Flood review calls for independent body to marshal London sewer investment

An independent review of the severe flooding that struck London in July 2021 has recommended the establishment of a body to pull together assessment and investment in the capital’s surface water and sewer systems.

Among the recommendations form the London Flood Review (LFR), commissioned by Thames Water, is a call for a “stabilising body with a strategic view and governance with all parties contributing” and working across “different organisational boundaries” to mitigate the impact future flooding.

The LFR forecast that weather events like those of July 2021 were “likely to occur more

frequently in the future.”Among the its aims was to assess how the drainage systems

performed. Its findings on that count included that “despite there being available capacity in

the sewer systems, flows of water were often held up by the gullies which did not have the

capacity to deal with such extreme flow rates.”

Its recommendations were grouped around five themes: governance, funding, evidence, communications and strategic planning. As well as the proposed strategic body, others included:

• seeking opportunities for partnership working in areas of known flood risk to spread the cost of potential schemes;

• sharing data relating to flood risk assets, high-risk areas and vulnerable customers, including across boroughs where flood risk may originate from other areas;

• enabling cross-organisational collaboration at short notice; and

• helping people to understand how they can protect their homes from flooding; and protecting those at highest risk of flooding by installing anti-flood devices or flood gates where appropriate.

Further proposed strategic measures included “influencing planning policy and working with developers to reduce flood risk to others from new developments and basement renovations.”

The floods in the summer of 2021 revealed that a quarter of London’s rail stations and 10 per cent of the rail network could face flooding in the future; 1 in 5 of the capital’s schools and almost half of its hospitals were totally or partially at risk of flooding; and over 200,000 London properties were similarly at risk.

Commenting on the publication of the final report, water strategist and LFR chair, Mike Woolgar said: "Our review of these events demonstrates the critical nature of collaborative working between all those who bear responsibility for water and flood risk management. I look forward to seeing the recommendations taken forward by those named within the report.”

The LFR was led by an independent expert group (IEG) of external specialists to ensure objectivity and impartiality, including Woolgar, flood modelling expert, Professor Roger Falconer and city resilience expert Lykke Leonardsen from Copenhagen.

To assist with the review, the IEG established a strategic stakeholder panel comprising senior representatives from the Greater London Authority, Transport for London, London Councils, the London Drainage Engineers Group, the Environment Agency, the Consumer Council for Water, the Thames Regional Flood and Coastal Committee. Ofwat also joined the SSP to act as an observer throughout the process.

Thames Water’s chief executive officer, Sarah Bentley, said “While there is much as an organisation we can learn from this review, the clear takeaway is the necessity of collaboration. Ensuring that our network can operate effectively, while minimising the risk of impact of future flooding, must be the shared focus of all organisations with responsibility for London’s water network and drainage systems.”