Trench over the defences

The natural plant communities that have developed on the calcium-rich but nutrient-low sand are very special with incredible variety and beauty.

Families enjoy walking to the beach or sitting by tranquil Kenfig Pool, the largest natural lake in Glamorgan. Children scamper about the sand dunes as if they were man-made playgrounds and surfers make their regular pilgrimage to surf at Kenfig Sands. It's an idyllic scene, cherished and rightly protected by modern society but, the sand dunes haven't always been this way.

Before the 13th century, dunes were probably restricted to the coastline but conditions slowly developed that led to huge quantities of sand being driven inland. The storm beach on the southwest-facing coast has the second highest tidal range in the world and takes the full brunt of Atlantic storms. Vast quantities of sand in the Bristol Channel, deposited during the last ice age, were close offshore. As the Little Ice Age started, the climate gradually became cooler and severe storms and storm surges became more frequent. Sand grains start moving when winds speeds are as low as 11mph but at these higher wind speeds, the quantity moved would have increased dramatically. Damage to frontal dunes and more frequent gales began driving sand inland. The people of Kenfig must have hated the sand as it slowly engulfed everything that had been achieved on the land.

Kenfig township had been a thriving and relatively sizeable Norman town. In 1349 there were 144 burgesses. In comparison, Cardiff had 423 and Neath 128. Kenfig had a chequered history, as it was ransacked by the Welsh on several occasions but each time was able to rebuild and recover. During Henry VIII's reign, an Act was passed that required every farmer in the neighbourhood to spend one day a year planting rushes on the dunes to keep them from moving. However, the unrelenting encroachment of sand for over 200 years eventually proved too much. The old town of Kenfig was abandoned and the community relocated further inland. Even the old church was buried by sand. When Leyland, the King's antiquary, visited the area in 1538, he wrote of the castle and village being in ruins and "almost shokid and devoured with sand that the Severne Se castith up".

Today the dunes at Kenfig themselves are under threat, described as sediment starved and suffering from high vegetation density. They are slowly but surely falling asleep, locked under a green mantle of thick grass, bracken, bramble and scrub. I am often asked "What has happened to all the sand?", "Where have all the trees come from?" and "Please cut paths again because they have become overgrown". There are several reasons why the dunes may have changed so much:

  • Wind speeds have dropped and storm events become less frequent.
  • Between 1933 and 1973 approximately 450 thousand tonnes of sand were mined from the beach and foredune areas. Sand has also been dredged from near shore and offshore areas over a long time period. These activities may have significantly reduced the amount of sand reaching the beach, though direct evidence is lacking.
  • The rabbit population drastically reduced as a result of the major myxomatosis outbreak in 1954 and has never fully recovered. Livestock grazing on the dunes declined in the 20th century and cattle grazing ceased altogether from the 1960s to 2005.
  • Increased atmospheric deposition of nitrates could be leading to faster plant growth.
  • Maintaining an open dune landscape with early succession habitats of sparsely covered sand has become a major management priority. Grazing by cattle and wintering sheep has been re-introduced to slow down the rate of vegetation change on the northern half of the reserve, a tractor cuts selected key habitats each year and machinery is used to scrape turves off some sandy wetlands. Children are encouraged to play in the remaining sandy blowouts to keep them open and wardens have tried creating burrows to help Kenfig's frustratingly bashful rabbit population.Over-stabilisation of sand dunes is not a problem unique to Kenfig. It is recognised as an issue over much of coastal Europe and considerable effort has been made to mobilise sand at several sites, notably in Holland where some success has been achieved through large-scale engineering works. Plans are afoot to remobilise part of the Kenfig dunes too but the work will be far from easy. It is estimated that re-mobilizing stable dunes is four times more difficult than stabilizing mobile dunes.Looking back at recent history for possible answers we can find a good example of human induced re- mobilisation. During the Second World War, Kenfig, in common with many other Welsh dune areas, was used for military training. Frequent use by military jeeps, mortar bomb practice and ground troop training exercises helped expose bare sand. Aerial photographs taken during the period 1946-48 show that much of the site was comparatively mobile, with extensive areas of bare sand and active dunes. However, such an approach to management now on such a loved nature reserve is unlikely to win much support!Time Team researchers visited us in early 2011 to see if the site was suitable for a programme. Thankfully the researchers thought there was excellent potential for an episode. The team hoped that the sand, that had done so much harm, may have also preserved enough for a successful three-days filming. A fantastic week was spent in early August striving to deliver a good piece of archaeological work and some enjoyable TV. The film crew and archaeologists were great fun to work with and we were impressed with how they accommodated the local community, many of whom came to see the dig and learn about the site. We were also grateful for the use of the Time Team excavator that was borrowed to create a nice south- facing sandy bank for rare plants to colonise nearby.ReferencesBLOTT, S. J.; PYE, K (2011) Kenfig Sand Dunes - Potential for Dune Reactivation. CCW Contract Science Report No: 971GRIFFITHS, B.; LYONS, J (1996) Llyfnwy's History of Kenfig 1857. The Kenfig SocietyKENFIG TEAM (1990s) History of Kenfig. Unpublished educational booklet produced for schools and visitors