Characterisation of the River Allow Catchment

Characterisation of
River Allow
Catchment
Based on report prepared by Katie Tedd for the EPA’s WFD Integration &
Coordination Unit
November 2014

1
Table of Contents
Physical setting .......................................................................................................................................2
Topography.........................................................................................................................................2
Surface water networks......................................................................................................................2
Climate................................................................................................................................................2
Soils.....................................................................................................................................................2
Subsoils ...............................................................................................................................................2
Geology...............................................................................................................................................3
Hydrogeology......................................................................................................................................3
Protected Areas ..................................................................................................................................4
River Allow surface water.....................................................................................................................17
Hydrometric data..............................................................................................................................17
Chemistry data..................................................................................................................................18
Biological data...................................................................................................................................18
Water Framework Directive surface water body status...................................................................19
River Allow groundwater ......................................................................................................................23
Groundwater levels...........................................................................................................................23
Groundwater quality.........................................................................................................................24
Water Framework Directive groundwater body status....................................................................25
Pressures...............................................................................................................................................27
Diffuse pressures ..............................................................................................................................27
Point pressures .................................................................................................................................27
Susceptibility.....................................................................................................................................27
Conceptual model.................................................................................................................................34

2
Physical setting
The River Allow catchment is located in north county Cork, to the north west of Mallow. The
catchment has an area of 310 km2
. Newmarket and Kanturk are the largest towns within the
catchment (see Figure 1).
Topography
The River Allow catchment is located in the upper north-west reaches of the Munster Blackwater
(Figure 2). It is bounded to the north-west by the Mullaghareirk Mountains (highest elevation 408
maOD). Ground elevation steadily decreases from north-west to south-east (Figure 3) where the
River Allow joins the River Blackwater at an elevation of 70 maOD.
Surface water networks
The River Allow rises in the Mullaghareirk Mountains (Figure 3). It initially flows south-east for
approximately 12 km, then south for approximately 16 km, before flowing into the River Blackwater.
The River Dalua, a major tributary of the River Allow, rises in the high land to the south of the
Mullaghaeirk Mountains. It also initially flows south-east for approximately 12 km, before flowing
eastward and into the River Allow at Kanturk. The Rivers Owenanare, Glenlara and Owenkeal are
tributaries of the River Dalua. A smaller tributary, the River Brogeen, joins the River Allow
approximately 1 km downstream of the River Dalua.
Climate
Met Eireann’s rainfall isohyet map shows the annual mean precipitation varies between 1100 and
1700 mm across the catchment. The highest rainfall is in the west of the catchment and rainfall
steadily decreases to the south-east.
The effective rainfall in the catchment would vary between 1030 mm/a in the western uplands of
the catchment and 560 mm/a in the south-east of the catchment. Over the catchment area of 310
km2
,this estimate of effective rainfall is equivalent to between 5 and 10 m3
/s at the outflow of the
catchment.
Soils
The indicative soil type map (EPA/Teagasc, 2006) shows the majority of the soils in the catchment
area (70 %) are deep poorly drained mineral soils (see Figure 7). 5 % of the catchment area is
Blanket Peat associated with the upland areas in the west of the catchment. Mineral alluvium is
associated with the river channels. The remainder is shallow and deep well drained mineral soils.
Subsoils
The majority of the catchment (85%) is underlain by Shale and sandstone Till (see Figure 9). The
remaining 15% of the catchment is underlain by Bedrock at or near the surface and Peat and
Alluvium in approximately equal proportions. 0.5% of the catchment is underlain by Made ground.

