64b2c39e-d465-11e4-87df-f0def148f590 eng utf8 dataset Environment Agency DSPcustomerforum@environment-agency.gov.uk pointOfContact 2025-07-25 Environment Agency Metadata Profile 1.1 http://www.opengis.net/def/crs/EPSG/0/27700 Historic GQA Headline Indicators of Water Courses - Nutrients - phosphate GQA grades 2010 (Wales) 2010-01-01 creation 64b2c39e-d465-11e4-87df-f0def148f590 This record is for Approval for Access product AfA163.4 'Historic GQA Headline Indicators of Water Courses - Nutrients - phosphate GQA grades 2010 (Wales)'. The General Quality Assessment Headline Indicator scheme (GQAHI) was the Environment Agency's national method for creating a water quality indicator based on rivers and canals in England. This was a reduced network compared to the original GQA network used in England from 1990 to 2006. The Nutrients GQAHI scheme had over 3000 sampling sites which provide information for approximately 22500 km of watercourses. In Wales we maintained the full GQA network until 2010 based on 800 sampling sites which provided information for approximately 4700km. The GQAHI/GQA scheme was designed to provide an accurate and consistent assessment of the state of water quality and how it changes over time. The Nutrients GQA described quality in terms of two nutrients: nitrates (mg NO3 /l) and phosphates (mg P/l) and graded from 1 to 6. Grades were allocated for both phosphate and nitrate; they were not combined into a single nutrients grade. There were no set 'good' or 'bad' concentrations for nutrients in rivers in the way that we describe chemical and biological quality. Rivers in different parts of the country have naturally different concentrations of nutrients. ‘Very low’ nutrient concentrations, for example, are not necessarily good or bad; the classifications merely stated that concentrations in this river were very low relative to other rivers. Classification for phosphate: Grade limit (mgP/l) Average Description <0.02 Very low >0.02 to 0.06 Low >0.06 to 0.1 Moderate >0.1 to 0.2 High >0.2 to 1.0 Very high >1.0 Excessively high Classification for nitrate Grade limit (mg NO3/l) Average Description <5 Very low >5 to 10 Low >10 to 20 Moderately low >20 to30 Moderate >30 to 40 High >40 Very high 2009 is the final year of the scheme. Attribution statement: © Environment Agency copyright and/or database right 2019. All rights reserved. Environment Agency DSPcustomerforum@environment-agency.gov.uk https://environment.data.gov.uk/support Defra Data Services Forum pointOfContact notPlanned environment inlandWaters theme water quality GEMET - Concepts, version 2.4 2010-01-13 publication geonetwork.thesaurus.external.theme.gemet monitoring technique GEMET - Concepts, version 2.4 2010-01-13 publication geonetwork.thesaurus.external.theme.gemet monitoring data GEMET - Concepts, version 2.4 2010-01-13 publication geonetwork.thesaurus.external.theme.gemet Open Government Licence otherRestrictions license copyright There are no public access constraints to this data. Use of this data is subject to the licence identified. otherRestrictions license copyright There are no public access constraints to this data. Use of this data is subject to the licence identified. eng utf8 environment inlandWaters true -6.236 2.072 49.943 55.816 1990-01-01 2010-12-31 Proprietary format | ESRI, Intergraph, MS Access (MDB) Unknown https://environment.data.gov.uk/api/file/download?fileDataSetId=cde2136a-2e63-42d5-9474-ae05cf15a736&fileName=Historic_GQA_Headline_Indicators_of_Water_Courses_-_Nutrients_-_phosphate_GQA_grades_2010_(Wales).zip http Historic_GQA_Headline_Indicators_of_Water_Courses_-_Nutrients_-_phosphate_GQA_grades_2010_(Wales).zip Historic_GQA_Headline_Indicators_of_Water_Courses_-_Nutrients_-_phosphate_GQA_grades_2010_(Wales).zip download on Defra Data Services Platform dataset The Nutrients GQAHI described quality in terms of nutrients specifically Phosphate and Nitrates. At each sample points twelve water column samples were collected per annum and each assessment was based on a three year period. Data is represented as river stretches and stored in an zipped access database in four tables on the O drive (Environment Agency's shared drive).