Dublin Waste to Energy Water Discharge Biological Surveys
Produced by
AQUAFACT International Services Ltd
On behalf of COVANTA
August 2020
AQUAFACT INTERNATIONAL SERVICES LTD. 12 KILKERRIN PARK LIOSBAN INDUSTRIAL ESTATE TUAM ROAD GALWAY. www.aquafact.ie [email protected] tel +353 (0) 91 756812 fax +353 (0) 91 756888 Report Approval Sheet Client Covanta Report Title Dublin Waste to Energy Water Discharge Biological Surveys
Job Number JN1586 Report Status Draft Issue Date 19th August 2020
Issue Document Rev Status Author (s) Approved by: Date File Name JN1586 Liffey E.McCormack 1 Draft 19.08.20 Ecological & Kevin Mark Costelloe Survey Draft McCaffrey
Table of Contents
1. Introduction 1
2. Methodology 1
2.1. Fish Survey ...... 1 2.2. Benthic survey ...... 3 2.2.1. Particle Size Analyses (PSA) ...... 4
3. Results 6
3.1. Fish Survey ...... 6 3.1.1. Seine ...... 6 3.1.2. Beam Trawl ...... 1 3.1.3. Fyke Nets ...... 1 3.1.4. Physical and chemical data ...... 2 3.2. Benthic Survey ...... 3 3.2.1. Sediments ...... 3 3.2.2. Fauna ...... 5
4. Discussion 6
5. References 7
List of Figures
Figure 2.1: Fish survey station locations ...... 2
Figure 2.2 Benthic survey ...... 4
Figure 3.1: Abundance and species richness for seining, fyke net and beam trawl stations ...... 1
Figure 3.2: High abundance of crab in fyke nets...... 2
List of Tables
Table 2:1: Sampling Locations (2-3/07/20)...... 3
Table 2:2 Sample Location (3/07/20) ...... 4
Table 3:1: Fish species abundance for all fishing methods (1-2/07/20)...... 1 Table 3:2: Physiochemical Data...... 3
Table 3:3 Granulometry ...... 4
Table 3:4 Organic carbon results ...... 5
List of Appendices Appendix 1 Fish Species Abundance Appendix 2 Benthic Species Abundance Appendix 3 Section 14 Licence Appendix 4 Photo log
Dublin Waste to Energy Biological Surveys Covanta August 2020
1. Introduction
AQUAFACT International Services Ltd. was commissioned by Covanta to carry out a biological survey of the receiving environment for the heated discharge to the Liffey from their Dublin Waste to Energy plant. This survey was carried out on the 1-2/07/20 to satisfy condition number 6.16.3 of IE license W0232-01.
The aim of this study was to assess the diversity and abundance of fish and benthic assemblages in the Liffey estuary, focusing on the area adjacent to the Dublin Waste to Energy plant heated water discharge (Figure 2.1).
The Dublin City Council Biodiversity Plan was consulted when scoping the biological surveys. The location of the discharge site is not located within a designated conservation site (i.e. SAC/SPA). The discharge site is located within the Water Framework Directive Liffey Estuary Transitional waterbody and as a result the biological survey proposed was consistent with the standard WFD monitoring surveys carried out in transitional and coastal waterbodies all around the country. Inland Fisheries Ireland were consulted with regards to the proposed fish surveys. In addition, both surveys were designed to complement the surveys carried out for the EIA.
2. Methodology
2.1. Fish Survey
The proposed method to sample the fish population at the mouth of the Liffey followed the approach outlined for transitional waters under the Water Framework Directive (WFD Common Implementation Strategy, 2003). The same sites sampled on two previous occasions by Ecoserve (2008; 2009) and twice by AQUAFACT (2015; 2018) were revisited (Figure 2.1). A seine net (dimensions of 43 x 4 m with mesh of size 25 mm and 12.5 in its wings) was used at these sites during the low water period of the tidal cycle (Low water occurred at 15:54pm). Three replicates were taken at each site. The net was deployed using a boat and buoy, the buoy being attached to a towing line, while the net was fed from the boat in an arc until both towing lines met; the net was then hauled into the boat. Where the shore was suitable, a person stood on shore and held the towing line while the boat fed out the net arcing back
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Dublin Waste to Energy Biological Surveys Covanta August 2020 around to the shore. The net was then hauled up onto the shore. Seine nets were deployed on the 1/07/20.
