Erosion in the National Park
  
The word erosion (meaning gnawing
away) is used to describe the gradual wearing away of the earth's surface
by the natural elements of water, ice and frost or wind. Erosion is going
on all around, all the time. The landscape has been shaped by erosion over
millions of years. Some changes hardly show - in other cases great changes
happen in a few years.
 Back to top
- - - - - - - - - - - - - - - - - -
Peak district landscape
In the Dark Peak area of the Peak District National
Park the underlying rocks are gritstone and shale. Here there are large
areas of moorland where heather, cotton grasses or moorland grasses dominate.
Many of these moors are managed for grouse and are also grazed by sheep. There
is public access to much of the moorland and footpaths crisscross the land.
The well-known and well-walked Pennine Way starts at Edale in the Peak District
National Park and runs to Kirk Yetholm in Scotland.
In the more southern White Peak area of the Park the underlying rock
is limestone. The landscape is made up of a grassy plateau dotted with small
farms and cut by steep dales containing a wonderful variety of wildlife. Such
dales are often the most popular spots for visitors. Footpaths extend over
many farms and through most of the dales.
Back
to top
- - - - - - - - - - - - - - - - - -
Erosion In The Peak District National Park
The natural forces of erosion
have shaped the landscape of the Peak District and are continuing
to change its shape.
- Water in cracks and crevices in limestone, freezes and expands.
This action had its greatest effect during the ice ages as the land
froze and thawed again and again, over many hundreds of thousands
of years. Fragments of rock were gradually broken off and formed
scree at the foot of the cliffs.
- The steep dales have been carved out by swift-running water - from
melting glaciers during the ice ages as well as from rivers. Water
continues to dissolve limestone, forming caves and washing away fragments
of rock. Where layers of shale become waterlogged under layers of
gritstone, landslips occur.
- wind blows dust against the rocks and over thousands of years particles
are broken off and the surface worn down.
- Vegetation plays an important part in protecting the land from
excess soil erosion. Grass roots build up fine soil particles into
large crumbs that are not easily eroded. Roots and leaves of plants
decay in the soil and form a sticky substance (humus) that has the
same effect. Intensive cultivation keeps the soil bare in winter
and tills the soil to fine particles which are then easily eroded
by wind and rain. Fortunately most of the Peak District's farmland
is used for grass production, though some is ploughed up and reseeded
every few years.
Erosion in the Peak National Park is a problem in two main areas -
on the moorland in the Dark Peak and on the footpaths that cross both
the moors and the farms and dales of the White Peak.
Reservoirs in the moorland area are also affected by erosion. Peat and soil
particles washed into the reservoir from the surrounding land, gradually
reduce the water storage capacity and reduce drinking water clarity to below
the accepted EC levels.
Back to top
- - - - - - - - - - - - - - - - - - Human Influence on Erosion
Over the last few thousand years, human
action has had an increasing part to play in erosion. The human
effect may be indirect (overcultivation of the land) or may be direct
- the action of thousands of trampling feet.
Vegetation is also removed by accidental fires and by heavy trampling
on the most popular footpaths. Many factors prevent the vegetation
from regenerating. Large areas laid bare in this way are then greatly
affected by the natural forces of erosion.
Back to top
- - - - - - - - - - - - - - - - - - Moorland Erosion
The Causes of Moorland Erosion
Two processes are involved:-
- the destruction of the vegetation cover and the prevention of the
regeneration of the plants
- the removal of the exposed material, especially peat, by water
and wind. Peat was formed from the remains of vegetation which haven't
decayed because of acidity and lack of oxygen.
The first step is to identify the size of the problem and then to
find ways to deal with it. The Moorland Erosion Project was
set up in 1979. In a study of 13 moorland parishes in the Peak National
Park, extensive erosion was found, particularly in the North-west.
A number of factors were identified as contributing to the destruction
of the vegetation and the subsequent erosion of the peat:-
1. Sheep have grazed the moors for hundreds - even
thousands - of years. The numbers of sheep have gradually increased.
Since 1950 the number has increased by 300%. Large numbers of ewes
graze the moorland right through the winter. This overgrazing removes
the vegetation (mainly heather and grasses). As flowers are eaten
so the seeds which would have allowed regeneration are lost and the
effects of overgrazing become long lasting.
 |
moorland fire
|
2. Accidental fires during spells of dry weather kill off both
the living plants and the dormant seeds in the soil. Vegetation is removed
and regeneration is prevented. Severe fires can burn peat away.