3
The Shale and sandstone till and peat subsoils have low permeability (see Figure 10). The Alluvium
and Made ground have moderate permeability. Where Bedrock is at or near the surface, the
permeability is recorded as N/A, indicating that subsoil deposits are less than 3 m thick.
The vulnerability of an aquifer to contamination, or groundwater vulnerability, is determined mainly
according to the thickness and permeability of the subsoil. The groundwater vulnerability in the
River Allow catchment is spatially variable driven by variable subsoil thicknesses (see Figure 11).
Geology
The River Allow is underlain by Namurian sandstones and shales. Several small inliers of Dinantian
limestones are exposed (see Figure 12).
Within the River Allow catchment, the rocks are folded into a series of east-west trending synclines
and anticlines. The inliers of the Dinantian limestones are exposed along the axis of two of these
anticlines (see Figure 12).
The GSI has identified the Glenaween Shale and Clare Shale Formations as being rich in pyrite and
therefore, are potentially denitrifying which means they have the potential to reduce nitrate
concentrations (EPA, 2013).
Hydrogeology
The majority of the Namurian sandstones and shales in the catchment and the Dinantian Limestones
(undifferentiated) are designated as Bedrock which is Moderately productive only in Local zones (Ll
aquifer type) (Figure 13). The Clare Shale Formation is designated as Bedrock which is generally
unproductive (Pu aquifer type). Alteration, cementation and structural deformation mean that
groundwater flow through these aquifers will be through secondary porosity and will be dominated
by fracture flow.
Ll and Pu aquifers are considered to be poorly productive aquifers (PPAs). PPAs are of particular
significance as they cover nearly two-thirds of the total land area of Ireland. Although they are
generally not regarded as important sources of water for public water supply (although occasionally
high-yielding wells can be drilled in fault-zones), they are nonetheless believed to be important in
terms of delivering water (and associated pollutants) to rivers and lakes via shallow groundwater
pathways.
Groundwater recharge was calculated for the GSI’s groundwater recharge map of Ireland by
multiplying the effective rainfall by a set of recharge coefficients which are based upon
hydrogeological settings. In areas underlain by poor aquifers, such as in the River Allow catchment,
a recharge ‘cap’ may be applied. The maximum recharge to areas underlain by Ll aquifers is taken to
be between 150-200 mm/a; the maximum recharge in areas underlain by Pl and Pu aquifers is taken
to be 100 mm/a. Figure 14 shows that groundwater recharge to the River Allow catchment varies
between 1 and 200 mm/a.
Compared to the effective rainfall calculated for the catchment (560 to 1030 mm/a), the
groundwater recharge is low and indicates that surface water is likely to dominate flow in the

4
catchment. An estimate of the proportion of effective rainfall which will run off is likely to vary
between 65 % and 99 % across the catchment.
Protected Areas
There are a number of protected areas within the River Allow catchment. Much of the River
Blackwater, including the Allow catchment (see Figure 15) is designated as a Special Area of
Conservation. It is designated for a range of 19 species and habitats, of which Alluvial Forests and
Yew Woodlands are the priority. The River Allow and its tributaries are of particular importance as
they provide habitat for a number of EU Habitats Directive Annex II listed species including the
Freshwater Pearl Mussel (Margaritifera margaritifera), Salmon (Salmo salar) and Otter (Lutra lutra).
The upper reaches of the River Allow form part of a Special Protection Area which includes the
Stack’s to Mullaghareirk Mountains, West Limerick hills and Mount Eagle (see Figure 15).

River Owenkeal
RiverAllow
RiverDalua
River Brogeen
RiverOwenanare
RiverGlenlara
RampartStream
RiverG
lashawee
River Allow
River Allow catchment
0 2 4 6 81
Kilometers
¯
Figure 1: Location of River Allow catchment. Map also shows surface water netwroks.
Source: OSi

Figure 3: Topography of the River Allow catchment
River Allow
River Allow Catchment
Ground elevation (maOD)
0 - 65
66 - 140
141 - 250
251 - 415
416 - 1,100
M
ullaghareirk
M
ountains
source: Ordnance Survey Ireland. All rights reserved.
Licence number EN0059208.

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Kanturk (VOC Sch) rainfall station
Newmarket (New Street) rainfall station
Freemount pumping station rainfall stationNewmarket Ballinatona P.H. rainfall station
River Allow
Met Eireann Stations
!( Rainfall Station
Rainfall Isohyet (mm/a)
1200
1300
1400
1500
1600
1700
0 2 4 6 81
Kilometers
¯
Data source: Met Eireann / EPA
Figure 4: Average annual rainfall and location of Met Eireean rainfall stations within the River Allow catchment.

