Posted by: KimBoland | March 4, 2015

Cwm Ivy – A Changing Landscape

Following the high tides at the end of February 2015, there have been some great photographs shared on social media, and we’ve had a huge interest in the changing coastline of Cwm Ivy.

 

Here, Alan Kearsley-Evans, our Coast & Countryside Manager, explains all about the changes ahead ….

 

Background:

Cwm Ivy marsh is a small parcel of land on the coast of North Gower.  It was claimed from the sea to be used as farmland in the 17th Century and was protected by a sea defence which over the years increased in size and strength.  Now after nearly 400 years as farmland the landscape is changing and the sea is moving back in.

Sea wall at Cwm Ivy, North Gower

Sea wall at Cwm Ivy

It is a decade since the National Trust released its seminal ‘Shifting Shores’ report which held one clear message – as a nation we can no longer build our way out of trouble on the coast. This means at sites such as Cwm Ivy we no longer try to defy nature by holding back the tide but allow as natural a process as possible to take place.

 

The challenges:

In November 2013, Cwm Ivy sea wall was showing signs of distress. Repeated heavy rain had swelled the stream to unprecedented levels and the sluice gate designed to drain the marsh simply wasn’t able to remove water fast enough. The pressure of water forced a small hole under the wall and the following winter of storms, rain, high tides and storm surges began to widen the hole and allow significant amount of sea water in to the fresh water marsh. It wasn’t until August 2014 however that the wall eventually had a catastrophic failure and effectively ended its time as a ‘sea defence’.

Looking forward:

Thanks to the vision of the shifting shores document of allowing coastal realignment to happen as naturally as possible we are now spending our efforts not on maintaining the defence but restoring the footpath access along the wall and managing the change in habitats from freshwater marsh to saltmarsh. We are working with engineers from Natural Resources Wales (NRW) and the rights of way officers from City and County of Swansea to get the footpath back open as fast as possible. NRW have the ultimate responsibility for the decision of what is done to the wall and a bridge across the breach can only be made when they are satisfied with the engineering solution. They are currently looking into the repair options and we hope to have a decision made on this matter soon.

 

The plants on the marsh are visibly changing day by day as the tide comes and goes and adds a fresh layer of salt to everything it touches. The farmland grasses died back almost instantly in August and the trees rapidly began dropping leaves and most will be standing dead wood by spring this year. Is this a problem? Visually this is not currently an improvement over the lush greens we are used to seeing as a fresh water habitat. However this transition, as unsightly as it is will be temporary and once the saltmarsh plants start to take a hold Cwm Ivy Marsh will begin to re-green and take on a similar colour as Llanrhidian marsh behind it.

As the trees succumb to the salt and begin to die the standing deadwood we will be left as standing dead wood is in fact a very precious habitat indeed. As humans have increasingly organised and ‘tidied’ the countryside so we have reduced and removed marginal habitats such as dead wood. Standing deadwood is essential for birds such as wood peckers to feed on and they are superb habitat for a whole host of invertebrates.

 

Once the saltmarsh plants start to colonise the area then we can really start to look to the future and make plans for the new and exciting species we hope to see arrive.  Amongst these may be hen harriers, lapwing and even ospreys! We have already seen an increase in activity from otters and kingfishers in the marsh as the receding tide leaves behind pools full of fish – easy pickings for these impressive predators.  Later this month, we will be erecting the first of two new bird hides overlooking the marsh.

 

Celebrating:

On Tuesday 31st March, between 2pm – 4pm, we are inviting people to  join us to celebrate the National Trust’s most successful campaign, the Neptune Coastline Campaign, which has safeguarded over 100 miles of coast in Wales, starting with Whiteford Burrows in 1965. Author Patrick Barkham will also be signing copies of his new book ‘Coastlines’.  Further details on this event will follow very shortly.

 

 

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Responses

  1. […] Myself and a few volunteers dragged ourselves out of bed early last Saturday morning to watch the high tides at Cwm Ivy. It was something to watch the sea rushing in through the gap in the wall. For more information on this click here. […]


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