Seems to refer to "The Weir Pool", located at the grassland southwest of Grennan College and is visible on Maxar Premium and Esri (which is older at the moment of writing).

Suggested tags; survey needed

leisure=swimming_area
sport=swimming
name=The Weir Pool
operator=Thomastown Community River Trust
operator:website=http://www.tcrt.ie/
contact:email=theweirpool@gmail.com
contact:facebook=ThomastownCommunityRiverTrust
contact:instagram=ttownweirpool
access=yes
opening_hours=24/7
fee=no
supervised=yes @ ...

For "supervised" and regulations see the current sign on location.

Operator website seems no longer maintained but is still linked from their Facebook. They have an old email address displayed on this website;
donalddaws@gmail.com

I believe you when you say it's EU-funded, though I couldn't find it specifically being so.