A study commissioned by the Department for Infrastructure has recommended building a £20m flood prevention scheme in Downpatrick.

The town was hit by serious flooding in November 2023 when Storm Ciarán brought exceptionally heavy rain to Northern Ireland.

The engineers’ report suggests a scheme involving culverts, embankments and pumps.

The infrastructure minister said further work would be undertaken to determine whether the scheme would be economically viable.

Liz Kimmins added: “Flooding in Downpatrick – and how to reduce that flood risk – is an extremely complex issue with many variables.

“That is why it was important that a comprehensive study was carried out to inform the most viable and effective way ahead.”

The study, produced by engineering consultancy Amey, considered 14 possible schemes.

These were reduced to a shortlist of two, which were considered technically viable.

The preferred option would offer flood protection to 78 businesses and 28 homes.

The total estimated cost of £22.5m includes maintenance costs of around £2m.

A cost-benefit analysis suggests the scheme would prevent flood damage, which would cost around £26m to repair.

The study cautions that what is proposed is a “complex scheme” and that given the risks and unknowns at this stage, it may become economically unviable as work on the design proceeds.

It concludes: “Further investigations are recommended prior to detailed design to mitigate some of these key risks and confirm economic viability through a business case.”

Mal McGrady is the chairman of the Downpatrick regeneration working group, he said action needs to be taken now before flooding happens again.

“We can’t rely on chance… we have to have preventative measures in place… we need infrastructure changes in place to make sure this never happens again.”

He said the experts, the feasibility study and report should show how the damage from flooding has happened.

“Reports will have set out and will set out what caused this or what potential accumulation of events caused this.”

After speaking with the Infrastructure minister, Mr McGrady said the costing of the scheme is coming out at “£22 odd million”.

He said the concern with that number is where the money will be found.

He added that the unspent funding was not an option: “My understanding is that that (funding) has already been redistributed to other ministerial portfolios and has probably been spent at this stage, so we are probably looking at new money.”

by Barra Best, BBC News NI weather presenter

Homes and businesses in Downpatrick were left underwater when Storm Ciarán hit in November 2023.

The town centre and surrounding areas suffered severe flooding following weeks of heavy rainfall, with Market Street and low-lying parts of the town particularly hard hit.

Floodwater was made worse by high spring tides that prevented the River Quoile from discharging into Strangford Lough, which would have helped lower flood levels.

Downpatrick has suffered similar flooding incidents in the past.

The commissioned study highlighted the need to protect sensitive habitats around Stangford Lough, as well as archaeological and historic sites in Downpatrick.

With climate change expected to increase the frequency and severity of flooding, the Downpatrick Flood Alleviation Scheme, if it proceeds, could prove a critical step towards safeguarding the town’s homes, businesses, and heritage.

It comes after Infrastructure Minister Liz Kimmins said on Thursday that updated legislation for water and flood management would be a “major step forward”.

The NI Executive has approved bringing the Water, Sustainable Drainage and Flood Management Bill to the assembly which, Kimmins said, would help “meet the needs of our growing population and adapt to changing weather patterns”.