Figure 2.1: Fish survey station locations
Three beam trawl locations sampled by AQUAFACT in 2015 and 2018 (AQUAFACT, 2015; AQUAFACT, 2018) were revisited. The beam trawls were deployed from the back of the boat and towed for 5 minutes after which time, it was then hauled in by hand. Beam trawls were deployed on the 1/07/20. Fyke nets (15m in length with a 0.8m diameter front hoop, joined by an 8m leader with a 10mm square mesh) were used at two stations. The fyke nets were set parallel to the river bank and staked open with a stake at the end of either wing. Table 2.1 shows the coordinates of each of the sampling sites.
Species were identified, counted and measured directly after capture and were released before leaving the site. The following water quality parameters were recorded at the seining stations using a Hydrolab surveyor and DS5x probe: salinity, dissolved oxygen, temperature and pH (See Figure 2.1 for location).
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Table 2:1: Sampling Locations (1-2/07/20).
Station Latitude Longitude Seine 1 53.3443 -6.22058 Seine 2 53.3422 -6.19362 Seine 3 53.3496 -6.18645 Seine 4 53.3418 -6.18158 Fyke 1 53.3463 -6.18722 Fyke 2 53.3501 -6.18729 Beam Trawl 1 Start 53.3472 -6.16158 Beam Trawl 1 End 53.3485 -6.16792
Beam Trawl 2 Start 53.3489 -6.17655 Beam Trawl 2 End 53.3520 -6.17730 Beam Trawl 3 Start 53.3462 -6.18668
Beam Trawl 3 End 53.3499 -6.18808
2.2. Benthic survey
A 0.1m2 van Veen grab sampler was used to collect grab samples upstream and downstream of the heated water outfall. Two stations upstream and 2 stations downstream were sampled (at varying distances from the discharge). Benthic samples were taken on the 2/07/20. All faunal samples were sieved on a 1mm mesh sieve, preserved, sorted and all specimens identified to species level where possible. Biotopes were assigned to each station and comparisons made with each other and with previous surveys. See Figure 2.2 for benthic grab locations.
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Figure 2.2 Benthic survey Table 2:2 Sample Location (2/07/20)
Station Latitude Longitude G1 53.342174 -6.197087 G2 53.342208 -6.195520 G3 53.342598 -6.197950 G4 53.342826 -6.200030
2.2.1. Particle Size Analyses (PSA)
AQUAFACT carried out the PSA analysis in-house using the following methodology: 1. Approximately 100g of dried sediment (previously washed in distilled water and dried) was weighed out and placed in a labelled 1L glass beaker to which 100ml of a 6 percent hydrogen peroxide solution was added. This was allowed to stand overnight in a fume hood. 2. The beaker was placed on a hot plate and heated gently. Small quantities of hydrogen peroxide were added to the beaker until there was no further reaction. This peroxide treatment removed any organic material from the sediment which can interfere with grain size determination.
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3. The beaker was then emptied of sediment and rinsed into a 63μm sieve. This was then washed with distilled water to remove any residual hydrogen peroxide. The sample retained on the sieve was then carefully washed back into the glass beaker up to a volume of approximately 250ml of distilled water. 4. 10ml of sodium hexametaphosphate solution was added to the beaker and this solution was stirred for ten minutes and then allowed to stand overnight. This treatment helped to dissociate the clay particles from one another. 5. The beaker with the sediment and sodium hexametaphosphate solution was washed and rinsed into a 63μm sieve. The retained sample was carefully washed from the sieve into a labelled aluminium tray and placed in an oven for drying at 100ºC for 24 hours. 6. The dried sediment was then passed through a Wentworth series of analytical sieves (>8,000 to 63μm; single phi units). The weight of material retained in each sieve was weighed and recorded. The material which passed through the 63μm sieve was also weighed and the value added to the value measured in Point 5 (above). 7. The total silt/clay fraction was determined by subtracting all weighed fractions from the initial starting weight of sediment as the less than 63μm fraction was lost during the various washing stages. 8. The following range of particle sizes: <63m, 63<125m, 125<250m, 250<500m, 500<1000m, 1000<2000m, 2000<4000m and 4000<8000m were reported.
