Drilling contractors will begin investigation work in the Hirael area of Bangor next week, to establish the ground conditions on which new sea defences can be built.
The Hirael Flood Alleviation Scheme is a project looking to reduce the risk of flooding to commercial and residential properties in the lower Hirael area over the next 100 years. The project is still in the planning stage and various options are being considered.
The main benefit of the project is the reduction of the risk of tidal and surface water flooding properties in Hirael. The proposed scheme(s) will reduce this risk for 79 properties from a major tidal flooding event up until 2050, after which time, further consideration of the management solutions will be required.
Historic flooding in Hirael has been caused by high rainfall coinciding with a high tide. The Afon Adda, which flows underground for 4 km through the centre of Bangor was diverted through culverts which were too small, and therefore when high tide occurred at the same time as peak river flow, the culvert was overwhelmed.
Extensive engineering works to alleviate the flood risk from the Afon Adda were completed in 2008, however, flood risk from the coast remains a risk to the area. With current sea level rise predictions due to climate change, the main risk to Hirael now comes from tidal flooding.
The coastal frontage of Beach Road is comprised of a mixture of defences which are beginning to show their age, and modelling has revealed they would only protect Hirael from a 1 in 3 year flood event (33% chance of such a flood happening in one year).
The current favoured option is building a new sea wall along the promenade and therefore preliminary ground investigations must be completed at eight locations between Glandwr Road and Beach Road car park. Other sea defence options include a flood gate situated to the south of Beach Road car park and raising the level of car park.
Drilling contractors will begin ground investigations from the 25th January to 31st March. These essential works are being carried out to establish the ground conditions on which the new defences will be built, and will assist engineers in designing the wall’s foundations.
This will bring some, mostly sound, disruption to the community for short periods during the work, and will involve temporary closures of seafront footpaths. For a short time, there will be no through access to ‘Y Bae’ via Glandwr Road.
For more information and updates, visit: https://hirael.ygc.cymru/
This flood animation shows the flood extent and water depth caused by a 1 in 50 year, 8-hour long storm event if there were no defences in place in 2055, and if the current promenade was left unmaintained.
Photos: Hirael Bay Bangor – Flooding in Hirael (Orme Road) in 1923.
