Tackling flooding

We are steadily working to reduce the number of properties at risk of flooding from our assets. We want to ensure that the probability of this happening is less than once in any person’s lifetime and so we continue to make significant reductions in the number of properties at risk.

There are a range of approaches for reducing flooding from the sewerage system, including enlarging pipework, separating foul and rainwater sewers, lining sewers to avoid infiltration by groundwater and the building of storm tanks.

Over the last five years we have invested more than £60m in flood alleviation schemes to reduce the risk of sewer flooding at more than 800 properties across our region as part of our commitment to ensure our operations provide adequate drainage for properties and do not adversely impact on the environment.

On average this means that more than three properties a month have been taken off the flood register over the five-year period.

The largest scheme completed recently is the Bristol tunnel project. This project, aimed at reducing the risk of sewer flooding in the centre of Bristol, involved the construction of a 850m long tunnel 65m below the city centre at a cost of £9.5m.

It has been viewed as the most ambitious engineering scheme in the city for more than a decade, but provided a more sustainable and cost beneficial solution than other options such as traditional pumping.

Other projects we have completed to safeguard homes include:

• a £3.5m scheme to alleviate flooding in Poole which involved the creation of a 480m long tunnel below the A35 Bournemouth Road that was designed to minimise the impact of the work on motorists. To do this special tunnelling equipment was used so that the busy road could remain open while work took place. This combined with a number of other smaller schemes in the Poole area removed 45 properties from the flood register
• 1km of sewer was laid in Bournemouth to reduce the risk of flooding at 27 properties in and around Elms Way. The project took just over three months to complete with work carried out in seven roads helping to remove 44 properties from the flood register
• the provision of an above ground attenuation pond in Bristol to help solve a surface water flooding problem. This sustainable urban drainage scheme was carried out in partnership with Bristol City Council and provided a more sustainable option than the traditional method of underground concrete storm tanks.

Where next?

Wessex Water is planning to invest around £500 million over the next five years to improve sewerage and sewage treatment infrastructure.

It will involve reducing the risk of flooding for more than 500 properties and public areas and making improvements to meet new environmental standards.