Application of GIS to estimate soil erosion using RUSLE

This paper describes the use of the Arc/Info and ArcView GIS tools to estimate soil erosion with Universal Soil Loss Equation (USLE).Calculations are be done by using capabilities available.This study start with a digital elevation model(DEM) of Shaanxi,which was created by digitizing contour and spot heights from the topographic map on 1:250000 scale and grid themes for the USLE K and C factors.It is note worthy that USLE K can be obtained by adding the K factor as an attribute to a soil theme‘s table.The C can be obtained from tables or using the information about land use and management given by USLE program.A land use theme can be used to add the C factors as an attribute field.The purpose of this study is to establish spatial information of soil erosion using USLE and GIS and discuss the analysis of the soil erosion and slope failures in GIS and formulate the possible framework.     

区域尺度海河流域水土流失风险评估

借鉴USLE的因子选择及综合方法,在遥感和GIS的支撑下对海河流域的水土流失风险进行评估,并对其空间分布特征进行分析.结果表明:海河流域山区水土流失风险显著高于平原地区,北三河山区水土流失风险最低,太行山区最高,永定河上游介于两者之间;水土流失风险"很低"等级主要分布在小于5°的平坦地区,"中"、"高"水土流失风险面积...     

A comparative study of soil erosion modelling by MMF,USLE and RUSLE

The quantitative assessment of spatial soil erosion is valuable information to control the erosion. The study area in a part of Narmada river in central India is selected. The main objective is to assess and compare the results obtained from three soil erosion models using GIS platform. Variation in the rate of erosion of the three models is compared considering varying slope, soil and land use of the area. Three models selected are Morgan–Morgan–Finney (MMF), Universal Soil Loss Equation (USLE) and Revised Universal Soil Loss Equation (RUSLE). The best fit or the most reliable model for the study area is selected after validation with the observed sedimentation data. The results give –39.45%, –9.60% and 4.80% difference in the values of sedimentation by MMF, USLE and RUSLE, respectively, from the observed data. Finally, RUSLE model has been found to be most reliable for the study area.     

Simulating the effects of land use changes on soil erosion using RUSLE model

The aim of this paper is to evaluate the impacts of land use change on soil loss. Soil loss was quantified using the revised universal soil loss equation model in Darabkola catchment. Land use maps of 1992, 1998 and 2012 were derived from Landsat Thematic Mapper data. The mean annual soil loss was therefore determined for these years. The results showed open-canopy forest area decreased by 36% between 1992 and 1998. Likewise, the decreasing trend of forest lands which are near to residential areas has continued from 1795 ha in 1998 to 1765 ha in 2012. Also the results indicate that the maximum annual soil loss ranged from 5.06, 6.19 and 15.23 ton h^?1 y^?1 in 1992, 1998 and 2012, respectively. Also, by assuming that all watershed conditions and land uses be constant in the future, then the area of close- and open-canopy forest and dry agricultural lands will be 23.23, 2.88 and 29.89 ha in 2040, respectively.     

GIS下地貌形态特征对土壤水土流失研究的影响

水土流失会导致生态环境恶化、自然灾害频发,近年来,以水土保持为主要内容的生态环境建设越来越受到关注。本文利用SRTM数据,其分辨率为3弧秒,确定模型所需的各种因子,借助地理信息系统软件Arc GIS空间分析平台,处理研究区域的DEM数据,生成研究区坡度、坡向、地表切割深度和平面曲率图、剖面曲率图。利用对这些因子的分析结果,选择美国通用的水土流失方程(USLE)对研究区域的土壤侵蚀强度进行计算,从而确定了地貌形态特征对土壤水土流失的影响。     

Uncertainty analysis of soil erosion modelling using different resolution of open-source DEMs

The Digital Elevation Model (DEM) is one of the important parameters of soil erosion assessment and notable uncertainties are found in using different resolutions of the DEM. Revised Universal Soil Loss Equation model has been applied to analyze the effect of open-source DEMs with different resolution and accuracy on the uncertainties of soil erosion modelling in a part of the Narmada river basin in Madhya Pradesh in central India. Selected open-source DEMs are GTOPO30 (1 km), SRTM (30 and 90 m), CARTOSAT (30 m) and ASTER (30 m), used for estimating erosion rate. Results with better accuracy are achieved with the high-resolution DEMs (30 m) with higher vertical accuracy than the coarse resolution DEMs with lower accuracy. This study has presented potential uncertainties introduced by the open-source DEMs in soil erosion modelling for better understanding of appropriate selection and acceptable errors for researchers.     

