Application Of Remote Sensing And Gis In Civil Engineering 66236o

APPLICATION OF REMOTE SENSING AND GIS IN CIVIL ENGINEERING Sandeepan Saha* Civil Engineering Department Meghnad Saha Institute of Technology (WBUT)

Abstract

Remote Sensing and GIS techniques become potential and indispensable tools for solving many problems of civil engineering and terrain. Remote sensing observations provides data on earth’s resources in a spatial format, GIS co-relates different kinds of spatial data and their attribute data, so as to use them in various fields of civil engineering. Different themes namely, terrain, geology, hydrology drainage, land use and so on can be extracted from remote sensing data. All the above thematic information along with their attributes can be integrated to solve many problems of civil engineering. Some current uses of GIS and Remote Sensing in civil projects are housing, sanitation, power, water supply, disposal of effluents, urban growth, irrigation project design and planning, new road alignment etc. For this Remote sensing and GIS are used to generate development models by integrating the information on natural resources, demographic and socio -economic data in a GIS domain with satellite data. Landslides in mountainous areas causing heavy loss can also be mapped and landslide prone zones can also be delineated. Development of hydropower sites and irrigation project can also be formulated by integrating terrain (DEM) and thematic maps (land use, geology, DEM). All these can be derived from high resolution stereo pair of remote sensing data. These techniques are also useful in rehabilitation also. Other uses are Exploration and Management through Rainwater Harvesting, Identification & Management of Drinking Water Potential, Ground water Potential Zoning, Watershed Management and irrigational Network Planning and tourism. These techniques are also vital tools for urban and rural developing planning.

___________________________________ * Student, 4th Year, B. Tech in Civil Engineering Mobile: 09830713676 e-mail- [email protected] 1. Remote Sensing

Remote Sensing is the science and art of acquiring information (spectral, spatial, and temporal) about material, objects, area, or phenomenon, without coming into physical with the objects, or area, or phenomenon under investigation. Without direct , some means of transferring information through space must be utilised. In practice, remote sensing is the stand-off collection through the use of a variety of devices for gathering information on a given object or area. . In remote sensing, information transfer is accomplished by use of electromagnetic radiation (EMR). EMR is a form of energy that reveals its presence by the observable effects it produces when it strikes the matter. EMR is considered to span the spectrum of wavelengths from 1010 mm to cosmic rays up to 1010 nm, the broadcast wavelengths, which extend from 0.30-15mm. 2. Geographic Information System

A Geographic Information System (GIS) integrates hardware, software, and data for capturing, managing, analyzing, and displaying all forms of geographically referenced information. GIS also allows the integration of these data sets for deriving meaningful information and outputting the information derivatives in map format or tabular format. Three Views of a GIS

A GIS can be viewed in three ways: 1) The Database View: A GIS is a unique kind of database of the world—a geographic database (geo database). It is an "Information System for Geography." Fundamentally, a GIS is based on a structured database that describes the world in geographic . Fig. 1 schematically represents a GIS (website referred in references).

Fig. 1 Schematic representation of a GIS

2) The Map View: A GIS is a set of intelligent maps and other views that show features and feature relationships on the earth's surface. Maps of the underlying geographic information can be constructed and used as "windows into the database" to queries, analysis, and editing of the information. Fig. 2 schematically represents a GIS (website referred in references).

Fig. 2 Schematic representation of a Map 3) The Model View: A GIS is a set of information transformation tools that derive new geographic datasets from existing datasets. These geo-processing functions take information from existing datasets, apply analytic functions, and write results into new derived datasets. Fig. 3 schematically represents a GIS (website referred in references).

Fig. 3 Schematic representation of a Model

By combining data and applying some analytic rules, we can create a model that helps answer the question you have posed. In the Fig. 4, GPS and GIS were used to accurately model the expected location and distribution of debris for the Space Shuttle Columbia, which broke up upon re-entry over eastern Texas on February 1, 2003.

Fig. 4 Together, these three views are critical parts of an intelligent GIS and are used at varying levels in all GIS applications.