River Allow
Soil type
Deep poorly drained mineral soils
Deep well drained mineral soils
Shallow well drained mineral soils
Peat
Mineral alluvium
Made ground
0 2 4 6 81
Kilometers
¯
Figure 7: Soil types from the EPA/ Teagasc (2006) indicative soil mapping within the River Allow catchment
Source: EPA / Teagasc, 2006

River Allow
Soil association
Rock
Kilrush
Crosstown
Peat
Borrisoleigh
River
Knockastanna
Urban
0 2 4 6 81
Kilometers
¯
Data source: EPA / Teagasc 2014
Irish National Soils Map, 1:250,000k
Figure 8: Soil types from the EPA / Teagasc (2014) Irish National Soils Map in the River Allow catchment

River Allow
Subsoil type
Bedrock at or near surface
Shale and sandstone till
Peat
Alluvium
Made ground
0 2 4 6 81
Kilometers
¯
Data source: GSI/Teagasc/EPA, 2006
Figure 9: Subsoil type within the River Allow catchment

River Allow
Subsoil Permeability
Moderate
Low
N/A
0 2 4 6 81
Kilometers
¯
Data source: GSI, 2011
Figure 10: Subsoil permeability within the River Allow catchment

River Allow
Groundwater vulnerability
X
E
H
M
L
Water
0 2 4 6 81
Kilometers
¯
Figure 11: Groundwater vulnerability within the River Allow catchment

¿
¿
¿
¿
¿
X X
X
X X X
X
X X
X
XX
River Allow
Geological features
Fault
X
XXAnticlinal axis
Unconformity
¿ Disused coal and/or culm pits
Bedrock Geology
Feale Sandstone Formation
Glenoween Shale Formation
Cloone Flagstone Formation
Clare Shale Formation
Namurian (undifferentiated)
Dinantian Limestones (undifferentiated)
0 2 4 6 81
Kilometers
¯
Figure 12: Bedrock geology of the River Allow catchment

River Allow
Bedrock aquifers
Ll Locally important aquifer which is moderately productive only in local zones
Pu Poor Aquifer - Bedrock which is generally unproductive
0 2 4 6 81
Kilometers
¯
Figure 13: Aquifer type within the River Allow catchment

River Allow
Annual groundwater recharge (mm)
0
1-50
51-100
101-150
151-200
201-250
251-300
301-350
351-400
401-450
451-500
501-550
551-600
601-700
701-800
801-900
901-1000
1001-1400
1401-2000
water
0 2 4 6 81
Kilometers
¯
Data source: GSI
Figure 14: Annual groundwter recharge within the River Allow catchment.

River Allow
Protected areas
Special Area of Conservation
Special Protection Area
Proposed Natural Heritage Area
0 2 4 6 81
Kilometers
¯
Figure 15: Protected areas within the River Allow catchment
Source: NPWS

17
River Allow surface water
Hydrometric data
The Office of Public Works (OPW), Cork County Council and the EPA monitor or have monitored
surface level and flow at eight sites within the catchment. The details of these stations are outlined
in Figure 16.
Flow statistics for the sites may be seen in Table 4 and flow duration curves in Figure 17.
Station name Waterbody
Daily mean flow (m
3
/s)
Minimum 95%ile Mean Maximum
Freemount Allow 0.02 0.05 1.29 6.83
Kilbrin Road Allow 0.02 0.14 2.79 43.0
Riverview Allow 0.18 0.65 7.69 84.9
Allen’s Bridge Dalua 0.11 0.25 3.02 53.5
Table 4 Flow statistics for the hydrometric stations which have relevant available data
Figure 17 Flow Duration curves for the Rivers Allow and Dalua at the four hydrometric stations in Table 4. Flow
duration curves for the River Allow at Freemount and Kilbrin Road are derived from less than 10 years of data and are
shown for information only.

