4. STAGE 2: APPROPRIATE ASSESSMENT
4.1 D ESCRIPTION OF THE R ECEIVING E NVIRONMENT
The River Allow (EPA code 18A02), rises on the eastern flanks of the Mullaghareirk Mountains, flowing in an easterly direction for twelve kilometres before turning south at Freemount, and continuing for a further 12 kilometres to Kanturk town, the main centre of population in the Allow River catchment. The Allow catchment area is 323.46km2 and is located in the South Western IRBD. Five kilometres downstream of Kanturk the Allow flows into the Blackwater River (EPA code 18B02).
The River Allow is included in the Blackwater River cSAC, and has been designated partly on the basis of the presence of freshwater pearl mussel populations within this watercourse and also within the River Blackwater main channel, occurring directly downstream of the Allow confluence. The Annex I habitat ‘floating river vegetation’ and Annex II listed Atlantic salmon, otter and lamprey species also occur within the River Allow catchment adding to its conservation importance.
4.1.1.1 Water quality in the River Allow
From the River Blackwater (Munster) Water Management Unit (WMU) Action Plan (SWRBD, 2010) the River Allow is identified as being of ‘moderate status’, i.e. unsatisfactory. This is dictated by the ecological status of the river, driven by the unsatisfactory status of the Annex II listed Freshwater pearl mussel in the catchment, above Kanturk. The Kanturk Wastewater Treatment Plant operated by Cork County Council is identified as a point pressure in the Blackwater WMU (SWRBD, 2010), affecting both the River Allow and River Blackwater. This is based on visual impacts within the designated Natura 2000 site (SWRBD, 2010).
According to the EPA water quality monitoring for 2009 the River Allow achieved a biological water quality rating of Q4 at the monitoring station (EPA station 0490) approximately 1.3km downstream of Kanturk, which also lies downstream of the existing Kanturk Creamery and Kanturk WwTP discharges. The Allow was also rated as Q4 directly upstream of its confluence with the River Blackwater at Leader Bridge (EPA station 0600). Above Kanturk the River Allow is rated as Q4-5 within the freshwater pearl mussel reaches of the river at John’s Bridge (EPA station 0300).
Cork County Council undertakes chemical water quality at monitoring stations on the River Allow upstream and downstream of Kanturk town as part of the EC Water Framework Directive (WFD) monitoring programme. The downstream station is located downstream of both the Kanturk WwTP discharge and the North Cork Co-op discharge to the River Allow.
The upstream monitoring station results for 2010 and 2011 are presented in Table 1, with the downstream monitoring results for 2010 and 2011 presented in Table 2. WFD Good status and High status limits from the Surface Water Regulations (2009) are shown. From this data it can be seen that the chemical water quality in the River Allow is adversely affected downstream of Kanturk on one occasion only, on the 26th of August, likely during low flow conditions. The increased dilution available downstream of the Dalua River confluence below Kanturk Bridge accounts for the reduction in Orthophosphate and Ammonium downstream during March 2010. Elevated Orthophosphate and BOD at the downstream station during 2010 indicate water quality problems in the River Allow downstream of the Kanturk WwTP discharge and cannot be directly associated with the North Cork Creamery Co-op.
North Cork Co-op undertook water sampling upstream and downstream of the effluent plant discharge on 28th July 2011. Upstream and downstream of the discharge the respective BOD was <2mg/l and <2mg/l, Ammonia was 0.12mg/l and 0.14mg/l, Nitrate was 1.5mg/l and 1.6mg/l while Orthophosphate was 0.04mg/l and 0.08mg/l. These results indicate that the existing discharge is adversely affecting chemical water quality with the nutrient Orthophosphate doubling in concentration downstream of the discharge (See Appendix 4 for results).
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Table 1 River Allow chemical water quality upstream of Kanturk, from Cork Co. Co. data 4.1.1.2 Waste Assimilation Capacity in the River Allow
From the flow duration curve returned by the EPA Hydrotool, the 95%ile flow of the Allow River (river segment code 18_54) is 0.771m3/s while the mean flow is 8.203m3/s (mean flow taken as the 30%ile flow as in MacCarthaigh (1997)). In the Allow River upstream of the effluent discharge, the background concentration for BOD (<2mg/l), Ammonia (0.12mg/l) and Orthophosphate (0.04mg/l) means there is limited or no Waste Assimilation Capacity (WAC).
These values are the results from a single sample and have been provided by North Cork Co-op. It is also noted that the Level of Detection (L.O.D) used in relation to BOD was not adequate for assessments following the Surface Water Quality Objective Regulations (2009).
Cork County Council results were not used as they are for the Allow River – the discharge is to the Allow River downstream of its confluence with the Dalua River. The WAC assessment is provided in Appendix 2.
