Oban flood risk is real
Further to your article on the rejection of planning permission for a site in Oban town centre, which I note has attracted some incredulity from a few local people, I am writing to you as a local environmental consultant with many years’ experience in the field of flood risk.
Most people don’t realise that as per Scottish Planning Policy, which the council, SEPA and developers have to follow, a new residential development must be assessed against a minimum of a 1-in-200-year risk of it flooding plus the effects of climate change on flood levels. This is to protect the property, not increase the flood risk to properties downstream by removing floodplain storage (albeit not applicable here) and importantly provide safe egress for inhabitants and ingress for emergency services.
In living memory Oban has probably only experienced less than a 1-in-50-year flood event but a 1-in-200-year event will inevitably happen and could occur at any point. Indeed, a 1-in-200-year flood could theoretically occur this year or in the near future.
As many readers will be aware, the climate change crisis is already having an effect on rainfall. With respect to flood risk, intensity is increasing and will continue to do so over the foreseeable future.
In terms of the existing developments mentioned in social media responses to your article, there has been an ongoing increase in the effect of climate change on future flood levels. Pre-2019 SEPA required an uplift of 20 per cent on the 1-in-200-year watercourse flows in Scotland. For burns such as those in Oban this now stands at 46 per cent to 2080.
Much of Oban will undoubtedly flood in the future/near future and you only need to look at SEPA’s flood map (available online) to get an indication of this. Indeed, a well-advertised informal local drop-in session was held in the Corran Halls in 2019 where the council and their environmental consultants flagged up the risk to the town. Proposed mitigation measures included construction of a circa shoulder height sea wall along the promenade and beyond, creation of floodwater storage at Mossfield Stadium/the golf course and close to the hospital, and increasing the capacity of the pumping station on the Black Lynn which historically has been needed to stop the banks over topping, particularly during high tides/ rainfall.
Very sadly, despite the widespread advertising of this meeting, only a handful of the public attended. Had some of those making the comments attended, they would perhaps appreciate the forthcoming risks to the town.