InSAR monitoring for the Thames Tideway Tunnel | United Kingdom

A super sewer

London relies on a 150-year-old sewer system built for a population less than half its current size. As a result, millions of tonnes of raw sewage spills, untreated, into the Thames river each year. Tideway is the company building the Thames Tideway Tunnel, a 25 km “super sewer” running under the Thames, designed to clean up the river for the good of the city and its wildlife. To monitor the impact of construction over a large area, CVB decided to use ATLAS InSAR data as it enables the monitoring of large areas with a significant point density at millimetric precision.

ATLAS InSAR monitoring was applied over the East tunnel alignment including a “corridor” of 500m on either side of the tunnel. The area of interest for this study covered the East section of the Thames Tideway Tunnel alignment over a distance of more than 5.5km, covering 2 separate tunnel drives between Bermondsey and Stratford, and Bermondsey and Greenwich.

Control of the impact of the work

The ATLAS InSAR monitoring solution was successfully applied in the Thames Tideway East section for CVB JV over a period of 4 years between January 2014 to December 2017. ATLAS InSAR has proven to be an efficient and cost-effective tool for the long-term monitoring of construction works and built environments.

The baseline study, has been derived by using 83 high-resolution TerraSAR-X images acquired in descending mode which have provided up to 147,126 measurement points.

The results were delivered through the Beyond Satellite web-based platform that enables the integration between ATLAS InSAR data and classic monitoring methods.