Watershed prioritisation for soil conservation — a GIS approach

In order to check the premature siltation of the reservoirs, the Government of India has launched the schemes of soil conservation and integrated watershed management in the catchments of River Valley Projects (RVPs) and Flood Prone Rivers. However, due to lack of sufficient funds and manpower for surveys and soil and water conservation programmes, a priority approach for treatment of the watersheds was developed and followed for implementation of soil conservation and watershed management schemes in India.

This paper deals with the prioritisation of watersheds using GIS approach in a part of Musi river catchment in RR district of Andhra Pradesh. The GIS software package, ARC/INFO version 5.0, was used to digitize, edit, display, analyse and plot the maps. It was concluded that by the creation of computerised data base for the maps, the composite map generation and calculation of area statistics are performed much faster and more accurately compared to the conventional method.     

Knowledge Based Soil Attribute Mapping In GIS: The Expector Method

EXPECTOR is a method of combining data and 'expert' knowledge within a Geographic Information System to provide information on the occurrence of spatially distributed attributes. It was developed to predict soil property values from spatially variable input data. Although initially developed to provide soil surveyors with a quantitative soil mapping method, it also has applications in land evaluation, land capability assessment, geological mapping and in precision agriculture. It operates on the basis that the state of a particular property, which may be difficult to measure directly, can be inferred from other (more measurable) entities and a knowledge of their inter–relationships. The method has been implemented as a stand–alone 'Knowledge Editing' module for the PC that can be linked to raster GIS packages. This paper describes the basis of the method and illustrates its use with an example describing the production of a surface clay content map for a small catchment in south–western Western Australia.     

Photo-interpetation for erosion assessment in the beas catchment

Panchromatic vertical aerial photographs in the scale of 1: 15,000 were interpreted for assessment of erosion in the Bcas River Valley Project catchment, Himachal Pradesh in terms of the erosion intensity units. The erosion intensity units imply the relative quantum of sediment yield as deduced from the probable interaction of the significant parameters of erosion comprising physiography, slope, soil characteristics, Vegetation, land use and the visible erosion conditions. The procedure of photo-interpretation as also computation of sediment yield index for each of the different watersheds in the Beas RVP catchment is discussed. The survey revealed that out ofa total of 494 watersheds involving an area of 5.5 lakh ha, 132 watersheds comprising an area of 1.55 lakh ha, have silt yield index of over 1150 and need soil conservation measures on priority basis. Application of photo-interpretation has proved 2 times more efficient than the conventionai method that was followed in a piain area of Matatilla RVP catchment. In a more simpler terrain than Beas catchment and with ideal photographic scale of 1:60,000, the efficiency is expected to increase by 2-3 times than was achieved in Beas RVP catchment     

Land resource inventories for integrated land use planning with special reference to the catchment of Pohru river in Jammu and Kashmir state

A Soil and land Use Map of Pohru catchment was prepared through the adoption of a systematic Air Photo-interpretation procedure including selective field studies in such a manner that the ten delineated mapping units were co-extensive with major Land Resource Areas. Defined in terms of physiography, soil profile, soil erosion and present land use each of the ten units has unique characteristics requiring differential management, which was arrived at through joint field studies by Pedologists who prepared the Map, Foresters, Soil Conservationists, Agronomists. a Horticulturist and an Agricultural Chemist. Stemming from this integrated effort a Land Use Plan for the catchment was drawn up with its major objective as the conservation of Land and Soil Resources leading to a reduction in sediment yields that are now so high as to clog the Jhelum river at the polnt where Pohru river joins it. In respect of four Land Resource areas, the plan prescribes radical readjustments of Land Use such as conversion of Forest Department owned Himalayan Southern slopes to grass lands, change of cropping pattern in Karewa side slopes and conversion of the northern and southern Himalayan footslopes now under cultivation into orchards. The areal extents of the different Land Resource Areas as also the cost of implementing the conservation recommendations have been furnished for every one of the twentyeight watersheds falling under the eight subcatchments of the Pohru catchment. The total cost of implementing the conservation recommendations approximates to about fifty five million rupees.     

土壤调查地区级汇总的遥感制图试验研究

本研究的目的是探讨利用遥感影像数据,对县级土壤调查资料进行地区级汇总的制图工作方法。我们依据的制图综合原则是:(1)以现有的土壤图为基础,充分尊重原图上的界线,主要以土层界线重新综合;(2)研究并搞清各种土壤分布规律和它们之间的组合规律,然后进行归并和区分;(3)参照卫星影像特征和判读标志,对某些明显与实地不符之处,以影像和实地调查资料进行修正,有些土壤类型以组合形式表达。本文对利用遥感数据进行制图综合的工作方法进行了详细描述,其中包括:制图单元的综合和比例尺的改变,底图的制作和利用卫星影像对综合后的土壤图进行编制等。研究结果表明,此种方法与常规方法比较,特别是对有一定物质和技术条件的单位(如省级),不仅在土壤调查中,而且在资源调查中皆可采用此种编图技术,收到节省人力、物力和时间的效果。     

