1C3: Using Nationwide InSAR Data in Dam Monitoring
July 13, 2022
Equipment and Technology
Monitoring settlement and deformations is of utmost importance for dam safety. Movement in a dam body might be an indication of active failure modes and should therefore be covered by instrumentation. Historically, monitoring has been point-based where bolts and reflectors have been measured into geodetic networks. In previous studies (Ekström and Lier, 2013) and (Lier et al, 2016), the case for improved settlement monitoring has been advanced, both due to the poor resolution of traditional mapping and quality issues of geodetic measurements compared to the minute settlement that needs to be recorded. Due to the accuracy of InSAR, it has been demonstrated to be highly useful in dam instrumentation and safety (Lier et al, 2015), but limited by cost and complexity. In light of this, the free data of ESAs Sentinel-1 program and the subsequent development of national settlement mapping services leading up to the Copernicus EU-GMS (Ground Monitoring Service) is notable. Here, the movements of entire nations and ultimately entire Europe, will be monitored in minute detail with the goal of annual updates. In order to ascertain the future impact of the EU-GMS on dam safety, where free settlement data will be made public, this project aims to evaluate the use of the national mapping by InSAR of Sweden. Here a total of 13 dams have been selected by the largest dam owner and utility of Sweden, Vattenfall. Using an in-house developed analytic platform, we aim to analyze the coverage, distribution and representative values of ground motion and compare to traditional geodetic monitoring. We aim to demonstrate that the services provided by the coming EU-GMS can be a compliment to existing instrumentation. In addition to analyses of the EU-GMS level data, the additional value provided by custom analysis and the addition of reflectors will be discussed. The latter has had its value demonstrated as a link between the InSAR data and the geodetic network, not as a replacement but as a QC feature. In conclusion, the implication of the future continent-wide motion mapping services will be discussed. This will not only involve instrumentation aspects, but also public information as these platforms is expected to be widely accessible to the public.