Memorandum submitted by Wildwood Trust
(FL 83)
EXECUTIVE SUMMARY
Land drainage and agricultural flood defences
are chiefly responsible for flash flooding events witness in the
UK in recent years. Government policy in tackling excessive agricultural
drainage and the re-creation of wetlands on the banks of our rivers
could protect communities from flooding. This policy change would
have many advantages:
— Reduce Government spending by many
hundreds of millions over the next 100 years.
— Support a huge increase in biodiversity
meeting a number of Government biodiversity targets and International
Treaties.
— Mitigate the effects of climate change
if rainfall amounts increase.
— Mitigate global climate change by
a massive increase in our "Carbon Sink", wetlands are
our most important carbon sink and sequestrate far more carbon
in their peaty soils than woodlands or any other form of habitat.
— Increase flow of water into ground
water systems, reducing the need for capital investment in reservoirs
and water treatment facilities in certain areas of the country,
most notably the South East of England, which will help prevent
water shortages and hose pipe bans.
This has already been realised by many of our
European neighbours and policies to block upland drainage and
retreat agricultural dykes have now been successfully put in place
to protect built up areas from flooding, saving many lives and
hundreds of millions of euros in the process.
1. WETLANDS,
DRAINAGE AND
FLOODING
1.1. Wildwood Trust wishes to highlight
the successful methods of cost effective flood mitigation practised
by our European neighbours and urge the Government to save the
taxpayer hundreds of millions of pounds and address a root cause
of the flooding incidences seen in recent years.
1.2. Wildwood Trust's position is based
on the premise that land use change, especially agricultural land
use, is responsible for the flooding events witnessed recently
in June and at Boscastle in 2004.
1.3. Due to the complex nature of the problem,
little media attention has focused on the fact that our land is
now better drained than in the past. When we experience heavy
rains the water rushes off our land into drainage ditches and
straight into river systems. In the past wetlands and limited
drainage buffered the effects of heavy rainfall. In a vicious
circle our flood defences then try to stop this water flooding
villages, towns and farmland which just makes the flooding worse
further downstream as we try to contain more and more water in
our river systems.
1.4. It took many deaths by flooding for
our European neighbours to learn from the mistakes we have all
made in trying to turn our river systems into artificial drainage
channels. One such incident in which a flood overran a dyke next
to a school, killing 12 children, was the event that saw the creation
of the Dutch Blauwe Kamer Nature Reserve. Wildwood Trust's partnership
with the Blauwe Kamer Nature Reserve has made us aware of the
inadequacies of our flood defence policies.
2. ARTIFICIAL
DRAINAGE
2.1. The drainage of land, especially upland
areas to improve grazing quality or for forestry planting, has
been blamed for increasing the danger of flash floods of some
upland river basins. This is because the drains remove water from
the land more rapidly, resulting in all the water from a rain
storm running off the land in a short period of time. The devastating
effects of the Boscastle flood are due to this and not changes
in rainfall patterns.
3. DESTRUCTION
OF WETLANDS
3.1. The destruction of wetlands by agricultural
dykes, small flood defences along most of the rivers in the UK,
has lost a huge water buffer which protected cities and towns
from flooding. Wetlands regulate floods, sustain flows during
dry periods and recharge groundwater. The role of wetlands in
relation to water flow can be likened to that of a sponge in that
they are able to absorb significant volumes of water. That water
is then released slowly, reducing peak flow levels in water courses
fed by the wetland. This slow release of water tends to reduce
the likelihood of flooding lower down the river catchments. Equally,
where there has been no rain the wetland continues to release
its stored water, maintaining flow levels in streams and rivers.
The wetland "sponge" drains into groundwater in the
same way as it does into surface waters.
3.2. Wildwood Trust urges Government policy
to restrict the level at which water is allowed to be drained
from the land and to abolish Internal Drainage Boards and give
authority to the Environment Agency to regulate drainage with
the policy of flood prevention.
3.3. Agricultural subsidies through the
Higher Level Stewardship scheme, administered by Natural England,
could be used to fund the retreat of agricultural dykes along
riverbanks allowing the creation of flood plains to help buffer
the effects of flooding.
3.4. In a number of European countries such
as the Netherlands, Belgium, Germany and Denmark land policy has
been to retreat agricultural dykes from river banks creating more
"natural" flood plains. These newly created flood plains
act as a sponge to slow water flow and absorb water, helping buffer
the effects of heavy rainfall.
3.5. This policy will require statutory
instruments and powers to be given to the Environment Agency.
4. The benefits of such a policy will be
to:
4.1. Reduce flooding.
4.2. Reduce Government spending by many
hundreds of millions over the next 100 years.
4.3. Support a huge increase in biodiversity
meeting a number of Government Biodiversity Targets and International
Treaties.
4.4. Mitigate the effects of Climate change
if rainfall amounts increase.
4.5. Mitigate Global Climate change by a
massive increase in our "Carbon Sink", wetlands are
our most important carbon sink and sequestrate far more carbon
in their peaty soils than woodlands or any other form of habitat.
4.6. Increase flow of water into ground
water systems, reducing the need for capital investment in reservoirs
and water treatment facilities in certain areas of the country,
most notably the South East of England, which will help prevent
water shortages and hose pipe bans.
Peter Smith
Chief Executive, Wildwood Trust
August 2007
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