Hydro G Final report - Kildare.ie

Hydro-G FINAL REPORT
this terrace, there is a deep drop in elevation, which is a natural feature although deepening by
approximately 1m did occur in 1990’s to prevent people from entering the Intel site from the Leixlip
Spa site (pers. comm. with Mr Cullen, Intel Ireland). After the Roman Bath end of this terrace, the
topography drops significantly.
The second terrace comprises a narrow strip with water flowing overland at its eastern side. This
water originates from two streams that flow out from the Lower Pond of the first terrace. Water
discharges into this terrace also from the outlet from the Roman Bath. This terrace is generally wet
and it is difficult to distinguish whether water comes from the overland flow only or also seeps from
the ground. Large amounts of calcium carbonate (tufa, calcite) are present in numerous locations on
the ground surface. Well structured calcite can be found on a slope where water cascades from the
two streams formed after the Lower Pond. However, small pieces of tufa can be also found on the
ground throughout the terrace, which suggests that water seeps also directly from the ground.
Flows are relatively strong at this terrace. However, sloping topography rules out measuring of
these flows.
The third terrace contains a small pond surrounded by wetland vegetation. Bedrock outcrops are
visible and large calcite deposits can be found in various locations, but specifically in eastern parts of
the pond (referred thereafter as ‘tufa pond’). A large hole was found in the bedrock face, on the
eastern side of the terrace, and a distinct water discharge was recorded in this location.
The fourth terrace covers an extensive area between (and beneath) the ‘tufa pond’ and the river
floodplain. This terrace is overgrown with rush-like vegetation and the ground is soft and soggy.
Water movement on this terrace is through numerous small streams, which run towards the river.
Two major streams were recorded, one on the eastern end and one on the western end of the
terrace.
The floodplain constitutes the fifth terrace. A walkover survey was conducted. Streams were
identified discharging into the river. No distinct springs were identified. However, this terrace is
overgrown with dense reed-type vegetation. Other terraces are grass-moss covered. This area was
grazed historically but this practice was discontinued in the 1980’s.
3.2. Water Flow within the Site including Spring and Seepage Locations
The following springs and seepages were identified during the Hydro-G’s site visits:
1. The Spa Well – a warm spring at the most elevated, southern end of the site;
2. Cold seepage springs at the east side of the first terrace (in vicinity of ‘filtering ponds’);
3. Cold springs at the third terrace. There are numerous springs at this level. Distinct water
discharges were identified at the southern verge of the ‘tufa pond’ and through a large hole
in the bedrock face (0.3m x 0.4m) at the eastern side of the rock cliff and from the ground
on the western side of the site;
4. No distinct seepages and springs were identified at the fourth terrace. However, tufa
deposition is common in a base of small streams that run on both western and eastern sides
of the site. More solid deposits were identified in places where the topographic gradient is
high and water cascades from one step to onother.
Project No.: 07_136 -9-
Leixlip Spa