Organic carbon analysis was carried out using the Loss on Ignition technique by ALS Laboratories in Loughrea.
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3. Results
3.1. Fish Survey
Twelve species of fish were recorded in the survey, eight of which were caught by the seining method, three using fyke nets and two using the beam trawls. Large quantities of shore crab and shrimp were caught in all fishing methods used. Large numbers of sea gooseberries were also recorded in the beam trawls. See Appendix 1 for full species abundance list and Appendix 4 for photos of species caught from the fish survey.
3.1.1. Seine
The highest Species richness was recorded at Seine 2 which recorded 6 species. Species richness for the seining stations ranged from 4 to 6 species. Abundance was highest at Seine 4 (284) and lowest at Seine 3 (63). Table 3.1 presents the results from the seine nets.
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Table 3:1: Fish species abundance for all fishing methods (1-2/07/20).
Scientific name Common Name Seine 1 Seine 2 Seine 3 Seine 4 Fyke 1 Fyke 2 Beam 1 Beam 2 Beam 3
Pomatoschistus Common goby 63 58 46 280 - - - - - microps Pleuronectes platessa Plaice 14 3 8 1 - - - 1 1 Syngnathus Nilsson’s 1 - - 1 - - - - - rostellatus pipefish Taurulus bubalis Sea scorpion - 1 7 1 - - - - - Pollachius pollachius Pollack 3 1 1 ------Anguilla anguilla Eel - - - - 1 1 - - - Gaidropsarus Shore Rockling - - - - 1 1 - - - mediterraneus Sepiola atlantica Little cuttlefish - 1 1 ------Spinachia spinachia Fifteen-spined - 1 ------stickleback Clupea harengus Herring - - - 1 - - - - - Gadus morhua juv. Atlantic Cod ------2 - - Merlangius Whiting - - - - 1 - - - - merlangus
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Figure 3.1: Abundance and species richness for seining, fyke net and beam trawl stations
3.1.2. Beam Trawl
Two species were caught in the beam trawls Atlantic cod and plaice. Only one species was record per station. Two cod were recorded at Beam 1 and one plaice was recorded at beam 2 & 3. Beam trawls were carried out on 1/07/20 (Table 3.1 present the results from the beam trawls).
3.1.3. Fyke Nets
Three species were caught in the fyke nets, eel, shore rockling and whiting. Eel and shore rockling were caught in both fyke nets while whiting was only recorded in Fyke 1. Only one individual was recorded for each species per fyke net (Table 3.1 present the results from the fyke nets). Fyke nets were deployed on 1/07/20 and retrieved 2/07/20. A large number of shore crabs were record in both fyke nets (Figure 3.2).
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Figure 3.2: High abundance of crab in fyke nets.
3.1.4. Physical and chemical data
Salinity ranged from 15.81 PSU (Seine 1) to 31.68 PSU (Seine 4). Oxygen levels ranged from 7.53 mg/l (Seine 40 to 8.11 mg/l (Seine 1). Temperature ranged from 15.39 ˚C (Seine 1) to 15.81 ˚C (Seine 3). pH ranged from 7.95 (Seine 4) to 8.1 (Seine 1). Table 3.2 shows the physical and chemical data.
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Table 3:2: Physiochemical Data.
