[5] A channel was constructed from the basin to an elongated oval stone well chamber with steps descending to the interior at either end.

[5] The spa remained neglected for many years, until 1972 when An Foras Forbartha (who were later absorbed into the Environmental Protection Agency (Ireland)) reported the area as being of scientific interest.

[12] [13] The Louisa Bridge Spring and Roman Bath is situated in the Rye Water Valley/Carton Special Area of Conservation (Site code: 001398).

[14] One of the qualifying features of this area for SAC status is the presence of the Habitats Directive Annex I priority habitat as 'petrifying springs with tufa formation (cratoneurion)' (the other qualifications are the presence of the Narrow-mouthed Whorl Snail (Vertigo angustior) and Desmoulin's Whorl Snail (Vertigo moulinsiana).

The European Environment Agency notes that the Kingfisher (Alcedo atthis), a species protected by the EU Birds Directive, occurs at this site.

[15] The seepage of the springs of the Leixlip Spa flows down the terraces at the site to the River Rye, providing an interesting ecosystem, as described in the National Parks and Wildlife Service (Ireland) Site Synopsis: "The marsh, mineral spring and seepage area found at Louisa Bridge supports a good diversity of plant species, including stoneworts, Marsh Arrowgrass (Triglochin palustris), Purple Moor-grass (Molinia caerulea), sedges (Carex spp.

The mineral spring found at the site is of a type considered to be rare in Europe and is a habitat listed on Annex I of the E.U.

The Red Data Book species Blue Fleabane (Erigeron acer) is found growing on a wall at Louisa Bridge.

"[2]In this Special Area of Conservation, the site surveyed by the National Parks and Wildlife Service (Ireland) was found to contain a complex of tufa-forming springs, flushes and pools as well as paludal tufa, oncoids/ooids and marl.

"The petrifying springs at Leixlip Spa give rise to a mosaic of wetland habitats of immense significance for the rarity, fragility and species-richness of the flora and fauna they support , creating a unique and irreplaceable natural resource.

[19] The work by Blake noted that the Irish thermal springs are found in Carboniferous limestone bedrock along a lineament running from North East to South West Ireland, broadly along the line of the Iapetus Suture Zone.

Blake also noted that this spring has a residence time in excess of 30,000 years, suggesting the waters are a mixture of groundwaters from different recharge areas and sources.