Flood risk highlighted eight years ago

THE risk of severe flooding in various parts of Ennis from underground channels connecting tributaries and loughs within the River Fergus system, was highlighted in a report commissioned by Ennis District Council in 2001, The Clare Champion can exclusively reveal.
Consultants who prepared the Ennis Main Drainage and Flooding Study for the council warned that flooding of swallow holes in a number of locations could happen due to limited capacity and vulnerability to partial collapse or blockage.
They warned that surface flooding could occur upstream of swallow holes that couldn’t discharge quickly enough at St Flannan’s, Drumcaran More on the Lahinch Road and Ballybeg and drownstream of springs that couldn’t connect with the river due to high flood levels in the Tobairteascain area.
Water flowed over the boundary wall of St Flannan’s and Lough Girroga burst its banks resulting in substantial flooding on the Gort Road, including the industrial estate during the recent flooding after unprecedented rainfall levels.
The report stated that the swallow hole at Drumcaran More had an overflow culvert diverting high water levels to Loughvilla, which was likely to have caused flooding problems in the area.
“Other swallow hole systems which cause or could potentially cause flooding include St Flannan’s swallow hole, which has an inefficient overflow culvert system and Ballybeg swallow hole, which doesn’t have an overflow culvert.
“In the absence of overflow channels, the potential for conduit failure and severe flooding is real and must be reflected in the prevention of building developments below the level of existing overland flow outlets from the swallow holes and turloughs,” the report stated.
They proposed that construction works were necessary to augment the natural systems at St Flannan’s, Ballybeg, Drumcaran More, Drumcliff Road, Lough Girroga and Roslevan at a cost of €1 million.
Meanwhile, the need to address the insufficient flood storage volumes in the Lower Fergus was flagged in another report commissioned by Ennis Town Council, compiled by JB Barry and Partners, White Young Green.
Clare County Council purchased about 270 acres as a designated floodplain area, known as the Doora floodplain, for the tidal sluices barrage upstream of Clarecastle Bridge under the 1943 District of Fergus Drainage Act.
The report recommended that this floodplain be opened up to the Fergus Lower so that its storage could be fully utilised on successive tidal closure periods.
Councillor Johnny Flynn told The Clare Champion that these reports highlighted the need to fast-track work on the River Fergus Lower Drainage Scheme, which will provide flood protection works from Bank Place down to Doora Bridge.
He also said flood protection works are necessary to protect housing estates at Abbeyville, Bruach na hAbhann, Tobairteascain and Westfields, while work is also necessary around St Flannan’s and the Kildysart Road.
He said another phase would be needed to improve the storage capacity of the Lower River Fergus, provide new embankments and protect houses in Cloughleigh, Claureen, Watery Road and Oak Park.
Councillor Flynn expressed concern that over 80 acres of the Doora floodplain was filled in to facilitate the construction of the former county landfill facility.
Councillor Brian Meaney warned that the council would have to examine the adequacy of proposed flood protection measures, as the high watermark at Ballycoree Bridge recorded a reading of 2.7 metres compared to 2.29m in 1999 and 2.1m in 1954.
He claimed some control measures on the River Fergus had been illegally removed because of flooding on agricultural land, while the construction of the landfill and houses on floodplains had substantially reduced the storage capacity of the Lower Fergus floodplain.
Expressing concern about rising sea levels, he warned that local authorities are entering new territory in terms of flood protection; waterflow on the River Fergus on November 20 was one and half times higher than previous recorded levels.
Clare County Council senior engineer, Tom Tiernan, admitted that, apart from works in Loughvella funded from the council’s own resources, the construction works identified in 2001 didn’t take place due to the absence of an appropriate minor works scheme administered by the Office of Public Works.
Mr Tiernan noted this issue had been addressed by the OPW and the council would highlight the works that need to be carried out.
Because Ennis was at the wrong end of the priority list for flood protection works in 2001, Mr Tiernan recalled the town council engaged the consultants at its own expense to complete the study, which was sent to the OPW and helped to secure the Ennis Flood Relief Scheme.
He said the OPW had introduced a new minor works scheme to address issues such as the swallow hole protection outlined in 2001, which should be completed once they complied with the scheme and subject to the availability of funding.
Asked about the impact of Doora Landfill on storage capacity, he said it is extremely difficult to predict what would or would not have happened in relation to a particular development in light of the unprecedented rainfall.
He added the OPW is reviewing new protection works in light of what had happened in Ennis last month and would take into account what its officials had observed first hand on the ground and submissions from local authorities.