Soil erosion susceptibility mapping of Hangu Region,Kohat Plateau of Pakistan using GIS and RS-based models

Soil erosion is a crucial geo-environmental hazard worldwide that affects water quality and agriculture,decreases reservoir storage capacity due to sedimentation,and increases the danger of flooding and landslides.Thus,this study uses geospatial modeling to produce soil erosion susceptibility maps(SESM)for the Hangu region,Khyber Pakhtunkhwa(KPK),Pakistan.The Hangu region,located in the Kohat Plateau of KPK,Pakistan,is particularly susceptible to soil erosion due to its unique geomorphological and climatic characteristics.Moreover,the Hangu region is characterized by a combination of steep slopes,variable rainfall patterns,diverse land use,and distinct soil types,all of which contribute to the complexity and severity of soil erosion processes.These factors necessitate a detailed and region-specific study to develop effective soil conservation strategies.In this research,we detected and mapped 1013 soil erosion points and prepared 12 predisposing factors(elevation,aspect,slope,Normalized Differentiate Vegetation Index(NDVI),drainage network,curvature,Land Use Land Cover(LULC),rainfall,lithology,contour,soil texture,and road network)of soil erosion using GIS platform.Additionally,GIS-based statistical models like the weight of evidence(WOE)and frequency ratio(FR)were applied to produce the SESM for the study area.The SESM was reclassified into four classes,i.e.,low,medium,high,and very high zone.The results of WOE for SESM show that 16.39%,33.02%,29.27%,and 21.30%of areas are covered by low,medium,high,and very high zones,respectively.In contrast,the FR results revealed that 16.50%,24.33%,35.55%,and 23.59%of the areas are occupied by low,medium,high,and very high classes.Furthermore,the reliability of applied models was evaluated using the Area Under Curve(AUC)technique.The validation results utilizing the area under curve showed that the success rate curve(SRC)and predicted rate curve(PRC)for WOE are 82%and 86%,respectively,while SRC and PRC for FR are 85%and 96%,respectively.The validation results revealed that the FR model performance is better and more reliable than the WOE.

A GIS-based Modeling Approach for Fast Assessment of Soil Erosion by Water at Regional Scale, Loess Plateau of China

The objective of this study is to develop a unique modeling approach for fast assessment of massive soil erosion by water at a regional scale in the Loess Plateau, China. This approach relies on an understanding of both regional patterns of soil loss and its impact factors in the plateau area. Based on the regional characteristics of pre- cipitation, vegetation and land form, and with the use of Landsat TM and ground investigation data, the entire Loess Plateau was first divided into 3 380 Fundamental Assessment Units (FAUs) to adapt to this regional modeling and fast assessment. A set of easily available parameters reflecting relevant water erosion factors at a regional scale was then developed, in which dynamic and static factors were discriminated. ArcInfo GIS was used to integrate all es- sential data into a central database. A resulting mathematical model was established to link the sediment yields and the selected variables on the basis of FAUs through overlay in GIS and multiple regression analyses. The sensitivity analyses and validation results show that this approach works effectively in assessing large area soil erosion, and also helps to understand the regional associations of erosion and its impact factors, and thus might significantly contribute to planning and policymaking for a large area erosion control in the Loess Plateau.

A Catastrophe Model to Assess Soil Restoration Under Ecological Restoration in the Red Soil Hilly Region of China

Current methods that utilize simple data or models to evaluate soil restoration under ecological restoration are not sufficiently rigorous.Soil restoration under ecological restoration measures was evaluated in the red soil hilly region of China by applying the catastrophe model.Among 89 soil sites selected,26(29.21%) were in the middle lobe,10(11.24%) in the upper lobe,and 53(70.79%)in the lower lobe of the process surface in the Cusp catastrophe model.The catastrophic direction of the 26 unstable soil sites was to the upper lobe of the process surface according to vegetation cover change and fieldwork.There was a significant negative correlation of the variation in bifurcation set(? value) with vegetation cover increase,and a higher vegetation cover increase was related to higher unstable probability.The four ecological restoration measures were listed in the order:low-quality forest improvement(LQFI)>arbor-bush-herb mixed plantation(ABHMP)>orchard improvement(OI)>closing measures(CM) according to the proportions of unstable soil sites,which were all higher than no restoration measure,while they were in the order:LQFI<ABHMP<OI<CM according to their ? values,which were all lower than those of no restoration measure.Farmers' assessment of soil restoration under the four ecological restoration measures was in accordance with the proportions of unstable soil sites and inversely proportional to the? value.Therefore,farmers' assessment can prove the evaluation of soil restoration under ecological restoration measures based on catastrophe model.

