(Below is an extract from New Civil Engineer published in August 2023)
Environment Agency has spent £70M on pre-construction for £640M River Thames Scheme
14 AUG, 2023 BY THOMAS JOHNSON
The Environment Agency has spent £70M on pre-construction work for the £640M River Thames Scheme in Surrey since it was conceived in 2014.
The information was revealed in a Freedom of Information (FOI) request submitted by NCE to the Environment Agency. The figure represents an approximate £7M per annum over the last 10 years.
Developed in collaboration with Surrey County Council, the scheme will see works undertaken between Teddington and Egham along the River Thames in Surrey, one of the largest areas of undefended developed flood plain in England. With flooding increasing as the climate changes, the River Thames Scheme represents a new landscape based approach to creating a more resilient and sustainable community, protecting over 11,000 homes and businesses as well as infrastructure such as the M3.
The River Thames Scheme will see the creation of over 8km of new flood channels from the Thames to carry excess rainfall and prevent the river from bursting its banks. The flow capacity of existing Sunbury, Molesey and Teddington weirs will be increased.
River structures will be improved and new road and pedestrian bridges constructed to accommodate the new channels. The scheme will also see the creation of new public green spaces, cycle and footpaths and wildlife habitats.
The Environment Agency said the majority of the £70M investment so far has been spent in the design and development of the flood channel and associated green infrastructure. This included an extensive programme of site investigation works and environmental data gathering.
It added: “A proportion of our spend has been used on implementing measures to help mitigate flood risk in the area of the scheme, 400 properties were eligible for property level protection that has been installed as part of the scheme delivery and a major incident plan has been developed and is in place to enable the Environment Agency and Surrey County Council to respond in the event of future flooding.”
When heavy rain goes into the River Thames upstream, water levels rise increasing the flood risk. To help combat this, the new flood channel sections will operate by gradually carrying the additional flow so the water in the river stays within its banks. The Environment Agency believes the additional capacity of the flood channels and weir gates will greatly reduce the flood risk.
The Environment Agency further revealed some land parcels required for the scheme have already been purchased. The scheme had an initial budget of £37M for the appraisal phase, which included provisions for the property protection and major incident plan. The appraisal phase was successfully completed in 2019, at a cost of £35M, within the agreed budget.
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