3. The Climate with its high rainfall and low temperatures,
means a very short growing season. This also makes it hard for seeds
to grow into viable plants before winter frost lifts them out of the
peat. The highest moorland, which has the lowest temperatures and is
the most exposed, has the highest level of erosion. When ground is left
bare, normal weathering is intensified by the high rainfall and the freeze-thaw
effect of the low temperatures.
4.Heavy trampling by visitors to the moorland areas of
the Peak National Park kills off the vegetation on some areas of
deep peat, which is highly 'trample sensitive'. A few thousand
footsteps per year may be enough to cause erosion. This can cause
a very marked localised effect but makes a relatively minor contribution
to the major peat erosion.
|
5. During the 19th century a high concentration of sulphur
dioxide (SO2) was given off by factories around the edges of the
Peak District. These gasses caused Acid Rain which killed
lichens and mosses such as sphagnum. Sphagnum acted as a giant
sponge, protecting the surface of the peat. The levels of smoke
and sulphur pollution have declined during the 20th century but
pollution from nitrogen oxides (from vehicle emissions) and hydrocarbons
has increased; the peat remains extremely acid and sphagnum is
still confined to springs.
Erosion of the moorland has economic effects for the farmer and landowner. Loss
of vegetation means that sheep and grouse (which feed on heather) have less to
eat and so fewer can live on the moor. In some soils, damage to grass and heather
can encourage bracken to spread.
Combatting Moorland Erosion
The ways of combatting moorland erosion are by management to prevent further
erosion and by restoration of the areas already damaged.
The Moorland Restoration Project was set up in 1983. This project set
up and monitored revegetation trials on several sites. Overall conclusions (written
up in the Phase 2 report) were that revegetation was possible, although the results
varied greatly. In all cases, stopping sheep grazing by fencing was the most
vital treatment.
In 1987 the Moorland Management Project succeeded the Restoration Project,
with the aim of encouraging good management of the moorland to ensure its longterm
survival. The Phase 3 Report, Restoring Moorland was produced in 1997 and reported
on 12 specific projects attempting moorland restoration through a variety of
different methods. The emphasis has been on finding cheap ways of revegetation,
using easily available machinery.
Back to top
- - - - - - - - - - - - - - - - - - Moorland restoration
The simplest project (on Kinder Scout) involved
only the limiting of sheep grazing. This resulted in a reduction of
bare ground; an increase in cover and of flowering in wavy hair-grass,
heather and bilberry; and an increase in the numbers of red grouse.
Successful revegetation took place on Burbage Moor where a bare area
had been created by an accidental summer fire. Here, sheep were not
removed but heather seed was spread using a muck-spreader. After 6
years, 54% of the bare area was covered with heather.
 |
Experimental erosion control near
Kinder Scout
|
On trampled areas around Snake Summit, transplants of crowberry, hare's tail
cotton-grass, wavy hair-grass and mat grass were used. Fertiliser and lime were
added to combat the acidity of the bare peat. Survival was good for the grasses.
A complicated trial in Kinderlow, involved excluding grazing (on part of the
area) and the application of lime, fertiliser, grass seed and heather seed. Best
results were found on gentle slopes with mineral soils where grazing was excluded.
Practical restoration work has taken place on Holme Moss where the area was treated
first with a mechanical application of fertiliser, lime and grass seed (to provide
a nurse crop of grass which would stabilise the bare ground). Heather, crowberry,
bilberry and cotton grass were added later. On some areas of deep, mobile peat
the grass seed was applied onto a woven mesh, laid directly on the bare peat.
Trials at the different sites have shown that eroded areas of moorland can be
revegetated by
1. Reducing grazing pressure - or removing entirely (where there
is still some vegetation)
2. Mechanised spreading of heather and wavy hair-grass seed using agricultural
machinery (on large bare areas)
3. Planting a nurse crop of grass (bents and fescues), on the worst areas
of bare peat
4. Using netting to stabilise very mobile deep peat, while a nurse crop is
established.
Back to top
- - - - - - - - - - - - - - - - - -
Avoiding Erosion
The main aim now is to avoid further erosion:-
- Damage from fires can be limited by good fire-fighting plans and
by making firebreaks (cutting wide paths through the heather) to
stop the spread of any accidental fires. Publicity to make people
aware of the risk from discarded cigarette ends is also very important.
