The identification of acid-sensitive waters currently uses coarse methods of designation i.e. pH (<5.5) and low alkalinity (<10 mg CaCO3 l-1). While these measures are clearly indicative of low buffering capacity, they are extremely variable within any one catchment, depending on flow conditions and geology. The contribution of sodium (Na+) to the sum of the major cations (Sodium Dominance Index, SDI, or Weathering Index) in river waters has been proposed as an indicator of the acid sensitivity of rivers in upland Scotland, particularly where sea salt inputs dominate the base cation composition. The extent of SDI is considered a quantitative indication of catchment weathering rate, incorporating the effects of diverse geological composition. This project set out to evaluate the efficacy of the SDI approach to site designation under Irish conditions. Two initial hypotheses were tested: that SDI is more stable across flow conditions than the two most commonly used indicators (i.e. alkalinity and pH) and is thus a better indicator of stream sensitivity to acidification than these traditional indictors and that there is a graded response by the stream macroinvertebrates to values of the index, and hence some ecological underpinning of the chemical relationship.

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Cruikshanks, R. Kelly-Quinn, M. O'Halloran, J.   "WaterAc Project - An investigation of the Sodium Dominance Index as a measure of Acid Sensitivity in Irish Streams.". Associated datasets and digitial information objects connected to this resource are available at: Secure Archive For Environmental Research Data (SAFER) managed by Environmental Protection Agency Ireland https://eparesearch.epa.ie/safer/resource?id=2062406b-5fda-102a-90c6-0593d266866d (Last Accessed: 2024-10-11)

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SAFER-Data Display URL	https://eparesearch.epa.ie/safer/iso19115/display?isoID=30
Resource Keywords	alkalinity, conductivity, pH macorinvertebrates WaterAC
EPA/ERTDI/STRIVE Project Code	2000-LS-3.2.1-M2
EPA/ERTDI/STRIVE Project Theme	Water Quality
Resource Availability:	Public-Open
Limitations on the use of this Resource	Usage of the data is currently restricted and will not be made publicly available from this website until pending publications have been published. You must contact the Point of Contacts listed below directly if you wish to obtain and use the data. In any publication outputs please cite the original producers and owners of this data correctly using the suggested citation information given below
Number of Attached Files (Publicly and Openly Available for Download):	3
Project Start Date	Thursday 1st August 2002 (01-08-2002)
Earliest Recorded Date within any attached datasets or digital objects	Sunday 1st December 2002 (01-12-2002)
Most Recent Recorded Date within any attached datasets or digital objects	Wednesday 4th January 2006 (04-01-2006)
Published on SAFER	Wednesday 30th May 2007 (30-05-2007)
Date of Last Edit	Thursday 26th February 2009 at 12:21:59 (26-02-2009)
Datasets or Files Updated On	Thursday 26th February 2009 at 12:15:36 (26-02-2009)

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Description of Geographical Characteristics of This Project or Dataset
Site selection for the extensive sampling was undertaken in consultation with EPA/COFORD to ensure collection of data for areas where a paucity of data exists. This included site visits and detailed examination of forest management plans, and the determination of Q-value data availability. All information was collated in an ArcView GIS database which was completed in June 2002. A total of 257 potential sites were identified across Ireland (192 non-forested and 65 forested) potential sites were of good water quality with a minimum EPA rating of Q4 and above, which meant there was no evidence of organic pollution or eutrophication based on macro-invertebrate fauna (EPA, 2000). For practical purposes, the country was divided into two areas, (Northern Ireland was not surveyed i.e. North-East Corner) each research group being responsible for one of these areas (Figure 3.1). Final site sampling distribution was weighted, based on the base cation weathering index map obtained from Aherne and Farrell (2000)

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The following is a list of projects, datasets, and resources on SAFER-Data from which users downloaded attachments from soon after downloading attachments from this resource WaterAc Project - An investigation of the Sodium Dominance Index as a measure of Acid Sensitivity in Irish Streams.. You can view the full description for projects, datasets, and resources by using the links supplied.

• Foresty Operations and Eutrophication - The Influence of Forestry and Forest Operations on Water (PEnrich) View Full Metadata Description
• Biodiversity in Ireland Plantation Forests (BIOFOREST) View Full Metadata Description
• A Framework for the Assessment of Groundwater - Dependent Terrestrial Ecosystems under the Water Framework Directive View Full Metadata Description
• Eutrophication From Agricultural Sources - Soil and Phosphorus: Catchment Studies View Full Metadata Description
• Quantification of Erosion and Phosphorus Release from a Peat Soil Forest Catchment View Full Metadata Description

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