长江上游小流域土壤侵蚀动态模拟与分析

以长江上游甘肃省尚沟流域为研究区,在遥感影像和GIS空间分析技术支撑下,根据USLE因子算法生成各因子栅格图,借助地图代数运算,估算了尚沟流域1998年和2004年的土壤侵蚀量,并对2004年土壤侵蚀与其环境背景因子进行叠加和空间统计分析。在此基础上,构建了与GIS软件平台集成的地理元胞自动机,模拟了该流域2004年、2010年和2020年土壤侵蚀空间演化情形。结果表明:研究区平均侵蚀量从1998年的6598.1t/km2下降到2004年的5923.3t/km2,侵蚀面积净减少172.3hm2,输沙量减少9.15×104t;1300～1400m的海拔高程带、25～35°坡度带、南坡和旱耕地是发生水土流失的主要区域;经模拟,2010年总侵蚀面积为93.49km2,侵蚀总量73.15×104t,侵蚀模数为5126t/km2,土壤侵蚀状况总体上将有所减缓。     

Risk assessment of soil erosion in semi-arid mountainous watershed in Saudi Arabia by RUSLE model coupled with remote sensing and GIS

Soil erosion is the most important factor in land degradation and influences desertification in semi-arid areas. A comprehensive methodology that integrates revised universal soil loss equation (RUSLE) model and GIS was adopted to determine the soil erosion risk (SER) in semi-arid Aseer region, Saudi Arabia. Geoenvironmental factors viz. rainfall (R), soil erodibility (K), slope (LS), cover management and practice factors were computed to determine their effects on average annual soil loss. The high potential soil erosion, resulting from high denuded slope, devoid of vegetation cover and high intensity rainfall, is located towards the north western part of the study area. The analysis is investigated that the SER over the vegetation cover including dense vegetation, sparse vegetation and bushes increases with the higher altitude and higher slope angle. The erosion maps generated with RUSLE integrated with GIS can serve as effective inputs in deriving strategies for land planning/management in the environmentally sensitive mountainous areas.     

甘孜州九龙县水土流失评价研究

本文以九龙县为研究区,根据沟壑密度、坡度、植被盖度、土地利用类型和高程5个因子,结合ARC-GIS空间分析功能和MATLAB数学建模编程的功能,应用GA-BP模型(遗传算法优化BP神经网络)对研究区的水土流失进行非线性智能定量评价,并与层次分析法的结果对比分析,阐述了GA-BP模型的优越性。本次研究可以为九龙县水土流失预防和治理提供有益的参考。     

Effect of slope steepness parameter computations on soil loss estimation: review of methods using GIS

In the analysis of soil loss equation, the researchers have suggested two methods of deriving the slope steepness parameter. One method is having percentage slope term, while the other method is having sinθ as its term. In this paper, both the methods were analysed and compared in soil loss computation using Revised Universal Soil Loss Equation, over a Gangapur catchment area in India, having steep slopes. The soil loss rates derived were 0.98 million tonnes per year in case of steepness parameter derived by sinθ and 1.226 million tonnes per year in case of steepness parameter derived by percentage slope term. The observed rate of soil loss is 1.23 million tonnes per year. This methodology of soil loss estimation was also validated with similar catchment of Punegaon dam. It is concluded that for medium to steep terrain, percentage slope method estimates more accurate soil loss than other empirical methods for slope steepness estimation.     

基于DEM的USLE土壤侵蚀方程地形因子获取与分析

坡长和坡度是研究水土流失问题中必须要考虑的重要地形因子,坡长的空间分布特征和规律、地貌发育对坡长的影响,以及坡长与坡度之间的关系,是研究水土流失、侵蚀规律的重要条件之一。利用GIS以及相关软件为平台,在黑龙江省通河地区建立USLE水土流失方程模型,研究LS因子在水土流失中的影响以及作用,并探讨DEM数据分辨率变化对LS值的影响。     

云蒙湖流域不同坡度的土壤侵蚀特征

针对定量分析土壤侵蚀在各坡度等级上的空间分布研究较少的现状,该文选用通用的土壤流失预报方程,对云蒙湖流域1986—2010年间的土壤水力侵蚀状况进行了定量的估算,以探讨不同坡度上的土壤侵蚀特征,并进一步分析了土壤侵蚀变化与人类活动的关系。分析得出:土壤侵蚀强度发生在人类活动比较频繁的区域上(8~25°坡度)更为严重;2010年比1986年强度以上所占比例在15°坡度等级上相对更低,在15°坡度等级上有所增加;云蒙湖流域主要土壤侵蚀量发生在25°坡度上;2010年比1986年耕地面积减少、林地和居民用地面积增加是土壤侵蚀降低的主要因素。     

