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COASTAL ENVIRONMENTS 3 human activity – coastal land uses coastal management schemes. In the UK, 23% of our total land area lies within 10kms of the coast.
This means that 17 million people live within this coastal zone and this level of usage puts pressure on our natural coasts leading to a need for coastal management schemes.
How is the land along the coast used?
32% pasture – grazing animals
25% arable – growing crops
10% woodland and heathland habitat
30% is covered by buildings, roads and recreational facilities
The remaining 3% consists of natural cliffs, beaches and mudflats.
Source of photos: www.geograph.co.uk (creative commons licence)
Coastal management in England and Wales is the responsibility of a wide range of organisations with no overall integrated approach. This has sometimes led to delays and conflicts. Organisations include:
Department for Environment, Food and Rural Affairs (defra)
County, rural and urban local authorities
National Parks Authorities
National Nature Reserves
Each local authority has a statutory duty to provide coastal management plans which meet the Government’s policy aim:
“To reduce the risk to people and the developed and natural environment from flooding and coastal erosion by encouraging the provision of technically, environmentally and economically sound and sustainable defence measures.”
In addition, the local authorities are obliged to “discourage inappropriate development in areas at risk from flooding and coastal erosion”.
Assistance with funding for coastal management schemes comes from the government but local authorities may need to borrow money or raise local taxes in order to pay the full costs which in may cases come to millions of pounds.
Planners have the added complication of taking into account:
1. Predicted sea level rises due to global warming
2.Sea level rises or land level rises due to isostatic readjustment following the retreat of the glaciers at the end of the last ice age.
A key component in managing the coast has been the development of Shoreline Management Plans (SMP) which set out a strategy for the coastal management of a section of the coastline. Each SMP covers an area of coastline known as a sub-cell within a littoral sediment cell, of which there are eleven on the England and Wales coastline.
A sediment cell is defined as a length of coastline, which is relatively self-contained as far as the movement of sand or shingle is concerned, and where interruption to such movement should not have a significant effect on adjacent sediment cells.
Each major littoral cell is divided into a number of sub-cells, based on the best available knowledge of large-scale processes.
In order to encourage improved co-operation between authorities a series of Coastal Groups have been established based on the littoral cell boundaries.
The production of each Shoreline Management Plans (SMP) involves the appointment of expert firms of consulting engineers to undertake a detailed study of all the issues affecting the coast such as land use, environmental protection, economics and the action of the coastal processes.
Coastal defence construction features generally fall into two categories:
Static shoreline structures such as those constructed from timber, steel, concrete, asphalt and rubble.
These involve linear structures such as sea walls and revetments and control structures such as artificial headlands and groynes.
Mobile/ responsive defence measures which seek to work with nature rather than control it.
Such structures may consist of sand or shingle beaches and dunes or banks which may be natural or constructed, and may include control structures. These can include the soft solutions of beach nourishment, cliff/dune stabilisation, bypassing and managed retreat.
Rock revetments – these have a high cost of about £100-300,000 per 100m length, but require relatively low maintenance. The permeable face absorbs wave energy and encourages upper beach stability.
Permeable revetments can be built from gabions, timber or concrete armour units.
Sea walls – these have a very high cost of about £200 - 500,000 per 100m length. They provide good medium term protection, but continued erosion will cause long term failure (30-50 year life expectancy).
Seawalls are near vertical structures of concrete, masonry or sheet piles, designed to withstand severe wave attack. Their use was popular in the past but they are now normally considered to be costly and detrimental to the stability of beaches.
Beach nourishment – this method has a moderate to high cost of between £5-200,000 per 100m frontage, and it requires ongoing maintenance. Allows natural beach processes to continue but use of inappropriate material may alter appearance of beach or function of beach processes.
Sand dune planting – stabilising natural sand dunes by planting marram grass to anchor the wind-blown sand has low costs of only £400 - £2000 per 100m frontage, but it requires on-going maintenance.
It has minimal impact on the natural system and fences can be used to control public access.
Damaged fences and accumulated debris can, however, be unsightly.