County Monaghan Groundwater Protection Scheme Main Report September 2002 Billy Moore, B.E., M.Sc., F.I.E.I. Melissa Swartz and Donal Daly County Engineer Groundwater Section County Offices, The Glen Geological Survey of Ireland Monaghan Beggars Bush Haddington Road, Dublin 4 Monaghan Groundwater Protection Scheme Authors Melissa Swartz, Groundwater Section, Geological Survey of Ireland Donal Daly, Groundwater Section, Geological Survey of Ireland with contributions by: Vincent Fitzsimons, Groundwater Section, Geological Survey of Ireland in collaboration with: Monaghan County Council Monaghan Groundwater Protection Scheme TABLE OF CONTENTS 1 INTRODUCTION...................................................................................................................................................... 1 1.1 GROUNDWATER PROTECTION – A PRIORITY ISSUE FOR LOCAL AUTHORITIES......................................................... 1 1.2 GROUNDWATER – A RESOURCE AT RISK................................................................................................................. 1 1.3 GROUNDWATER PROTECTION THROUGH LAND-USE PLANNING: A MEANS OF PREVENTING CONTAMINATION....... 2 1.4 ‘GROUNDWATER PROTECTION SCHEMES’ – A NATIONAL METHODOLOGY FOR GROUNDWATER POLLUTION PREVENTION ..................................................................................................................................................................... 2 1.5 OBJECTIVES OF THE COUNTY MONAGHAN GROUNDWATER PROTECTION SCHEME.................................................. 3 1.6 SCOPE OF COUNTY MONAGHAN GROUNDWATER PROTECTION SCHEME.................................................................. 4 1.7 LINK WITH COUNTY DEVELOPMENT PLAN AND MEASURES REPORT ....................................................................... 5 1.7.1 County Development Plan, 1999 .................................................................................................................... 5 1.7.2 Measures Report, 1999 ................................................................................................................................... 5 1.8 STRUCTURE OF REPORT............................................................................................................................................ 5 1.9 ACKNOWLEDGEMENTS ............................................................................................................................................. 6 2 BEDROCK GEOLOGY............................................................................................................................................ 8 2.1 INTRODUCTION......................................................................................................................................................... 8 2.2 LOWER PALAEOZOIC ROCKS .................................................................................................................................. 10 2.2.1 Ordovician Rocks.......................................................................................................................................... 10 2.2.2 Ordovician/Silurian Rocks............................................................................................................................ 10 2.3 DEVONIAN ROCKS.................................................................................................................................................. 12 2.4 LOWER CARBONIFEROUS ROCKS............................................................................................................................ 12 2.5 NAMURIAN AND WESTPHALIAN (UPPER CARBONIFEROUS) ROCKS ....................................................................... 14 2.5.1 Namurian Rocks............................................................................................................................................ 15 2.5.2 Westphalian Rocks........................................................................................................................................ 15 2.6 PERMIAN AND TRIASSIC ROCKS ............................................................................................................................. 15 2.6.1 Permian Rocks .............................................................................................................................................. 15 2.6.2 Triassic Rocks............................................................................................................................................... 15 2.7 STRUCTURAL HISTORY........................................................................................................................................... 15 3 SUBSOIL GEOLOGY............................................................................................................................................. 17 3.1 INTRODUCTION....................................................................................................................................................... 17 3.2 SUBSOIL TYPES ...................................................................................................................................................... 17 3.2.1 Till................................................................................................................................................................. 18 3.2.2 Sands and Gravels ........................................................................................................................................ 18 3.2.3 Till with Gravel............................................................................................................................................. 18 3.2.4 Alluvium........................................................................................................................................................ 18 3.2.5 Peat............................................................................................................................................................... 19 3.2.6 Lake Deposits................................................................................................................................................ 19 3.3 DEPTH TO BEDROCK............................................................................................................................................... 19 3.4 ICE FLOW DIRECTION ............................................................................................................................................. 19 4 HYDROGEOLOGY AND AQUIFER CLASSIFICATION ................................................................................ 20 4.1 INTRODUCTION....................................................................................................................................................... 20 4.2 DATA AVAILABILITY.............................................................................................................................................. 20 4.3 RAINFALL, EVAPOTRANSPIRATION AND POTENTIAL RECHARGE............................................................................ 20 4.4 GROUNDWATER USAGE.......................................................................................................................................... 21 4.5 AQUIFER CLASSIFICATION...................................................................................................................................... 21 4.5.1 Use of Borehole Yields in Defining Aquifers ................................................................................................ 22 4.5.2 Use of Well Productivity Classes in Defining Aquifers................................................................................. 23 4.5.3 Karstification ................................................................................................................................................ 23 4.5.4 Dolomitisation .............................................................................................................................................. 23 4.5.5 Bedrock Aquifers........................................................................................................................................... 24 4.5.6 Sand/Gravel Aquifers.................................................................................................................................... 24 4.6 AQUIFER DELINEATION .......................................................................................................................................... 26 4.7 REGIONALLY IMPORTANT KARST AQUIFERS (RK) ................................................................................................. 26 4.7.1 Carrickmacross Area: Mullaghfin Limestone (MF) and Milverton Group Limestone (MLV)...................... 26 4.8 REGIONALLY IMPORTANT FISSURED AQUIFERS (RF).............................................................................................. 30 4.8.1 Monaghan-Clones Area: Fearnaght Sandstone (FT), Cooldaragh Formation (CH), Ulster Canal Limestone (UC), Ballysteen Limestone (BA), Ballyshannon Limestone (BS), Dartry Limestone (DA), Drumgesh Shale (DH) and Benbulben Shale (basal only) (BN)..................................................................................................................... 30 i Monaghan Groundwater Protection Scheme 4.8.2 The Knockatallon/Tydavnet Area: Dartry Limestone (DA) and Meenymore (ME) ...................................... 35 4.8.3 Carrickleck