Over the past two years, we have seen record levels of rainfall across our region and while we’re working hard to make sure our network is resilient against these types of events, we can’t do it alone. Protecting our region’s homes and businesses is complex and requires a collaborative effort. Anglian Water’s Rob Kelly, who is currently on secondment into the Norfolk Strategic Flooding Alliance as Water Management Director, explains what really happens to our water system during periods of heavy rainfall and the power a multi-agency approach can have on effective water management.  

The extremes of both record breaking heat and rainfall we’ve experienced over the last two years along, should not be viewed as one-off events, but as definite examples of a changing climate.  Two summers ago, we saw temperatures soaring above 40 degrees in parts of Lincolnshire, yet earlier this year some places in the East experienced 300% more rainfall compared to average. According to the Met Office's latest State of the Climate report,  these extremes of temperature and unpredictable weather are getting much more frequent. 

With more intense rainfall, shifting weather patterns and less green space in our communities, our drainage system is having to process more than ever before. Since the infrastructure was built, the population in our region has grown by more than a third. We’ve also seen a shift in customer behaviour, resulting in increasing problems with sewer blockages caused by wipes and other unflushables being wrongly disposed of (around 40,000 a year).  

We’ve spent millions upgrading our existing infrastructure, building new sewers to allow for the growing population, and increasing their capacity to store more rainwater amid the changing climate, but there is still more to do – and crucially more to do together, we cannot solve this alone. 

Many parts of the drainage system aren’t our responsibility – road drains, gullies, ditches, rivers and canals, all have different owners and when each system becomes overwhelmed, we can't solve the problem by staying in our own lane. Effective management of the drainage system requires a combined effort from everyone involved, including our customers. 
Even with significant investment, our system is struggling to cope. We need to work with other agencies to prevent water from entering the foul system in the first place.  

Dealing with excess rainwater 

This year, we experienced unprecedented levels of rainfall and 12 named storms. Rainwater from one roof entering the foul system generates the same volume of water as 100 homes would usually flush away in a day from their toilets and sinks. In a small town of 5,000 homes, this is like instantly connecting 500,000 extra homes to the sewer system.  

If other parts of the drainage system are not maintained or working as they should, this number can multiply rapidly, inundating the sewer system but also the surrounding infrastructure and environment.  

Historically, we have treated each of these challenges as separate entities but really, they are interconnected systems which need to be maintained and managed together.  

Anglian Water is responsible for two areas: maintaining and upgrading sewers; and slowing flow from properties. Our network and pumping stations are designed based on the size of population, with extra capacity built in to manage excess flow, but despite operating to maximum capacity and as designed, during periods of intense rainfall, our sewers suffer from hydraulic overload – meaning, there is more water than there are places to store it.  

We’re the largest water and sewerage company in England and Wales geographically, and when it comes to dealing with flooding, we have an extensive team of experts, partners and engineers across our business.  The work always starts by ensuring our assets are fit for purpose and not the cause of disruption, starting with our sewer pipes.  

Since last winter, we have completed thousands of metres of sewer-lining work across our region, to prevent groundwater from entering. We have also replumbed misconnected drains, where either the foul sewer has been incorrectly plumbed into the surface water sewer (or vice versa), either instance can put extra pressure on the network. By focusing on proactive repairs and the adoption of cutting-edge technology, we can safeguard infrastructure, as well as the communities and the local environment.  

A multi-agency approach 

Unfortunately, there are no quick wins to tackle flooding, but by joining forces with local councils, the Environment Agency, Highway Authorities and Lead Local Flood Authorities, we can continue to address the problem together.    

 
Working in partnership with local councils, we’re also looking at how we can utilise more green solutions, such as Sustainable Drainage Systems (SUDs) and installing reed beds across our region. these nature-based solutions allow us to control the flow of water, without the need for carbon-intensive infrastructure, as well as restoring natural habitats, and green spaces within our local communities. 

Over the past year, we have engaged with stakeholders, empowering and enabling them to become part of the solution. We’re supporting nine multi-agency flooding groups across our region, in areas particularly vulnerable to flooding, on a range of mitigation measures, like working with landowner's owners to clear ditches and helping to rectify misconnections. We also continue to work closely with our customers to reduce the number of unflushables products entering our sewage systems in the first instance.  

The most established flooding partnership is the Norfolk Strategic Flood Alliance (NSFA). Founded in the winter of 2021, when there was widespread flooding across the county, NSFA is formed of the Environment Agency, Norfolk County Council (including highways), the Broads Authority and the Water Management Alliance. Using a catchment-based approach, NSFA works to take a holistic approach to water to protect communities and infrastructure within Norfolk from the risks of inland and coastal flooding, as well as drought. The flooding issues faced across Norfolk are complex and difficult to solve. Having already anticipated another difficult wet season this year (outlined in this blog), NSFA is working with local stakeholders and communities to help them prepare and protect their homes and business from damage. It’s a great example of how taking a systematic, partnership approach can deliver real change at a local level. 

It’s important to explain why flooding and drainage is so complicated. We take our role seriously in ensuring our network is resilient against wet weather, but it will only be by working with others that we’ll stand a fighting chance of protecting our region from the devastating effects of flooding.