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5.6 Biological quality elements

The WFD normative definitions give qualitative descriptions at bad status, there are severe alterations such that a large
of the high, good and moderate status of each biological proportion of the reference biological community is absent.
quality element in each surface water category. High Biological status is defined by a wide range of aquatic
ecological status is achieved when each of the relevant biota, depending on the water category – river, lake, coastal
biological, hydromorphological and physico-chemical or transitional (Figure 1.19). Although the monitoring of
elements match their reference conditions. At good phytoplankton is a requirement for the classification of
ecological status, none of the biological quality elements can rivers, it is not used in the UK because, with a few exceptions,
be more than slightly altered from their reference conditions. rivers in the UK are rarely long enough to allow growth
At moderate status, one or more of the biological elements of phytoplankton. In freshwaters, macrophytes and
may be moderately altered. At poor status, the alterations to phytobenthos are combined as one quality element. In the
one or more of the biological quality elements are major and, UK, only diatoms are used to define phytobenthos status.

Transitional Coastal
Rivers Lakes waters waters

Phytoplankton

Macrophytes & Angiosperms
(Seagrass, saltmarsh)
Phytobenthos Macroalgae
(diatoms) (fuccoid extent)

Macroinvertebrates

Fish

Figure 1.19
Biological quality elements used to classify the status of different surface water categories for the WFD.
(River phytoplankton are shaded out because they are not used for status assessment in the UK.)

For the second WFD cycle the UK improved some of the
metrics and methods used to assess water body status in
its key document published by Defra in May 2014, entitled
Water Framework Directive implementation in England
and Wales: new and updated standards to protect the
(19)
water environment
This ensured consistency across the UK as the second WFD
cycle was developed. It provides additional information on
metrics and software tools that might be considered for use
outside the UK.

These changes were incorporated in legislation in The
Water Framework Directive (Standards and Classification)
Directions (England and Wales) 2015. https://
(18)
www.legislation.gov.uk/uksi/2015/1623/pdfs/
uksiod_20151623_en_003.pdf

Figure 1.20
Front cover Defra 2014, Water Framework Directive
implementation in England and Wales: new and updated
standards to protect the water environment (19)

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