South East Strategic Reservoir Option (SESRO) Preliminary Market Engagement 2025​

Meeting the water resource supply-demand balance to ensure resilient supplies during droughts is becoming ever more challenging with increasing pressures from climate change, population growth, societal expectations and increasing environmental aspirations. In response, OFWAT has established RAPID comprising the three water industry regulators: Ofwat, the Environment Agency and Drinking Water Inspectorate - to support and oversee the development of SROs in order to secure long-term drought resilience on behalf of customers while protecting the environment and benefiting wider society. The South East Strategic Reservoir Option (SESRO) is a new storage reservoir which would be sited in the Upper Thames catchment, south-west of Abingdon in Oxfordshire. SESRO is envisaged as a regional asset and is being developed by Thames Water on behalf of three water companies - Thames Water, Affinity Water and Southern Water. The reservoir would be filled with water pumped from the River Thames during periods of high river flow. When river levels drop, or demand for water increases, water would be released under gravity back into the River Thames, for re-abstraction downstream. The reservoir would help to protect supplies and manage future water quality issues created by a changing climate as well as offering regional and local benefits, including environmental and biodiversity improvements and public access and recreation. The project involves construction of the new bunded reservoir with a capacity of up to 150Mm3 and a surface area of approximately 7km2. The reservoir is needed to be operational by 2040. To read more about the SESRO project, please visit the following link: https://thames-wrmp.co.uk/projects/sesro/ Additional information: The CPV codes set out in this PIN are included to give an indication of the likely scope of works and services. TWUL does not guarantee that all the activities referenced by the CPV codes will form part of any future tender notice(s), nor is the list exhaustive of all activities which may be included in any procurement process under this project.