Physical management of the coast attempts to control natural processes such as erosion and longshore drift. Hard engineering options tend to be expensive, short-term options. They may also have a high impact on the landscape or environment and be unsustainable.
Soft engineering options are often less expensive than hard engineering options. They are usually more long-term and sustainable , with less impact on the environment. There are two main types of soft engineering.
Coastal management strategies Physical management of the coast attempts to control natural processes such as erosion and longshore drift. Hard engineering options Hard engineering options tend to be expensive, short-term options. Sea defence often consists of dikes or seawalls of some kind, or in the form of artificial dunes [1]. This is the common definition for Sea defence, other definitions can be discussed in the article. DHI Water and Environment, pp. This material is brought onshore by barge, and moved about by large trucks and diggers.
It will blend in with the beach if the sediment is locally sourced such as the new sand dune at Seaton Sluice, which was created from dredged sediment for the River Blyth and will have benefits for tourists. However, this method needs constant maintenance or else this new sediment will also eventually be eroded by the sea! Dune regeneration basically involves artificially creating new sand dunes along the coastline to act as a buffer between the land and the sea.
Sand dunes occur naturally but are under threat because they are fragile and people walk all over them, ride horses and motorbikes on them and destroy the dune ecosystem. Using fencing to help trap sand, planting Marram grass into coconut matting as was done at Seaton Sluice and encouraging dune formation helps to protect these systems which protect our coastline and absorb storm and wave energy.
However, it is time consuming to plant the Marram grass and fence off areas, and is less effective than hard engineering schemes. Managed retreat is a method whereby we humans concede defeat to the power of the sea and allow it to erode and create salt marshes for example.
We can also allow cliff erosion to occur in areas of low value farmland and just compensate farmers for their losses, rather than construct more expensive coastal defences. This can only work where the coasts of compensation are significantly less than the coasts of building coastal defences, and can be a cheap option.
It can also be beneficial to plants and animals by providing new habitat. This method is highly controversial however, as land is lost and the human cost can be greater than just financial.
It has been estimated that approximately properties are currently vulnerable to coastal erosion but by , up to 2, residential properties and 15km of major road and railway may become vulnerable. Seven sisters East Sussex, UK has been affected by erosion for thousands of years but the process is now speeding up.
The cliffs are eroding by on average 0. The erosion is unpredictable. For example, there were no significant cliff falls here for many years and then a 3m deep section was lost overnight in January of This means that it is becoming more important for councils and governments to manage their coastlines in order to protect them from increasing coastal erosion and flooding due to altering sea levels.
This will reduce flood risk for more than , households, on top of the , homes already protected since The traditional approach to any threat of coastal erosion or flooding has been the use of hard engineering sea defences. The most common are sea walls : walls of concrete constructed parallel to the coastline as a barrier, supported by iron pilings dug into the underlying rock; groynes : these are wooden or concrete structures perpendicular to the shoreline. They work by blocking part of the littoral drift, whereby they trap or maintain sand on their upstream side; and breakwaters: which are offshore concrete walls that break waves out at sea so that their erosive power is reduced when they reach the coast.
An example of this practise that we can observe is at the Holderness coast, in the north east of England.
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