The raingarden gold-rush ??????

The raingarden gold-rush ??????

With water companies investing billions in solutions to CSOs and proposals to invest increasing proportions of those billions on nature-based solutions year by year, once the low hanging grey solution fruit have been exhausted, how is this all going to pan out?

Teething problems

Interest in retrofit #SuDS solutions such as #bioretention #raingardens was already growing and we've completed a number of these around London before the recent commitments from water companies (and permission for the water companies to charge customers to meet those commitments).

With that modest growth we've seen a range of issues already - particularly with ‘bioretention’, or highway, raingardens:

  • Raingardens that simply won't work at all because water can't flow into them (often identified by the swathe of dead plants!).
  • Raingardens that will offer only modest performance because outlets are too close to inlets, overflows are at the same level as the soil, soil levels are too high to hold water whist it percolates through soil layers, or flows that can easily bypass treatment/attenuation layers through continuous perforated pipe runs from gully inlets connected directly to the sewer.
  • Raingardens that may likely fail over time due to methods of runoff inletting that allow silts and litter to enter drainage and filtration layers directly allowing blocking and blinding, with bypassing able to occur – invisible failure.
  • Raingardens on steep slopes resulting in flows passing straight through.
  • Overflows higher than the lowest inlets resulting in flows back onto the highway.
  • Raingardens with a mismatch of sandy soils and plant species choice that are likely to fail.
  • A lack of understanding or commitment to maintenance to keep them functioning and providing value to communities and wildlife.
  • Different theories and approaches to soils and substrates around the country becoming locally ‘written in stone’.
  • Poor construction due to lack of experience or understanding of these relatively new (to the UK) technologies and ideas resulting in compounding of the above issues.

Add exponential growth

So, this is BEFORE the massive investment by water companies!

With rapid growth in demand, before the industry has really got to grips with the technologies, I believe there is a very real and significant risk that we will have many failed, failing, ailing and unsightly raingardens that could set us back in terms of perceived value for money and public acceptance and adoption which I have covered in previous posts.

= exponential price increases

I also believe market forces will positively crackle with excitement at the rapid increase in demand for bioretention raingardens and prices will rocket accordingly in a kind of SuDS ‘gold-rush’, resulting in significantly less value for money as these get rolled out at scale.?

All these water companies spending many millions per year across the UK – where are the skills, labour and materials going to come from – and at what cost?

Add to that the ubiquitous virtue tax.? New, in-demand, beneficial, healthy and sustainable ideas often attract a commercial ‘tax’. Organic. Vegetarian. Vegan. Dietary requirements. Eco.

Different and good for people and planet = £££

We’ve already heard from a SAB how they are convinced that maintenance contractors are charging a premium for SuDS maintenance that is not explained by the modest change in maintenance tasks associated with SuDS.? Because it’s new, a public and environmental ‘good’, and in demand.

Opportunities for SMEs and communities

All this investment could benefit thousands of businesses and generate skills and jobs across the country to design, build and maintain wonderful green assets in our urban communities - for the long-term. This was one of the selling points of going down the nature-based route, rather than grey engineering, flagged up in the Philadelphia cost benefit analysis comparing SuDS with super-sewers which tend to benefit singular or a few multinational companies - often taking that money out of the local or even national economy.

The risk though is that with such a rapid rise in demand and roll-out at scale, a default to large engineering consultants and contractors will be the norm, limiting local benefits, the ability for community and wildlife focussed third sector organisations such as Rivers Trusts to deliver multi-beneficial projects, application of existing industry knowledge, community involvement, opportunities for innovation and local expression, and development of local skills and jobs.

I'd like to see a proper commitment from water companies and councils given funding to deliver these assets to spread investment fairly, maximise local economic and skills benefits and prioritise SMEs, whilst creating a collaborative environment of sharing of experiences, ideas and innovation.

So where to go from here?

Training and sharing knowledge could, we believe, be one of the most powerful tools to avoid these issues.? And it’s something we believe we can significantly contribute to.

If you are interested in urban bioretention raingardens and want to learn more about how to site, size, design, build and maintain them whilst avoiding the common pitfalls then look out for one of our ‘masterclasses’ coming your way soon.

The next one is in London next Friday 13th October at the Garden Museum, Lambeth, London – and there are still some tickets available if you’re quick:

https://www.eventbrite.com/e/urban-raingarden-design-masterclass-tickets-718427846027


Janet Manning

Water Management Horticultural Consultant. Formerly the UK's first garden water scientist at Cranfield University and the Royal Horticultural Society. mains2rains.uk

1 年
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Sarah Jones-Morris

Director of Landsmith Associates | FLI FIPM | Cofounder of Association of Collaborative Design | Building with Nature Assessor/Auditor | Design Council Expert| Part-time Lecturer at University of Gloucestershire

1 年

Excellent Kevin Barton FLI !

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Phil Williams

Director of The Environmental Protection Group. Dedicated to making the world a better and more sustainable place.

1 年

Couldn’t agree more Kevin Barton FLI. 15-20yrs ago you could count on one hand the companies advocating,designing and building SuDS. SME’s like The Environmental Protection Group Ltd Robert Bray Associates Illman Young Landscape Design Ltd Dusty Gedge who have been in this from the beginning have encountered many of the problems, issues and uniquenesses that retrofit SuDS present. While an SME doesn’t have the turnover or the number of staff of the big practice, it may well have the answers to the questions being posed.

Carolyn Willitts

Landscape Architect, Founder & Director of CW Studio

1 年

Hi Kevin, do you have any dates for your next one after the Garden Museum? Thank you!

Tom Swithinbank

Senior Project Manager, Public Realm and Sustainability, Bristol City Centre BID and Redcliffe & Temple BID

1 年

Interesting, we’ve an event on this topic on Monday, do share with colleagues! https://www.eventbrite.co.uk/e/using-rainwater-saving-money-improving-cities-tickets-676555524787?

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