Dáil Éireann Debate, Wednesday - 29 November 2023
54. Deputy Brendan Griffin asked the Minister for Public Expenditure, National Development Plan Delivery and Reform if he will review the impact of coastal protection works at Rossbeigh, County Kerry; if he will consider a view sent in correspondence (details supplied); and if he will make a statement on the matter. [52892/23]
View answerErosion of the sand dunes at Rossbeigh is particularly evident from 2001 onwards. This erosion impacted both the width and volume of the sand dunes, particularly in the northern extent, culminating in a breach of the sand dunes in December 2008. Both the accelerated erosion from 2001 onwards, and the breach itself in 2008 can be linked to a spike in the frequency and duration of storm events which would have contributed directly to the behaviour of the dune system.
The dune system has continued to evolve since the breach, with a variety of post-breach surveys and analysis undertaken to help monitor this behaviour. This evolution occurs over years or even decades. The breach has widened gradually over time, as would be expected, and a further loss in the area of sand dunes at Rossbeigh has been observed.
Aided by the formation of a sand bar to the seaward side of the dune habitat, the rate of vegetation loss has decreased over the years. Colonisation of marram grass around the breached area and an increase in the overall vegetated area have been evident in recent years. The observed regeneration of the dune habitat will remain vulnerable to storm events in particular, but will continue to be monitored, with a particular focus on sediment transport processes and the evolution of the breach location.
There is no evidence to support the removal of the installed rock armour at the southern extent of Rossbeigh. This rock armour protects dune habitat, the access road, and the playground. The removal of the rock armour would increase the vulnerability of these assets.
It is also noted that the dune system as a whole is still in a phase of post-breach evolution. The formation of offshore features and tidal channels impacts on the existing breach and are directly linked to sediment transport processes in the area.
The installation of groynes would represent a significant human intervention impacting sediment transport processes. Whilst the merits of such interventions remain under consideration if they are beneficial to the long-term sustainability of the dune system, there is no merit in the installation of such measures at this time, particularly considering the more recent recovery of the dune habitat.
A variety of monitoring has taken place over the years. Satellite imagery and aerial photography provide an excellent source of data to quantify and monitor change including the area of dune habitat, the width of the spit, the migration of the vegetation line, and the evolution of sand bars. A range of topographical and bathymetry survey is available to complement the aerial photography and satellite imagery and assist in monitoring the evolution of Rossbeigh. Aerial photography and digital elevation data was also collected by the OPW as part of the Coastal Aerial LiDAR Survey 2021 – South to West Coast of Ireland project.
This data will feed into the monitoring of physical coastal change and the subsequent assessment of coastal change risk as set out in the Report of the Inter-Departmental Group on National Coastal Change Management Strategy.
Where vulnerable locations are identified, local authorities and State agencies will continue to engage with local communities to help ascertain the most appropriate interventions.
The works referred to in the Question were undertaken by Kerry County Council in 2014 and the OPW is not aware of any study by the Council to assess the impact of the rock armour on sediment transport.
