Thames Water service reservoir stability investigations

In 2021, Thames Water commissioned a project to evaluate and prioritise the refurbishment of embankments for 12 non-statutory service reservoirs in the Thames Valley Operational area. The goal was to create customised technical solutions and a prioritisation plan for refurbishment at each site. Historical data and site inspections by geotechnical engineers were used to identify issues and determine the need for further investigations. The cost of ground investigation for all 12 sites was higher than the client suggested, and a re-evaluated approach was to prioritise ground investigation and slope analysis for higher-risk embankments. The key findings from these investigations highlighted the significance of environmental conditions, climate change, control of burrowing animals, the effect that roof leak tests can have on embankment stability, and appropriate backfilling methods for embankment design. The project involved slope analysis of the embankments and recommendations for improvements for each non-statutory service reservoir embankment.