Ecological River Quality
Indicator
Percentage of the County's rivers that are in each category of
the Water Framework Directive (WFD) classification scheme.
Status
Ecological river quality is fair and improving.
Overview
River water quality is affected by many factors. These can
generally be divided into point sources, which have a traceable
discharge point, and diffuse sources, which cannot usually be
traced back to a single discharge point. Examples of point sources
include domestic and industrial waste water; examples of diffuse
sources include polluted water and sediment washing off fields,
recreational areas, roads and pavements. There have been big
improvements in waste water discharges over recent years but
pollution from diffuse sources is becoming an increasing
threat.
To compare the quality of water, the Environment Agency uses the
Water Framework Directive (WFD) classification scheme, which
replaced the General Quality Assessment (GQA) in 2007. Although a
headline dataset for GQA will still be produced until 2009, owing
to changes in this network, the results are only available at a
regional, and not county, level.
For surface waters there are two separate WFD classifications
for water bodies: ecological and chemical.
Ecological Status
An ecological classification comprises:
•The condition of biological elements, for example fish
•Concentrations of supporting physico-chemical elements, for
example oxygen or ammonia
•Concentrations of specific pollutants, for example copper
•And for high status, largely undisturbed hydromorphology
Ecological status class is recorded on the scale of high, good,
moderate, poor or bad. 'High' denotes largely undisturbed
conditions and the other classes represent increasing deviation
from this undisturbed, or reference, condition. The ecological
status classification for the water body, and the confidence in
this, is determined by our confidence in our assessment of the
worst scoring quality element.
It should be noted that water bodies which have been modified
for certain uses - such as flood defence or navigation - are
designated as 'artificial' or 'heavily modified'. These water
bodies are assessed using a different methodology which also looks
at whether factors to minimise the ecological impact of the
modification are in place. The water bodies are assessed against
Ecological 'Potential' rather than 'Status' and the results for
these were unavailable at the time of writing. 23% of rivers in
Worcestershire are candidate artificial or heavily modified water
bodies.
Performance
Under the WFD scheme, the results for the different ecological
elements are combined under one final classification and the lowest
scoring parameter determines the overall class – known as 'one out,
all out'.
As a result, 1.7 percent of the river water bodies in
Worcestershire reached the required 'good ecological status' under
WFD in 2007. 71.4 percent of the rivers are at moderate status and
23.2 percent are at poor ecological status. 3.7% of rivers were
'not yet assessed'.
This dataset forms the baseline year for Ecological status.
Geographical Context
92.8% of the rivers measured in Worcestershire in 2006 were good
or fair biological quality, compared with the regional figure of
89.7%. Therefore the reduction in river quality in Worcestershire
in recent years is in line with the regional trend.
Actions
The largest challenge for those working to improve the quality
of Worcestershire's rivers is in tackling sources of run-off from
roads and fields. These diffuse sources of pollution are difficult
to attribute to a single discharge point and will not be affected
by the regulatory approach that has been successfully adopted to
reduce the impacts of point source pollution.
Further Information
The General Quality Assessment (GQA) has been superseded by the
Water Framework Directive (WFD) compliance scheme. For information
about river quality see the Environment Agency's
water quality website
For detailed information about your own area/river visit the
Environment Agency's What's
in your backyard? Page.
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