#coastal - Works to protect cliffs along Killiney Bay, in south Co. Dublin, from coastal erosion, have stepped up in recent weeks as sea born rock armour from neighbouring Co. Wicklow is been delivered onto the beach, writes Jehan Ashmore.
Integral to the works is the Irish flagged landing craft vessel, James, which Afloat reported last month following completion of refurbishment at the Kish Lighthouse for Irish Lights.
The work on Killiney Beach involves the craft operated by O'Malley Marine Plant, to shuttle loads of limestone varying between 3.5 to 5 tonnes apiece. The source for the armour is from the Roadstone Quarry with associated jetty located south of Arklow Port.
The Dun Laoghaire-Rathdown County Council coastal project at Seafield, Shankill, is the Corbawn Lane Beach Access and Coastal Project Improvement Works located at Shanganagh Cliffs, which historically is vulnerable to coastal erosion. The works involve a 180m stretch along the cliff.
According to DLRCC, the project cost as set out in the Council's 2018-2020 Capital Programme is €928,000 and allows for design, construction, project management and related costs.
Access from the cliff down to the beach was only made possible by pedestrians taking use of a series of public steps. Due to the works, DLRCC say it is not be possible to use this public access, and, depending on tide levels, it may not be possible to travel along the beach past the works.
As for direct access to the beach by road this is not possible, forcing the project to engage the services of James. The craft is ideal for such scenarios as the shallow draft vessel can approach the beach head-on and then lower its ro-ro landing ramp onto the shoreline. At this stage of the logistics, awaiting heavy machinery on the shore then drive on board to be loaded with limestone and transferred ashore.
Main contractors for the coastal works is MJS Civil Engineering based in Newtownmountkennedy. Co. Wicklow. The project arose following conclusions published in DLRCC's Coastal Defence Strategy Study 2010 and where a presentation was held in 2017 to outline recommendations.
Among the study's survey, three distinct areas along the Killiney Beach and neighbouring coastlines were identified. As for those at Seafield, findings concluded that this stretch south of Killiney beach, were deemed to have unacceptable risks, as the cliff at Shanganagh is eroding and is unstable.
Prior to the sea-born deliveries, stablising the cliff was carried out. According to MJS, a trench was dug at the foot of the cliffs formed of soft clay, this led to a concrete wing wall constructed to underpin the works. At this stage the rock-armour is now been placed firmly at the wall to secure and strenghten this part of the coastline.
Afloat confirmed with O'Malley Marine, that the works to haul the rock armour, from their side of the sea based operations is envisaged to be completed between 3-4 months.
In addition, MJS cited a minimum of 6,000 tons will be required at the foot of the cliffs, though potentially this estimate could increase to 10,000 tons. The engineering firm expected work to be completed in July.