Annual Groundwater Monitoring Interpretative Report-2016 Issued to the Environmental Protection Agency (2016) (PO386-03

Transcription

1 LICENCE REFERENCE No. RISK ASSESSMENT METHODOLOGY STAGE & STEP ANNUAL INTERPRETATIVE REPORT REPORT VERSION FINAL Annual Groundwater Monitoring Interpretative Report-2016 Issued to the Environmental Protection Agency (2016) (

2 Project Title: Annual Groundwater Interpretative Report 2016 Licence No. Project No: 16-2 Contract No Report Ref: Status: Final Client: plc Client Details: Issued By: (GES Ltd Green Road, Carlow Document Production / Approval Record Prepared by (consultant) Name Signature Date Position Jer Keohane Insert here Insert here BSc, MSc, C.Geol, FCIWEM, C.WEM. MIEI % Input 100 Approved by (consultant) Insert here Insert here Insert here Insert here Insert here Site Approval by Insert here Insert here Insert here Insert here N/A 2 10 Dec-2016

3 LIMITATION This interpretative report was prepared using data provided by plc. Groundwater samples are taken by the Licensee with some parameters analysed in house and the majority of parameters analysed by an accredited external laboratory Dec-2016

4 TABLE OF CONTENTS Section Page No EXECUTIVE SUMMARY... II 1. INTRODUCTION PROJECT CONTRACTUAL BASIS & PERSONNEL INVOLVED BACKGROUND INFORMATION PROJECT OBJECTIVES SCOPE OF WORKS GROUNDWATER SAMPLING & MONITORING LABORATORY ANALYSES RESULTS & DISCUSSION OF MONITORING PROGRAMME GROUNDWATER RESULTS POTENTIAL POLLUTANT LINKAGES SUMMARY, CONCLUSIONS AND RECOMMENDATIONS SUMMARY AND CONCLUSIONS RECOMMENDED WAY FORWARD APPENDICES Appendix A Hydrogeological maps i 10-DEC-2016

5 TABLE OF CONTENTS EXECUTIVE SUMMARY Quarterly sampling of the groundwater network on the site is undertaken for an agreed range of parameters. The results of analysis are discussed in this report in the context of the previously established conceptual site model. The results demonstrate generally stable groundwater quality with some exceedances of GTV and IGV. However it is not considered that any intervention needs to be undertaken. The recommended way forward is continued monitoring to establish long term trends. ii 10-DEC-2016

6 AG4 iii 10-DEC-2016

7 1. INTRODUCTION 1.1. PROJECT CONTRACTUAL BASIS & PERSONNEL INVOLVED Sampling is undertaken by JJ O Sullivan who is the manager of the wastewater treatment plant and is appropriately qualified to undertake sampling of the wells on site. Some analysis is undertaken on site and the majority are undertaken off-site by ALS who are an accredited laboratory. The interpretative report is prepared by Jer Keohane who has 33 years experience BACKGROUND INFORMATION SITE LOCATION The treatment facility is located in the townland of Rathgoggan North, approximately 2.5km north of the main manufacturing plant as shown below EFFLUENT GENERATION AND TREATMENT Effluent generated at the milk processing plant is discharged through a 350mm diameter pipeline to the wastewater treatment facility. The WWTP comprises preliminary (balancing & dissolved air floatation (DAF)), secondary (aerobic reactor) and tertiary (rapid sand filters and lagoons) treatment stages. The site on which the treatment facility lies is dissected by the Charleville Stream, 1 10-Dec-2016

8 which forms the Cork-Limerick county boundary. Whilst the treatment plant is on the Cork side of the stream, treated effluent is transferred to lagoons on the Limerick side of the stream. The lagoons to the west of the river, now only hold rainwater. There is a total storage capacity of approximately 600,000m 3 provided in 6 No. lagoons covering approximately 22 Hectares to the east of the stream, although the area actually used is substantially smaller, approximately 13 Ha, since a large lagoon to the east of the complex is not used. Effluent is stored in the lagoons until there are at least six dilutions available in the receiving water. Typically, there is no discharge from the installation between May and September as there are usually insufficient dilutions available during this period, i.e. no discharge under 95%ile flow conditions. The volume to be discharged annually ranges from 618,000m 3 to 795,000m 3 and the pump/discharge rate ranges from approximately 19m 3 /hr to a maximum rate of 750m 3 /hr. The discharge volume increases proportionally as the flow in the stream increases; while maintaining a ratio of 1:6 (as a minimum) of discharge rate to stream flowrate. The number of dilutions in the receiving water is never less than 6 at any time during discharge. Due to the relatively small size of the Charleville Stream/Glen river, the periods during which discharge can occur is significantly curtailed. This may result in treated effluent being stored for up to 6 months. TOPOGRAPHY The general topographical setting for the site comprises extensive, flat, poorly drained farmland at a typical elevation of 60m O.D RECEPTORS SURFACE WATER FEATURES The Charleville Stream/Glen River is a tributary of the Maigue River and is one of a number of tributaries draining the higher ground to the south and west in a trellis drainage pattern as shown in the surface water map below. The Charleville stream flows north through the site and is met by another tributary, just north of the site, The Helena Stream before flowing into the Maigue. The Maigue River then flows North through Bruree, Croom and Adare on its way to the Shannon Estuary Dec-2016