Soil Resource Database at Village Level for Developmental Planning

A study was carried out in village Mohammadabad, Nalgonda district, Andhra Pradesh to demonstrate the potential of high-resolution remote sensing data in generating soil resource database at village level that would facilitate natural resource developmental planning. For this study, detail soil resource database was generated by interpreting IRS Resourcesat-1 LISS-IV + Cartosat-1 merged data and by undertaking soil survey and soil analysis. This database was integrated with cadastral map and was analysed for preparation of an action plan for the village that included recommendation on suitable crops, soil and water conservation measures and distribution of soil health card to farmers. The study indicates that the LISS-IV + Cartosat-1 merged satellite data helps in mapping soils at phase level and in delineation of more number of pure soil mapping units i.e. consociations at 1:10.000 scale. The plot-wise resource potential and constraints reveals that significant inter and intra-field soil variability exists. Soil fertility assessment indicates that the soils of the village are low to medium in fertility (available NPK Content) and micronutrients like copper, manganese and iron content is above the critical level for optimum growth of crops while zinc content is less than the critical level.     

Integrated approach of using remote sensing and GIS to study watershed prioritization and productivity

Soil data obtained from soil resource inventory, land and climate were derived from the remote sensing satellite data (Landsat TM, bands 1 to 7) and were integrated in GIS environment to obtain the soil erosion loss using USLE model for the watershed area. The priorities of different sub-watershed areas for soil conservation measures were identified. Land productivity index was also used as a measure for land evaluation. Different soil and land attribute maps were generated in GIS, and R,K,LS,C and P factor maps were derived. By integrating these soil erosion map was generated. The mapping units, found not suitable for agriculture production, were delineated and mapped as non-arable land. The area suitable for agricultural production was carved out for imparting the productivity analysis; the land suitable for raising agricultural crops was delineated into different mapping units as productivity ratings good, fair, moderate and poor. The analysis performed using remote sensing and GIS helped to generate the attribute maps with more accuracy and the ability of integrating these in GIS environment provided the ease to get the required kind of analysis. Conventional methods of land evaluation procedures in terms of either soil erosion or productivity are found not comparable with the out put generated by using remote sensing and GIS as the limitations in generating the attribute maps and their integration. The results obtained in this case study show the use of different kinds of data derived from different sources in land evaluation appraisals.     

Soil erosion assessment in Rangit catchment,India through a process-based model in the geospatial environment

The accurate assessment of soil erosion in the spatial environment can give valuable input in designing reservoirs and for preparing watershed management action plans. Rangit River in northeastern India is affected by severe soil erosion, causing reduction in its reservoir capacity. The main aim of the paper is to estimate the soil erosion in the Rangit catchment, India through a process-based soil erosion model that integrates remote sensing and field data in the geospatial domain, and also to identify the problem areas for further watershed management action plans. Various topographic parameters that were derived from land use, soil texture and a digital elevation model were used for the estimation of soil erosion. The Morgan, Morgan and Finny model was used to compute soil erosion. Based on the drainage pattern, the catchment was divided into eight sub-catchments for detailed study. Annual soil erosion was estimated for four years from 2002 to 2005 using the corresponding year’s meteorological data. Estimated soil erosion was compared with the field data in each year and found very good correlation.     

无线数字测图程序设计中的关键技术

在数字化测图软件中,对数据进行属性拓展和添加连接关系并对图面进行美观,是软件的主体机构,但如何将野外碎步点实时展绘到测图软件里形成空间属性数据,是关系到成图质量的关键.本文就如何在数字测图的过程中通过无线传输技术通讯全站仪,将全站仪传回的数据进行分析、验证,实时将所测点位展绘到测图软件中的关键技术进行讨论.     

水土保持系列专题制图研究

介绍了水土保持图的基本概念,结合实际工作总结出了计算机技术支持下的水土保持系列专题制图技术思路,以邙山小流域为例对水土保持制系列制图进行了具体实践,给出了部分水土保持专题图示例,对今后进行水土保持制图研究具有一定的指导意义。     

水土保持系列专题制图研究

介绍了水土保持图的基本概念,结合实际工作总结出了计算机技术支持下的水土保持系列专题制图技术思路,以邙山小流域为例对水土保持制系列制图进行了具体实践,给出了部分水土保持专题图示例,对今后进行水土保持制图研究具有一定的指导意义.     

Soil resource assessment and mapping using remote sensing and GIS

In this study digital image processing for physiographic analysis and soil resource mapping of Solani watershed was carried out using satellite remote sensing data and GIS. Digital image processing of satellite data facilitated in accurately delineating and identifying various soil mapping units. The physiography of the study area is mainly influenced by denudational and colluvial processes in the upper part and by sedimentation processes in the lower part. Topography of the land and nature of parent material along with the time factor seemed to have played a vital role in the genesis of soils. Majority of the mapping units are Typic Haplustepts with Entisols and Inceptisols being the major soil orders. The soils of the Siwalik hills experiences severe erosion, which prevents the maturation of soil profile. The present study demonstrated that satellite remote sensing and GIS is a valuable tool for physiographic analysis and soil resource mapping.     

