Environmental Engineering Reference
In-Depth Information
repair. This has serious implications for contaminated
land, and most migratory fi sh, such as sea trout (
Salmo
trutta
), Atlantic salmon (
Salmo salar
) and sturgeon
(
Acipenser sturio
), are virtually extinct.
The idea that river restoration is important remains
a divided issue among EU member states. Spain has an
active Restoration Centre, but the country is still grap-
pling with over-use of and over-reliance on river water
for irrigation and increased urbanization, especially in
southern parts of the country. This has gone hand in
hand with continued building of major dams and an
increase in pollutants both of which have been detri-
mental to the ecological status of many Spanish rivers.
In comparison, the Netherlands already has a suite of
government policies and subsidies in place, aimed at
putting river restoration high on the national agenda.
Many river restoration centres throughout Europe are
now promoting the importance of rivers and fl ood-
plains to support ecological diversity and sustainable
options for fl ood management. To date, the United
Kingdom, Italy, Denmark, the Netherlands, Spain,
Norway, Romania and Russia all have such centres,
with an overarching
European Centre for River Restora-
tion
acting as coordinator and clearinghouse. Further-
more, the World Wildlife Fund project
Europe Living
Rivers
is also championing the idea of restoring rivers
and wetlands across Europe. This project is working to
protect and restore over 65 partnership river projects
within 25 European countries.
In the United Kingdom, there is growing acceptance
that any fl ood control measure should ensure that
there is no net loss of
biodiversity
and that, wherever
possible, environmental enhancement should be pro-
moted; to this end, the UK government (DEFRA 2002)
has published guidance on the environmental
appraisal of fl ood defence to help ensure that the impli-
cations for fl ood prevention and management are fully
considered in decision making. Such schemes remain
in their infancy, yet as many existing fl ood defence
schemes will soon no longer be viable to maintain on
economic grounds alone, the justifi cations for more
ecologically friendly options are likely to be considered
more seriously, as sustainable and long-term cost-
effective alternatives to raising existing fl ood wall
defences. Developments in urban landscape planning
and design, inclusion of sustainable urban drainage
systems in national and local authority planning guid-
ance and better integrated solutions (from engineers,
ecologists and landscape architects working together,
amongst others) to old problems all add to a wide
knowledge base readily available through Europe-wide
collaborations.
There is now also much discussion about future
climate change
and the impact on biodiversity (Gitay
et al
. 2002) and how best to manage our rivers to
miti-
gate
habitat stress (Palmer
et al
. 2008 ). By extension,
this has implications for river systems and their future
fl ow regimes. This in turn could have an adverse effect
on ecological status and hence any future restoration
initiatives should build in some design fl exibility to
account for changing scenarios and appreciate that
rivers are very sensitive to change (see Downs & Thorne
1998). More recently, Durance and Ormerod (2008)
have concurred with these views, showing that macro-
invertebrates are extremely sensitive to small tempera-
ture changes, but conversely, restoration measures can
offset some of the negative impacts.
Inevitably, any river restoration put into practice
will be subject to a degree of risk and
uncertainty
(Darby & Sear 2008). By ensuring that new schemes
are fully appraised, both pre- and post-project, in terms
of their impact on the river geomorphology, ecology
and public perception, those charged with restoring
rivers today can learn from each completed scheme. To
put this into perspective, it is essential that new projects
be monitored against initial specifi c and measurable
objectives, such as habitat enhancement or increased
channel morphological diversity. New methods to
achieve this are being discussed (England
et al
. 2008 ),
and it is recognized that monitoring has to be cost-
effective and linked to the size and risk of a specifi c
project. Only by including appropriate levels of moni-
toring can we be certain of the extent to which any
scheme can be classifi ed as either a success or a failure
and allow scientists to ascertain what types of schemes
are best suited to different environments and for
various requirements. We can then build on a growing
evidence base to provide for a future of sustainable
river systems that work with natural processes and
functions.
ACKNOWLEDGEMENTS
The River Restoration Centre is very grateful for the
data and information sent from Beppe Baldo and his
team at the Italian River Restoration Centre (CIRF),
James Holloway (the River Restoration Centre) for his
comments on the text and information supplied by
Andrew Black and David Gilvear about increased
