Utility Week

UTILITY WEEK | FEBRUARY 2023 | 13 Water I t's July 2021, a mother passes her baby through a basement flat window as flood waters rise towards the ceiling; hospitals are forced to transfer patients as they close their doors and extreme weather brings transport systems to a halt. Such scenes might be familiar in news reports from less developed parts of south Asia, but the scene described is the experience of Londoners as the very real impacts of climate change begin to hit home. "We were really lucky that we didn't have any deaths," Victoria Boorman, policy and programme water lead in the climate change adaptation team at the Greater London Authority (GLA) tells Utility Week. "There were stories of water reaching ceilings in basement flats. It shows how vulnerable major cities like London, with high concen- trations of people, are to climate shiŠs." Urban creep has come at the expense of permeable green spaces, meaning that rain- fall has nowhere to go but into overwhelmed drains and sewers, which can lead to flood- ing as well as triggering combined sewer overflows (CSOs). The water industry has long been calling on government to change key policy that will ease the strain on sew- ers. Nearly three years aŠer its first report on implementing sustainable drainage systems (SuDS), the Department for Environment, Food & Rural Affairs (Defra) has responded by mandating SuDS at all home-building schemes and removing developers' auto- matic right to connect to drainage systems. But the green light from Westminster is only the first hurdle to implementing SuDS because the complexity of stakeholders and funding pools means collaboration on an epic scale is required. Facing into that challenge, what are the hurdles, and what progress is being made? Problems on the surface Surface water poses both the greatest flood- ing risk and is the least understood. That is according to the National Infrastructure Commission (NIC), which delivered a land- mark report to government at the end of last year in which its top recommendation was to mandate SuDS for all new developments in England. The government has taken this onboard and started off 2023 by doing just this, with implementation planned by 2024 aŠer con- sultation. Enacting schedule 3 of the Flood and Water Management Act will also see developers lose the automatic right to con- nect to sewer systems without the consent of the operator. This will mirror the approach adopted in Wales from 2015. This is a huge step in the right direction to mitigate the risk of surface water flooding and something the water sector has before calling for in the battle against a changing climate and population growth that has in places overstretched infrastructure. Towns and cities that have lost perme- able land to urban development face the risk of flooding from surface water that must be redirected away from sewer networks. This presents an opportunity to use a nature- based solution as opposed to traditional engineering that can be carbon intensive. SuDS mimic natural water retention and can include wetlands, raingardens, retention ponds and tree planting to slow the flow of excess surface water. Spongifying London – a challenge across 32 local authorities The GLA's Boorman explains how the intense flooding in London in July 2021 was a cata- lyst for action. Mayor of London Sadiq Khan, who has no formal responsibility on flooding, decided to bring together all the parties with a responsi- bility or roles related to surface water flood- ing to create a London-wide strategy. "There are international examples of city- wide strategies, but nothing on the scale or complexity of London, so it's a really big job to not only write that plan but make sure it can be delivered," Boorman says. "What became obvious from these meet- ings was the need to work across the bor- oughs, because rain can fall in one place but its impact is felt as it flows into another. We need to encourage cross-boundary working through the London strategy to identify and facilitate work done by one borough to ben- efit another. That isn't easy with the current legislation, which is why collaboration is so important." Where will the money come from? Boorman and her team felt the NIC's report could have gone further on funding, which she says remains a significant issue. "Local flood authorities in different boroughs talk about the difficulties they have in secur- ing funding for SuDS schemes. There is a big issue with scaling up and delivering the amount of sustainable drainage needed, which the NIC report didn't really draw out. "The government really needs to focus on that to enable us to deliver the schemes needed to manage the risk going forward and the increasing risks climate change will bring." Funding comes from multiple pots, which again requires cooperation and coordination to apply for multiple funds – including from continued overleaf

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