Too many flood defence projects in Northern Ireland are being completed late and over budget, a report has warned.
In some cases the costs have spiralled more than 200% over initial estimates.
The details emerge in an Audit Office report published today which examines Northern Ireland’s flood prevention and management plans.
It concludes that more can be done to improve systems for preventing and managing flooding.
Key issues include the time and cost overruns in a number of major projects. Too many calls to a flooding hotline were abandoned, while the report also states the need for a more effective, co-ordinated approach to flood risk identification.
Auditor General Kieran Donnelly said: “Flooding is a natural process that can be devastating to those affected. It is important that when public money is spent on flood prevention and management it is done so wisely.”
It is estimated that 46,000 of Northern Ireland’s 830,000 properties are within an area likely to be flooded once every 100 years.
Several serious episodes of flooding have occurred over the last 20 years. The most recent were caused by storms Desmond, Eva and Frank around the turn of the year, which left roads closed and homes ruined.
It is generally accepted that Northern Ireland is likely to experience more frequent flooding in the future. Most storm water drainage systems are designed to cope with a one in 30 year flood, but experts predict that this will be exceeded.
The Rivers Agency is the statutory drainage and flood defence authority for Northern Ireland.
Several other departments and agencies also have significant flood-related responsibilities, including TransportNI, NI Water, the Department for Infrastructure and local councils.
Over the last five years the Rivers Agency has invested nearly £33m in new flood defence assets, improving protection to 694 homes by completing 20 projects.
Post-project evaluations found two cases had significant cost overruns. New flood walls at Moneymore were built at a cost of £2.2m – 85% more than the estimated cost of £1.2m. The increase in cost was due to a low initial estimate for the works, an increase in the extent of the works, and the contract being undertaken when the economy was buoyant.
In the second case, a section within a project at the Mount Vernon stream in Belfast, estimated at £189,000, was completed at a cost of more than £590,000 – 231% over budget.
This was due to less accurate and very optimistic initial estimates and greater uncertainty at conceptual design stage.
Auditors found eight out of 13 capital projects (62%) between 2007 and 2015 finished over time or budget.
Today’s report also says a hotline for flooding victims needs to be improved. Statistics show that calls abandoned peaked in 2012 at 27%. This number fell to below 8%, but has since risen to nearly 16% in 2015.
Mr Donnelly added: “My report recommends that work is needed to ensure that the Flooding Information Line, the main source of contact for those affected by flooding, is improved and that further work is undertaken to ensure that new flood defence assets are completed on time and within budget.”