Limerick and Clare are on flood-watch after the ESB increased the flow through the Parteen Weir for a second day running.
The flow rate is now 405 cubic metres per second, and water levels are continuing to rise on Lough Derg following days of heavy rainfall.
At its previous peak - in the days after Storm Desmond - the flow was 440 cubic metres per second.
ESB is warning that the increased flow means areas downstream in Limerick and Clare are at risk of flooding.
