County Kildare Groundwater Protection Scheme Volume I: Main Report First Draft. December 2002 John Lahart Coran Kelly and Vincent Fitzsimons Director of Services Groundwater Section Housing and Water Services Geological Survey of Ireland Kildare County Council Beggars Bush Newbridge Haddington Road Kildare Dublin 4 First Draft 5/12/02 Authors Coran Kelly, Groundwater Section, Geological Survey of Ireland Vincent Fitzsimons, Groundwater Section, Geological Survey of Ireland Subsoils mapped by: Claire Glanville, Quaternary Section, Geological Survey of Ireland Willie Warren, Quaternary Section, Geological Survey of Ireland in partnership with: Kildare County Council First Draft 5/12/02 Kildare Groundwater Protection Scheme. Volume I. Kildare County Council and the Geological Survey of Ireland Executive Summary The Groundwater Protection Scheme for Kildare County Council provides a preliminary assessment of the relative risk to groundwater quality across the county. The main elements of the risk assessment are groundwater vulnerability (primarily subsoil thickness, subsoil permeability and karst features), aquifer potential, and source protection. The source protection element involves the delineation of protection areas around the recharge areas for selected public and group scheme groundwater supplies. The results can’t be used as a substitute for site investigation for particular developments, but have proved very useful in providing Kildare County Council with an independent, defensible, planning tool for a wide range of new developments: • Major developments (e.g. for landfill site selection, developments requiring waste management and integrated pollution licensing): helping to short-list suitable sites for detailed site investigation. • Minor developments (e.g. domestic wastewater treatment systems): helping to prioritise the allocation of Local Authority planning staff resources. The main output of the Protection Scheme is a digital Geographic Information System which is designed to be compatible with existing Kildare County Council planning tools. It provides ‘Groundwater Protection Responses’ for all areas of the county. These responses incorporate the potential hazard posed by selected activities with the vulnerability, aquifer and source protection assessments to provide site suitability guidance for all areas of the county. The activities in question currently include landfill, IPC landspreading of piggery/poultry wastes, and domestic wastewater treatment systems. The responses are developed through a collaboration of the Geological Survey of Ireland, the EPA and the Department of the Environment and Local Government. An additional output comprises paper maps of the protection scheme, and two report volumes. Volume I outlines the basis for the vulnerability and aquifer zones delineated in the paper maps and GIS. Explanations include assumptions made, calculations/data sources used, and limitations. Volume II outlines the basis for the source protection zones delineated in the maps and GIS. Again, the text includes assumptions made, calculations and data sources used, and limitations. First Draft 5/12/02 i Kildare Groundwater Protection Scheme. Volume I. Kildare County Council and the Geological Survey of Ireland Table of Contents EXECUTIVE SUMMARY ......................................................................................................................................... I 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 PREVENTING GROUNDWATER POLLUTION................................................................................................................................2 1.5 OBJECTIVES OF THE COUNTY KILDARE GROUNDWATER PROTECTION SCHEME ......................................... 3 1.6 SCOPE OF COUNTY KILDARE GROUNDWATER PROTECTION SCHEME ......................................................... 4 1.7 KILDARE COUNTY DEVELOPMENT PLAN.................................................................................................... 5 1.8 STRUCTURE OF REPORT .............................................................................................................................. 5 1.9 ACKNOWLEDGEMENTS ............................................................................................................................... 5 2 BEDROCK GEOLOGY .............................................................................................................................. 7 2.1 INTRODUCTION ........................................................................................................................................... 7 2.2 LOWER PALAEOZOIC ROCKS ...................................................................................................................... 7 2.3 THE LEINSTER GRANITE ............................................................................................................................. 7 2.4 THE CARBONIFEROUS SUCCESSION ............................................................................................................ 9 2.5 STRUCTURE AND GEOLOGICAL HISTORY.................................................................................................. 10 3 SUBSOIL (QUATERNARY) GEOLOGY............................................................................................... 12 3.1 INTRODUCTION ......................................................................................................................................... 12 3.2 SUBSOIL TYPES......................................................................................................................................... 12 3.3 DEPTH TO BEDROCK ................................................................................................................................. 13 4 HYDROGEOLOGY AND AQUIFER CLASSIFICATION .................................................................. 14 4.1 INTRODUCTION ......................................................................................................................................... 14 4.2 DATA AVAILABILITY ................................................................................................................................ 14 4.3 RAINFALL, EVAPOTRANSPIRATION AND RECHARGE................................................................................. 14 4.4 BACKGROUND TO AQUIFER CLASSIFICATION ........................................................................................... 14 4.5 CLASSIFICATION OF THE LOWER PALAEOZOIC AQUIFERS......................................................................... 19 4.6 CLASSIFICATION OF THE GRANITE AQUIFER............................................................................................. 22 4.7 CLASSIFICATION OF THE OLD RED SANDSTONE (ORS) AQUIFER.............................................................. 22 4.8 CLASSIFICATION OF THE LOWER LIMESTONE SHALES .............................................................................. 23 4.9 CLASSIFICATION OF THE BALLYSTEEN-TYPE LIMESTONE AQUIFERS........................................................ 23 4.10 CLASSIFICATION OF THE WAULSORTIAN LIMESTONE AQUIFER............................................................ 24 4.11 CLASSIFICATION OF THE ALLENWOOD, MILFORD AND RICKARDSTOWN LIMESTONE AQUIFERS ......... 25 4.12 CLASSIFICATION OF THE EDENDERRY OOLITE (LIMESTONE) AQUIFER................................................. 25 4.13 CLASSIFICATION OF THE BALLYADAMS LIMESTONE AQUIFER ............................................................. 26 4.14 CLASSIFICATION OF THE CALP LIMESTONE AND TOBER COLLEEN LIMESTONE AQUIFERS................... 26 4.15 CLASSIFICATION OF THE NAMURIAN AQUIFER..................................................................................... 28 4.16 CLASSIFICATION OF THE VOLCANICS OCCURRING IN THE CARBONIFEROUS ......................................... 29 4.17 CLASSIFICATION OF THE SAND & GRAVEL AQUIFERS.......................................................................... 29 5 GROUNDWATER VULNERABILITY................................................................................................... 35 5.1 INTRODUCTION ......................................................................................................................................... 35 5.2 SOURCES OF DATA.................................................................................................................................... 36 5.3 PERMEABILITY ASSESSMENT CRITERIA .................................................................................................... 36 5.4 MAPPING PERMEABILITY OVER LARGE AREAS......................................................................................... 37 5.5 RESULTS OF PERMEABILITY MAPPING...................................................................................................... 38