Directing polluted road runoff to on-street “Raingardens” is a tried and tested technique to reduce flood risk.

Earlier this month as part of my work outside the Council I gave an invited lecture in Beijing to engineers, planners and academics from across the developing world about managing the impact of climate change. Over the duration of the weeklong workshop I was humbled to learn more about the enormity of the risk facing places like Ecuador, Nepal, Vietnam, Bangladesh and Laos in dealing with a problem that is not their making. I returned from this trip determined to redouble Edinburgh’s efforts to tackle climate change.

The flooding Edinburgh experienced this year may have been localised, but the impact on individuals has was non-trivial. Although this weather is not a prediction of what our capital can expect in the future, it is a taste of what climate change may bring. I was therefore pleased to contribute to a motion which asks the Council to review its climate change preparedness and resilience. The text of the motion is as follows:

Climate Change Impact and Management

Council:
1. Acknowledges the severe weather conditions experienced by the city and elsewhere in recent weeks and recognises that these events may be a taste of what climate change could bring.
2. Recognises that these put significant strain on drainage systems and other infrastructure, causing some surface water flooding and damage to property.
3. Acknowledges that there is a need for the Council to be prepared and far-sighted in its approach to building in resilience in the city, alongside its work to make Edinburgh a net zero carbon city by 2030.
4. Acknowledges the comments of flood insurance specialist Professor David Crichton in which he indicated that many local authorities in Scotland have already been ‘good at managing risk’.
5. Requests a report to Council which indicates clearly the work already being undertaken and needed across the Council to meet heightened demands caused by extreme weather and future considerations, within 3 cycles.

Although this motion goes far beyond flooding, I am keen to push the Council to do more to manage runoff. Rainwater runoff from roads, roofs and car-parks in many parts of our Capital (esp pre WEWS Act) adds to flood risk and pollutes our watercourses, and tackling this problem at source as much as possible is the most sustainable approach.  I hope to amend the above motion to include two key changes.

Firstly,  as part of Climate Change Impact & Management report I will propose that Council Officers enter discussions with Scottish Water and the Scottish Government, and report on the feasibility of offering advice and incentives to property owners who wish to manage surface water within their own curtilage rather than discharging to the surface water or combined drainage system. This could draw inspiration from:

1. Portland’s Downspout Disconnection Programme (this disconnected over 56,000 roofs from the city’s combined sewer system)
2. The Puget Sound’s 12,000 Raingarden Project
3. Melbourne’s 10,000 Raingarden Project

Secondly, as part of Climate Change Impact & Management report I will propose that Council Officers investigate and report on the feasibility of installing on-street bioretention planters to intercept polluted road runoff and support biodiversity as part of the ongoing investment programme.  This could draw inspiration from:

1. Case studies developed by TfL
2. Water Research Foundation Guidance
3. Portland’s Green Streets Programme

These are small changes which will make our capital more resilient to climate change, whilst also reducing the amount of pollutants reaching water courses and increasing biodiversity. People will ask about the cost, but the reason other cities are taking this approach is because it is cheaper.

A cityscape like this is the alternative: