Reliable Construction Monitoring

Belo Monte Dam in Brazil

The Challenge

Large construction projects need to be regularly monitored to ensure operational safety, effectively manage the progress and assess any potential impacts on the environment. In 2011, the construction of Belo Monte Dam commenced in the state of Pará in Brazil. The dam is intended to be a combination of three dams retaining the water of the Xingu River in two large water reservoirs covering nearly 1,000km². Thus a very broad area needs to be monitored to keep up-to-date about the construction progress, while at the same time zoom-ins are required to obtain detailed information about changes such as forest clearance, levelling works, construction of access roads, storage and housing facilities. 

The Solution

Terrasar-X StripMap Data - Belo Monte Dam from Oct. 2011 and March 2014

Comparing TerraSAR-X StripMap data
(3m resolution) from October 2011 and March 2014 provides a large-area overview
of the ongoing changes
© 2014 DLR e.V. and Airbus DS / Infoterra GmbH

Due to the location of the Belo Monte Dam construction site in the frequently cloud-covered Amazon rainforest, the Geo-intelligence experts of Airbus Defence and Space tasked the high-resolution SAR satellite TerraSAR-X  to regularly acquire imagery over the area. Thanks to the sensor’s weather independence, frequent revisit capacity and high geo-location accuracy, TerraSAR-X is ideally suited for change detection and monitoring of remote and overcast regions.

The TerraSAR-X data acquired was analysed applying Amplitude Change Detection methodologies. For this images with identical acquisition geometry recorded at different dates are combined in a colour composite: areas not affected by changes remain black and white, areas subject to change are highlighted in colour.

StripMap imagery with a 3m resolution and a scene size of 1,500km² provided a broad overview of larger scale changes of the water channels and reservoirs, infrastructure construction works and excavation areas.

Staring SpotLight acquisitions were then used to zoom-in on the areas with significant changes. This imaging mode provides the highest commercially available resolution of up to 25cm and facilitates the mapping, monitoring and analysis of even small-scale changes. The analysis of the Staring SpotLight data revealed details about the construction works (building of workers’ housing, material and tools storage) and related activities (excavations, vehicle movement) as well as changes to the surrounding environment (vegetation change due to water table change, clear cuts).

Terrasar-X Staring SpotLight Imagery - Analysis of construction of workers’ housing and infrastructure buildings

Analysis of construction of workers’ housing and infrastructure
buildings in Staring SpotLight imagery
© 2014 DLR e.V. and Airbus DS / Infoterra GmbH

Terrasar-X Staring SpotLight Imagery - Changed vegetation and excavation areas

Changed vegetation and excavation areas identified in
Staring SpotLight imagery
© 2014 DLR e.V. and Airbus DS / Infoterra GmbH

Key Benefits
  • Availability of imagery with different resolution and scene sizes supports a targeted monitoring approach reducing the need for on-site inspections
  • Improved identification of potential hazards for health and safety as well as adverse impacts on the environment and biodiversity, facilitating the timely implementation of countermeasures


Construction owners and organisations, operators, authorities and also environmental protection agencies can utilise TerraSAR-X data to monitor the construction projects regularly to assess the progress and observe potential impacts on the environment. No matter how remote or inaccessible a site may be, frequent revisit capacity and weather independent data acquisition facilitates timely and precise change detection and analysis. Thus it supports informed decision-making and can ultimately reduce time and expenditure for monitoring efforts.

In addition to observing construction progress, TerraSAR-X data can also deliver valuable information for other stages of civil engineering or infrastructure projects such as feasibility or design studies, risk or environmental impact modelling as well as resource management. Change monitoring can also be combined very effectively with quantitative monitoring of surface movements related to construction, e.g. in the context of underground tunnelling operations.

TerraSAR-X for Civil Engineering

The Perfect Solution for Construction Site Monitoring

  • TerraSAR-X data provides large area coverage for overview as well as zoom-in capabilities to identify the smallest details
  • TerraSAR-X’s unrivalled geo-location accuracy supports highly precise change detection and monitoring
  • Automated processing techniques enable rapid and cost-effective solutions
  • Improved monitoring frequency with the upcoming TerraSAR-X / PAZ constellation  (2015)
  • Ideal complementarity with optical imagery