SHANNON’S flood defences are not adequate, and unless €14.6 million is invested, a massive €693 million worth of damage could result.
That is the conclusion of the report on the Shannon Town and Airport embankments, carried out on behalf of Clare County Council, the Office of Public Works and Shannon Group.
The report warns, “There are considerable concerns regarding the adequacy of the existing embankment flood defences fronting both Shannon Town and Airport. The findings of the investigations undertaken for this report confirm that these concerns are justified. The embankments do not provide an adequate standard of protection from flooding from the Shannon Estuary.”
It said that because of the hydraulic connectivity between the town and the airport, and the common flood risk, measures should be taken jointly by the three bodies. Regarding what works should be carried out, the report says, “The preferred method of providing an appropriate standard of defence to the two frontages is by the raising, widening and armouring of the back faces and crest of all the embankments along the frontage, and the armouring of the front face of the Airport embankments and E6 (a name given to one of the embankments in the report) fronting Shannon town. This method is estimated to cost in the region of €14.6 million including an allowance for a mid range climate change scenario. This reduces flood risk relating to water levels overflowing and waves overtopping the embankments, and, more importantly, the risk of breaches in the embankments due to erosion of the front, crest and back face of the embankments.”
Explaining the benefits of the solution proposed, the report says, “It is considered to be an option that satisfies the requirements of reducing overflowing and overtopping volumes, reducing breach risk due to erosion of the crest and back face; and reducing breach risk due to wave action on the front face.
“This option should be combined with monitoring, maintenance, flood warning, development restrictions and other non structural means of managing flood risk. It is a resilient solution and is easily adaptable to increases in sea levels and storminess in the future. Other options considered either do not provide the necessary standard of protection, or are extremely costly. All options relating to holding the line of the existing embankments are likely to have a similar range of ecological and environmental impacts.”
If nothing is done, the consequences will be serious, the report warns. “Sections of embankments do not provide an appropriate standard of protection. In the event of failure in the do nothing case there will be a loss of the Airport, the Town and adjacent industrial areas. The value of the infrastructural assets in the Airport itself is estimated at greater than €318 million. Residential properties within the Town are likely to have a value in excess of €375 million (based on a population of 10,000, four people per house and a value of €150,000 per house). This ignores commercial properties and community infrastructure within the town and the value of 100ha industrial area adjacent to the town and airport. This would be lost in the do nothing case.”
Writing in the report, Clare County Council chief executive, Pat Dowling, said, “The report clearly shows the risk to Shannon in its totality and raises a number of red flags which we cannot ignore. It now requires a concerted response and a determination to protect our town, jobs, airport and communities for future generations. In this regard it is agreed that the protection of the town and airport embankments should proceed as one project.”
The Project Steering Group, which consists of the County Council, the OPW and Shannon Group, are to oversee the progression of a combined embankments and town project, to detailed design stage.
Councillor Gerry Flynn said he has long sought to have improvements made to flood defences, and was pleased the importance of the work is now being acknowledged. “I’ve been following this up for years and banging my head against the wall, but finally they came to the table and accepted that the town and the airport cannot be treated separately, and that there’s a necessity for this work to be carried out.”
He praised the now retired Council engineer Tom Tiernan who he said had provided him with very helpful and accurate information, while he said more delays in putting Shannon’s defences right must be avoided. “The appointment of consultants to take it to the next level and the allocation of funding from the Department is crucial.”