GSI Source Protection Areas

Areas surrounding individual groundwater sources are termed source protection areas (SPAs). Two source protection areas are recommended for delineation: Inner Protection Area (SI); Outer Protection Area (SO), encompassing the remainder of the source catchment area or ZOC. Inner Protection Area (SI) This area is designed to protect against the effects of human activities that might have an immediate effect on the source and, in particular, against microbial pollution. The area is defined by a 100-day time of travel (TOT) from any point below the water table to the source. (The TOT varies significantly between regulatory agencies in different countries. The 100-day limit is chosen for Ireland as a relatively conservative limit to allow for the heterogeneous nature of Irish aquifers and to reduce the risk of pollution from bacteria and viruses, which in some circumstances can live longer than 50 days in groundwater.) In karst areas, it will not usually be feasible to delineate 100-day TOT boundaries, as there are large variations in permeability, high flow velocities and a low level of predictability. In these areas, the total catchment area of the source will frequently be classed as SI. Outer Protection Area (SO) This area covers the remainder of the ZOC (or complete catchment area) of the groundwater source. It is defined as the area needed to support an abstraction from long-term groundwater recharge i.e. the proportion of effective rainfall that infiltrates to the water table. The abstraction rate used in delineating the zone will depend on the views and recommendations of the source owner. A factor of safety can be taken into account whereby the maximum daily abstraction rate is increased (typically by 50%) for expansion of the ZOC in dry periods, and possibly to allow for possible future increases in abstraction. In order to take account of the heterogeneity of many Irish aquifers and possible errors in estimating the groundwater flow direction, a variation in the flow direction (typically ±10-20°) is frequently included as a safety margin in delineating the ZOC. In delineating the inner (SI) and outer (SO) protection areas, there are two broad approaches: first, using arbitrary fixed radii, which do not incorporate hydrogeological considerations; and secondly, a scientific approach using hydrogeological information and analysis, in particular the hydrogeological characteristics of the aquifer, the direction of groundwater flow, the pumping rate and the recharge. The SPAs in this dataset are based on scientific, hydrogeological mapping. There are several hydrogeological methods for delineating SPAs. They vary in complexity, cost and the level of data and hydrogeological analysis required. Four methods, in order of increasing technical sophistication, are used: (i) calculated fixed radius; (ii) analytical methods; (iii) hydrogeological mapping; and (iv) numerical modelling. The GSI and EPA use the latter three methods for Source Protection Area delineation for public supplies. Even with relatively good hydrogeological data, the heterogeneity of Irish aquifers will generally prevent the delineation of definitive SPA boundaries. Consequently, the boundaries must be seen as a guide for decision-making, which can be reappraised in the light of new knowledge or changed circumstances. The boundaries of the SPAs are based on the horizontal flow of water to the source and, in the case particularly of the Inner Protection Area, on the time of travel in the aquifer. Consequently, the vertical movement of a water particle or contaminant from the land surface to the water table is not taken into account. This vertical movement is a critical factor in contaminant attenuation, contaminant flow velocities and in dictating the likelihood of contamination. It can be taken into account by mapping the groundwater vulnerability to contamination.

Alternate title: IE.GeologicalSurveyIreland.SourceProtectionAreas

Date (Creation): 2012-01-12T00:00:00

Date (Publication): 2020-01-16T00:00:00

Citation identifier: GE.IE.EPA.GEOL.VECTOR.SDE.GEOL_SourceProtectionAreas

Purpose: Groundwater sources, particularly public, group scheme and industrial supplies, are of critical importance in many regions. Consequently, the objective of source protection zones is to provide protection by placing tighter controls on activities within all or part of the zone of contribution (ZOC) of the source.

Status: On going

Point of contact

Organisation name	Individual name	Electronic mail address	Role
Geological Survey Ireland	Groundwater Section	info@gsi.ie	Point of contact

Maintenance and update frequency: As needed

GEMET - Concepts, version 2.4

water
geology
groundwater
groundwater quality
water quality
water geographic
groundwater pollution
hydrogeology

GemetInspireTheme

Geology

Environmental Protection Agency

waterbody
groundwater
hydrology
source protection area
groundwater protection schemes
subsoil permeability
groundwater quality
water contamination

ISO 3166

Use limitation: Data is for public use under Creative Commons CC-By 4.0

Access constraints: License

Other constraints: https://creativecommons.org/licenses/by/4.0/

Spatial representation type: Vector

Denominator: 50000

Language: English

Character set: UTF8

Topic category

Environment

Begin date: 2012-01-12T00:00:00

End date: 2012-01-12T00:00:00

Vertical extent

Minimum value: 0

Maximum value: 1014

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Vertical datum

Reference system identifier: http://www.opengis.net/def/crs/EPSG/0/29902
EPSG Geodetic Parameter Dataset EPSG 2009-11-25

Distribution format

Name	Version
ESRI Shapefile	10.x

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
Geological Survey Ireland	Groundwater Section	info@gsi.ie	Distributor

Hierarchy level: Dataset

Conformance result

Title: INSPIRE Data Specification on Geology

Alternate title: INSPIRE Data Specifications v3.0

Date (Publication): 2014-04-17

Explanation: The INSPIRE Directive or INSPIRE lays down a general framework for a Spatial Data Infrastructure (SDI) for the purposes of European Community environmental policies and policies or activities which may have an impact on the environment.

Pass: No

Conformance result

Title: COMMISSION REGULATION (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services

Alternate title: INSPIRE Interoperability Regulation

Date (Publication): 2010-12-08

Explanation: Level of conformance with the COMMISSION REGULATION (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services

Pass: No

Statement: Areas surrounding individual groundwater sources are termed source protection areas (SPAs). Two source protection areas are recommended for delineation: • Inner Protection Area (SI); • Outer Protection Area (SO), encompassing the remainder of the source catchment area or ZOC.

Metadata

File identifier: f2260f30-5434-48ea-aed4-e062ab69f117 XML

Metadata language: English

Character set: UTF8

Hierarchy level: Dataset

Date stamp: 2023-08-21T14:00:59.489Z

Metadata standard name: ISDI Metadata Profile

Metadata standard version: 1.2

Metadata author

Organisation name	Individual name	Electronic mail address	Role
Environmental Protection Agency	GIS Team	gis@edenireland.ie	Point of contact

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