Historic General Quality Assessment (GQA) Headline Indicators of Water Courses - Biology
The General Quality Assessment (GQA) Headline Indicator scheme or GQAHI (previously known as GQA) was the national indicator for water quality in rivers and canals. It was designed to provide an accurate and consistent assessment of the state of water quality and how it changes over time. These assessments were made for Biological, Chemical and Nutrients and undertaken for discrete river stretches. This datasets relates to the biological assessments. The Biology assessment gave an indicator of the overall 'health' of rivers. It describes water quality in terms of 83 groups of macroinvertebrates. Some of these are pollution sensitive so their presence suggested better water quality. A category was assigned to the river stretch where the monitoring point was located: - A - Very Good: Biology similar to that expected for an average and unpolluted river of this size, type and location. High diversity of groups, usually with several species in each. Rare to find dominance of any one group. - B - Good: Biology falls a little short of that expected for an unpolluted river. Small reduction in the number of groups that are sensitive to pollution. Moderate increase in the number of individuals in the groups that tolerate pollution. - C - Fairly Good: Biology worse than expected for an unpolluted river. Many sensitive groups absent or number of individuals reduced. Marked rise in numbers of individuals in groups that tolerate pollution. - D - Fair: Sensitive groups scarce and contains only small numbers of individuals. A range of pollution tolerant groups present, some with high numbers of individuals. - E - Poor: Biology restricted to pollution tolerant species with some groups dominant in terms of the numbers of individuals. Sensitive groups rare or absent. - F - Bad: Biology limited to a small number of very tolerant groups (such as worms, midge larvae and leeches), present in very high numbers. In the worst case, there may be no life present. Sample points represent one or many stretches.
- Identification
- Extent
- Distribution
- Quality
- Keywords
- Spatial Reference System
- Content
- Constraints
- Maintenance
- Metadata
Identification
- Identifier
- NRW_DS116324
- Alternative Title
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- AfA161 Historic GQA Headline Indicators of Water Courses – Biology
- Metadata Language
- English
- Lineage
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The assessment was made by carrying out a bi-yearly (Spring/Autumn) three minute active sampling with a pond net and a one-minute visual search for animals living on the surface or attached to rocks or vegetation. The number of taxa present were recorded and the Biological Monitoring Working Party score calculated. These values were then compared with values expected at a site in a similar, but totally unpolluted river. The mathematical model RIVPACS (the River Invertebrate Prediction and Classification System) was used to predict fauna in the absence of pollution. Issues to Note: Additional attributes are added annually (2008 attributes are represented) with 2009 being the last year of the scheme. In 2007 the GQA river network was reduced to the GQAHI river network. The data described have been amended to be consistent for all years.
- Dataset Reference Date (Publication)
- 2016-01-01
Temporal Extent
- Begin date
- 2000-01-01
- End date
- 2010-01-01
- Topic category
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- Inland waters
Extent
Extent
- Geographic Extent
- Wales (WLS)
))
Distribution
Distribution
- Format Type and Description
-
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Documents
Documents
()
- Specification
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Excel format
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Documents
Documents
()
- Resource Locator
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Download Data
World Wide Web page
Quality
Data quality
- Quality Scope
- Dataset
- Lineage
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The assessment was made by carrying out a bi-yearly (Spring/Autumn) three minute active sampling with a pond net and a one-minute visual search for animals living on the surface or attached to rocks or vegetation. The number of taxa present were recorded and the Biological Monitoring Working Party score calculated. These values were then compared with values expected at a site in a similar, but totally unpolluted river. The mathematical model RIVPACS (the River Invertebrate Prediction and Classification System) was used to predict fauna in the absence of pollution. Issues to Note: Additional attributes are added annually (2008 attributes are represented) with 2009 being the last year of the scheme. In 2007 the GQA river network was reduced to the GQAHI river network. The data described have been amended to be consistent for all years.
Keywords
Keywords
- Type
- Theme
Citation
- Date (Publication)
- 2008-06-01
Keywords
Keywords
Spatial Reference System
- Code
- NONE
Content
Content Information
NRW Profile
Custom Elements
Constraints
Constraints
Limitations on Public Access and Use
- Restriction type
- Other restrictions
Access Constraints Directive
- Limitations
- no limitations
Access Constraints Text
- Other constraints
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There are no access restrictions on this data. NRW may release, publish or disseminate it freely.
Use Constraints
- Use constraints type
- Other restrictions
- Other constraints
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© CNC/NRW Data may be re-used under the terms of the Open Government Licence providing it is done so, acknowledging both the source and NRW's copyright. It is the recipient's responsibility to ensure the data is fit for the intended purpose. Attribution statement: Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved.
Metadata
Metadata
- File Identifier
- 4f4c4942-4343-5764-6473-313136333234 XML
- Metadata Language
- English
- Parent Identifier
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Historic General Quality Assessment (GQA) Headline Indicators of Water Courses
NRW_DS118585
- Resource type
- Dataset
- Metadata Date
- 2024-05-30T15:37:21.835Z
- Metadata Standard Name
- NRW
- Metadata Standard Version
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1.0