18
Chemistry data
The EPA does not monitor river water chemistry within the catchment of the River Allow. The
closest river water chemistry station is on the River Blackwater at Killavullen Bridge, 26km
downstream of the River Allow’s confluence with the River Blackwater (see Table 5).
Station name Waterbody Easting Northing Status Authority
Data available
Data available
From To
Killavullen
Bridge
Blackwater 164841 99774 Active Cork Co Co 25/01/2010 12/12/2013 Chemistry
Table 5 Details of the nearest river water chemistry station
Table 6 provides a summary of selected parameters for surface water chemistry at the Killavullen
Bridge monitoring point on the River Blackwater. All available surface water chemistry for this
monitoring point may be found in Appendix B. The mean concentrations for the data available (2010
to 2013) for the selected parameters indicate that the chemical water quality is generally of good
status when compared to the threshold values in the 2009 surface water regulations (Government
of Ireland, 2009).
Parameter
Concentration
UnitsMean 95
th
%ile
Total BOD - 5 days 1.4 3.0 mg/l O2
Dissolved Oxygen 68 104 mg/l O2
Dissolved Oxygen 97 101 % saturation
pH 7.7 8.1 pH units
Ammonia 0.040 0.077 mg/l N
Nitrate 2.33 2.85 mg/l N
Nitrite 0.008 0.01 mg/l N
ortho-Phosphate 0.028 0.050 mg/l P
Total Phosphorus 0.032 0.055 mg/l P
Table 6 Mean and 95
th
percentile concentrations for surface water at the Killavullen Bridge monitoring point on the
River Blackwater. Data presented is from 2010 to 2013 and for selected parameters. The parameters are outlined in
part A of the physico-chemical conditions supporting the biological elements in the 2009 surface water regulations
(Government of Ireland, 2009).
Biological data
The majority of the Q values taken between 2012 and 2014 in the River Allow catchment rank the
water as Q4 (unpolluted, Good Status) (see Figure 18). Two sites on the River Allow and one site on
the River Dalua rank the water as Q5 (unpolluted, High Status). One site on the upper reaches of the
River Glenlara is ranked as Q3 (slightly polluted, Moderate Status).

19
Water Framework Directive surface water body status
Water Framework Directive river waterbody status is based upon biological, chemical, physio-
chemical, and in some cases, hydromorphological, elements. The 2007-2009 river waterbody status
is varied within the catchment of the River Allow (see Figure 19). The River Allow is at moderate
status, the River Dalua and its tributaries are at good status, with the exception of the River Glenlara
which is at moderate status, and the River Brogeen was at bad status. The apparent discrepancy
between the WFD status (2007-2009) and the presented biological (2012-2014) and chemical data
(2010-2014) are due to the different sampling periods presented, but also the protected area
objectives of the River, i,e. Conservation status of the FPM.
For example, in 2009 the upstream biological monitoring station on the River Brogeen recorded a Q-
value of Q2, meaning the 2007-2009 WFD status for the River Brogeen was Bad. The biological
quality at that site has since improved to a Q-value of Q4 and this is likely to be reflected in the
updated 2010-2012 WFD river waterbody status.

!(
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9
9
9
9
9
9
9
9
9
9
9
9
9
99
9
9
9
9
9
9
9
9
9
9
9
9
9
$+
$+
$+
")
")
")
")
")
")") ")
Killavullen Br river chemistry MP
(26 km downstream)
Church Street hydrometric station
Kilbrin Road hydrometric station
Greenane staff gauge
Allow RWSS groundwater quality MP
Freemount staff gauge
Ballinatona groundwater quality MP
Grillough staff gauge
Riverview hydrometric station
Taur Group Scheme
groundwater level MP
Allen's Bridge hydrometric station
Liscongill staff gauge
#*
River Allow
Groundwater MPs
$+ Groundwater levels
$+ Groundwater quality
Zone of contribution
River monitoring points
9 River Biology (Q values) MPs
") Hydrometric recorder, LA
") Hydrometric recorder, OPW
") Hydrometric staff gauge, LA
#* River Chemistry MPs
0 2 4 6 81
Kilometers
¯
Data source: Met Eireann / EPA
Figure 16: Surface water and groundwater monitoring locations within the River Allow catchment.

99
99
99 99
99
99
99
99
99
99
99
99
99
99
9999
99
99
99
Q values 2012-14
99 Q 4-5, high status
99 Q 4, good status
99 Q 3-4, moderate status
River Allow
0 2 4 6 81
Kilometers
¯
Data source: EPA
Figure 18: Biological Q values for the River Allow catchment.