Monthly soil erosion monitoring based on remotely sensed biophysical parameters: a case study in Strymonas river basin towards a functional pan-European service

Abstract

Currently, many soil erosion studies at local, regional, national or continental scale use models based on the USLE-family approaches. Applications of these models pay little attention to seasonal changes, despite evidence in the literature which suggests that erosion risk may change rapidly according to intra-annual rainfall figures and vegetation phenology. This paper emphasises the aspect of seasonality in soil erosion mapping by using month-step rainfall erosivity data and biophysical time series data derived from remote-sensing. The latter, together with other existing pan-European geo-databases sets the basis for a functional pan-European service for soil erosion monitoring at a scale of 1:500,000. This potential service has led to the establishment of a new modelling approach (called the G2 model) based on the inheritance of USLE-family models. The G2 model proposes innovative techniques for the estimation of vegetation and protection factors. The model has been applied in a 14,500 km² study area in SE Europe covering a major part of the basin of the cross-border river, Strymonas. Model results were verified with erosion and sedimentation figures from previous research. The study confirmed that monthly erosion mapping would identify the critical months and would allow erosion figures to be linked to specific land uses.     

An integrated approach for prioritization of reservoir catchment using remote sensing and geographic information system techniques

This study is aimed at evolving a watershed prioritization of reservoir catchment based on vegetation, morphological and topographical parameters, and average annual soil loss using geographic information system (GIS) and remote sensing techniques. A large multipurpose river valley project, Upper Indravati reservoir, situated in the state of Orissa, India, has been chosen for the present work. Watershed prioritization is useful to soil conservationist and decision makers. This study integrates the watershed erosion response model (WERM) and universal soil loss equation (USLE) with a geographic information system (GIS) to estimate the erosion risk assessment parameters of the catchment. The total catchment is divided into 15 sub-watersheds. Various erosion risk parameters are determined for all the sub-watersheds separately. Average annual soil loss is also estimated for the sub-watersheds using USLE. The integrated effect of all these parameters is evaluated to recommend the priority rating of the watersheds for soil conservation planning.     

基于卫星雷达测高技术的湖库动态监测理论、方法和研究进展

水位是反映水体变化的重要变量,利用卫星测高技术获取湖库的水位信息,很大程度上改变了传统地面观测数据匮乏的现状.本文综述了卫星雷达测高技术在湖泊和水库动态监测方面的理论、主要的数据处理方法和数据产品,以及当前的主要研究进展.从文献检索可以看出,当前的应用研究对象主要聚焦在个别湖泊或小范围内的湖泊群;在数据处理方面,数据以...     

水土流失区土地利用动态的遥感监测——以晋西三川河流域为例

本文以晋西三川河流域为试验区,利用不同时期的航空像片,采取集群抽样法,借助计算机建立信息数据库,并统计计算和辅助制图,进行土地资源动态监测,查清这一中型流域23年来土地利用动态变化情况及水土保持综合治理效益。     

Spatial statistical techniques for aggregating point objects extracted from high spatial resolution remotely sensed imagery

 Using a local maximum filter, individual trees were extracted from a 1 m spatial resolution IKONOS image and represented as points. The spatial pattern of individual trees was determined to represent forest age (a surrogate for forest structure). Point attributes, based on the spatial pattern of trees, were generated via nearest neighbour statistics and used as the basis for aggregating points into forest structure units. The forest structure units allowed for the mapping of a forested area into one of three age categories: young (1–20 years), intermediate (21–120 years), and mature (>120 years). This research indicates a new approach to image processing, where objects generated from the processing of image data (rather than pixels or spectral values) are subjected to spatial statistical analysis to estimate an attribute relating an aspect of forest structure. Received: 22 April 2002 / Accepted: 23 November 2002     

Land cover mapping in the Upper Shire River catchment in Malawi using Landsat satellite data

Land cover mapping forms a reference base for resource managers in their decision-making processes to guide rural/urban growth and management of natural resources. The aim of this study was to map land cover dynamics within the Upper Shire River catchment, Malawi. The article promotes innovation of automated land cover mapping based on remote sensing information to generate data products that are both appropriate to, and usable within different scientific applications in developing countries such as Malawi. To determine land cover dynamics, 1989 and 2002 Landsat images were used. Image bands were combined in transformations and indices with physical meaning; together with spatial data, to enhance classification accuracy. A maximum likelihood classification for each image was computed for identification of land cover variables. The results showed that the combination of spatial and digital data enhanced classification accuracy and the ability to categorise land cover features, which are relatively inhomogeneous.     

基于多源遥感数据的生态系统保育土壤价值评估——以河北省北部四地市为例

为了给合理地利用土地资源和科学地进行环境保护提供依据,利用多源遥感影像数据,结合气象数据、土壤属性数据与DEM,对河北北部地区生态系统的土壤保持量进行了评估,并参考《森林生态系统服务功能评估规范》,对生态系统保护土壤肥力的价值与固土价值进行了评估.结果表明,研究区2008年度生态系统的土壤保持总量达到7.55亿t,对应...