Bog of the Ring
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~ OHDocNo: ._.. 4 Redd From: 6w s& 6. 8 Date Redd: 3-’3/ g 343f-4. Bog of the Ring Groundwater Source Protection Zones Prepared by: Natalya Hunter Williams Geological Survey of Ireland L. Assisted by: Coran Kelly, Geological Survey of Ireland Dona1 Daly, Geological Survey of Ireland Geoff Wright, Geological Survey of Ireland Monica Lee, For inspection Geological purposes only.Survey of Ireland PaulConsent Johnston, of copyright ownerTrinity required College, for any other Dublin use. David Ball, David Ball Associates In collaboration with: Fingal County Council March 2005 EPA Export 26-07-2013:00:20:51 Bog ofthe Ring Public W'uter Szcpply: Source Protection Zone.? TABLE OF CONTENTS 1: INTRODUCTION............................................................................................................................. 1 2.'LoCATION. SITE DESCRIPTION AND WELL HEAD PROTECTION ................................ 1 3: SUMMARY OF WELL DETAILS ................................................................................................. 2 .4. MljX"TODOLOGY............................................................................................................................ 3 4.1 Desk Study .............................................................................................................................. 3 4.2 Site visits and fieldwork .......................................................................................................... 4 4.3 Assessment .............................................................................................................................. 4 5: TOPOGRAPHY. SURFACE WATER HYDROLOGY AND LAND USE ................................. 4 6: GEOLOGY ........................................................................................................................................ 4 6.1 Introduction ............................................................................................................................. 4 6.2 Bedrock Geology..................................................................................................................... 5 6.3 Subsoil Geology ...................................................................................................................... 9 7: HYDROGEOLOGY ....................................................................................................................... 11 7.1 Introduction ........................................................................................................................... 11 7.2 Meteorology and Recharge ................................................................................................... 12 7.3 Groundwater Levels, Flow Directions and Gradients ........................................................... 13 7.4 . Aquifer Category ................................................................................................................... 16 7.5 'Aquifer Characteristics.......................................................................................................... 17 7.6 Hydrochemistry and Water Quality....................................................................................... 21 7.7 Conceptual Model ................................................................................................................. 28 7.8 Numerical Model ................................................................................................................... 30 8: DELINEATION OF SOURCE PROTECTION AREAS ............................................................ 35 8.1 Outer Protection Area ............................................................................................................ 35 8.2 Inner Protection Area ............................................................................................................ 36 9: VULNERABILITY........................................................................................................ ................ 38 9.1 Groundwater Protection Zones ........................................................................................ For inspection purposes only. :..... 38 Consent of copyright owner required for any other use. 9.2 Potential Pollution Sources ................................................................................................... 38 10: CONCLUSIONS AND RECOMMENDATIONS ...................................................................... 39 11: ACKNOWLEDGEMENTS.......................................................................................................... 40 12: REFERENCES.............................................................................................................................. 