- 8th September 2021
- Posted by: Miranda Pont
- Category: Blog
We have been working on flood risk in Scotland for over 20 years. In that time our technical experts have accrued excellent knowledge of the risk and the issues, and the structures in place to help. David Bassett, Director, reviews some of the more recent projects – from flood hazard mapping to flood resilience.
Through our work on the Scottish Flood Defence Asset Database we reviewed overall progress on flood risk reduction across Scotland in 2020 and presented this at the Sniffer conference in 2020. This helps understand the scale of flood risk across Scotland and showed that with climate change there will be an additional 110,000 properties at risk. At present we are reducing the risk to around 547 each year. Simply to keep paces with climate change, this would need to increase to 1833 per year. A significant increase! Scotland has reduced risk to around 13,000 properties since the 1961 Flood Act around 4.6% of those at risk, and in England the Environment Agency reduced risk to 182,000 properties in three years or 5.8% of the properties at risk.
Helping with flood resilience
Over the last 8 years, we have worked on a two successive frameworks with the Scottish Environment Protection Agency (SEPA) to develop flood resilience across Scotland. Within that time we have developed and improved flood forecasting and warning for large areas of the coast on the Solway and Moray Firths, Western Isles and between Aberdeen and Angus as well as on the River Carron, Annick Water, Brothock Water, South Esk and Carron in Stonehaven and several inland catchments.
New Pluvial Flood Hazard maps
Our most recent appointment is to develop new pluvial flood hazard mapping across Scotland. We will use Jflow to produce maps on a consistent 2m grid across the whole of the country. Using the regional pluvial mapping created by JBA in 2013, SEPA had developed their understanding of the risk posed by surface water flooding and particularly the increase in risk associated with climate change using a 20% uplift in rainfall. The SWMP guidance (2018) showed 23% of Annual Average Damages associated with flooding across Scotland were forecast to come from surface water flooding and of the 27,500 homes predicted to be at risk, 39% are in areas of higher social vulnerability. Climate change was predicted to increase the numbers of homes and business at risk by 45%.
Good mapping of surface water is really important as this type of flood risk impacts many urban areas, and increased density of development increases run off and flooding, and reduces the space for flood waters to flow safely through communities. The new mapping that we are generating for SEPA will use the latest ground models, revised rainfall and the new climate change prediction from UKCP18. This year were working on the pilot studies and will roll out modelling across Scotland in 2022. Recent flooding on the 3 July in Edinburgh showed the vulnerability of many areas. There appears to be good correlation with the regional maps and hopefully some of the new data will help with map verification.
We are also helping Local Authorities in Scotland to understand flood risk and opportunities for mitigation through Surface Water Management Plans including in areas of Argyll and Bute, Clackmannanshire and Angus. Even in Scotland where SuDS have been used for over 25 years, there are still significant problems to be resolved. Rene Dobson or Steven Thomson can help you with SWMP.
In some cases property level protection and resilience is being considered and we recently completed a pre-scheme survey of properties in Campbeltown, which is currently seeking funding. Shelley Evans can be contacted for more information about Property Level Protection and property flood resilience.
Recent Flood Protection Schemes
At a community scale, we have helped The Highland Council reduce risk to 276 homes in Smithton and Culloden, a community at risk from small watercourses and surface water flooding.
A presentation of the scheme can be found on 2021 Sniffer site Smithton and Culloden Flood Protection Scheme . As well as protecting homes, the scheme de-culverted and restored the Smithton Burn and developed two new online reservoirs in parkland. In Culloden park, wildlife areas were embedded within the scheme. Previously we have worked on improving defences in a variety of sites in urban areas such as at Renfrew and alongside sensitive rivers such as the South Esk in Brechin and in the Tweed catchment at Galashiels and Peebles. For more information on our capacity in Flood protection Schemes contact Rene Dobson.