Preventing grazing of any burnt area for 2 or 3 years can encourage
recovery.
- Through the establishment of the North Peak Environmentally Sensitive
Area (ESA) in 1988, and an ESA in the South West Peak in 1992, the
Ministry of Agriculture, Food and Fisheries (MAFF) gives financial
support to farmers managing their land in ways which conserve and
restore moorland. Reduction of grazing levels is a main feature of
the ESA.
Back to top
- - - - - - - - - - - - - - - - - -
Footpath Erosion
Footpath Erosion has become more of a problem
in recent years due to the increased popularity of walking and other
countryside activities - including mountain biking. Greater pressure
on the popular paths and the fragile nature of the ground they pass
over, has led to a number of problems. However this does only affect
a fairly small number of upland paths; the majority of the 2,000 miles
of public rights of way within the National Park are free from the
problems of erosion.
The worst erosion occurs where the footpath is on wet land (especially on deep
peat) or by a river bank. Many footpaths through popular honeypot sites have
become seriously eroded.
The Winnats Pass is a spectacular limestone gorge not far from the village of
Castleton. It is a popular tourist attraction as well as carrying the only road
beyond the village (the road past Mam Tor has been closed by a landslip). The
vegetation cover around the footpaths through the pass was monitored during the
1970's and areas at risk of erosion were identified. 40% of the area of the pass
was found to be at risk since the vegetation cover is both delicate and damaged.
The south facing side of the pass (near Speedwell car park) suffers the heaviest
use and the lower slopes in particular have deteriorated.
Back to top
- - - - - - - - - - - - - - - - - - Ways to combat Footpath Erosion
Some solutions have been tried
unsuccessfully - wooden fencing was laid on the path from Gradbach
Mill through Black Forest but this has sunk into the mud.
At Hollins Cross on the footpath between Edale and Castleton, serious
erosion has been halted by laying culverts and stonework on the worst
affected sections. Wooden boards divert the water away from the path.
However regeneration of the vegetation has not been very successful.
|
New footpath, Beresford Dale
|
More successful long term solutions have included re-routing paths and laying
a hard surface for walkers. A long-term restoration project in Dovedale has successfully
used these methods (see Fact sheet 8 - Dovedale )
In some areas footpaths can be re-routed away from wet peat and onto harder soils
which are better able to withstand trampling. These paths may be along the gritstone
edges or along grough (valley) bottoms.
A variety of products have been used to form a hard surface on frequently used
footpaths. Gritstone slabs have been used at Torside Clough and widely on the
Pennine Way. This is now the standard method for surfacing footpaths on moorland.
Other methods include using waste from road repairs at Wessended Head. A limestone
base has also been used with basalt topping or steelfelt a waste product of the
steel industry.
Restoration of footpaths is time consuming and very expensive. The cost of
restoring one metre of the Pennine Way has been estimated at £25 - £40
for paths in the Peak District National Park.
The only alternative to restoration is to limit the use of footpaths in the most
popular areas. This would be very difficult to enforce and new legislation would
be needed for any seasonal closures.
The Peak Park Trust Footpath Fund has been set up to try and meet some of the
expenses of restoring the Park's footpaths by involving the local community and
those who benefit from the paths. Local firms have volunteered to supply materials
for repairs and the public will be asked for contributions through collecting
boxes.
Back to top
- - - - - - - - - - - - - - - - - -
The Pennine Way
The most serious erosion has occurred on the Southern part of the Pennine Way.
This long distance footpath runs North from Edale in the Peak District National
Park - much of it over deep peat which is the surface most vulnerable to erosion
and the least capable of revegetation.
The Pennine Way Condition Survey in 1990 found that the damaged area of the Pennine
Way was five times as great as in the last survey in 1971. The worst eroded parts
of the whole Pennine Way lie in the Peak District and extend to 47 kilometres
of severely damaged path.
Ways of combatting this erosion include:-
1. Changing the route of the path
2. Restoring and revegetating the damaged areas and laying a firm path.
You can find out more about combatting erosion on the Pennine Way, in Fact
Zone19 - The Pennine Way Management Project.
The Peak District National Park lies in the centre of England surrounded by
large industrial towns. Up to 30 million visits every year mean that the problems
of erosion will not disappear. However changes in the landscape have been taking
place for millions of years and we need to consider whether we should be trying
so hard to undo the most recent changes. The aim has to be on achieving a balance
between the needs of farming, conservation and recreation.
Back
to top |