River Allow
River Waterbody status (2007-2009)
High
Good
Moderate
Bad
0 2 4 6 81
Kilometers
¯
Data source: EPA
Figure 19: 2007-2009 Water Framework Directive River waterbody status of the River Allow catchment.

23
River Allow groundwater
The EPA monitor three groundwater monitoring points within the River Allow catchment (see
Table 8 for details and Figure 16 for locations). Groundwater levels are monitored at the Taur Group
Water Scheme. Groundwater quality is monitored at Allow RWSS and Ballintona monitoring points.
Station name Waterbody Easting Northing
Data available
Data available
From To
Allow RWSS (BH1) Rathmore_W 139355 113873 01/08/2007 Present Groundwater quality
Ballinatona (Spring1) Rathmore_W 128306 112340 01/08/2007 Present Groundwater quality
Taur Group Water
Scheme
Rathmore_W 123566 109413 01/04/2008 Present Groundwater level
Table 8 Details of the groundwater monitoring stations within the River Allow catchment
Groundwater levels
Taur Group Scheme is a borehole which is more than 54 m deep located in the Namurian Cloone
Flagstone Formation. Groundwater levels at the Taur Group Scheme monitoring point are deep and
vary between 260 and 285 maOD (40 and 15 mbgl; the datum is 301 maOD) as shown in Figure 20.
Groundwater levels respond rapidly to rainfall events possibly indicating low storage. Annual
maxima are observed over the winter months when rainfall is highest. There is a large inter annual
variation in groundwater levels.
Figure 20 Groundwater levels at the Taur Group Scheme monitoring point. (Datum for the monitoring point is
301 maOD).

24
Groundwater quality
Groundwater quality is monitored at the Allow RWSS and Ballinatona monitoring points. Table 9
provides a summary of the field parameters, coliforms, major ions and nutrients.
On the whole, the mean concentrations for the groundwater quality data available (2007 to 2013)
for the selected parameters indicate that the groundwater quality is generally of good status when
compared to the threshold values in the 2010 groundwater regulations (Government of Ireland,
2010).
An exception is the mean ammonium concentration of 0.078 mg/l N at Allow RWSS monitoring point
which exceeds the threshold value of 0.065 mg/l N for the assessment of adverse impacts of
chemical inputs from groundwater to associated surface water bodies. The relatively high
ammonium concentration supports the possibility of denitrifying conditions.
Parameter
Allow RWSS (BH1) Ballinatona (Spr1)
Units
Mean 95th %ile Mean 95th %ile
Temperature 11.9 14.3 13.5 14.1 oC
Conductivity 314 399 472 508 uS/cm
pH 6.9 7.5 7.4 7.8 pH
Dissolved Oxygen 7.4 14.0 2.0 4.3 mg/l O2
Total Coliforms 39 48 221 731 No./100ml
Faecal Coliforms 1 1 2 7 No./100ml
Alkalinity 143 183 242 286 mg/l CaCO3
Chloride 20.59 26.60 15.92 20.12 mg/l Cl
Sulphate 11.77 22.85 6.98 8.00 mg/l SO4
Sodium 19.70 22.00 12.16 12.88 mg/l Na
Potassium 3.01 3.70 1.19 2.93 mg/l K
Magnesium 12.15 14.59 7.32 8.00 mg/l Mg
Calcium 31.69 35.90 84.17 90.92 mg/l Ca
Ammonium 0.078 0.129 0.021 0.052 mg/l N
Nitrite 0.015 0.025 0.010 0.025 mg/l N
Nitrate 0.49 1.66 0.56 0.66 mg/l N
Molybdate Reactive Phosphorus 0.008 0.014 0.009 0.014 mg/l P
Total Phosphorus 0.007 0.012 0.009 0.014 mg/l P
Table 9 Mean and 95
th
%ile groundwater concentrations for field parameters, coliforms, major ions and nutrients. All
chemical data received for groundwater monitoring points is included in Appendix C.
Time series data shows that discrete contamination events have occurred at both monitoring points
(see Table 10 for details). For example, in the Allow RWSS monitoring point, total coliforms are
typically very low but a high concentration (921 no/100ml), recorded in August 2008 increased the
mean. At the Ballinatona monitoring point, the ‘normal’ total coliforms concentration is typically
higher (approximately 50 no/100ml). In addition, a number of very high concentrations have also
increased the mean concentration. The peaks in total coliforms coincide with peaks in faecal
coliforms and chloride. This indicates that these sources are vulnerable to contamination. This is
consistent with the groundwater vulnerability within the zone of contribution of the sources which