3. Application of Remote Sensing and GIS in Civil Engineering

Remote sensing and GIS techniques become potential and indispensable tools for solving many problems of civil engineering. Remote sensing observations provides data on earth’s resources in a spatial format, GIS co-relates different kinds of spatial data and their attribute data, so as to use them in various fields of civil engineering. 3.1 In structural engineering:

Structural Health Monitoring (SHM) provides designers with of structural performance, assisting in development of structures with higher utility and lower manufacturing costs. Structural Health Monitoring nowadays continues to advance from conventional strain gauges to FBG Fibre Optic Sensors (FOS) and major breakthroughs in wireless remote monitoring. Fibre optic sensors use optical wavelength of fibre Bragg grating to measure temperature and strain. FOS has many advantages over the traditional electrical system such as: • Suitable for long-term permanent SHM: monitor structure during construction stage and whole lifespan as well • No calibration needed

• One cable can have hundreds of the sensors • Simple installation • Cable can run kilometres, no length limit • Fibre optic sensors use light signal - no electrical sparking, intrinsically safe • Gauge length can be few metres long to measure global behaviours of structures • Suitable for both static and dynamic measurement The primary of monitoring is to ensure the longevity and safety of the structure as well as optimizing its management. To implement corrective measures and maintenance action, monitoring must be enable the timely detection of any condition or behavior that could deteriorate the structure, deem it unsafe or potentially results in its failure. The monitoring programme plays a fundamental role during the construction phase as it enables the verification of design hypotheses and construction processes, affecting, in some cases, the construction rate of the structures and overall quality. Most defects are introduced already at the time of construction. Monitoring also allows performance evaluation of new materials and technologies used in bridge construction and rehabilitation. This objective is easily achieved with fibre optic sensors since these sensors effectively integrate in new materials such as fibrereinforced polymer composite. Furthermore, fibre optic sensors adapt perfectly to long-term monitoring of bridges behaviour as well as short-term monitoring of bridges dynamic behaviour under traffic load. Finally, monitoring can be used as a tool for “supervised lifetime extension” of bridges approaching the end of their life or in need of major repair. It ensures that such bridges are operated safely while allowing the postponement of major investments and traffic disruption.

(a) (b) Fig. 5 - FBG sensor installation in bridge rebar segments – (a) Individual component of a FBG Sensor and (b) FBG Sensor installed in a bridge.

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Fig. 6 FBG sensor response embedded in concrete structure (CGCRI,Kolkata) 3.2 Regional Planning and Site Investigations:

Site investigations in general require topographic and geologic considerations. Remote sensing data permits such an assessment. In case of dam site investigation, information on topography is essential. Geological consideration involves the different soil and rock types and physical properties. In selecting river-crossing sites for bridges and pipelines, an important consideration is the stability of slopes leading down to and up from the water crossing. Such slopes include riverbanks, terrace faces and valley wall. History of river erosion and sedimentation would give clues needed for locating the sites where scour is likely to occur. High spatial resolution satellite data with stereo vision capability can facilitate depth perception in the above said investigations and also for regional planning of large commercial airports, harbors, industrial towns and recreational sites. The hydro geological and geomorphologic information along with geological structures derived from satellite data are very useful in sitting the ground – water bore holes. 3.3 Town Planning and Urban Development:

To achieve the objectives of making metropolis cities more livable and of international standard, a co-coordinated and integrated approach among the various agencies involved in urban development and provision of services are needed including participatory process in planning and implementation at local body levels. As well as to have planned and organized disposal of population through growth centres, which will acts as counter-magnets to the cities growth. This growth may not able to withstand the existing infrastructure, traffic, road, drainage and utility networks etc. Advance urban planning is required for a planned development of the area for which up to date real time and accurate information are the vital important. Geographical Information system & Remote Sensing is inevitable technology in the development of national Infrastructure and planning and they provide solution related to many environmental

issue. It is very much important for urban planning activities & environmental improvement. For sustainable development of urban agglomeration, optimal urban land use plans and resources development models need to be generated by integrating the information on natural resources, demographic and socio – economic data in a GIS domain with the currently available satellite data. 3.4 Environment and Geology:

