Investing in flood defences

There was no better example of the value that comes from investment in flood defences than to return to the scene of one of the nations most vivid flooding disasters.

In 2005, just days into the new year, severe flooding hit Carlisle in the north west of England. After weeks of unsettled weather, heavy rain caused the River Eden to swell and burst its banks, pouring floodwater into 1,800 properties. Cars could be seen floating through the city centre and boats were needed to pluck people from rooftops. Three people lost their lives.

On November 19 last year, a day of record rainfall that left 1,500 properties flooded in other parts of Cumbria would have led to similar scenes in Carlisle, but for “almost-completed” flood defences.

Overnight emergency works by the Environment Agency to secure unfinished sections of the town’s new flood defence scheme ensured 800 properties were protected when the River Eden once more burst its banks. The organisation estimates that this prevented some £48 million worth of damage alone – £10m more than the cost of the scheme that was completed in June this year, 12 months ahead of schedule.

Flood defence scheme
The new flood defence scheme received the go-ahead in April 2004, only months before the January 2005 floods. At completion it includes 10km of raised defences, 30 flood gates, two new automated pumping stations, two raised footbridges and 1,500 metres of improved cycleway. This £38m scheme will reduce the risk of flooding to almost 3,500 homes and businesses in Carlisle.

Speaking at the opening of the new defence the Environment Agency’s Chairman Lord Chris Smith said: “It is essential that we continue to defend communities, businesses and the economy from the risk of flooding and coastal erosion. The Environment Agency has completed over 116 flood defence schemes in the past two years alone, providing increased protection to over 77,500 extra properties.”

Extreme weather that leads to flooding, like that experienced in Cumbria, is becoming more common with one in six properties in England and Wales at flood risk. It is only going to get worse as climate change brings wetter winters, stormier weather, rises in sea levels and greater extremes in weather conditions. So climate change must be incorporated into all future flood mitigation planning.  

Flood defence schemes provide benefits to communities including opportunities for economic development, jobs and tourism. The Environment Agency already seeks financial contributions from organisations that directly benefit from flood defence schemes and will look to increasing contributions from other sources to complement public investment from government.

Other defences completed in the first six months of 2010 include a major flood alleviation scheme in Gainsborough. Lincolnshire city lies at the most inland tidal reach of the River Trent and over 2,600 properties are at risk both from tidal surges and when floodwater comes down the catchment towards the sea.

Major flooding occurred in 1697, 1910, 1947, while tidal surges were a feature of the 1950s. Flood defences were initially constructed in 1960s, with some improvements most recently in 2003. But with the defences nearing the limit of their design life, the Environment Agency completed £19 million defences that have not only provided protection against a 1 in 200 year flood, but also created amenity that attracts development, events and people back to the waterside.

On the south coast in Lewes, East Sussex, more than 200 properties are now better protected as a result of improvements to existing flood wall heights, building new walls and installing floodgates. Designers of the scheme worked hard to ensure the materials and design of the new flood protection works match those traditionally used in the Cliffe conservation area, including special brick cladding for flood walls. The completion of this scheme follows on from work in 2004 that helped protect around 300 properties after severe flooding hit the town in October 2000.

In Nottingham, the first part of the cities £51 million Left Bank flood scheme was completed ahead of time. When totally finished, the defences will extend for an impressive 27 kilometres along the River Trent between Colwick in Nottingham’s east to the M1 in the west, providing flood protection for 16,000 properties. The Nottingham Left Bank Flood Alleviation Scheme is one of the biggest flood risk management schemes in England and Wales.

Projects i Gatwick
Meanwhile, Gatwick Airport and more than 1,300 homes and businesses across Crawley and Horley in West Sussex will benefit from an £11 million Environment Agency project that will significantly reduce the risk of flooding an area that suffered from the devastating floods in 1968 and 2000.

Scheduled to be fully completed by 2013, the scheme will also provide Gatwick Airport – the UK’s second largest airport and busiest single runway airport in the world – with far greater protection from the devastating affects of flooding. Gatwick Airport is contributing £4 million towards the scheme.

Significantly, the main engineering strategy is to build flood storage areas – which will hold large amounts of water during and after spells of heavy rainfall – including raising the level of the existing dam at Tilgate Lake in Crawley. The stored water will slowly be released back into the River Mole, which will help reduce the risk of high flows that would have again caused a flood risk to nearby homes.

To offset this loss of some woodland and vegetation, new trees will be replanted and new wildlife habitats will also be created.

Flood storage
Up in Yorkshire, Ripon residents will see their new £14.4 million flood alleviation scheme take shape throughout this financial year. The city sits at the confluence of the rivers Skell, Laver and Ure and has a long history of flooding; most recently in 1982, 1991, 1995, 2000, 2005 and 2007. The new scheme will significantly reduce the risk of flooding to 548 residential and 96 commercial properties.

The design includes a flood storage reservoir on the River Laver, which will reduce water levels in times of flood; walls and embankments along the River Skell; raising some roads and replacing Alma Weir with a new river level gauging station upstream. Construction of the scheme is due to be completed by spring 2011.

Overall, every £1 spent by the Environment Agency in protecting communities from flooding saves £8 spent repairing damage.

For more information
To find out if you are at risk and get early warnings, call Floodline on 0845 9881188 or go to www.environment-agency.gov.uk