25
have a high proportion of X-extreme and E-extreme vulnerability (see Figure 16 for zones of
contributions for the two monitoring points and Figure 11 for groundwater vulnerability).
Station name Date
Total Coliform concentration
(no/100ml)
Allow RWSS (BH1) 07/08/2008 921
02/10/2007 2000
07/08/2008 3973
Ballinatona (Spring1) 19/11/2009 308
03/11/2010 121
09/08/2012 113
Table 10 Details of contamination events at allow RWSS and Ballinatona monitoring points
Water Framework Directive groundwater body status
Water Framework Directive groundwater body status is based upon quantity and quality standards.
The vast majority of the River Allow catchment is located in the Rathmore_W groundwater body. In
the 2007-2009 classification, the Rathmore_W groundwater body was found to be at good status
(see Figure 21). Neighbouring groundwater bodies which contain small portions of the catchment
are also at good status.

Rathmore_W
Kanturk
Abbeyfeale
Glenville
Ballylongford
Shanagolden
Banteer
Newcastle West
Mitchelstown 1
North Kilmallock
Charleville
Mitchelstown A
Ballylongford_4
Abbeyfeale_2
River Allow
Groundwater body status
Good Status
Poor Status
0 2 4 6 81
Kilometers
¯
Data source: EPA
Figure 21: 2007-2009 Water Framework Directive groundwater body status of the River Allow catchment.
Names of groundwater bodies are shown.

27
Pressures
Diffuse pressures
Diffuse pressures in the catchment are likely to derive from agricultural and forestry activities.
Figure 24 shows the 2006 CORINE land use categories. The majority of the catchment (73%) is
pasture used for grazing. A small proportion of the land (3%) is used for arable land. 7% of the land
is categorised as other agriculture. 13% of the land is forestry particularly in the north-western part
of the catchment. Much of this forestry is being actively managed by Coillte and private forestry
companies. 6% of the land is peat bogs, much of which is Blanket Peat which is associated with the
upland areas in the west of the catchment.
The pressure magnitude layer (CSO, 2002) indicates that livestock density on pastoral land increases
from 0.5-1.5 LU/ha in the west of the catchment to 1.76-2.00 LU/ha in the east of the catchment
(see Figure 25). The same layer indicates that the proportion of tillage is greatest (up to 40%) in the
south and east of the catchment (see Figure 26).
Point pressures
Figure 27 outlines possible point pressures on water quality and quantity within the catchment. It
includes five Waste Water Treatment Plants (WWTPs). It is understood there are on-going water
quality issues from the WWTPs in the catchment, particularly the Freemount WWTP, which are
impacting on the pearl mussel populations. The catchment visit also identified Kanturk Dairy and
Newmarket Co-operative Creamery which may represent point pressures. Figure 27 also includes
known public and private water supplies. The largest abstractions are Ballintona PWS (7000m3/d)
and Allow PWS (2300m3/d).
Susceptibility
The EPA has developed a series of maps to describe the susceptibility of groundwater to
contamination by nitrate, pathogens and phosphorus (EPA, 2013). These maps are based on subsoil
permeability, groundwater vulnerability, aquifer type and soil type. Figure 22 shows that the
susceptibility of groundwater to percolation of nitrate in the catchment is almost entirely
categorised as low. Figure 23 shows that the susceptibility of groundwater to percolation of
pathogens and phosphorus is much more varied. The majority of the catchment (66%) is categorised
as low pathogen and phosphorus susceptibility. However 27% of the catchment is categorised as
high susceptibility and 6% as very high susceptibility meaning that in these settings groundwater
may be a pathway for delivering phosphorus to the river.