Whether for irrigation, power generation, drinking, manufacturing, or recreation, water is one of our most critical resources. Image interpretation can be used in a variety of ways to help monitor the quality, quantity of water resources. It is well proven in exploring ground water prospect zones. One such example is Rajiv Gandhi Drinking Water Mission with help of remote sensing and GIS. Sediment pollution is often clearly depicted on aerial and space images. Materials that form films on the water surface, such as oil films, can also be detected through the use of aerial and satellite images. Normal colours or ultraviolet aerial photography is often employed for the detection of oil films on water. Thick oil slicks have a distinct brown or black colour. Thinner oil sheens and oil rainbows have a characteristic silvery sheen or iridescent colour banding but do not have a distinct brown or black colour. Jharkhand State now-a- days are affected with ground water scarcity forcing the people to depend on the surface water like lakes, rivers etc. which are polluted like Damodar River and Suwarnrekha river. Damodar river flowing through coal fields is affected with sediment pollution carrying coal mining wastes leading to lowering of water level from November to June. A knowledge of groundwater location is important for both water supply and pollution control analysis. Remote sensing plays a vital role in delineating potential areas of groundwater occurrence for detailed exploration, thus reducing the cost and time involved in groundwater exploration. Potential groundwater areas cannot be seen on satellite images directly. The clue to the groundwater search is the fact that sub-surface geological elements forming aquifers have almost invariable surface expressions, which can be detected by remote sensing techniques (Joseph, 2005). Satellite data provide information about geomorphic features, structures, land uses and rock types (in a few cases) indicating the presence of groundwater. Some selected landforms and structural features that are indicators for potential groundwater zones are valley fills, palaeochannels, alluvial fans, dykes, interdunal depression etc. 3.5Water Resources Engineering: By analyzing multi-date RS data, it would be possible to monitor the effects of dam construction. Remotely sensed data of pre and post dam construction can reveal the forest and other land at different water levels. This would also help in preliminary investigation of impact assessment of dams and rehabilitation. To study the feasibility of inter basin transfer of surplus flood flows, RS data can be cost effective. In large area reconnaissance studies, various technically feasible and economically viable alternatives in locating surplus flow diversion routes to water deficient basins can be arrived at. Also, reservoir sites to store the surplus flows in these basins could be identified. Such projects of large dimensions require considerations of land use / land cover, soil and geological mapping, terrain evaluation, construction material inventory etc. the latter are derived from satellite remote sensing data of particular resolution depending upon the scale on which such information is required.

The water storage built in through reservoirs, tanks, etc., are often reduced due to sedimentation. Remotely sensed data can be used to monitor the water bodies over time and assess the silting condition. In case of gauged reservoirs of medium to large sizes, RS data can provide an assessment of sediment volume and reduction in the capacity of sediment volume and reduction in the capacity of the reservoir. In case of small water bodies such as tanks, it is possible to come out with a list of problematic tanks with symptoms of heavy siltation and loss of water holding capacity. The condition of tank bunds, fore shore encroachment, etc., also can be analysed with the help of high spatial resolution RS data.

Characterization of water bodies in of geological, geomorphological, hydro geological, soil and land use / land cover parameters carried out using RS data enables conservation of land and water resources. The RS based input integrated with ground based information through GIS is useful for broad reconnaissance level interpretation of land capability, irrigation suitability, potential land use, water harvesting areas, monitoring the effects of soil and water conservation measures, estimation of run off and sediment yields and monitoring land use change including land degradation. The commercial areas of irrigation projects are fed by different sources of irrigation like reservoir, tanks, ponds and wells. Assessment of command areas and crops would be highly useful in water release policy or conjunctive use of water in the overall project command area. Satellite data has been advantageously used to obtain such information on surface irrigation projects. In case of floods, appropriate flood management work has to be executed to reduce the damages and utilize the floodwaters. Using multi-date Preflood and post flood images) damage due to flood can be successfully assessed. This will help in mitigation and relief distribution. Satellite derived snow cover assessment is being extensively used as an important input in snow melt runoff prediction models to assist in multi purpose reservoir operations. Seasonal snow melt inflow forecasts for Bhakra reservoir in Sutlej basin are being operationally issued every year with the accuracy better than 90% to Bhakra Beas Management Board. 3.6 Landslides:

