Wild Dorset
RAIN, RAIN GO AWAY‌
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Adam Simon, Tamarisk Farm
o you remember playing with water and building dams as a child? Something we all learned very quickly was that water runs inexorably downhill. You can channel it, slow it down or hold it temporarily but ultimately it insists on going downwards. On our farm, water ends up harmlessly in the sea quite soon, but it can be troublesome en route. Readers will have noticed that, after the dry summer, we had a lot of rain early this winter and we have needed to help some of our water find the ways we wanted it to take rather than letting it choose its own. Anyway, the big child in me rather enjoyed the idea of hiring a mini-digger for a week and addressing the overdue drainage repairs. A couple of blocked culverts were cleared, a silted-up ditch was re-opened and a damaged field drain repaired. Three new shallow drains were created to reduce the spread of boggy patches, two new micro-ponds were dug, providing new habitat which will be valuable for at least a few years, and a water pipe was laid to service a new trough. I did score one own goal: water flowing off a steep, scrub-covered slope was elegantly redirected away from the arable field it had been water-logging onto a piece of permanent pasture where it could disperse. I found later that I had misjudged the slope and missed the right line so it was actually flooding onto the crop in the next field over! Fortunately, the problem was easily solved with an hour of hard sweating with a spade, and without burning more diesel. Underneath our farm are limestone layers topped with heavy clay. The limestone is porous, and water flowing through it dissolves channels, rather like a miniature cave system, that can erupt at the surface as a spring. Some of these stay constant for many years. Such a spring provided the water for the original village reservoir until the mains were connected in 1960 and it now waters five fields effectively. However, these springs can also pop up suddenly in unexpected places, run for a few years and then stop again. These flushes can be a blessing: a wet place in the field can bring in extra 36 | Bridport Times | February 2020
wildlife and be a great enhancement but they can be troublesome too, making access or cultivation tricky. The traditional answer to problems such as these is to drain the land. Surface ditches intercept water and protect the land below them. To make the most of this pattern of drainage ditches underground field drains can be constructed to break through natural water routes or collect percolating soil water. Here at Tamarisk Farm we find a pattern of drains laid and maintained over centuries emptying into the surface ditches. They are mostly of clay pipes but some earlier ones were made with flat stones placed to line and roof a channel, forming a network under a whole field. Over the years some have become damaged and, with no maps, repairs are difficult. We have had a few notable successes but it is a big job with a lot still to do. I once met a farmer with a very wet field which he said had drains he could not repair. His explanation was that the drains had been laid by hand by Italian prisoners of war. The trouble was that the supervising sergeant-major treated them very badly, including forcing them to dig 6 feet down. This would have been too deep to be useful anyway, but by way of revenge they had placed slates across the drains every few yards before covering them, so the whole project was doubly futile. Most of my work with the digger was simply taking away excess surface water so that it did no