of research involved in the relationship between grassland coverage and soil erosion, impacts of grassland on hydrodynamic parameters, effects of grassland on soil properties, reduction effects of grassland on runoff and sediment, and soil erosion process on grassland slope. However, there is little research on erosion effect induced by grassland cover. This paper mainly pointed out the following questions: First, grassland cover is influenced by many factors, but the relationship with soil erosion from the dynamic mechanism is rarely discussed; Second, there is no well-developed theory of overland flow erosion at present, which limits the study of hydrodynamic parameters on grassland slope; Third, establishment of mathematical model between grassland cover and soil resistance can accelerate the quantitative analysis of grassland influence on erosion; Fourth, comprehensive analysis of influencing factors on water reduction and sediment reduction effect on grassland are insufficient; Fifth, there are not many mechanisms to analyze the erosion process of grassland slope by using the hydrodynamic characteristics of slope; sixth, research results on grassland-induced erosion are mainly focused on leading to soil dry layer and we should continue to strengthen in the future. This paper summarized the previous results, and supplemented some studies about erosion caused by grassland, then pointed out the existing problems in current research and the areas that need to be strengthened in the future, aiming at reducing soil erosion on the Loess Plateau. 相似文献
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18.
长江中游河道岸滩侧蚀现象普遍,易对航道稳定形成不利影响,深入研究岸滩侧蚀冲刷机理及其航道响应过程具有重要意义。建立了考虑相邻土体影响的黏性岸滩侧蚀坍塌力学模式,以长江中游太平口水道为例,基于局部网格可动技术,构建了岸滩侧蚀及其河床冲淤变化的三维水沙动力学模型;在模型验证相似的基础上,分析了清水冲刷条件下腊林洲边滩侧蚀对太平口水道航道格局的影响。研究结果表明:模型可较好地模拟由岸滩侧蚀所引发的河势演变过程;上游来沙减少后,太平口水道河床以及未守护低滩部位将进一步产生冲刷;腊林洲边滩稳定与否,对太平口水道“南槽-北汊”航道格局的稳定具有重要作用。 相似文献
19.
Simulation and improvement of common land model on the bare soil of Loess Plateau underlying surface 总被引：3，自引：3，他引：0
Zhen-chao Li Zhi-gang Wei Chao Wang Zhi-yuan Zheng Hong Wei Hui Liu 《Environmental Earth Sciences》2012,66(4):1091-1097
Climate model has become an irreplaceable tool for the study and prediction of climate changes. The land surface process, as one of the important parts of all climate models, must be considered so that the simulative ability of climate models could be improved. Using the common land model (CoLM) that is driven by the LOPEX experiment data, the characteristics of land surface processes of the Loess Plateau are simulated. Furthermore, based on the comparison of the field observation data with the simulated results, the simulative performance of CoLM in the Loess Plateau region is also examined. The results show that, CoLM can be used in the Loess Plateau, and it perfectly simulates net radiations and net short-wave radiations. However, the simulated land-surface temperature is slightly higher than actual measured value, while the simulated soil temperature values in lower layers (5, 10, 20, 40 cm) are relatively less and the variety phase of these also lag. Moreover, the simulated sensible heat flux is a little larger, while the simulated soil thermal conductivity value is obviously lower. By modifying the calculation plan of soil thermal conductivity, the simulated result has been greatly improved. As a whole, if CoLM is applied in the Loess Plateau of Northwestern China, the parameterization of soil thermal conductivity should be ameliorated, which can improve its simulative capacity in the Loess Plateau regions. 相似文献
20.
The Loess Plateau is well known to the world because of its thick loess and severe soil erosion. Loess is a highly erosion-prone soil that is considerably susceptible to water erosion. The Loess Plateau also has a long cultivation history, hence population growth, vegetation degeneration serious soil and water loss were obviously problems on Loess Plateau. This article analyzes several strategies of soil and water conservation on the Loess Plateau, such as terracing, planting trees, natural vegetation rehabilitation and construction of warp land dams. Different periods had different strategies of soil and water conservation and each strategy had its characteristics and effects. Finally, the research directions and future perspectives of the Loess Plateau were discussed, including the strategies of sustainable eco-environment of Loess Plateau in China. 相似文献