There is no WAC for BOD at mean flow as the background value (taken as 2mg/l) is greater than the SWR (2009) for both good and high status. It is noted that the background BOD may be significantly less due to the lack of sampling data and inadequate LOD used, and that
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4.1.2 Ecological survey of the study area
The proposed milk evaporator and spray drying plant will be constructed within the existing Kanturk Creamery site, which comprises buildings and artificial surfaces (BL3). The River Allow adjacent to the existing creamery and proposed development site is an eroding watercourse (FW1), the riparian corridor is dominated by the non-native Himalayan balsam (Impatiens glandulifera) with an established stand of Japanese knotweed (Fallopia japonica) recorded on the bank at the site boundary. A treeline of ash (Fraxinus excelsior) and alder (Alnus glutinosa) was recorded on the river bank adjacent to the proposed development site, outside of the site boundary. The riparian treeline was found to be more intact further downstream, below the site. The opposite bank was dominated by reed canary grass (Phalaris arundinacea).
Macroinvertebrate kick-sampling was undertaken at three stations on the River Allow by ECOFACT aquatic ecologists during the preparation of the current assessment. These sites were located downstream of the existing discharge from the Kanturk Creamery site, adjacent to the existing site and upstream of the Kanturk Creamery site, directly downstream of the confluence of the Allow and Dalua Rivers as shown in Table 3. Table 4 presents the physical character of the aquatic habitat recorded at each site and Table 5 presents the chemical water quality results recorded from each site on the day of the survey. A detailed species list of the macroinvertebrates recorded from the three sites is included in Appendix 3.
Table 3 Locations of the biological sampling sites examined on the River Allow at Kanturk in June 2011.
Site 1 Site 2 Site 3
Location Approx. 50m downstream of the discharge from the Co-op effluent treatment plant discharge (approx.
750m downstream of confluence of the Allow and Dalua Rivers)
Adjacent to Co-op
R38514 02289 R38297 02679 R38290 03021
Table 4 Physical characteristics of the biological sampling sites on the River Allow at Kanturk in June 2011.
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4.1.2.1 Site 1
This site was located approximately 50 meters downstream of the discharge from the Co-op effluent treatment plant discharge (approx. 750m downstream of confluence of the Allow and Dalua Rivers). The river at this location had a mix of substrate types, flow features with some pool habitat recorded. This site was considered to be sub-optimal / optimal in terms of habitat for macroinvertebrates. A macroinvertebrate family richness of 21 was recorded at the downstream site. Trichopterans were the best represented group with 7 families recorded; cased caddisfly larvae of Sericostoma personatum, Athripsodes sp., Lepidostoma hirtum and Potamophylax latipennis along with caseless larvae of Hydropsyche siltalai, Rhyacophila dorsalis and Polycentropus flavomaculatus (generally recorded in small numbers). Six species of mayfly at larval stage were recorded and included Ecdyonurus insignis which occurred in fair numbers, Heptagenia sulphurea (present), Caenis rivulorum (fair numbers), Ephemerella ignita (fair numbers), Baetis muticus (scarce) and Baetis rhodani which was numerous. The only stonefly larvae recorded was Leutra hippopus which was scarce. True fly larvae of Simulidae were common and green chironomidae were found in small numbers. Gammarus duebeni was the sole crustacean representative at this site while the only Mollusc was Ancylus fluviatilis (both in small numbers). Other macroinvertebrates recorded included (Hydracarina), Erpobdella testacea, E.
octoculata and Elmis sp. of which there were small numbers in general.
4.1.2.2 Site 2
This site was located adjacent to Kankurk Co-op, or approximately 150 m downstream of confluence of the Allow and Dalua Rivers. The substrate at this riffled site was mostly of bedrock and was considered sub-optimal with reference to macroinvertebrate production. At this location, a rich macroinvertebrate assemblage was recorded with 24 different macroinvertebrate families occurring.
Together, the cased and caseless caddisfly larvae accounted for the most diverse taxonomic group with a total of 9 species recorded. These were generally recorded in small numbers and included Lepidostoma hirtum, Potamophylax latipennis, Hydropsyche siltalai, Rhyacophila dorsalis and Agapetus fuscipes. Ephmeropteran larvae were more abundant and with Baetis rhodani and Ephemerella ignita (numerous), Heptagenia sulphurea (fair numbers) and Baetis muticus (present). Stonefly larvae of Leutra hippopus were found in small numbers the only snail recorded at this location (Lymnaea peregra) was present. Small numbers of Ancylus fluviatilis and Gammarus duebeni were recorded. Three families of leech were recorded; Erpobdella octoculata, Piscicola geometra and Glossiphonia complanata.
