Thursday, August 11, 2016

'Not enough water for floods' — ESB

The lack of floods being released on the Liffey from Golden Falls at Ballymore is because there hasn't been enough rainfall to allow it, writes Brian Byrne.

That's the ESB response to a Diary query in relation to our earlier story on concerns about the health of the river as expressed by angling interests.

A spokesman said that water release at Golden Falls beyond the statutory requirement of 1.5 m3/sec at all times depends on the level of water in Pollaphuca reservoir.

"That level is maintained to strict minimum levels for water abstraction by Dublin Corporation," the ESB says. "Since mid-April we have been at or below our weekly guideline level in the Pollaphuca reservoir and consequently we have been only discharging at Pollaphuca to match the statutory requirement in Golden Falls."

The company says that statutory levels of water release were maintained all through the overhaul of the intake gate at the Golden Falls dam begun in May, work that was essential to the safe performance of the dam.

The spokesman also noted that all station works are scheduled to minimise impact on fisheries. "Analyses of the run of salmon through the Marine Institute fish counters located at Islandbridge and at Leixlip station indicate that salmon only began appearing in early June onwards. Salmon and trout spawning typically begins in late November up to mid-January with fry hatching and emergence in late April/May."

There have been similar instances in the recent past where only the statutory flow requirement was released continuously for several months due to low levels in Pollaphuca, during the periods March-October 2011 and March-October 2013.

Any decision to discharge more than statutory flow from Golden falls will require an increase in the level and water inflows into Pollaphuca reservoir, from significant increase in rainfall in the catchment, the ESB says.