The Green Economic Recovery

[3 min read]

In an unprecedented letter[1]the Secretary of State and the chief executives or equivalent of Ofwat, DWI, EA and CCWater, have called upon the water companies of England and Wales to accelerate planned investment programmes, implement new ideas and ‘go even further to deliver more’ to support a green recovery.

Two of the three specific proposals they suggest are:

• accelerate existing plans and environmental priorities within the agreed 2020-25 plans, considering the enhanced use of nature-based solutions to deliver them;
• implement specific new innovative ideas, which would benefit future generations or current customers. These could include: water resources, flood mitigation, net zero or water quality improvements.

There has been some discussion recently about ‘bathing water rivers’, i.e. stretches of river where it is safe, forma. Water quality perspective, to swim.  There are many in Europe, there are none in UK, though we do have many excellent and award winning bathing water beaches.

So why are there no bathing water rivers in the UK when wild swimming, paddle boarding and other inland water-based activities are becoming more popular?

To become bathing water designated any water body has to meet rigorous standards.  Most UK rivers would not achieve these standards because of pollution, either ‘point-source’ from permitted sewage treatment works’ discharges or ‘diffuse’ from agricultural run-off.  Those permitted discharges from sewage treatment works have to meet consents granted by the environmental regulators in the relevant UK nations. However there are other less regulated ‘point-source’ discharges, i.e. those form combined sewer overflows.  Essentially these are the safety valves for the sewer network that in times of heavy rainfall allow diluted sewage to overflow to water courses. Their aim is to prevent sewage backing up and flooding homes and other property. They are unfortunately a necessary feature of our legacy ‘combined sewer’ systems.  By ‘combined’ we mean the sewer system takes both sewage from homes and businesses and rainwater from roofs, driveways and other impermeable hard surfaces.  We now build sewers differently with separate ‘foul’ sewers for sewage and ‘storm’ sewers’ for rainwater. But these new sewers inevitably connect with older and combined sewers downstream – adding to their load and the problem.

So in times of storms many combined sewers simply get overloaded - essentially with fairly clean rainwater. And with changing weather patterns we’re experiencing more frequent and more intense rainfall events.  Those combined with increasing population, housing and commercial developments means there’s more hard, impermeable surfaces and more rainfall getting into sewers. If you like ‘the perfect storm’.

Th Government and regulators have said we should now be investing in the Green Recovery.  And we hear we should be investing in the Nations’ infrastructure.   So why don’t we just upsize these combined sewers or just separate them all out?

Well the cost would be enormous, the disruption to communities they pass through would be horrendous and the Carbon impact irresponsible.  And how long would an upsized system remain fit for purpose?

The right solution is to tackle the problem at source, i.e. prevent rainfall getting into combined sewers in the first place.  And there’s already a technique for doing that – sustainable drainage systems (aka SuDS).  They’re not new but they are increasing in favour. There are some excellent examples around of both new SuDS and retrofit SuDS.  And from April 2020 water companies in England have been adopting SuDS on new developments that come within the definition of a sewer[2].

So – summing up

T  More frequent , more intense rainfall plus more hard, impermeable surface means more surface/storm water entering sewer networks

T  More surface/storm water in sewers means more combined sewer overflows operating more often, and potentially more property flooding

T  More sewer overflows operating mean more pollution in water courses.

T   And the solution is tackle at source – prevent or minimise surface/storm water entering sewers using new and retrofit SuDS.

Jumping back to the Secretary of State and Regulators’ letter.

Retrofitting SuDS to reduce CSO discharges meets the principles set out in their letter, i.e.

• the enhanced use of nature-based solutions to deliver them (i.e. existing plans and environmental priorities)
• implement specific new innovative ideas, which would benefit future generations or current customers. These could include: water resources, flood mitigation, net zero or water quality improvements.  (SuDS can benefit all 4 of these)

I look forward therefore to seeing retrofit SuDS feature in the water companies’ proposals to

T  support the Green Economic Recovery and

T  contribute to a more resilient future – for current and future generations and the environment.

#GreenRecovery #rivers #SuDS

[1] https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/902487/green-recovery-letter-to-water-companies-200720.pdf

[2] https://www.water.org.uk/wp-content/uploads/2020/01/Water-UK-SuDS-brochure.pdf