At least two years before work starts on this flood relief scheme in Tipperary

It will be the middle of 2026 “at the earliest before a shovel goes into the ground” to begin work on the Marlfield Flood Alleviation Scheme in Clonmel.

This was stated by Tipperary County Council civil engineer Michael Scully at a meeting of Clonmel Borough District.

However, he said that work would be undertaken in the meantime to provide for more control of the lake, and more control of the stream that flows out of the lake. This would provide for more safety in Marlfield village, with a far less risk of flooding.
He described the overall project as “complex and complicated”.

After Cllrs Pat English and Michael Murphy had asked about the timeframe for the project, the county council engineer said they were “going into the unknown”.

In the UK there was a panel of experts for dealing with projects like this, but Ireland didn’t have anything like that and there was no legislation for dealing with dams.

They were relying on Nicholas O’Dwyer Consultants to go to the UK for advice and expertise, and that was slowing it down. He said it would be the end of the year before the preferred design option is available and they would have to go to the UK to get the design work done.

This was a proposed natural heritage area and upstream of a special area of conservation. He estimated that it would be next year before a planning application would be submitted.

Mr Scully said that two preferred options would be put out to public consultation at the Talbot Hotel in Clonmel in February.

These would be to either build a new dam behind the existing dam, which is 250 years old; or to see if the level of the water could be lowered, which would effectively return the lake to its original state as a marsh, with a river running through it.

Site investigations would also be carried out and these, along with the feedback from the public consultation, would result in a preferred option being chosen by the summer.

The engineer said that all of the modelling and surveying work had been completed, and an options development report had been produced by Nicholas O’Dwyer Consultants.

A public consultation process had taken place early in 2023, followed by a meeting with senior members of the OPW in November, and from which the two preferred options were decided.

Mr Scully said that the project had started out as a scheme to prevent flooding in Marlfield village. However it had “morphed into a far more complex scheme” to make the 250-year-old dam safe so that it would last another 250 years.

No drawings or designs of the dam or information about its construction were available and there was uncertainty about how it would continue to react to severe weather.

Because of this, it would take more time to present the final options that they were happy with and that they could stand over, he stated.

There were no concerns about the safety of the dam but they had to treat it as the worst case scenario because there was so much uncertainty about it.

The heavy rain last October and over Christmas hadn’t caused any flooding issues so the measures that had been taken so far had worked.

A fairly robust flood management plan was in place for the village.

An old sluice valve on the lake had been blocked and it provided no control over the level of the water.

A contractor would instal a new pipe from the sluice into the stream to provide control of the lake for future flood warnings.
Mr Scully said they hoped to have a contractor on site by the end of this year to do that work.

When Cllr Siobhán Ambrose asked about funding, he said that the OPW at the highest level had committed to backing the scheme.

The scheme would be designed for the worst flood that could happen in 100 years.

Cllr Niall Dennehy said that the visuals of the lake would be “seriously compromised” if the level of the water was reduced to leave a marshy bed with a river running through it.

District Mayor Richie Molloy said that Marlfield Lake was so important to the town from a tourism point of view and it was great to hear that this work is ongoing.