Station Salinity Dissolved oxygen Temperature pH PSU mg/l % saturation ˚C Seine 1 15.81 8.11 97.4 15.39 8.1 Seine 2 26.28 8.09 100.3 15.52 8.03 Seine 3 30.68 7.75 102.8 15.81 8.07 Seine 4 31.68 7.53 100.1 15.61 7.95
3.2. Benthic Survey
3.2.1. Sediments
Table 3.3 shows the sediment characteristics of the 4 faunal grab stations upstream and downstream of the discharge point.
G3 contained the highest percentage of gravel (1.2%), very coarse sand (2.9%), coarse sand (3.3%) and medium sand (13.7%). G2 had the highest percentage of fine sand (19.5%) and very fine sand (34.2%). G2 had the highest percentage of silt-clay (39.4%). The sediment sampled from the 4 stations was classified according to Folk (1954) as muddy sand (G1, G2 and G4) and slightly gravelly muddy sand (G3).
Organic matter values ranged from 5.68 (G4) to 8 (G2). Organic carbon levels were relatively high which is typical of the fine nature of the sediments in estuarine conditions.
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Table 3:3 Granulometry
Very Coarse Fine Sand Very Fine Gravel Coarse Sand Medium Sand Silt-Clay Station Sand (1- (125- Sand (62.5- Folk (1954) (>2mm) (0.5-1mm) (0.25-0.5mm) (<63mm) 2mm) 250mm) 125mm) G1 0.4 2.1 3.1 10.9 17.6 29.2 36.7 Muddy sand G2 0.8 2.2 1.9 8.8 19.5 34.2 32.6 Muddy sand G3 1.2 2.9 3.3 13.7 21 29.2 28.7 Slightly gravelly muddy sand G4 0.6 2.2 1.7 8.7 15.2 32.1 39.4 Muddy sand
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Table 3:4 Organic carbon results
Station Organic Carbon % G1 7.79 G2 8 G3 6.39 G4 5.68
3.2.2. Fauna
Appendix 2 contains the full species list returned from the grab samples. Station G1 was located just downstream at the mouth of the discharge point. The sediment at this station was classified as muddy sand according to Folk (1954) and the fauna was dominated by Capitella sp. complex (34 individuals, 42.5% species composition), Nematoda (20 individuals, 25% species composition), and Tubificoides benedii (14 individuals, 17.5% species composition). Other species recorded included Tubificoides brownae, Heteromastus filiformis, Parcicardium pinnulatum, Pholoe baltica, Carcinus maenus and Peringia ulvae. A biotope of SS.SMu.VS.CapTubi (Capitella and Tubificoides spp. in reduced salinity infralittoral muddy sediment) was assigned for this station.
Station G2 was located 100m downstream from G1 and the discharge point. The sediment at the station was classified as muddy sand according to Folk (1954) and the fauna was dominated by Nematoda (353 individuals, 85.27% species composition), Cirratulidae (damaged) (38 individuals, 9.18% species composition), and Capitella sp. complex (10 individuals, 2.42% species composition). Other species included Tubificoides brownae, Caulleriella alata, Tubificoides sp. (damaged), Thyasira sp. (damaged), and Tubificoides benedii. A biotope of SS.SMu.VS.CapTubi (Capitella and Tubificoides spp. in reduced salinity infralittoral muddy sediment) was assigned for this station.
Station G3 was located just upstream of the mouth of the discharge point. The sediment at this station was classified as slightly gravelly muddy sand according to Folk (1954) and the fauna was dominated by Capitella sp. complex (826 individuals, 60.12% species composition), Nematoda (502 individuals, 36.54% species composition) and Cirratulidae (damaged) (17 individuals, 1.24% species composition). Other species included Tubificoides benedii, Tubificoides brownae, Peringia ulvae, Mytilidae (juvenile), Caulleriella alata, Tubificoides sp. (damaged), Lagis koreni, and Kurtiella bidentata. A biotope of SS.SMu.VS.CapTubi (Capitella and Tubificoides spp. in reduced salinity infralittoral muddy sediment) was assigned for this station.
