Course 2

Geospatial Techniques for Dam Monitoring

(LNEC Library)

About the Course

Geospatial techniques comprehend a large group of techniques, mostly used for positioning, but that can also be applied for dam monitoring. The one-day course covers the most important engineering surveying techniques that use the following equipment: total stations, GNSS, SAR sensors, laser scanners, digital cameras on drones.

The first module presents the use of drones (UAV) in two different applications: visual inspections of dams and displacements monitoring of embankment dams. The UAV is a rapidly growing technology that allows for a cost-effective and fast mean for valuable geometric and visual data acquisition in dam monitoring. The choice of the aerial platform, the flight plans, photo processing, point cloud and ortomosaico generation will be topics to be covered.

The second module will be on continuous monitoring with robotic total stations and GNSS receivers. This equipment, together with special designed software, provide instantly accurate and reliable information about the behaviour of the structure. During the module there will be establish access to equipment operating on dams.

The third module will be focused on deformation measurement and monitoring using Synthetic Aperture Radar (SAR) imagery. Two main techniques will be considered. The first one is the satellite-based SAR interferometry, which can be used to monitor wide areas. The second one is the terrestrial SAR interferometry, which can be used to carry out detailed deformation analyses.

The last module will be on the use of laser scanner under the perspective of surface surveys, either from the outside, or inside, in galleries and caves, to a better knowledge of the shape and dimensions of structures, as well as to monitor embankment dams.

Speakers

Maria João Henriques is a Surveyor Engineer, Senior Research Officer of the Applied Geodetic Unit, of the Concrete Dams Department at LNEC, Portugal. She has more than 35 years of experience in the monitoring of structures by surveying methods. In the last years her activity has focused on the use of drones in the monitoring of civil engineering works, with special attention on visual inspections and on the determination of displacements.

José Nuno Lima is a Geographic Engineer, Research Officer at LNEC, Portugal, with more than 30 years of experience in Geodesy research, namely using the GNSS for dams and bridge monitoring.

João Marcelino is a Civil Engineer, Senior Research Officer and Head of the Geotechnics of Hydraulic Works Unit, of the Geotechnics Department of LNEC, with about 30 years of experience in embankment dams modelling, monitoring and safety control.

Michele Crosetto holds a civil engineering degree from the Politecnico di Torino (1993) and a doctorate in Topographic and Geodesic Sciences from the Politecnico di Milano (1998). He has worked in the Joint Research Centre of the European Commission in Ispra (Italy) and at the Cartographic Institute of Catalonia. He has formed part of the Institute of Geomatics since 2002. Since January 2014 is with CTTC, where now he is head of the Geomatics Division. His main research activity is related to the analysis of spaceborne, airborne and ground-based remote sensing data and the development of scientific and technical applications using active sensor types, as for example Synthetic Aperture Radar (SAR), Real Aperture Radar (RAR), etc. (to be confirmed).

Programme

9:00 - Welcome remarks (Maria João Henriques)

9:15 - Drones and digital cameras: their use in visual inspections and displacements monitoring (Maria João Henriques and João Marcelino)

    • Choice of equipment
    • Programming a flight plan
    • Processing the photos to create point clouds, orthomosaics, and digital surface models
    • Requirements for visual inspection and automatic extraction of features

11:00 - Coffee Break

11:30 - Continuous monitoring: GNSS and robotic total stations (José Nuno Lima)

    • Basic monitoring concepts.
    • Implementation of a continuous monitoring system (characterisation of the structure to be monitored and the surrounding area, network configuration, equipment, data collection, determination of displacements)
    • Case study (presentation of the system, remote system connection, access to the results)

13:00 - Lunch

14:00 - Deformation measurement and monitoring using Synthetic Aperture Radar (SAR) imagery (Michele Crosetto)

    • Satellite-based SAR interferometry
    • Terrestrial SAR interferometry

16:00 - Coffee Break

16:30 - Laser scanning (to be defined)