近景摄影测量在土壤侵蚀监测中的应用

针对当前近景摄影测量技术对影像采集设备以及操作人员专业性要求高的特点,该文在总结前人研究的基础上,提出了一种基于普通数码相机的近景摄影测量技术方法,并将其应用于微区土壤侵蚀监测试验中。通过该方法在人工水冲试验和天然降雨试验前后的土壤侵蚀动态监测得到:与传统土壤侵蚀监测方法相比,采用该方法测得的土壤侵蚀量精度分别可以达到75%和83.11%,单次测量精度最高可达94.33%。通过分析误差来源,结果表明:在一定条件下,可以实现基于普通数码相机的近景摄影测量技术在生产建设项目土壤侵蚀监测中的应用。     

DEM流域特征提取及其在非点源污染模拟中的应用

概述了数字高程模型(DEM)的特点及对其进行流域特征信息的提取原理和方法,结合流域非点源污染模拟研究的需要,在GIS软件和非点源污染模型SWAT的技术支持下,对密云县密云水库北部流域DEM进行了流域的刻划及模型运行单元HRUs的生成,最后从三个方面:对DEM在非点源污染研究中的应用进行了有益的探讨。     

永定河治理区土壤侵蚀时空变化分析

本文利用“北京一号”小卫星32 m多光谱数据提取研究区的植被覆盖信息与土地利用信息,利用1∶50 000DEM数据提取研究区坡度信息,采用中华人民共和国水利部部颁标准“土壤侵蚀分类分级标准SL 190-96”,评价研究区的水蚀风险等级;并结合全国第二次土壤侵蚀遥感(LandsatTM)调查数据,进行土壤侵蚀时空变化分析...     

大理河流域土壤侵蚀风险及其空间格局分析

本文利用遥感影像提取大理河流域相关信息,采用水利部部颁标准评价土壤侵蚀风险等级,并与地形特征进行叠加分析。结果显示:研究区侵蚀风险以中度和轻度为主;坡度是主要影响因素,坡度越大侵蚀风险区越集中,尤其是强度及以上区域,集中程度达到90%以上;侵蚀主要分布在1000m—1400m的两个高程带内。研究结果可以辅助管理部门进行侵蚀治理决策。     

空间插值算法在GIS中的应用

在GIS的研究中,通常需要具有一定规则的数据,而多数可获得的数据都是呈现离散状态并且是不规则分布的,这就需要应用空间插值的方法把离散的不规则数据转换成规则数据.本文介绍了几种常用的空间插值模型的原理与方法,并通过规则格网DEM的建立,说明空间插值算法在GIS中的应用.     

GIS和DEM技术在贵州省县级农用地分等定级数据库中的应用探讨

以贵州省县级农用地数据库的建立方法为例,概述在GIS和DEM技术支持下的农用地分等定级的技术路线,详述GIS环境下图库的建立、评价单元的划分、数字高程模型的应用和成果的应用等几项关键步骤,探讨如何以GIS技术建立县级农用地的分等定级体系.     

Digital close range photogrammetry for measurement of soil erosion

Many of the processes involved in soil erosion have dimensions on the millimetre scale. Modelling and quantification of such processes require information on soil surface topography with adequate resolution. The purpose of this study was to generate digital elevation models (DEMs) from soil surfaces with high spatial and temporal resolution. Digital photogrammetry was applied for measuring erosion rates on complex-shaped soil surfaces under laboratory rainfall conditions. A total of 60 DEMs were generated, covering a planimetric area of 16 m². The DEMs had a grid resolution of 3 mm. A vertical precision of approximately 1 mm was desired for DEM analysis. A consumer-grade digital camera was used for image acquisition. The camera was calibrated using BLUH software. Homologous points in overlapping images were identified with least squares matching software. Irregularly spaced object coordinates were interpolated to a regular grid in a geographic information system. The resulting DEMs represented the soil surface well. A precision of 1·26 mm in the vertical was attained. The precision of DEM production was limited to camera calibration. Improvements of the setup presented could include the use of better control points and more advanced image matching strategies for identification of homologous points. The DEMs allowed for detailed analysis of soil surface evolution.     

地形地质GIS三维可视化及应用

借助GIS强大的三维建模及可视化分析功能,以湖北省崇阳地区1：50 000区域地质成果为例,基于地理矢量数据、地质矢量数据和遥感影像数据,利用地形数据构建数字高程模型（DEM）,将DEM与遥感图像叠合生成三维影像图,建立集地形、地质、遥感等数据为一体的三维可视化模型,解决传统二维地质图件用于表示三维地质不直观等问题,提...