Landslide is the result of a wide variety of processes which include geological, geomorphological and meteorological factors. The important terrain factors are lithology, structure, drainage, slope, land use, geomorphology and road network. A complete landslide hazard assessment requires an analysis of all these factors leading to instability in the region. The feature extraction of some of these factors can be done from the interpretation of satellite images. With the increase in efficient digital computing facilities, the digital remote sensing data and their analysis have gained enormous importance. Then the spatial and temporal thematic informations derived from remote sensing and ground based information need to be integrated for data analysis. This can be very well achieved using GIS which has the capabilities to handle voluminous spatial data. With the help of GIS, it is possible to integrate the spatial data of different layers to determine the influence of the parameters on landslide occurrence. 3.7 Least cost highway alignment:

Highways are part of the infrastructure that makes up the spinal cord of modern society. GIS provides a valuable tool in the process of planning and design of highways. To obtain an optimum highway route alignment which is economical, suitable and compatible with the environment, various types of data have to consider simultaneously.

Handling and managing this large amount of data manually, is not easy. It is here GIS comes to help, because of its inherent property of handling large bulk of spatial data, non spatial data and its analysis. Remote sensing images of the study area were used as the source (spatial data). Various collateral data from various offices was collected to be used as non spatial data. These images were used to prepare the digitized formats required for the GIS techniques. Using the Resistance concept (such as areas suitable for the new alignment were assigned a low resistance value, whereas the areas not suitable for the new alignment were assigned a high resistance value) the data was prepared for analysis. Spatial Analyst tool of ArcGIS version 8.1 was used for performing the analysis. 3.8 Terrain Mapping and Analysis:

Assessment of the performance of the terrain for specific developmental activities can be made through terrain evaluation. For this, terrain information can be acquired from RS data and by generating the Digital Terrain Model (DTM). A DTM is an ordered array of numbers representing the spatial distribution of terrain characteristics stored in a computer so as to enable the determination of any quantitative data pertaining to terrain. DTMS is useful in investigation of a number of alternative horizontal and vertical alignments of canals, roads, pipelines or corridors for any such applications. In engineering construction like dam, the knowledge of material comprising the terrain is essential for proper planning, location, construction and maintenance of engineering facilities. For computation of hydrograph parameters like peak runoff rate, time of concentration and time to peak, the height and slope information derived from Digital Elevation Model (DEM) are useful. The information on regional engineering soils is essential for general planning and site evaluation purposes. High spatial resolution satellite data can be analyzed to delineate various landforms, mapping of soil classes of significance to engineering construction, delineation of landforms – engineering, soil relationships and grouping of landforms with various physiographic setting or terrain associations. Remote sensing based inventory of construction material such as boulders, quarry rock, sand – clay mixtures etc., would help to locate suitable sites of construction materials for building up of water resources engineering projects like dams, bridges, etc., across the rivers. 4. Conclusion

There are ample evidences of applying the recent advances in satellite based remote sensing and GIS technology in various fields of civil engineering. India’s space programme ensuring continuous availability of RS data and launching of future satellites carrying high spatial and spectral resolution sensors can go a long way in providing useful information required for civil engineering applications. 5. Acknowledgement

I would like to thank and express my sincere gratitude to Dr. M. Kudrat, scientist, IRSC for his kind inspiration for the preparation of this paper.

6. Reference

1. “An overview of Remote Sensing and GIS applications in civil engineering”, Director, NNRMS-RRSSC, ISRO Headquarters. 2. Application Note, Roctest Ltd., Canada-J4P 2P4. e-mail: [email protected], website – www.roctest.com 3. Chidambaram, M., “Scientific GIS Digital Base Maps- Urban Planning using GIS / RS Technologies. 4. www.GIS.com – the guide to geographic information system. 5. Joseph, G. (2005). Fundamentals of Remote Sensing (2nd ed.). University Press, Hyderabad. 6. Michael Goodchild, David J, David W Rhind, Paul A, (1990) “Geographical Information System, Management issues and Applications”, John Wiley & Sons, Vol 2. 7. Priyadarshi, N. (2004). Distribution of arsenic in Permian coals of North Karanpura coalfield, Jharkhand. Jr. Geol. Soc. India, vol.63, pp. 533-536. 8. Sarkar, S. & Kanungo, D.P., “Landslides in Relation to Terrain Parameters- A Remote Sensing and GIS approach. 9. Srirama, B., Bhatt, M.R. & Pathan, S.K.,“ Least Cost Highway Alignment Using GIS Technique.”