InSAR monitoring of UK embankment dams: influence of dam features on monitoring quality

Abstract

Radar interferometry (InSAR) is a satellite remote sensing technique which offers deformation monitoring at frequent intervals with sub-centimetre accuracy. The most popular form of InSAR monitoring for infrastructure is Persistent Scatterer Interferometry (PSI). This relies on the identification of persistent scatterers: permanent, rigid objects which can reliably backscatter a signal to the satellite receiver. As the typical UK embankment dam has grassed slopes, the majority of persistent scatterers are detected at hard infrastructure located at the dam crest. The aim of this paper is to study the influence of dam features on persistent scatterer detection and quality at Scottish Water embankment dams. Following a case study in which PSI can be shown to detect dam deformation associated with an extreme climate event (the summer 2018 heatwave), statistics from 17 Scottish embankment dams are used to determine which dam features lead to the best quality PSI results. The type of wave protection at the crest of a dam is the biggest influence, whereas the presence of an asphalt surfaced crest road is shown to have a surprisingly limited effect on persistent scatterer quality.