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Station G4 was located approximately 140m upstream from G3 and the discharge point. The sediment at this station was classified as muddy sand according to Folk (1954) and the fauna was dominated by Capitella sp. complex (3,214 individuals, 63.83% species composition), Nematoda (1,576 individuals, 31.3% species composition) and Caulleriella alata (115 individuals, 2.28% species composition). Other species included Tubificoides benedii, Cirratulidae (damaged), Tubificoides brownae, Malacoceros vulgaris, Cirriformia tentaculata, Tubificoides sp. (damaged), Kurtiella bidentata, Heteromastus filiformis, Balanus crenatus, Mytilidae (juvenile), and Veneridae (juvenile). A biotope of SS.SMu.VS.CapTubi (Capitella and Tubificoides spp. in reduced salinity infralittoral muddy sediment) was assigned for this station.
None of the species and habitats recorded during the current survey are of conservation importance or interest. Overall, they are typical of organically enriched or physically disturbed habitats in areas of reduced salinity with relatively low species richness.
4. Discussion
Two baseline fish surveys by Ecoserve and one by AQUAFACT were carried out to establish the existing environment pre-construction (Ecoserve, 2008; 2009; AQUAFACT, 2015). The Ecoserve reports recorded a total of six species: three-spined stickleback, flounder, common goby, thick lipped mullet, lesser sand eel and sprat, only three of which were recorded in the first survey i.e. common goby, flounder and sprat. The 2015 AQUAFACT survey recorded significantly higher species richness recording 13 species of which 10 were not recorded in previous surveys. These included trout, bass, sand smelt, plaice, nilsson’s pipefish, sea scorpion, lemon sole, pollack, eel and shore rockling. The increase in species richness was thought to be due to the time of year of the study and increased salinity in the estuary. The Liffey estuary is highly modified due to its location in the centre of Dublin and its use as a major port and as a consequence channels have been deepened and concrete piers have been constructed along the river bank. This greatly reduces shallow water habitats and species diversity. The 2018 AQUAFACT survey which used seine netting and beam trawls only recorded two fish species. This was attributed to low salinity and temperature at the time of sampling. A positive correlation of species richness with increase salinity has been noted across the previous two Ecoserve and two AQUAFACT surveys.
The recent survey recorded twelve species overall, which compares well with the 2015 AQUAFACT survey that recorded 13 species with recorded salinities similar to the current survey. Seven of the
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Dublin Waste to Energy Biological Surveys Covanta August 2020 species recoded in the current survey were also record in the 2015 survey. Six species recorded in the 2015 survey were not recorded in the current survey while five species recorded in this survey were not recorded in the 2015 survey. The current survey was carried out in July while the 2015 survey took place in May which could explain the change in community composition. The other surveys, which recorded low abundances and species richness, took place much earlier in the year (March, April).
The results from this fish survey compare well with precious surveys considering the water temperature and salinity levels recorded at the time of the survey. Considering the level of modification and anthropogenic inputs, the Liffey estuary still supports a reasonable diversity of fish species.
The 4 grab stations upstream and downstream from the discharge point are all typical of organically enriched or physically disturbed habitats in areas of reduced salinity with relatively low species richness. They have all been assigned the biotope SS.SMu.VS.CapTubi (Capitella and Tubificoides spp. in reduced salinity infralittoral muddy sediment) and exhibit varying dominance of Capitella sp. complex, Nematoda, Tubificoides spp. and Malacoceros vulgaris.
5. References
AQUAFACT (2015) Dublin Waste to Energy Fish Survey. Report for Dublin Waste to Energy (PM group). 7 pp. AQUAFACT (2018) Dublin Waste to Energy Fish Survey. Report for Dublin Waste to Energy (PM group). 20 pp. EcoServe (2009). Dublin Waste-to-Energy fish Survey 2nd baseline study. Report for Dublin-to- Waste Energy. 15 pp. EcoServe (2008). Dublin Waste-to-Energy fish Survey baseline study. Report for Dublin-to- Waste Energy. 14 pp. WFD Common Implementation Strategy (2003). Guidance on monitoring for the Water Framework Directive. Water Framework Directive Common Implementation Strategy, Working Group 2.7, Monitoring.