4.1.2.3 Site 3
This site was located upstream of Kankurk Co-op, or downstream of the confluence of the Allow and Dalua Rivers. This site was immediately downstream of a small weir. The right hand side of the river (looking in a downstream direction) was deemed to be influenced by the Dalua River and the left hand side by the Allow River. Macroinvertebrates in 24 different families were recorded at this location by sampling along the width of the river downstream of the weir. Macroinvertebrate habitat was considered optimal to sub-optimal.
A rich macroinvertebrate assemblage was recorded at this location (family diversity of 24).
Ephemeropterans, Plecopterans and Trichopterans were all well represented at this site. Mayfly larvae of Heptagenids were common with Heptagenia sulphurea, Rhithrogena semicolorata and
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4.1.3 Biological water quality 4.1.3.1 Site 1
Pollution sensitive (Group A) indictors (Heptagenidae) were recorded in fair numbers at this site.
The substrate at this location was lightly silted and Dissolved Oxygen (D.O.) was 106.6%. Using EPA freshwater biological monitoring criteria (Toner et al., 2005), this part of the river was rated
‘Unpolluted (Q4)’, equivalent to Water Framework Directive (WFD) ‘Good Status’. The Biological Monitoring Working Party (BMWP) score for this site was 132.2 which indicates ‘Very good’ water quality or ‘Unpolluted, un-impacted’ conditions. The Average Score per Taxon (ASPT) for this location was 7. Again, this score is well above the 5.5 score, above which water quality is deemed to be good. On a scale of 1-15, the Trent score for this site was 10.
4.1.3.2 Site 2
At this site, Group A mayfly larvae were present in fair numbers with Group C indicators comprising the bulk of the macroinvertebrate population. The substrate and floating river vegetation at this location was lightly silted and Dissolved Oxygen (D.O.) was 106.5%. This site was therefore rated ‘Unpolluted (Q4), equivalent to WFD ‘Good Status’. Very good water quality is also signified by the BMWP score of 139.6, the ASPT score of 6.6 and the Trent score of 11.
4.1.3.3 Site 3
This site contained three species of pollution sensitive mayfly larvae and three species of stonefly larvae with the former being common. It was clear that the rocks and other substrates in this part of the river had a light coat of silt. Dissolved Oxygen (D.O.) was 98.9%. Using these observations and the Q determination scheme, this site was rated ‘Unpolluted (Q4-5)’, equivalent to WFD ‘High Status’. This rating is supported with the other indices used to evaluate water quality. The BMWP score of 169.5 far exceeds the threshold score of 100 that indicates very good water quality.
Similarly, the ASPT was 7.7 and the Trent score was 13, the maximum attainable Trent score being 15.
4.1.4 Functional group analysis
Based on the results of the macroinvertebrates recorded during the biological sampling, there was little variation identified in the functional group analysis between the three sites, with regard to the feeding requirements of the macroinvertebrate communities identified (see Table 7). All sites had a macroinvertebrate assemblage indicative of heterotrophic conditions, the P/R ratio being less than 0.75. P/R is the ratio of behavioral drifters (filtering and gathering collectors) to accidental drifters (grazers, shredders and predators). The P/R ratio at Site 1, Site 2 and Site 3 was 0.35, 0.33 and 0.27 respectively. The juvenile salmonid index result for Site 1, Site 2 and Site 3 was 1.4, 1.12 and 1.25 in that order. These results show that there is a ‘Predictable’ macroinvertebrate food supply for young salmonids in the Allow River at Kanturk, where Site 1 is identified as being the most productive in terms of macroinvertebrate food availability for salmonids.
Table 6 Biological indices results and macroinvertebrate richness in the biological sites investigated in the River Allow at Kanturk in June 2011.
Biotic indices, ratings &
Quality status (EPA) Unpolluted Unpolluted Unpolluted
WFD Status Good Status Good Status High Status
Quality class Class A Class A Class A
BMWP score 132.2 139.6 169.5
BMWP category Very good Very good Very good
BMWP interpretation Unpolluted
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Table 7 Functional feeding group (FFG) characteristics of the sites investigated in the River Allow at Kanturk in June 2011.
FFG Site 1 Site 2 Site 3
Trophic status Heterotrophic Heterotrophic Heterotrophic
Juvenile salmonid index2 1.4 1.12 1.25
Predictable / Unpredictable food supply Predictable Predictable Predictable
1 Ratio of scrapers to total collectors and shredders (Plafkin et al., 1989).
2 Ratio of behavioural drifters (filtering and gathering collectors) / accidental drifters (scrapers, shredders and predators). From Rabenil et al., (2005).