114 SuDS retrofit – carrot or stick

Last week I was at the annual CIWEM Urban Drainage Group conference and this year celebrating the 40th anniversary of the founding of its predecessor WaPUG.? I remember trying to eavesdrop on the meeting that set up WaPUG as my desk was just next to the meeting room.

I came away with lots of new ideas that will probably keep me in blog posts for a couple of months, but let’s start with Session 1 on Sustainable Drainage Systems (SuDS) also known as source control, low impact development etc.

England is finally, slowly, moving towards implementing Schedule 3 of the 2010 Flood and Water Management Act that will require the use of SuDS on new developments.? That will help stop the situation getting worse; but what about retrofitting SuDS to existing developments.? That is a problem as much of the benefit from SuDS retrofit will accrue to the sewerage utility, but most of the action to implement them is the responsibility of householders or municipalities.? So how do we encourage SuDS retrofit.

The presentations in Session 1 helped me to identify four different approaches.?

• Market led
• Statutory
• Utility funded
• Municipality funded.

Market led

This approach would involve the beneficiary (the utility) paying offering a price per square metre of contributing surface diverted to SuDS rather than to sewer.? Organisations that could remove surface would bid to provide that service.? This mechanism already exists to some extent for property drainage.? Householders get a discount on their utility bill if they do not discharge surface water to sewer and commercial properties are generally charged by the square metre for surface water runoff.? However the current incentives are poorly structured and are not strong enough to encourage large scale action (See Episode 31 of the blog.)

But what about runoff from highways and other areas?

One presentation was about work in London that was moving towards a market approach.? A key component of this was implementing SuDS on the back of work on other utilities.? When a power utility or telecoms utility had planned excavations of the highway they would be encouraged through a market mechanism to liaise with the municipality to reinstate some or all of the excavation with SuDS rather than with paving.? In this way there would be a mechanism for a constant nibbling away of impermeable surfaces.

Big stick

Another presentation raised the possibility of a statutory requirement for SuDS retrofit.? If we can legally require new development to implement SuDS, why can we not legally require retrofit of SuDS to existing development.? Perhaps this would need to be targeted to those areas where SuDS would give the greatest benefit, such as those with storm overflows causing environmental impact of those with ongoing flooding problems.?

But who should be given this power?

• It could be given to sewerage undertakers and give powers over both property owners and highways authorities and other municipal bodies.? With the current lack of trust of sewerage utilities, there is a risk of push back from property owners who considered that they had a right to have their rainwater taken away.? Combining this requirement to disconnect with an improved rebate on charges for not discharging runoff could help to overcome this concern.
• Alternatively it could be given to municipalities with a power over property owners.? The municipalities could be more trusted by the public but they have less incentive to make use of the power as much of the benefit would be to the sewerage utilities.

I think that it is unlikely that this approach would be taken any time soon in England, but Wales is taking a lead on SuDS, so maybe they would consider it.

Utility funding

Another presentation was on the town wide SuDS retrofit in Mansfield where the work was being funded by the sewerage utility but with strong collaboration with the municipality as most of the retrofit was in highways or public open space.?

For the sewerage utilities the benefits are a cost effective reduction in inflow to the sewers that reduces the need for investment in new sewerage assets.? There are challenges around getting agreement for the retrofit, for engaging with the local communities where it is happening and over arrangements for future maintenance.? In the Mansfield case these had been overcome.

Municipality funding

The fourth presentation was from north America rather than the UK.? In this case the sewerage and drainage systems were the responsibility of the municipality so many of the challenges of different organisational responsibilities were reduced with one body responsible for highways, sewers and public open space.? However, I imagine that there could be plenty of inter-departmental rivalry between the different functions even within the one organisation.?

Unfortunately I do not see any possible way in which we will get one body responsible for all of these activities in the UK.

The way forward

SuDS retrofit will require collaboration between different organisations.? It will also involve considerable engagement with the local communities that will be affected – both negatively by having their urban landscape altered and positively by having their urban landscape improved and by having reduced risk of flooding and pollution.

An improved financial incentive to householders for reducing runoff from their properties should be part of the deal.?

Perhaps the importance of community engagement should influence the mix of carrot and stick is used and who wields them.? There may be research, but I have not seen it, on whether municipalities or sewerage utilities are better placed to encourage communities to embrace SuDS retrofit.? I imagine that it will vary from community to community and so there is not a single best model.? But I was encouraged to hear that various models are being tried and are potentially delivering results.? However, there is still a long way to go.