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Case Study:

Testing Roads Over Peatlands Pilot



County Offaly comprises 199,981 hectares. The topography of the county is generally flat and undulating except for the Slieve Bloom Mountains in the south west. Peatlands are found extensively around the county and these extend to approximately 32,400 hectares or 16% of the total area.

The road network in County Offaly consists of 2,164km of roads, with regional roads accounting for 392km. The county has historically experienced difficulty maintaining roads over peatlands with issues such as distortion and transverse cracking arising. However, harsh weather conditions in winter 2017-2018 followed by a significant drought period during summer 2018 resulted in a significant increase in the level of cracks and distortion of roads, including severe longitudinal cracking on many bog roads (Figure 1). In some locations, the surface of the road was good but required intervention because of cracking and distortion. Interventions on bog roads were outside the local authority’s roads programme and were carried out under emergency works.

Figure 1: Road cracking following drought in 2018.



In 2019, Offaly County Council received €165,000 from the Department of Transport, Tourism and Sport under the 2019 Regional and Local Road Grant Allocations to carry out a pilot scheme to determine the extent of peatlands situated under regional roads in the county. Offaly County Council initially carried out a desktop study
of the extent of peat under regional roads in the county to establish the routes for site investigation with high and recurring maintenance costs for each of the three municipal districts. Site investigation works on the identified routes determined the extent and depth of peat underlying key regional routes. A report and drawings have been prepared for the Department of Transport, Tourism and Sport, and the results will be used by Offaly County Council in making grant applications and prioritising future schemes.

Benefits of solution

The site investigation work will better inform Offaly County Council of the scale of the peat under the regional roads in the county and the level of investment that will be required to improve the road network by various methods.

Project Details:


Local authority project contact
Jean Ryan
A/Senior Engineer, Roads