While researching some family history, I was looking at an old diary and came across a mention of Roswell Pits in Cambridgeshire. I’d never heard of them and wondered if they were like the Neolithic flint mines at Grimes Graves in Norfolk which I had visited many times as a child.
However Roswell Pits were dug for gault, a type of clay which was completely waterproof so was valuable for keeping the river banks secure in the fens, the low-lying areas of East Anglia. centuries ago the whole area was marshy and swampy and transport was by boat; for hundreds of years fen farmers had tried to drain and control the water to use the fertile black peaty soil for their farming. In the 1650’s Cornelius Vermuyden a Dutch engineer and genius of water management was brought in to re-route rivers and establish dykes and ditches and a manageable drainage system. His work gangs were called Adventurers, which sounds so romantic!
His new system was so effective that as the land drained, the soil, which was mostly organic from thousand of years of decaying plants, began to dry out and shrink back from the rivers, which maintained their original height. The banks had to be protected and maintained to stop flooding as the edges collapsed; this could have sent water back over the farmland, drowning the crops . The solution was to build up the banks, with clay, and gault was ideal as it was impervious; luckily for the fenland farmers there was a source of gault close at hand, near the River Great Ouse; it was dug out and the Roswell Pits were established! Being so close to the river, the clay could be transported on boats and barges to where it was needed.
Now no longer in use the pits have flooded and are home to a wonderful variety of water-birds, wetland animals and interesting plants and flowers, and have been designated a SSSI – Site of Special Scientific Interest.
Lois Elsden 