Recently, the shingle ridge which protects the marsh from the sea has weakened due to high water levels and stormy weather and has been breached several times over the last few years.
Attempts to repair the ridge by filling the gaps with shingle and building new breakwaters have not been successful, so now a decision has been made to follow a policy of 'Natural Retreat' and see what happens. This could mean that Porlock Marsh will once again become a lagoon, as it apparently was 200 years ago.
Porlock Bay
image supplied by kind permission of Somerset Tourism, Somerset County Council
What you see today at Porlock is a dynamic example of natural coastal processes-the power of the sea pitched against the land. Rising sea level piled up shingle into a 'barrier beach' at Porlock more than eight thousand years ago. A storm in 1996 breached the beach leaving a permanent gap and subsequent storms have moved the beach 20-30m inland. After major storms the beach used to be rebuilt to protect the pastures and freshwater marsh behind it. The last major rebuild took place in 1990, but since then natural processes have been allowed to take over.
Coastal erosion has led to the exposure of areas of old land surface on Porlock Beach. The earliest remains there are of a submerged forest which is 5000-6000 years old. This was first observed in 1870, but is now disappearing rapidly. Nevertheless, tree stumps, branches and organic debris can still be seen at low tide.
Porlock Ridge is nationally important for the study of coastal geomorphology. The site is owned by the National Trust and Porlock Manor Estate.
Porlock Bay
In 1998 the remains of an aurochs (the precursor of modern cattle) were found on the beach protruding from the recently exposed blue clays of an old river channel. This animal died about 3500 years ago and is therefore one of the last aurochs to be found in Britain (they died out here around 1000 BC). The bones are on display in the Porlock Visitor Centre. In 2003 more animal bones were discovered on the beach. In addition, a piece of worked timber found embedded in beach clay close to the breach in the shingle ridge has been dated to around 900AD – finds of timber from this period are very rare indeed. Coastal change at Porlock is rapidly eroding this fragile information about past landscapes, but is also providing exciting opportunities to learn more.
A particular problem in recent years has been the weakening of the shingle ridge that protects Porlock Marsh, much of which is a Site of Special Scientific Interest. The ridge was probably first formed more than 8000 years ago and has been sustained, on and off, by stones from cliff falls at Culbone. The natural supply of stone from Culbone cliffs no longer reaches the beach while the shingle already there is constantly being transported by the sea to build up the eastern end of the beach while the western end becomes thinner.
A combination of high water levels and storm waves has led to the ridge being breached on several occasions, most recently in October 1996.
A view of the bay from Porlock Weir looking east
For many years attempts have been made to strengthen the ridge by the use of timber groynes and by replenishing the shingle but this has proved unsuccessful. In fact it has been suggested that the failure of the ridge was due partly to management measures over years which altered and steepened the profile of the ridge making it less stable. The October storm in fact made the ridge lower and wider and thus more stable.
Now, after consultation with the National Trust who own the eastern end of the ridge, Exmoor National Park Authority, English Nature and environmental consultants, it has been decided to follow a policy of ‘managed retreat’. Nature will be allowed to take its course and this is likely to result in a return to the situation of 200 years ago shown on maps of that period, with a breached ridge and a lagoon instead of a marsh.
Porlock Bay
Porlock Bay
Porlock Bay is just a small part of Exmoor's
34mile (55km) coastline. The bay is sheltered by the high moorlands surrounding
it.
In the delightful area between Minehead and Porlock, close to the sea, the climate is often so balmy that the locals say the grass grows all the year round. The fertile Vale of Porlock is renowned for its agriculture and horticulture.
The marsh at Porlock is home to a variety of birds including several pairs of Redshanks who breed here regularly, and has been designated a Site of Special Scientific Interest (SSSI).
The difference in height between the lowest water level on the spring tides and the highest is about 8.5
metres—nearly 30 feet. These two factors, the cliff falls to the west and the high tides have helped to fashion one of the most striking natural features of the Vale of Porlock, the natural 6,000-year-old shingle ridge which geologists believe was formed with the rise in sea levels at the end of the last ice age. The South West Coastal Footpath runs close by.
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