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.
- Dull adnabod
- Rhychwant
- Dosbarthiad
- Ansawdd
- Allweddeiriau
- System Cyfeirio Gofodol
- Cynnwys
- Cyfyngiadau
- Cynnal a chadw
- Metadata
Dull adnabod
- Dynodydd
- NRW_DS116324
- Teitl Amgen
-
- AfA161 Historic GQA Headline Indicators of Water Courses – Biology
- Laith Metadata
- English
- Datganiad
-
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.
- Dyddiad cyfeirnod y set ddata (Cyhoeddiad)
- 2016-01-01
Ystod amser
- Dyddiad cychwyn
- 2000-01-01
- Dyddiad gorffen
- 2010-01-01
- Categori pwnc
-
- Inland waters
Rhychwant
Rhychwant
- Hyd
- Wales (WLS)
))
Dosbarthiad
Dosbarthiad
- Fformat - Math a Disgrifiad
-
-
Documents
Documents
()
- Math
-
Excel format
-
Documents
Documents
()
- Lleolwr Adnoddau
-
Download Data
World Wide Web page
Ansawdd
Ansawdd Data
- Cwmpas Ansawdd
- Dataset
- Datganiad
-
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.
Allweddeiriau
Allweddair
- Math
- Theme
Dyfyniad
- Dyddiad (Cyhoeddiad)
- 2008-06-01
Allweddair
Allweddair
System Cyfeirio Gofodol
- Cod
- NONE
Cynnwys
Gwybodaeth Cynnwys
Proffil CNC
Elfennau CNC
Cyfyngiadau
Cyfyngiadau
Cyfyngiadau ar Fynediad a Defnydd Cyhoeddus
- Math o Gyfyngiad
- Other restrictions
Cyfarwyddeb Cyfyngiadau Mynediad
- Cyfyngiadau
- no limitations
Testun cyfyngiadau mynediad
- Cyfyngiadau eraill
-
There are no access restrictions on this data. NRW may release, publish or disseminate it freely.
Defnyddiwch gyfyngiadau
- Cyfyngiadau Defnyddio
- Other restrictions
- Cyfyngiadau eraill
-
© 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
- Dynodydd Ffeil
- 4f4c4942-4343-5764-6473-313136333234 XML
- Laith Metadata
- English
- Dynodydd Rhiant
-
Historic General Quality Assessment (GQA) Headline Indicators of Water Courses
NRW_DS118585
- Math o adnodd
- Dataset
- Dyddiad Metadata
- 2024-05-30T15:37:21.835Z
- Enw Safonol Metadata
- NRW
- Fersiwn Metadata
-
1.0