Newlands Cross Upgrade EIS - European Investment Bank

South Dublin County Council N7 Newlands Cross Upgrade
Environmental Impact Statement
Arup Consulting Engineers
for this entire length drains into the Fonthill Road drainage network. The median and
westbound verge over this length outfall to the Ballymount Park watercourse adjacent to
Belgard Road. Further east of Newlands Cross, the mainline drainage continues as far as the
Red Cow Roundabout and then outfalls into the M50 drainage network.
The Fonthill Road drainage network drains away from the N7 mainline towards the Camac
River. The Belgard Road drainage network drains towards the N7 mainline immediately
beyond Newlands Cross, and outfalls to the adjacent watercourse. This surface water
eventually makes its way into the Camac River. South east from Newlands Cross, along the
Belgard Road surface water drains away from the N7 mainline, and towards the Dodder River
catchment. It eventually drains into the Killinarden Stream in Tallaght which flows into the
Dodder River.
The existing drainage network at Newlands Cross is indicated in Figure 14.2.
14.3.2 Catchment Study
14.3.2.1 Camac River
The Camac River rises in the Dublin Mountains at Corbally near Saggart, southwest of
Dublin. It flows in a roughly northerly direction and is culverted at Clondalkin and under the
M50, just south of the Grand Canal. The river flows on an approximately parallel route to both
the N7 and the Nangor Road in the Clondalkin area. It flows primarily through Corkagh
Demesne and Clondalkin Park in Clondalkin and supplies surface water to a number of ponds
within these green spaces. A small tributary of the Camac flows from the area adjacent to
Cheeverstown Quarry under the N7 at the Kingswood Interchange and connects to the Camac
River west of Corkagh Demesne. After passing under the M50 the Camac River flows parallel
to the Nangor Road and passes through the areas of Bluebell and Lansdowne Valley Park in
Drimnagh. It crosses the Grand Canal at Davitt Road and flows in a north-easterly direction
through Inchicore and Kilmainham before discharging into the Liffey in proximity to St.
James’ Gate. The catchment of the Camac River upstream of the M50 is approximately 44
km 2 .
Ballymount Park is situated between the Belgard Road and the M50 and south of the N7. The
park has a surface water drainage system including a number of streams draining into a central
pond. Surface water runoff from the N7 between Newlands Cross and the N7 / M50 Red Cow
Junction drains to the Ballymount Park system. Surface water drains out of the pond and
subsequently flows in a north westerly direction culverted under the M50 and drains to the
Camac River at Walkinstown.
14.3.2.2 Water Quality
The biological river quality (Q or Biotic Index) classification system is set out by the EPA and
is summarised in Table 14.1.
Table 14.1 Biological Q rating Criteria (EPA, 2006) 4
Q Value
Community
Diversity
Water Quality Condition
5 High Good Satisfactory
4 Reduced Fair Satisfactory
3 Much Reduced Doubtful Unsatisfactory
2 Low Poor Unsatisfactory
1 Very Low Bad Unsatisfactory
0 None Very Bad Unsatisfactory
December 2007 Page 222