Bosherston Lakes

At first the Cawdors only dammed the easternmost valley to create a lake to set off their mansion. Even this caused problems, as the water kept disappearing through cracks in the karstic limestone. They brought in a canal engineer, James Cockshutt, to sort out the problems, and one evening in 1794 he had a vision.  He took an evening walk down to Broadhaven Beach, and coinciding with a high spring tide he came upon, “to my surprise… a beautiful sheet of water covering the whole Haven…I could not view it without awakening a hearty wish to see a Head [dam] constructed that should constantly retain the same appearance….”

The result was the Bosherston Lakes, or Lily Ponds as they are known locally, finally completed in 1860. The house itself was demolished by the Cawdors in 1963. By the 1970’s, after a century of war, social upheaval and neglect the lakes had become part of a wildlife habitat now qualifying for SAC status many times over for their charophyte communities, otters, dragonflies, birds and bats. The National Trust and Nature Conservancy Council (now the Countryside Council for Wales) have both been involved since 1976, the one acquiring the Stackpole Estate and the other declaring Stackpole National Nature Reserve. We have worked closely together ever since.

Watery problems - past and future

The lakes have overcome various difficulties in the last century, including being polluted by sewage and agricultural waste. Point sources of pollution have all been dealt with, but now the lakes face their greatest challenges – diffuse pollution and water abstraction in the wider catchment, and sea level rise. The lakes as we know them face drastic changes in the next hundred years, from sedimentation and nutrient enrichment to rising salt levels in the groundwater and an eventual return to being a tidal inlet. Negotiating these changes will be the challenge for managers to come.

Had there been a Countryside Council for Wales in 1780 the Cawdors would not have been allowed to create the lakes, as the system of turloughs or seasonal pools they replaced would have been an SSSI in their own right. Similarly, a better understanding of the karstic geology, a rock type that discourages surface water, might have dissuaded them.  But create them they did, and in doing so created a designated designed landscape of great importance and one that has become a much-loved visitor attraction in recent years. Currently everything points to the desirability of maintaining open, fresh water, whether SSSI features, designed landscape considerations or the expectations of visitors.