River Restoration - Case Studies

Geofactsheet explaining process of river restoration (small-scale management strategy for rivers) with associated case studies.

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G eo Factsheet
www.curriculum-press.co.uk Number 206
River restoration ­
Case Studies
Very few rivers have not been affected by human activity. All large rivers Fig. 1 A model of restoration, rehabilitation and remediation.
have been modified to some extent and it is only remote, isolated streams
that may have survived any impact from human activity. Rivers have
been straightened, deepened, diverted, dammed, altered by steel and High
concrete, and adapted to benefit people and reduce the risk of flooding.
However, many of these changes have had negative impacts and New
unforeseen consequences. For example, dams have reduced flooding, Ecosystem
improved navigation and allowed year round farming to occur. However,
Change in ecosystem quality
they have also triggered earthquakes, increased rates of evaporation and Restoration Original
increased rates of river erosion below the dam. The straightening of the Remediation Ecosystem
meanders on the Mississippi `worked' only for a short time. The river
began to meander again after being straightened and abandoned the new
channels that engineers had created. Thus human activity on rivers has
often been far from effective. Rehabilitation
Increasingly it is realised that there are many benefits of allowing rivers
to behave as naturally as possible. For examples, rivers meander and they Degradation
flood each year. Whilst it might not be possible to allow all parts of a
floodplain to be covered in water (due to housing, industry and
infrastructure) there may be selected parts that can be flooded (parks,
allotments) or sections of the river upstream where the land is largely Degraded
used for farming and so can form washlands. Ecosystem
The return of a river to its natural state is known as river restoration. It
is far more cost effective to keep streams and rivers clean than allowing Ecosystem structure: species richness
Low High
them to deteriorate and then have to undergo expensive rehabilitation and
restoration. It is also difficult and a very slow process restoring rivers,
whereas it is relatively cheap, easy and quick to keep them healthy.
However, rivers still require management to keep them healthy, and to
prevent them from deteriorating.
Rehabilitation refers to an improvement in the river quality, although it
The term restoration implies that the river is returned to its original may not reach the same quality as the original river. It is effectively a
quality (Fig. 1). Defining river quality is not easy for it includes a wide pragmatic approach to improving river standards, i.e. there is recognition
range of factors such as water chemistry, sediment and flow regime, that it is impossible to reach the original standard but it is possible to
plants and animals present, and the health of neighbouring riparian improve on the current condition of the river. This may mean fixing
(adjacent) areas. Restoration may not be possible in many cases (since (improving) only certain aspects of the stream. In contrast, remediation
rivers had a pristine quality before human activities affected them) so it recognises that the river has changed so much that the original condition
may only be possible to rehabilitate rivers instead. is no longer relevant and a new condition is designed.
Remediation aims to improve the ecology of the stream, but the end
Exam Hint: Find a river near where you live that has been `restored'. result may not necessarily resemble the original stream. In practice
Visit www.therrc.co.uk for details on projects around the UK. You are most restoration schemes will only partially restore or rehabilitate the
more likely to remember local details. river due to the large number of human-related uses in the floodplains,
e.g. buildings, industry, gas and electricity infrastructure, farmland
and transport.

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River restoration ­ Case Studies Geo Factsheet
River restoration
There is a need to restore rivers because many have been seriously River restoration schemes are becoming increasingly common as the
affected by urban and agricultural flood defences, land drainage and benefits of natural rivers and their floodplains are realised. The aims of
floodplain urbanisation.…read more

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River restoration ­ Case Studies Geo Factsheet
Case studies of restoration
Case Study 1: The River Cole
The River Cole is one of three river restoration sites financially · Stretch 3 The restoration of the ancient course of the Cole appears
supported by LIFE, an EU fund which provides grant aid for schemes to be possible at this site. Floodwaters have restored the flood
of environmental benefit (Fig. 3). The aim of the RRP for the River meadows along the western side of the mill.…read more

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River restoration ­ Case Studies Geo Factsheet
Case Study 2: The River Skerne, Darlington
The River Skerne shares many characteristics with other urban streams: · the growth of wetland plant species on the inside of meander belts.
· It has a high sediment load, especially of silt. · strengthening the banks by planting trees and reeds.
· It is slow moving. · creation of new wetland ecosystems.
· Banks are overgrown with weeds. · improving the water quality from the sewage works.…read more

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River restoration ­ Case Studies Geo Factsheet
Case Study 4: Changing river management - the Kissimee River
The world's largest wetland restoration project will spend US$700 The channelization of the Kissimee River had several unintended impacts:
million over two decades to revive the Florida Everglades It will · the loss of 30 000-35 000 acres of wetlands.
include a series of six artificial wetlands known as `storm water · a reduction in wading bird and waterfowl usage.…read more


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