Sun. May 22nd, 2022

Isle of Wight Observer News

The Island's Free Newspaper

VECTIS VIEW: Keith Herbert, Isle of Wight Area Manager for Southern Water

3 min read

The Island is a special and unique place. I feel extremely fortunate to have world-class beaches on my doorstep.

Whether it is a desolate, winter walk along Chilton Chine or August Bank Holiday weekend in Ryde, our beaches play an important part of everyday life on the Island – especially for my young family.

Water quality at our beaches is the best it has ever been and beats most areas of the UK and Europe. Thirteen of our fourteen bathing waters are classified as ‘Excellent’ by the Environment Agency – the highest possible standard.

However, during heavy rainfall many sewers overflow. The public have made it absolutely clear that this practice is no longer acceptable. The solution is not an easy one.

One issue is that 40 per cent of the flow is rainwater from domestic roofs and block paved driveways, 40 per cent is highway drainage and 15 per cent from gardens and open spaces. The engineering challenge is that during a storm, most areas can receive between 10 and 30 times the volume of water they get during dry weather. Storing this water or treating more is not economical or practical.

Storm water tanks are only part of the solution. A 10 million litre tank can fill in less than an hour during heavy rainfall and takes huge amounts of energy to pump and treat. By way of example, during a heavy storm, over 3,000 litres (3 tonnes) per second arrives at Sandown sewage treatment works, almost exclusively rainwater. Investing in solutions that slow the flow of water entering the sewer is a far stronger approach that will ultimately provide better outcomes for the environment.

Tackling this issue is now a priority and the Island has been selected for an industry-leading scheme to reduce sewer overflows by 80 per cent before 2030. This has never been trialled at scale in the UK and is in addition to Southern Water’s existing investment programme.

The focus of the project will be upstream catchment management. Rainwater does not need treating and can be released to the environment safely. Our research shows that if we remove 40 per cent of flow from our network, discharges will be reduced by over 80 per cent. We believe this can be achieved without digging up every road and diverting every highway gully.

Island towns were not designed with sustainable drainage in mind; however this can be changed. Collaborating with other agencies, customers and landowners, we can make small changes that have a big impact. One large water butt can detain the flow of a large summer storm from a medium sized property. Tree pits in town centres can intercept water that would otherwise overwhelm the sewers and contribute towards tree planting targets. Rain gardens or swales provide green open spaces and serve as soakaways during heavy rain. Raised flower beds fed from downpipes remove the need for regular watering and stop flow immediately hitting the sewer network.

Rolled out on scale, these initiatives will have a huge impact and ‘slow the flow’. But it isn’t just physical things that can improve the situation. New developments must be designed with water efficiency and drainage in mind. It isn’t acceptable for stormwater drainage to be connected into the foul sewer; other solutions need to be found, even if they are more expensive. We also plan to incentivise homeowners who remove their roof or driveway drainage from the sewer.

Everyone wants to see an end to stormwater discharges and we are committed to protecting our natural environment and glorious beaches. Southern Water is taking the lead on this; however, to be successful, it will require everyone to work together on this shared problem.