London’s First Vertical Rain Garden — The Green Roof Consultancy

London’s First Vertical Rain Garden - The Green Roof Consultancy

Posted by Dusty Gedge on Monday, November 25, 2013 Leave a Comment

Rain gardens don’t normally go vertically. But the one we designed is exactly that a rain garden on a wall. Yes, a green wall that is secretly and unbeknown to the viewer on the street,  one big rain storage beast.  London’s and perhaps the world’s, first vertical rain garden.

Vertical Rain Garden cum Living Wall 

Londons First Vertical Rain Garden

The wall is on Tooley Street, directly across from the City Hall. Now that is significant, as the project was funded by the Drain London run from City Hall. The location means that it is only a short stroll for the London Green Team to show visiting dignitaries. The other reason for this wall being selected was that the size of wall would probably retain most the rain that falls on the narrow pitched roof above. The wall is not far from where Tooley Street meets Tower Bridge road – a dip in the road that floods regularly.

Team London Bridge GI Audit

  The vertical living wall cum rain garden arose out of work on the London Bridge Green Infrastructure Audit. Funded by Drain London and commissioned by Team London Bridge. the project aimed to audit existing green infrastructure in the area and identify where new GI could be installed.

Green roofs and walls were located and mapped, along with trees, parks and pocket green spaces. Then came the exciting job of identifying where new green roofs, green walls and rain gardens could potentially be installed.

The wall at Tooley Street was begging to us to be greened and made us really keen to go one step beyond just a green wall for visual and biodiversity objectives. Could we add one further element in the sustainable agenda store rainwater and take SUDS to the vertical?

The Concept and Design

  The concept was quite simple. Design and specify a green wall with a mix of native (for biodiversity) and non-native (for winter colour and visual effect) green wall plants. Create a system that would hold rainwater in times of heavy intense summer storms. This rainwater should be enough to irrigate the wall without any use of potable water.

Detail of the Vertical Rain Garden cum Living Wall.

The original concept included more conventional rain gardens on the street. These would take any excess rainwater from the vertical rain garden and also rainwater from the street.

We created a computer graphic of the concept that was included in our report to Team London Bridge, and the concept then received funding to take it to implementation.

From Audit to Concept to Implementation

Here at GRC and with our sister company, The Ecology Consultancy, we are proud of our work on the London green infrastructure audits and even prouder that we have successfully implemented a number of projects. Taking the vision of a greener London and bringing this to life on the streets and roofs is what this process is all about in the end. The Tooley Street vertical rain garden is a perfect example of this.

Working with Treebox Ltd and their unique panel system, a secret hidden element was added big storm water store. Add a little plumbing to ensure that water from the roof could be directed into the secret chamber and leave if need be, the wall was installed in March 2013.

Maintenance Friendly Green Wall

Now because the irrigation is provided by rain water, the actually costs of maintaining the living wall is even lower than that for hanging flower baskets. As maintenance, along with  unsustainable use of rain water, is often seen as a reason not to have a living wall, our vertical rain garden helps to debunk this argument.

So lets do some arithmetic. Their are about 5 hanging baskets in the vicinity of the vertical rain garden cum living wall. Now we are lead to believe, each of these costs £2 a basket to maintain per week. Now a good estimate is that 5 hanging baskets cover an area of of a little more than 0.5m2. Therefore the maintenance costs 0.5m2 of hanging baskets is a grand total of £240 per season, assuming 6 months. One metre would be £480

The vertical rain garden cum living wall costs a total of £1200 per year for the whole 25m2. Therefore at £48 per m2 this is much cheaper than hanging baskets. And you get more green for your buck!

£ 480 versus £40 that speaks for itself

Therefore lets green the walls of London with vertical rain gardens cum living walls.

The Vertical Rain Garden in Action

  Like are other award winning green wall in the Victoria BID area, what has been good to see is the reaction of the public. Visiting the vertical rain garden cum living wall on a regular basis, we have noticed how many people walking along Tooley Street stop and ‘wonder’ at the green marvel. We have been fortunate to take a number of international visitors to the wall, from as far afield as Portland, Oregon and Melbourne, Victoria.

We think this is the first vertical rain garden in the world. We know our friends in Portland, Oregon are in the process of designing and implementing such a project. If you know of another vertical rain garden cum living wall, anywhere in the world do let us know. However we know for sure that this is London’s first and we hope the first of many.

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