# Commission Decision (EU) 2017/848 of 17 May 2017 laying down criteria and methodological standards on good environmental status of marine waters and specifications and standardised methods for monitoring and assessment, and repealing Decision 2010/477/EU (Text with EEA relevance), Division: Criteria, including criteria elements, and methodological standards

Extent: E+W+S+N.I.

Guidance documents published in the context of the Common Implementation Strategy for any enactment which gives effect to Directive 2000/60/EC may be relevant in this assessment (e.g. ‘No 13 — Overall Approach to the Classification of Ecological Status and Ecological Potential’ and ‘No 23 — Eutrophication Assessment in the Context of European Water Policies’).
Criteria elements
Criteria
Methodological standards
Nutrients in the water column: Dissolved Inorganic Nitrogen (DIN), Total Nitrogen (TN), Dissolved Inorganic Phosphorus (DIP), Total Phosphorus (TP).
Within coastal waters, as used under any enactment which gives effect to Directive 2000/60/EC.
Beyond coastal waters, the Secretary of State, in consultation with the devolved policy authorities, may decide at regional or subregional level to not use one or several of these nutrient elements.
D5C1 — Primary:
Nutrient concentrations are not at levels that indicate adverse eutrophication effects.
The threshold values are as follows:
(a)in coastal waters, the values set in accordance with any enactment which gives effect to Directive 2000/60/EC;
(b)beyond coastal waters, values consistent with those for coastal waters under any enactment which gives effect to Directive 2000/60/EC. The Secretary of State, in consultation with the devolved policy authorities, shall establish those values through regional or subregional cooperation
Scale of assessment:
within coastal waters, as used under any enactment which gives effect to Directive 2000/60/EC,
beyond coastal waters, subdivisions of the region or subregion, divided where needed by national boundaries.
Use of criteria:
The extent to which good environmental status has been achieved shall be expressed for each area assessed as follows:
(a)the values achieved for each criterion used, and an estimate of the extent of the assessment area over which the threshold values set have been achieved;
(b)in coastal waters, the criteria shall be used in accordance with the requirements of any enactment which gives effect to Directive 2000/60/EC to conclude on whether the water body is subject to eutrophication;
(c)beyond coastal waters, an estimate of the extent of the area (as a proportion (percentage)) that is not subject to eutrophication (as indicated by the results of all criteria used, integrated in a manner agreed ... at regional or subregional level).
Beyond coastal waters, the use of the secondary criteria shall be agreed at regional or subregional level.
The outcomes of the assessments shall also contribute to assessments for pelagic habitats under Descriptor 1 as follows:
the distribution and an estimate of the extent of the area (as a proportion (percentage)) that is subject to eutrophication in the water column (as indicated by whether the threshold values for criteria D5C2, D5C3 and D5C4, when used, have been achieved);
The outcomes of the assessments shall also contribute to assessments for benthic habitats under Descriptors 1 and 6 as follows:
the distribution and an estimate of the extent of the area (as a proportion (percentage)) that is subject to eutrophication on the seabed (as indicated by whether the threshold values for criteria D5C4, D5C5, D5C6, D5C7 and D5C8, when used, have been achieved).
Chlorophyll a in the water column
D5C2 — Primary:
Chlorophyll a concentrations are not at levels that indicate adverse effects of nutrient enrichment.
The threshold values are as follows:
(a)in coastal waters, the values set in accordance with any enactment which gives effect to Directive 2000/60/EC;
(b)beyond coastal waters, values consistent with those for coastal waters under any enactment which gives effect to Directive 2000/60/EC. the Secretary of State, in consultation with the devolved policy authorities, shall establish those values through regional or subregional cooperation.
Harmful algal blooms (e.g. cyanobacteria) in the water column
D5C3 — Secondary:
The number, spatial extent and duration of harmful algal bloom events are not at levels that indicate adverse effects of nutrient enrichment.
The Secretary of State, in consultation with the devolved policy authorities, shall establish threshold values for these levels through regional or subregional cooperation.
Photic limit (transparency) of the water column
D5C4 — Secondary:
The photic limit (transparency) of the water column is not reduced, due to increases in suspended algae, to a level that indicates adverse effects of nutrient enrichment.
The threshold values are as follows:
(a)in coastal waters, the values set in accordance with any enactment which gives effect to Directive 2000/60/EC;
(b)beyond coastal waters, values consistent with those for coastal waters under any enactment which gives effect to Directive 2000/60/EC. the Secretary of State, in consultation with the devolved policy authorities, shall establish those values through regional or subregional cooperation.
Dissolved oxygen in the bottom of the water column
D5C5 — Primary (may be substituted by D5C8):
The concentration of dissolved oxygen is not reduced, due to nutrient enrichment, to levels that indicate adverse effects on benthic habitats (including on associated biota and mobile species) or other eutrophication effects.
The threshold values are as follows:
(a)in coastal waters, the values set in accordance with any enactment which gives effect to Directive 2000/60/EC;
(b)beyond coastal waters, values consistent with those for coastal waters under any enactment which gives effect to Directive 2000/60/EC. the Secretary of State, in consultation with the devolved policy authorities, shall establish those values through regional or subregional cooperation.
Opportunistic macroalgae of benthic habitats
D5C6 — Secondary:
The abundance of opportunistic macroalgae is not at levels that indicate adverse effects of nutrient enrichment.
The threshold values are as follows:
(a)in coastal waters, the values set in accordance with any enactment which gives effect to Directive 2000/60/EC;
(b)should this criterion be relevant for waters beyond coastal waters, values consistent with those for coastal waters under any enactment which gives effect to Directive 2000/60/EC. the Secretary of State, in consultation with the devolved policy authorities, shall establish those values through regional or subregional cooperation.
Macrophyte communities (perennial seaweeds and seagrasses such as fucoids, eelgrass and Neptune grass) of benthic habitats
D5C7 — Secondary:
The species composition and relative abundance or depth distribution of macrophyte communities achieve values that indicate there is no adverse effect due to nutrient enrichment including via a decrease in water transparency, as follows:
(a)in coastal waters, the values set in accordance with any enactment which gives effect to Directive 2000/60/EC;
(b)should this criterion be relevant for waters beyond coastal waters, values consistent with those for coastal waters under any enactment which gives effect to Directive 2000/60/EC. The Secretary of State, in consultation with the devolved policy authorities, shall establish those values through regional or subregional cooperation.
Macrofaunal communities of benthic habitats
D5C8 — Secondary (except when used as a substitute for D5C5):
The species composition and relative abundance of macrofaunal communities, achieve values that indicate that there is no adverse effect due to nutrient and organic enrichment, as follows:
(a)in coastal waters, the values for benthic biological quality elements set in accordance with any enactment which gives effect to Directive 2000/60/EC;
(b)beyond coastal waters, values consistent with those for coastal waters under any enactment which gives effect to Directive 2000/60/EC. The Secretary of State, in consultation with the devolved policy authorities, shall establish those values through regional or subregional cooperation.

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Source: https://www.legislation.gov.uk/eudn/2017/848/annex/part/I/division/3/division/1 (the official version)
Page: https://openlegislation.uk/eu-decision-2017-848/annex/part-I/division-3/division-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.