West Offaly Power Thermal Discharge Synthesis Report Document No.: QS-000152-01-R402-000 Jointly Prepared by ESB International and Aquatic Services Unit For inspection purposes only. Consent of copyright owner required for any other use. Date: February 2018 ESB International, One Dublin Airport Central, Dublin Airport, Cloghran, Co. Dublin, Ireland. Phone +353 (0)1 703 8000 www.esbinternational.ie Aquatic Services Unit (UCC), Environmental Research Institute (UCC), Lee Road, Cork. Phone +353 (0)21 4901934 www.ucc.ie/en/asu/ Copyright © ESB International Limited, all rights reserved. EPA Export 28-05-2019:04:13:00 West Offaly Power Thermal Discharge Synthesis Report QS-000152 File Reference: Client / ESB Generation and Wholesale Markets Recipient: West Offaly Power Thermal Discharges Project Title: West Offaly Power Thermal Discharge Synthesis Report Report Title: QS-000152-01-R402-000 Report No.: Revision No.: Gerard Morgan (ASU) and Date: February 2018 Prepared by: Dr Adrian Buckley (ESBI) Manager ASU Title: Environmental Consultant Date: February 2018 Verified by: James Fitzpatrick Title: Senior Consultant Date: February 2018 Approved by: Dr Paddy Kavanagh Title: Senior Consultant Copyright © ESB International Limited All rights reserved. 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Change History of Report Date New Author Summary of Change Revision QS-000152-01-R402-000 2 EPA Export 28-05-2019:04:13:00 West Offaly Power Thermal Discharge Synthesis Report Table of Contents 1 Introduction 6 1.1 West Offaly Power 6 1.2 Scope of Report 7 1.3 Thermal Plumes 7 2 Environmental Setting 9 2.1 Cooling water discharge 9 2.2 Hydrology 11 2.3 Water Framework Directive 15 2.4 Draft River Basin Management Plan for Ireland 2018 - 2021 16 3 Thermal Plumes Studies 17 4 Continuous Temperature Monitoring 20 4.1 Introduction 20 4.2 Thermal Plume 21 4.3 General Ambient Temperature Trends 22 4.4 Temperature Averages 23 5 Fisheries 26 5.1 Fyke Net Surveys For inspection purposes only. 26 Consent of copyright owner required for any other use. 5.1.1 Species Present and Overall & Relative Abundances28 5.1.2 Possible Temperature Related Affects in the Data 31 5.1.3 Overall Conclusions – Fyke Net Survey 33 5.2 Comparison of IFI data (2010 and 2016) with Fyke Net Surveys (2016/2017) 34 5.3 Literature Review of Potential Fisheries Impacts 36 6 Diatoms 38 6.1 General Trends 38 6.2 Another possible diatom indicator species 39 6.3 Summary 40 7 Macrophytes 43 8 Macroinvertebrates 45 QS-000152-01-R402-000 3 EPA Export 28-05-2019:04:13:00 West Offaly Power Thermal Discharge Synthesis Report 9 Assessment of acceptability of thermal plume mixing zone at WOP 46 10 Conclusions 48 10.1 Thermal plume surveys 48 10.2 Fish 49 10.3 Diatoms 49 10.4 Macrophytes 50 10.5 Macroinvertebrates 50 11 Overall Conclusion 51 12 Recommendations 53 13 References 54 Appendix A: Graphical Information Referenced in Main Report Appendix B: Aquatic Services Unit Literature Review of Potential Fisheries Impacts – Documentation Table of Tables Table 2-1: Selected River Shannon Hydrometric Gauges (WOP) ....................................... 12 Table 3-1 Flow and Load Conditions during thermal plume surveys at WOP ...................... 17 Table 3-2 WOP Non-Conformances associated For inspection purposes with only. results of survey of July 2014. ........... 19 Consent of copyright owner required for any other use. Table 4-1: Continuous Monitoring Points at WOP ............................................................... 20 Table 4-2 Non-Conformances associated with results of Continuous Monitoring at WOP ... 25 Table 5-1 Fyke net survey dates and maximum temperatures at WOP ............................... 29 Table 5-2 Total of each species caught during each survey in the Shannon River at WOP in decreasing order ................................................................................................................. 29 Table 5-3 Fish numbers caught at each site in the Shannon River at WOP in the 5 surveys30 Table 6-1 Diatom determined ecological status at WOP sites 2014-2016 ........................... 40 Table of Figures Figure 1-1: General Location of West Offaly Power at Shannonbridge .................................. 6 Figure 2-1: West Offaly Power at Shannonbridge ................................................................. 9 Figure 2-2 River Shannon cross-sections at Shannonbridge ............................................... 10 QS-000152-01-R402-000 4 EPA Export 28-05-2019:04:13:00 West Offaly Power Thermal Discharge Synthesis Report Figure 2-3 Location of River Shannon cross-sections at Shannonbridge (IHD) ................... 