River Allow
CORINE land use
Pastures
Arable land
Other agriculture
Peat bogs
Forests
Urban
0 2 4 6 81
Kilometers
¯
Figure 24: 2006 CORINE land use within the River Allow catchment
Source: EPA

River Allow
Livestock units (LU/ha)
0.00 - 0.50
0.51 - 1.50
1.51 - 1.75
1.76 - 2.00
0 2 4 6 81
Kilometers
¯
Figure 25: Livestock density within the River Allow catchment
Source: CSO, 2002

River Allow
Percentage of tillage (%)
0 - 1
2 - 10
11 - 40
0 2 4 6 81
Kilometers
¯
Figure 26: Percentage of tillage within the River Allow catchment
Source: CSO, 2002

")
")
")
")
#*
#*
#*
#*
#*
#*
#*
#*
#*
#*
#*#*
#*#*
#*
Newmarket WWTP
Secondary treatment
Population 1100
Freemount WWTP
Treatment unknown
Population unknown
Allow PWS
River intake and 2 boreholes
2300 m3/d
Taur Group Scheme
1 borehole
Abstraction unknown
Ballinatona PWS
2 springs
7000 m3/d
Meelin WWTP
Secondary treatment
Population 110
Kanturk WWTP
Seconary treatment
Population 1700
Boherbue WWTP
Secondary treatment
Population 600
327m3/d
164m3/d
43.6m3/d
43.6m3/d
0m3/d
261.6m3/d
109.1m3/d
163.6m3/d
32.7m3/d
261.6m3/d
River Allow
Abstractions
#* Public or group water supplies
#* Agricultural and domestic supplies
Waste Water
") Waste water treament plants
Sewered areas
0 2 4 6 81
Kilometers
¯
Figure 27: Point pressures within the River Allow catchment including abstractions and waste water treatment plants.
The recorded yield is shown for the water abstractions.
Source: GSI and EPA

River Allow
N Susceptibility to groundwater
Low
Moderate
Very High
Made ground
0 2 4 6 81
Kilometers
¯
Figure 22: Susceptibility of groundwater to percolation of nitrate within the River Allow catchment
Source: EPA

River Allow
P Susceptibility to groundwater
Low
High
Very High
Made Ground
0 2 4 6 81
Kilometers
¯
Figure 23: Susceptibility of groundwater to percolation of molybdate reactive phosphorus within the River Allow
catchment
Source: EPA

34
Conceptual model
Figure 28 shows a schematic conceptual model for the River Allow catchment. It includes the
following elements:
• Effective rainfall varying between 560 and 1030 mm/a across the catchment;
• 65-99 % of effective rainfall forming runoff over the poorly draining soils;
• Low permeability Shale and Sandstone Tills of varying depths;
• Groundwater recharge varying between 1 and 200 mm/a across the catchment (equivalent
to 1-35% of effective rainfall);
• Surface water run-off and near surface water pathways are the predominant pathway to
River Allow
• Flow through a potential transition zone between the Shale and Sandstone Tills and the
Namurian Sandstone and Shale locally important bedrock aquifer;
• Groundwater flow via fractures in the folded and fractured (i) Namurian Sandstone and
Shale locally important bedrock aquifer (Ll and Pu aquifers) and (ii) underlying Dinantian
Limestone unproductive bedrock aquifer (Ll aquifer) which generally have low permeability
characteristics;
• Upward hydraulic gradient into the River Allow which has a mean flow of 8 m3
/s at the
bottom of the catchment.

Transition zone
Shale and
Sandstone Till
Folded and faulted
Namurian Sandstones and
Shales Ll and Pu aquifers
Water Flow
Figure 28 Conceptual model of water flow within the River Allow catchment (after EPA, 2013)
65-99% of ER as runoff over
poorly draining soils and low
permeability subsoils
Flow through the
transition zone
Flow through
discrete fractures
Upward gradient
Towards river
Effective Rainfall (ER)
560-1030 mm/a
Groundwater recharge
1-200 mm/a
Folded and faulted
Dinantian Limestone
Ll aquifer

Characterisation of the River Allow Catchment

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Characterisation of the River Allow Catchment