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Appendix 1 Fish Species Abundance
Fish species caught during July 2020 Dublin Waste to Energy fish survey.
Beam Beam Beam Species Common name Seine 1 Seine 2 Seine 3 Seine 4 Fyke 1 Fyke 2 trawl 1 trawl 2 trawl 3 Pomatoschistus microps juv Common goby Abundance 63 58 46 280 Pleuronectes platessa juv. Plaice Abundance 14 3 8 1 1 1 Syngnathus rostellatus Nilsson’s pipefish Abundance 1 1 Taurulus bubalis Sea scorpion Abundance 1 7 1 Pollachius pollachius Pollack Abundance 3 1 1 Anguilla anguilla Eel Abundance 1 1 Gaidropsarus mediterraneus Shore Rockling Abundance 1 1 Sepiola atlantica Little cuttlefish Abundance 1 1 Spinachia spinachia Fifteen-spined stickleback Abundance 1 Clupea harengus Herring Abundance 1 Gadus morhua juv. Atlantic Cod Abundance 2 Merlangius merlangus Whiting Abundance 1 Total abundance 81 65 63 284 3 2 2 1 1 Species richness 4 6 5 5 3 2 1 1 1 Crangon crangon shrimp P= present P P P P P P P Carcinus maenas Shore crab P P P P P P P P P
Appendix 2 Benthic Species Abundance
JN1586 Liffey benthos Station AphiaID G1 G2 G3 G4 NEMATODA 799
Nematoda 799 20 353 502 1576 ANNELIDA 882
POLYCHAETA 883
PHYLLODOCIDA 892
Pholoidae 941
Pholoe baltica (sensu Petersen) 130599 1
SPIONIDA 889
Spionidae 913
Malacoceros vulgaris 131134 5
CAPITELLIDA 890
Capitellidae 921
Capitella sp. complex 129211 34 10 826 3214 Heteromastus filiformis 129884 3 2
TEREBELLIDA 900
Cirratulidae 919
Cirratulidae (damaged) 919 38 17 28
Caulleriella alata 129943 2 2 115
Cirriformia tentaculata 129964 5
Pectinariidae 980
Lagis koreni 152367 1
OLIGOCHAETA 2036
HAPLOTAXIDA 2118
Naididae 2039
Tubificoides sp. (damaged) 137393 2 2 1
Tubificoides brownae 137572 4 6 6 10 Tubificoides benedii 137571 14 1 8 73 ARTHROPODA 1065
CRUSTACEA 1066
CIRRIPEDIA 1082
Balanidae 106057
Balanus crenatus 106215 1
DECAPODA 1130
BRACHYURA 106673
JN1586 Liffey benthos Station AphiaID G1 G2 G3 G4 Carcinidae 557511
Carcinus maenas 107381 1
MOLLUSCA 51
GASTROPODA 101
LITTORINIMORPHA 382213
Hydrobiidae 120
Peringia ulvae 151628 1 5
BIVALVIA 105
MYTILIDA 210
Mytilidae 211
Mytilidae (juvenile) 211 4 1
LUCINIDA 489106
Thyasiridae 219
Thyasira sp. (juvenile) 138552 2
IMPARIDENTIA 869600
Lasaeidae 222
Kurtiella bidentata 345281 1 3
CARDIIDA 869602
Cardiidae 229
Parvicardium pinnulatum 181343 2
VENERIDA 217
Veneridae 243
Veneridae (juvenile) 243 1
Appendix 3 Section 14 Licence
Appendix 4 Photo Log
Pollack
Common goby
Plaice
Nilsson’s pipefish
Herring
Sea scorpion
Cod
Shore rockling (Whiting and shore crab)
Eel
Sea gooseberries, shrimp, plaice and shore crab