40 13: APPENDIX .................................................................................................................................... 42 -1 EPA Export 26-07-2013:00:20:51 I Bog ofthe Ring Piihlic Water Supply: Source Protection Zones :I LIST OF FIGURES FIGURE 1: PRODUCTION WELL 2 (Pw2), SHOWING THE CONCRETE PLATFORM, RAILINGS, WELL-HEAD PROTECTION CABIN AND PUMP-CONTROL HOUSING.................................................................................. .2 FIGURE 2: BEDROCKGEOLOGY IN THE BOG OF THE RING AREA. SEE TABLE3 FOR BEDROCK.“ GEOLOGY CODES AND DESCRIPTIONS......................................................................................................... .7 FIGURE3: CROSS-SECTION................................................................................................................................ .8 FIGURE4: SUBSOIL GEOLOGYMAPPED BY TEAGASCIN THE BOGOF THE RING AREA (MEEHAN,2004). SEE SECTION 6.3 FOR DESCRIPTIONS AND CODES,’EXCEPTlNG: ............................................................... 10 FIGURE 5: GROUNDWATERLEVEL MAP IN THE BOGOF THE RING AREA. NOTETHAT THE CONTOURS ARE AN INTERPRETATION BASED ON WELL DATA, TOPOGRAPHY AND SURFACE WATER FEATURES ........ 15 FIGURE6: AQUIFERCATEGORIES IN THE BOGOF THE RING AREA (GSI, 2004). SEE SECTION 7.4 FOR DESCRIPTIONS AND CODES. ...................................................................................................................... 19 FIGURE 7: DIAGRAMSHOWING THE NUMERICAL MODEL BOUNDARIES. SEE TEXT FOR DISCUSSION. ............. 32 FIGURE8: ZONE OF CONTRIBUTION (zoc) TO THE BOG OF THE RING WELLS, SHOWING THE INNER (SI) AND OUTER (so)PROTECTION ZONES. .................................................................................................... 37 LIST OF FIGURES IN THE APPENDIX Figure A.l: Map showing the locations of wells discussed in the text. Figure A.2: Maps showing (a) recharge zonation and (b) recharge values in mm/yr used in the numerical model. Figure A.3: Maps showing (a) cell permeability (dd) and (b) cell transmissivity (m2/d)used in the numerical model. Figure A.4: Map showing “actual” heads against modelled heads. l Figure AS: Map showing pumping water levels against modelled pumping water levels. LIST OF TABLES 0 TABLE1 : SUMMARY OF THE LOCATIONS OF THE WELLS AT BOGOF THE .G ................................................. 1 TABLE2: SUMMARY OF WELL DETAILS ............................................................................................................. 3 TABLE3: BEDROCK GEOLOGYOF THE BOGOF THE RING AREA ....................................................................... 6 TABLE4: RECHARGE COEFFICIENTS (RC) FOR DIFFERENT SUBSOIL PERMEABILITIES AND THICKNESSES....... 12 TABLE5: SUMMARY OF AQUIFER CHARACTERISTICS ...................................................................................... 20 TABLE6: SUMMARY OF HYDROCHEMISTRYDATA FROM CO. CO. SAMPLING ................................................ 24 TABLE7: SUMMARY OF HYDROCHEMISTRYDATA FROM THE TRIAL WELLS AT BOG OF THE RING. For inspection purposes only. DATAFROM K.T. CULLENConsent & CO. of (1994,copyright 2000(A))owner required .................................................................................. for any other use. 26 TABLE8: SUMMARY OF THE AQUIFER PROPERTIES USED IN THE NUMERICAL MODEL .................................... 33 TABLE9: ABSTRACTIONSAT THE BOG OF THE RING PUBLIC SUPPLY WELLS. ............................................... 34 TABLE10: MATRJXOF SOURCE PROTECTION ZONES FOR THE BOGOF THE RING PUBLIC SUPPLY ................. 38 LIST OF MAPS Map 1 Bedrock Geology of the Bog of the Ring Area Map 2 Subsoil Geology of the Bog of the Ring Area Map 3 Aquifers of the Bog of the Ring Area Map 4 Groundwater Vulnerability zones at the Bog of the Ring Source Map 5 Groundwater Source Protection Zones at the Bog of the Ring Source 11 EPA Export 26-07-2013:00:20:51 Bog of the Ring Puhlic Water Strpply: Source Protection Zones Bog of the Ring Public Water Supply Wells: Groundwater Protection Zones 1: Introduction The objectives of the report are as follows: To delineate source protection zones for the four Bog of the Ring public supply wells. 0 To outline the principal hydrogeological characteristics of the Bog of the Ring area. To assist Fingal County Council in protecting the water supply from contamination. To assist Fingal County Council in estimating groundwater resources. 2: Location, Site Description and Well Head Protection Four boreholes are used for the Bog of the Ring Public Water Supply. The boreholes are located in a roughly WNW-ESE line along the Bog Road, in the Townlands of Ring Commons and Killougher. Three of the boreholes are within 1 km of each other, with the fourth borehole about 1.5 km further to the west. Currently, all