Simulation study on dynamic mechanism of land use and soil erosion in loess hilly regions of Shanxi and Shaanxi provinces

SOIL erosion in the hilly region of Shanxi and Shaanxi provinces is very severe, and unreason-able land use is the main reason. There have been many research reports on the prediction ofsoil erosion, and most of them use regression methods. The resulting co-relative equations areused to predict small-scale erosion of fields or farms and to select agricultural measures.

Research on wind erosion processes and controlling factors based on wind tunnel test and 3D laser scanning technology

The study of wind erosion processes is of great importance to the prevention and control of soil wind erosion.In this study,three structurally intact soil samples were collected from the steppe of Inner Mongolia Autonomous Region,China and placed in a wind tunnel where they were subjected to six different wind speeds(10,15,17,20,25,and 30 m/s)to simulate wind erosion in the wind tunnel.After each test,the soil surfaces were scanned by a 3D laser scanner to create a high-resolution Digital Elevation Model(DEM),and the changes in wind erosion mass and microtopography were quantified.Based on this,we performed further analysis of wind erosion-controlling factors.The study results showed that the average measurement error between the 3D laser scanning method and weighing method was 6.23%for the three undisturbed soil samples.With increasing wind speed,the microtopography on the undisturbed soil surface first became smooth,and then fine stripes and pits gradually developed.In the initial stage of wind erosion processes,the ability of the soil to resist wind erosion was mainly affected by the soil hardness.In the late stage of wind erosion processes,the degree of soil erosion was mainly affected by soil organic matter and CaCO_(3)content.The results of this study are expected to provide a theoretical basis for soil wind erosion control and promote the application of 3D laser scanners in wind erosion monitoring.

基于“3S”技术的典型草原栗钙土层结构模型

针对典型草原土壤结构特征及草原风蚀退化的现状,在内蒙古自治区锡林郭勒盟乌珠穆沁典型草原地区,选取约400km2面积的研究区,采用"3S"一体化技术,获取典型草原地表特征及采样点的三维坐标数据,通过实地打点取样,测量栗钙土层厚度,并结合SuperMap软件建立栗钙土层结构DEM模型。经分析研究可知:栗钙土层结构受多种因素影响,不同地形结构可能有不同的土层厚度。建立土壤结构模型,研究环境条件与土壤结构关系,推断土壤的空间分布,可以实现草原土壤结构动态监测,为预防和控制风蚀沙化提供基础数据,为典型草原生态保护与合理利用提供了科学依据。

3S技术在土壤侵蚀调查中的应用

以克拉玛依市土壤侵蚀为例,论述了利用3S技术在土壤侵蚀调查中的应用,介绍了利用地理信息系统技术进行土壤侵蚀调查的一般方法和步骤,并对土壤侵蚀分区结果进行了分析。

基于GIS技术和RUSLE模型的喀斯特流域土壤侵蚀时空特征分析——以贵州省乌江流域为例

通过RUSLE模型和GIS技术,利用降雨数据、土地利用数据等,估算乌江流域2000、2005、2010年及2015年4个时间段的土壤侵蚀量,并分析其土壤侵蚀的时空变化特征。结果表明:2000~2010年土壤侵蚀量呈下降趋势,2010~2015年呈上升趋势。在时间变化上,微度侵蚀面积由2000年的43.86%增至2015年的63.16%;轻度、中度、强度和极强度侵蚀面积分别由2000年的23.30%、18.08%、10.24%和4.38%降至2015年的14.76%、13.50%、5.18%和3.13%;剧烈侵蚀面积由2000年的0.14%增至2015年的0.29%。在空间分布上,土壤侵蚀较严重的区域均分布在西南部和东北部,以中、强度为主;其他区域以微、轻度为主。总体上,乌江流域2000~2015年土壤侵蚀量呈下降趋势;侵蚀度以微、轻度为主且呈逐渐降低趋势;土壤侵蚀较严重地区多分布在流域西南部和东北部,以度、强度为主,而其他区域主要以微、轻度为主。

基于GIS的喀斯特流域土壤侵蚀模数估算——以贵阳麦西河流域为例

水土流失是喀斯特流域主要的生态问题,通过收集贵阳市麦西河流域气象、土地利用、土壤等数据,利用3S的技术方法建立流域土壤侵蚀空间数据库,应用USLE模型构建流域土壤侵蚀评价模型,运用GIS的空间数据处理方法,实现对麦西河流域土壤侵蚀模数的估算。结果表明:麦西河流域年均土壤侵蚀速率为1 230.81t/(hm2.a),侵蚀强度类型以微度和轻度为主;中度以上侵蚀类型主要发生在坡度大于25°,植被覆盖较差的山体位置,尤其是旱地类型;从子流域上看麦乃7号子流域土壤流失较为严重。