11 Figure 2-4: Locations of West Offaly Power, Shannonbridge Gauge and Athlone Weir ....... 13 Figure 2-5: Flow Duration Curve - River Shannon at Athlone 1951-2017 ............................ 14 Figure 2-6 WFD river water body status at WOP ................................................................. 15 Figure 4-1: Continuous Monitoring Points at WOP .............................................................. 20 Figure 4-2 Water Levels at Shannonbridge (www.waterlevel.ie.) ........................................ 22 Figure 4-3 Upstream (S1 - ambient) temperatures at 0.3m depth at WOP for 13 reporting periods between July 2016 and December 2017 ................................................................. 23 Figure 5-1 Aerial photos showing fyke net fishing locations in the Shannon River at WOP . 27 Figure 5-2 Average depth-averaged temperature at or nearby the 5 paired fyke net sampling stations at WOP for each of the 5 fishing surveys. (Data extracted from IHD temperature monitoring reports). ............................................................................................................. 28 Figure 5-3 This shows the total number of fish of each species collected at all left (warm water) and right (cooler water) sites in each of the 5 survey periods at WOP ................................. 32 Figure 5-4 Proportional composition of fish species taken in an electrofishing survey in 2010 by IFI upstream of WOP at Clonmacnoise .......................................................................... 34 Figure 5-5 Proportional composition of fish species (based on CPUE) taken in an electrofishing survey in 2016 by IFI upstream (Site 19) and downstream (Site 21) of WOP at Shannonbridge ........................................................................................................................................... 35 Figure 6-1 Aerial view of WOP stretch showing 2015 & 2016 biological survey locations ... 39 Figure 6-2 WOP 2016- Relative abundance of A. minutissimum in relation to thermal outfall (green dashed line) ............................................................................................................. 41 For inspection purposes only. Figure 6-3 WOP 2016 RelativeConsent abundance of copyright owner A. requiredminutissimum for any other use. vs temperature (normalised), thermal outfall = green dashed line ..................................................................................... 41 Figure 6-4 Proportional composition of C. p. euglypta and A. minutissimum in diatom samples at WOP sites in 2015 .......................................................................................................... 42 Figure 6-5 Proportional composition of C. p. euglypta and A. minutissimum in diatom samples at WOP sites in 2016 .......................................................................................................... 42 Figure A-1. Summary temperature data at WOP in degrees Celsius (°C) from the monthly continuous in-river monitoring from July 2016 to December 2017* Figure A-2: Proportional composition of the total number of fish caught in all 5 surveys at WOP (2016-2017) Figure A-3: Pie charts showing the proportional composition of each species taken in each of 5 fyke net surveys in WOP (August & October 2016 and February, November and December 2017) QS-000152-01-R402-000 5 EPA Export 28-05-2019:04:13:00 West Offaly Power Thermal Discharge Synthesis Report 1 Introduction 1.1 West Offaly Power West Offaly Power Generating Station (WOP) is located adjacent to the River Shannon at Shannonbridge County Offaly. See Figure 1-1. The station is a peat fired base load station i.e. continuous operation, subject to availability. The installed capacity is 150MWe and the station was commissioned in 2005. The milled peat-fired boiler generates steam which is used to drive turbines which produce electricity. The steam is then cooled to hot water and recirculated to the boiler. The steam is cooled by water abstracted from and returned to the River Shannon. The aqueous principal discharge from the power station is cooling water discharge. The station discharges approximately 186MWth to the river Shannon when on full load. This consists of a flow through the condenser of 5.5 m3/s with a temperature rise of approximately 8°C. The flow through the condenser will vary slightly depending on the level of the River Shannon with a corresponding variation in the rise in temperature.