Unless a water treatment plant linked to the Vartry Reservoir in Roundwood, Co Wicklow, is upgraded, Irish Water would eventually have to restrict water supply to Wicklow Town and Greystones and places in between, or cease new connections to the system, an oral hearing into the proposal heard on Monday.
However, if the proposed upgrade proceeds communities served would be provided with “safe and sustainable drinking water” complying with standards. The upgrade is geared to increase treatment plant output by 10 to 15 million litres of water per day.
The volume of water taken from the reservoir, which dates from the 1860s, or the catchment of the Vartry River, which flows from the reservoir, through the Devil's Glen and Ashford, and into the Irish Sea north of Rathnew, would be the same as now.
Irish Water has also committed to providing five million litres per day into the river on a consistent basis, which the utility says will protect the river, animals, fish and plants reliant on it, during periods of drought.
The oral hearing is being held by An Bord Pleanála at the Glen View Hotel in the Glen O'The Downs, Co Wicklow. It is presided over by senior inspector Mairead Kenny.
‘Some disruption’
Rory Mulcahy SC, appearing on behalf of Irish Water, said the extraction of water that would be treated in the new plant was “not capable” of having an adverse effect on wetlands associated with the Vartry River or the woods of the Devil’s Glen. During the two-year construction of the plant, to be built beside the existing water treatment facility, there would be “some disruption” to animals and plant life but this was not expected to be adverse, he said.
The river had sea trout, brown trout and minnows and the discharge of five million litres a day into the river would have a positive effect on it, he said.
Dr Martin O’Farrell, a fisheries biologist, said it was clear “that the proposed release of daily water met the required level of water to support the fish population”.
The existing plant was become “increasingly inefficient,” said Mr Mulcahy. “Due to the condition of the existing plant, the volume of treated water leaking from the plant has increased over the last number of years and the cost and work involved in maintaining the plant and the existing water supply is also increasing.”
Permission for the plant was granted by Wicklow County Council in November 2016. But environmental concerns from a diverse range of sources, including Inland Fisheries Ireland, the River Vartry Protection Society and the Vartry Anglers Conservation Club, and local interests including Mount Usher Gardens in Ashford and the Avoca food, plant and retail chain prompted an appeal to the planning board.
Appearing for objectors, solicitor Alan Doyle said there were two main areas of concern: the flow of water into the river; and waste from the plant. The proposal was ad hoc and seemed to be “a little bit here, a little bit there” amounting to the reconstruction of a 150-year-old structure.
According to Irish Water, he said, between 10 and 15 million litres a day leaked from under the reservoir dam and an unknown amount of water also leaked from the Callow Hill tunnel. Therefore, the amount of water getting into the river catchment area was far greater than the five million litres Irish Water was proposing to discharge.
He questioned the data on water flow through the Devil’s Glen on which the utility was basing its discharge plans. He also questioned what would happen to waste from the treatment plant, which he described as a “sludge” containing fluorine and aluminium sulphite.
Irish Water planned initially to discharge “four mega litres” of waste water from the treatment plant “indirectly into the Vartry River”, but now said the waste water from the plant would be “backed washed” into the reservoir, he said.
‘Residue’ worries
This, Mr Doyle said, meant that Irish Water now planned to take the waste water from the plant “and blow the residue back into the reservoir where it was going to miraculously disappear”.
He said there was no information as to whether this residue would eventually reach a level that it would “totally choke the water treatment plant”.
“There is no proposal in this application to do anything with the sludge. It is simply going to disappear and that Irish Water’s justification for the proposal,” said Mr Doyle, adding that “waste is going to build up over time until the point where it causes a catastrophic failure at some point in time”.