基于T-S模糊神经网络模型的榆林市土壤风蚀危险度评价

选择位于风沙过渡区的榆林市为研究区域,以GIS技术和T-S模糊神经网络为依托,从土壤风蚀影响因子及风蚀动力学机制出发构建区域土壤风蚀危险度模型。基于此模型,对榆林市土壤风蚀危险度空间分异特征进行了分析,结果表明:T-S模糊神经网络模型可有效地揭示出区域土壤风蚀危险度与环境之间的映射关系,为土壤风蚀预测提供依据;风力、植被、气温、降水、地形等环境要素控制着土壤风蚀危险度空间分异格局;榆林市土壤风蚀危险度空间分异格局表现为:危险度从西北向东南逐渐降低。

基于USLE模型的祁连山南坡土壤侵蚀现状评价

借助"3S"技术,应用USLE模型,对祁连山南坡土壤侵蚀现状进行了定量评估,分析了高程、坡度、植被覆盖度等土壤侵蚀的主要影响因子,得到了土壤侵蚀的空间分布特征.结果显示:2014年祁连山南坡土壤侵蚀量为1.54×107t/a,侵蚀面积为2.21×104km2.从面积来看,以微度侵蚀为主,占土壤侵蚀总面积的70.43%;从侵蚀量来看,以轻、中度侵蚀为主,占总侵蚀量的87.67%;强度侵蚀和极强度侵蚀面积及其侵蚀量所占比例均极小,无剧烈侵蚀;从空间分布来看,微度侵蚀多分布在山体之间地势平坦区域,轻度侵蚀及以上级别主要分布在托勒山、走廊南山、冷龙岭、大通山及其托勒南山沿线.坡度、植被覆盖度、海拔与土壤侵蚀模数相关性显著,土壤侵蚀级别与侵蚀量随着海拔和坡度的增加而上升,随植被覆盖度的增加而下降.

1991—2020年全球沟蚀研究进展

[目的]分析1991—2020年国内外沟蚀领域不同时期的国际研究形势、研究现状以及研究热点的变化趋势,定量分析沟蚀测量技术和沟蚀模型的发展趋势,旨在促进沟蚀研究的深入发展并为相关领域学者提供参考信息。[方法]采用Web of Science核心合集中1991—2020年的2568篇沟蚀相关文献进行计量分析,使用VOSviewer软件对国家和机构研究形势以及沟蚀研究热点变化趋势进行可视化分析。[结果]近30 a沟蚀的研究呈现上升趋势,且在2011—2020年迅猛上升。中国(23.7%)和美国(20.8%)为沟蚀研究的主要国家,发文量占全球的44.5%,且两国间合作更密切。全球沟蚀研究排名前10的机构中,中国的机构占3所(中国科学院、西北农林科技大学和北京师范大学)。沟蚀研究涉及多个学科领域,以地质学最多。沟蚀影响因子、沟蚀测量技术和沟蚀研究模型为沟蚀领域主要研究热点。径流、土地利用、植被、降雨和土壤等影响因子一直是沟蚀研究的重点。近些年气候变化特别是极端降雨对沟蚀的影响越来越受重视。高精度的3 D立体测量技术逐步替代2 D平面测量技术,并得到广泛应用。经验模型应用早,应用最广泛,2000年之后基于定量分析的估算模型开始建立,提高了沟蚀监测及预报的精度。[结论]未来沟蚀研究应在植被恢复后极端降雨下沟蚀的形成、不同因素对于沟蚀过程的交互影响、沟蚀监测新方法的开发以及沟道侵蚀过程预测模型等方面加强工作。

核分析技术在土壤侵蚀研究中的应用

利用核分析技术研究土壤侵蚀是近30多年来发展起来的新兴技术，它能对土壤侵蚀时空变化两个方面进行定量监测，与传统研究方法相比，具有很多的优越性。本文对几种天然放射性或大气沉降的核素及稀土元素示踪在土壤侵蚀研究中的应用及研究现状进行了综述；总结了利用137Cs、210Pb、7Be、226Ra、232Th，以及稀土元素（REE）研究土壤侵蚀及沉积速率的一些数学模型；探讨了它们的优势与不足，并就核分析技术的发展趋势进行了论述。

江西兴国土壤侵蚀动态的研究

利用遥感、GIS和灰色预测模型研究了中国南方典型区土壤侵蚀的状况 .结果表明 ,从 1958— 1988年 ,兴国县的水土流失面积和侵蚀量分别下降了 19 0 9%和 43 0 5% ;灰色预测显示无明显侵蚀区水土流失面积由 1988年的818 0 4km达到 1995年的 12 76 69km2 ;总侵蚀量由 60 7 2 1× 10 4 t a下降到 472 12× 10 4 t a .比较不同土地利用类型的产沙模数显示 ,林地的产沙模数最小 ,为 177 16～ 187 75t (km2 ·a) ,裸地最大 ,为 10 62 6 76～ 112 65 48t (km2 ·a) .由此证明 ,高覆盖植被可以减低水土流失 。

