Naas lakes due for dredging

The Naas lakes are due for silt dredging, a process that last happened 15 years ago and cost €300,000.

However, the suggestion of a local councillor could see this task eliminated from the council’s cost book if it was to work – by using natural filtration.

At a recent meeting of the Naas members, cllr Seamie Moore brought a motion “that the council considers the diverting the incoming element of the hospital lakes feeder river through an existing wetlands area”. 

“This would benefit the natural plant growth in the swampy area and drain the outfall of its nutrient enrichments that professionally acquired reports indicate are the reasons for the suffocating algae growth prevalent in the lakes over the past several years,” he continued.

“This is depriving water-based bird life of its normal feeding grounds, and has also reduced the fish stocks in all of the sequentially linked rivers and lakes that follow,” he pointed out.

“This proposal will be considered as part of any proposed works to the lakes, and can be examined,” agreed Simon Wallace, Kildare’s parks commissioner, who said it could be looked at alongside the dredging proposal which his section is grappling with at the moment.

“The (lakes feeder) river comes in from the Ballymore and Killashee areas, and somebody out there is not very careful with the use of nitrates – and there’s a lot that comes in,” he said.

“These nitrates begin to cause the pond scum, but because the mud on the bottom (also brought by the feeder river) is rising, therefor the gap between the mud and the surface gets smaller, which makes the water warmer, which promotes more growth,” he said.

“Now, there is a swampy area beside this river, before the lakes, on the Kilashee side, and I want to use that swamp as a natural filter,” he reasoned.

“I got the idea from seeing systems like this being incorporated in new estates as a climate change measure, as a feature of this is it grows the swamp ” he said, although, he did concede a minor problem with his suggestion.

“The feeder river travels alongside the swamp are, and I’m asking to divert this river into there. 

"Although the first thing would be to find the farmer who’s spreading the nitrates. Simon Wallace said it could be looked at when they’re looking at the dredging, which I accept,” said cllr Moore. 

"I know that is going to be a very substantial sum of money to dredge (he recalled €300,000, 15 years ago), and they had to take it away and leave it somewhere to dry. 

"I think it was thousands of tonnes, but it's hard to judge when the muck is wet."