Developers need to pay more attention to flood risk

September 26, 2017 / Isla MacFarlane
Developers need to pay more attention to flood risk

Approximately 5 million properties in England are at risk from flooding. Globally, a procession of high-powered hurricanes are devastating the USA and Caribbean islands, whilst in the UK, freak storms and heavy rainfall have displaced thousands and seen many lose their homes in the past two years.

Building on floodplains has been suggested as one of the main reasons behind the surge in homes being lost or severely damaged to the recent floods, however, Gwyn Roberts, Project Lead at BRE’s Home Quality Mark, believes the issue must be considered across numerous levels.

“Keeping the water out might sound like a simple task in building design but coupled with other requirements of a home, such as access, security and energy efficiency, it isn’t always that simple,” Roberts said. “Understanding if the location of your home is likely to flood is the first step. It’s estimated that over 10,000 new homes are built on floodplains each year, which could largely be down to the fact the land is cheaper and thus provides more attractive returns to a developer, also there are no national regulations preventing development on a floodplain.

“Therefore, it’s important that new homes are built to withstand the devastating effects of flooding. The Home Quality Mark (HQM), a new national building standard, takes account of property resilience work, as well as addressing flooding from a community point of view, working to ensure developers build homes that are equipped to combat the effects of flooding and limit the impact upon the existing community.”

Creating new development often leads to greater levels of hard standing, which is a critical issue. However, HQM claim to push developers to do more in reducing the rate and volume of water leaving the site. This means existing homes and business in the local communities are less likely to be flooded.

HQM also said that it looks at the new property itself, ensuring that where there is a risk of flooding the developer has taken action to keep the water out of the home and ensure there is safe passage out.

At a regional or city level, flooding can occur for numerous different reasons from coastal erosion to rivers bursting their banks or high sea levels. Home Quality Mark is part of the BREEAM family of international, science based, certification schemes, which also includes CEEQUAL  for civil engineering.  A number of Flood Alleviation schemes have achieved CEEQUAL awards for sustainability.

A large scale example of city level flood protection is the Thames Barrier, which protects 125 km2 of Central London, which has an estimated 300,00 homes at risk of flooding. The most at risk area is Hammersmith & Fulham, where defences against the River Thames are not as abundant as they are along the central stretch of the river.

Working to protect the entire city, the Thames Barrier stops high tides and storm surges moving in from the sea and can also ease fluvial flooding from upstream during periods of heavy rain. Routinely tested, (the last being on Sunday 10th September the gates close by rotating 90 degrees into the fully closed position.  The Thames Barrier was built in the 1980s to protect from tidal surges, following Britain’s worst flood on record in 1953 when 300 people were killed by the North Sea flood.

Gwyn added, “Whilst the Thames Barrier works to protect London from the debilitating effects of flooding, it’s essential we learn from the devastation of the past and what’s happening in the present to build homes of all types, with suitable prevention measures to better protect homeowners and their surroundings.”

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