土壤侵蚀模型研究进展

对国内外有关土壤侵蚀模型的研究成果进行了总结,分析了物理模拟过程模型、动力学模拟模型和因子分析模型3个土壤侵蚀模型的特点,探讨了土壤侵蚀模型研究的未来发展趋势,认为在物理模拟过程和动力学模型研究中,要加强相关理论基础研究;而因子分析模型研究中,必须结合应用模糊数学理论和聚类分析成果。

采煤活动对唐山城市建设场地稳定性的影响分析

通过InSAR地表变形监测技术和数学模型理论计算,采空塌后期场区地基土的稳定性主要取决于采空区顶部的土体而不是岩体。城市规划区内局部有5层可采煤层,尤其是-200m以下的煤层停采在20世纪70年代以前,已完全塌落、压密、再造。而塌后期的土体底部粘土隔水层被拉裂,在双层水位作用下发生潜蚀形成土洞造成地面不均匀沉陷,影响城市建设场地的稳定性。

土壤风蚀新技术应用研究进展

土壤风蚀是全球性的生态环境问题。本文从土壤风蚀的发展历程出发,阐述了定性研究、定量研究"3S"等新技术在土壤风蚀中的应用,总结了国内外不同时期取得的代表性研究成果,探讨了"3S"在对风蚀模型应用中的重大意义,并且讨论了在已有的土壤风蚀研究中需要注重的热点问题。在此基础上,对土壤风蚀以后的研究方向进行了展望。

基于生态功能分区的沱江流域土壤侵蚀研究

运用RS和GIS技术,在综合分析沱江流域自然人文环境特征的基础上,科学合理地选取评价指标,建立生态功能区划指标体系,划分出对应的生态功能区.选用RUSLE模型计算沱江流域土壤侵蚀结果,分析不同生态功能区内土壤侵蚀的分布特征及二者之间的关系,结果表明:沱江流域可划分为农业种植区、河道保护区、土壤侵蚀控制区、重要自然与文化遗产保护区及地质灾害保护区.目前沱江流域土壤侵蚀以微度和轻度侵蚀为主,分别占研究区面积的76.42%和18.62%,各等级侵蚀面积占研究区面积比例按从大到小的顺序排序为微度、轻度、中度、强度、极强度、剧烈.沱江流域中部、西北部草地林地覆盖区多属于强度及以上土壤侵蚀等级;沱江流域中部、东南部耕地利用区多属于中度及以下土壤侵蚀等级.生态功能区与土壤侵蚀分布特征关系密切,从空间分布来看,农业种植区内主要是微度和轻度土壤侵蚀等级,土壤侵蚀控制区内主要是强度及以上土壤侵蚀等级;从数量分布来看,除土壤侵蚀控制区和地质灾害保护区外,其他几个生态功能区内的土壤侵蚀等级栅格数量均从微度到剧烈逐渐减少.此研究有利于明确沱江流域的生态功能和生态环境问题,为相关部门制定水土流失防治措施和保护生态功能提供理论参考.

轨道交通工程的施工管理技术

随着科学技术的快速发展,建筑行业技术也不断创新。BIM技术是建筑工程施工中常用的一种管理技术,同时也是城市轨道交通未来发展的主要支撑。论文以实际工程为例,充分利用BI M技术从施工风险控制、施工进度控制、施工质量控制等几个方面,对轨道交通工程的施工管理技术进行探讨,保证了轨道交通工程的施工质量。

基于统计检验的降雨侵蚀力简易计算模型比较

降雨侵蚀力因子(R)的准确估算对提高侵蚀预测的精度具有重要作用,但R的计算需要高时间分辨率的降雨过程资料。基于日、月、年降雨资料,目前已开发了众多的R值简易计算模型(PR)。本文通过Meng’s检验比较了不同PR模型结果与R的相关性是否存在显著性差异,并以此为基础评估了国内外15种PR模型在中国东部地区的适用性。结果表明,15种PR模型计算结果与R均显著相关(r>0.59,p<0.03),表明这些方法均适用于中国东部地区,但由于存在系统偏差,许多模型需要按文中建立的回归关系式校正后得到更优的估算结果。相关系数的统计学比较表明,日降雨PR模型的计算结果与R相关性明显优于年和月降雨模型,而年和月降雨模型差异不明显。所有模型中,3种基于中国数据(包括国内最常用的章文波模型和第一次全国水利普查采用的模型)和1种基于澳大利亚数据建立的日降雨PR模型的相关性并列处于最高等级(r>0.99),但该澳大利亚模型的计算偏差随纬度增高而变大,章文波模型也存在约30%的系统误差,两者校正后使用能获得更好的效果;第一次全国水利普查采用的模型则可以直接用于R的估算,不需要进行校正处理。论文最终给出了获取不同时间分辨率降雨资料时建议使用的PR模型。