9 Reference to the EPA hydrotool report, indicates that the Charleville stream has a catchment of approximately 13.6km 2 by the time it reaches the site. A simple water balance on this catchment gives the following The 50%ile flow from hydrotool is 0.149m3/s, which suggests that the annual groundwater recharge component is 0.054m3/s or 26% of the total available recharge which is in keeping with the general guidelines from guidance document GW5-WFD pressures and impacts assessment methodology for low and moderate permeability subsoils. GEOLOGY and HYDROGEOLOGY 3 10-Dec-2016

10 Bedrock Geology Reference to the available geological information indicates that the site is underlain by Limestone bedrock, comprising a dark shaly LIMESTONE. Rock outcrop is recorded along a ridge at Cregane less than 1km north and west of the site. Further south the town of Charleville is mainly underlain by Shale and mudstone. A local geology map is provided in the appendices Subsoils Geology Reference to the available GSI information indicates that the site lies on Till derived from Devonian sandstones. A cover layer of lake sediments is also indicated in the area, which is expected to be thinly developed, but nonetheless significant in the impedance of groundwater recharge. Before the lagoons were developed, a site investigation was undertaken in Five cable tool boreholes were drilled. The boreholes in general encountered a STIFF to HARD CLAY in all boreholes with a thin gravel horizon noted in one borehole. A maximum thickness of 13m was encountered in one borehole, and no borehole penetrated the full thickness of the overburden. A rotary borehole encountered bedrock at 15m. A local subsoil map is provided in the appendices. Hydrogeology Reference is made to the Charleville GWB report prepared by the GSI to establish groundwater conditions. The bedrock under the site is considered to be a Locally Important Aquifer Ll which is moderately productive only in local zones. Transmissivity values of 5-20m 2 /day are typical with gradients upto The report also suggest that flow will be concentrated in the upper 15m zone of the rock. A well test undertaken on AGW4 in 1998 indicated a T value of approx. 1m 2 /day so the lower value of 5m 2 /day from the GWB report is taken for the purposes of this assessment. Water levels in the boreholes suggest that the aquifer is generally confined, with potentiometric heads in the overlying Boulder Clay. Darcy s law is used to determine the volumetric groundwater throughput Dec-2016

11 Q = kia = (T/b) x 0.02 x 15 x 1000 = (5/15) x 0.02 x15 x 1000 = 100m 3 /day. The groundwater flow direction will be to the North. Discharge mechanisms will comprise upwelling into surface water, where subsoils are thin or permeable. There is evidence of warm springs at Knocksouna 3km to the NE, which suggests groundwater returning from depth. Groundwater Surface Water Interactions The GWB report, suggests that groundwater may only be in hydraulic connection with Rivers along only parts of their lengths, where subsoils are thinly developed. The subsoils are upto 17m in this area. Groundwater Sources The nearest groundwater source is at Bruree, Co. Limerick approximately 5km north of the site. The EPA source report was referred to as part of this study. The source is to the north of the River Maigue, the delineated source protection area is also completely north of the River. The risk to this source from the activities on site are considered to be extremely low. There may be some private boreholes downgradient of the site, but none were identified within 1km of the lagoons. Groundwater Dependent TE No GWDTE has been identified in the proximity of the site 1.3. PROJECT OBJECTIVES This report was prepared to discuss the results of analysis from sampling undertaken in SCOPE OF WORKS GROUNDWATER SAMPLING & MONITORING The sampling was undertaken by JJ O Sullivan who is the wastewater treatment plant manager Dec-2016

12 LABORATORY ANALYSES Some analysis was undertaken in house, but the majority of parameters were analysed by ALS in an external accredited laboratory. 2. RESULTS & DISCUSSION OF MONITORING PROGRAMME 2.1. GROUNDWATER RESULTS The groundwater quality is similar to previous years. The 8-year trend graphs for key parameters are shown for each borehole with trend lines where applicable. AG4 is considered to be upgradient The E.Conductivity values over 8 years have been consistent, and are well below the 800uS/cm threshold value. The long term trend shows a slight downward slope 6 10-Dec-2016

13 There appears to be a slight long term downward trend in the case of Chloride consistent with a similar trend in conductivity, but the values are generally at background. The ammonia values show a long term steady trend, with generally spiky results. It is not clear what causes this, but it may be related to the aquifer cycling between confined and unconfined states 7 10-Dec-2016

14 DGW is downgradient and covers the western side of the River. The conductivity values are generally stable at background values over the long term with a slight downward trend The pattern of results for Chloride and Potassium are similar to the E-Conductivity values and show long term values typical of background 8 10-Dec-2016

15 The second quarter value in 2016 upset a general steady downward trend since mid-2015 in Ammonia concentrations, with the last quarter of 2016 showing a slight increase again. This may be due more to aquifer conditions than any sources of contamination. DGE is downgradient of the lagoon complex and to the East of the Charleville stream DGE is downgradient to the east of the Charleville Stream. The E-Conductivity values have been very steady for the past 8 years Dec-2016

