A 20-Year View of Monitoring Ecological Quality in English and Welsh Rivers - River Conservation and Management - page 75

current state of rivers in England and Wales,
and to identify changes between 1995-1996 and
2007-2008 (Environment Agency, 2010b; Seager
et al ., this volume). Establishing a baseline was
especially important as a national overview was
lacking in 1990, while the need to consider
physical habitat is now enshrined in European river
management legislation, notably the WFD (Council
of the European Communities, 2000; Boon et al .,
2010). The first RHS baseline survey (1995-1996)
revealed the distribution of river channel features,
habitat types and channel modifications across
the UK for the first time (Raven et al ., 1998).
One of the key findings was the extent of
physical modification to channels, usually for
land drainage or flood defence purposes. Only
16% of sampled river channels in England and
Wales could be considered 'near-natural' - free or
virtually free from any of the physical modifications
recorded by RHS (Raven et al ., 1998). The results
therefore highlighted the challenge of meeting
'good ecological status' under the WFD, with
physical modification being a major pressure.
The second RHS baseline (2007-2008) improved
coverage of lower-order streams in England and
Wales, leading to a more comprehensive national
picture. The potential of the dataset is shown
by the detailed national mapping of habitat
features (e.g. Figure 7.1; Environment Agency,
2010b). Analysis of the two baseline surveys also
permits an examination of changes in habitat
features, the extent of channel modifications and
the spread of invasive non-native species (Figure
7.1; Environment Agency, 2010b; Seager et al .,
this volume). The limited temporal dimension
(compared with GQA) prevents trends from
being established at this stage, but differences
between the two baseline surveys can highlight
potential trends that can be investigated with
specific monitoring and ideally with future baseline
surveys.

improvements in some aspects of river quality,
notably reduced concentrations of key pollutants
associated with urban and industrial effluents,
and an associated shift in the benthic fauna
towards that more typical of unpolluted waters.
This represents a major environmental success,
although the extent to which the patterns
represent a response to active regulation and other
interventions as distinct from industrial decline
is unclear. The second major change is that the
picture of river environments is more complete,
most notably through the addition of physical
habitat assessment. This provides the basis for
much more effective river management.
Beyond revealing current status and reporting
change, monitoring over the last 20 years (and
indeed previously) has generated a major data
resource that will assist river management and
research in the future. Some of the greatest
opportunities might arise through combining data
from different monitoring schemes (Vaughan and
Ormerod, 2010).

Opportunities and challenges in new
uses for monitoring data
Common properties of monitoring data include
extensive (often national) geographical coverage,
multi-year time series, large numbers of sampling
locations and a scheme for quality assurance to
ensure consistent data quality. Together, these
properties suggest that monitoring data can address
themes at a regional or national scale and also
those requiring a temporal dimension. Where it
is possible to combine data from several different
monitoring schemes, environmental or biological
co-variates of such spatial and temporal patterns
can be studied, providing a starting point for
studying the mechanisms underlying the observed
patterns (Vaughan et al ., 2009).
There is rich scope for research based on the
wide variety of monitoring data collected from
rivers in the UK. Examples include: (i) relating
benthic macroinvertebrates to water chemistry,
effluent discharges and physical modification of the
channel (Murphy and Davy-Bowker, 2005; Monk
et al ., 2008; Dunbar et al ., 2010); (ii) investigating
the habitat preferences of macrophytes (Dawson
et al ., 1999); (iii) identifying water quality and

Taking stock - 20 years of river
monitoring

A review of river monitoring reveals two significant
changes since 1990. The first has been substantial