16 The Chloride and Potassium values mirror the conductivity values and are very steady. The Ammonia values are showing a slight long term downward trend. however, values have been increasing but spiky since early Dec-2016

17 The phosphorous results for all boreholes are shown above. There is general agreement between the values from all boreholes, with peaks occurring at similar times. The average values suggest higher upgradient than downgradient concentrations, and there is no explanation for this. Iron and Manganese are endemic in the groundwater body, and appear in samples upgradient and down gradient. When the rolling averages are calculated for each parameter it can been seen that the values are generally steady and in general the rolling averages are lower than those reported in Dec-2016

18 BOREHOLE PARAMETER 8-year rolling average AG4 Conductivity 587 Ammonia Chloride Potassium DGW Conductivity Ammonia 0.15 Chloride Potassium 1.34 DGE Conductivity Ammonia 0.12 Chloride Potassium 1.15 The rolling averages all suggest poorer water quality down gradient. Only ammonia in DGE, is consistently higher than the upgradient value, through the year, and as discussed above this may be due to reducing conditions developing in the downgradient part of the aquifer. When compared to the groundwater threshold values in SI 9 of 2010 the downgradient ammonia values for four samples in DGE slightly exceed the threshold value. The only other exceedances apply to Iron and Manganese, which are considered to be naturally elevated in the area. The groundwater quality east of the River is of marginally poorer quality than that to the west Dec-2016

19 2.2. POTENTIAL POLLUTANT LINKAGES There is evidence that the downgradient wells have slightly poorer groundwater than the upgradient well, but the differences are not significant enough to suggest that any of the potential pollutant linkages are being developed to a significant degree. There is some evidence of improving long-term trends 3. SUMMARY, CONCLUSIONS AND RECOMMENDATIONS 3.1. SUMMARY AND CONCLUSIONS The groundwater monitoring data for 2016 suggests a generally stable groundwater quality RECOMMENDED WAY FORWARD No intervention is warranted on this site, as the trends do not suggest a worsening status, and the exceedances are marginal in the context of the site setting. oo00oo Respectfully submitted On behalf of GES Limited (/Lead Consultant) Dec-2016

20 APPENDIX 1 LONG TERM MONITORING RESULTS Dec-2016

21 AG4 GTV IGV max average Nitrate Iron Potassium Calcium Magnesium Manganese Alkalinity NAC Chloride Sulphate Fluoride Sulphide Nitrite Ionic Balance COD Phosphorous ph Suspended Solids Ammonia Conductivity DGW Nitrate Iron Potassium Calcium Magnesium Manganese Alkalinity NAC Chloride Sulphate Fluoride Sulphide Nitrite Ionic Balance COD Phosphorous ph Suspended Solids Ammonia Conductivity DGE Nitrate Iron Potassium Calcium Magnesium Manganese Alkalinity NAC Chloride Sulphate Fluoride Sulphide Nitrite Ionic Balance COD Phosphorous ph Suspended Solids Ammonia Conductivity

22 HYDROGEOLOGICAL MAPS Dec-2016

23 Charleville- Subsoils Co ns en to f c Fo op r i yr ns ig pe ht ct ow ion ne pu r r rp eq os ui es re o d nl fo y. ra ny ot he ru se. Legend m. This map and its data may not be used or reproduced for commercial purposes without the prior written permission of Ordnance Survey of Ireland. This map is a user generated static output from an Internet mapping site and is for general reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. Map center: , Scale: 1:27,321 Snapshot Date: 21-Mar-2013 Copyright Ordnance Survey Ireland/Government of Ireland,DCENR,GSI. Ordnance Survey Ireland Licence No. EN

24 Charleville-vulnerability map Co ns en to f c Fo op r i yr ns ig pe ht ct ow ion ne pu r r rp eq os ui es re o d nl fo y. ra ny ot he ru se. Legend m. This map and its data may not be used or reproduced for commercial purposes without the prior written permission of Ordnance Survey of Ireland. This map is a user generated static output from an Internet mapping site and is for general reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. Map center: , Scale: 1:27,321 Snapshot Date: 21-Mar-2013 Copyright Ordnance Survey Ireland/Government of Ireland,DCENR,GSI. Ordnance Survey Ireland Licence No. EN

25 - Charleville-Aquifers Legend km. This map and its data may not be used or reproduced for commercial purposes without the prior written permission of Ordnance Survey of Ireland. This map is a user generated static output from an Internet mapping site and is for general reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. Map center: , Snapshot Date: 21-Mar-2013 Scale: 1:78,552 Copyright Ordnance Survey Ireland/Government of Ireland,DCENR,GSI. Ordnance Survey Ireland Licence No. EN

26 Nearest groundwater sources Legend km. This map and its data may not be used or reproduced for commercial purposes without the prior written permission of Ordnance Survey of Ireland. This map is a user generated static output from an Internet mapping site and is for general reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. Map center: , Snapshot Date: 21-Mar-2013 Scale: 1:78,552 Copyright Ordnance Survey Ireland/Government of Ireland,DCENR,GSI. Ordnance Survey Ireland Licence No. EN