Watermeadows, which have largely disappeared these days, were areas of grassland alongside rivers which were flooded during the winter to provide an early crop of hay. Before the 17th C the crude flooding was not particularly effective and only in the 18th C were changes made which transformed the crop yields and allowed more stock to survive through the winter. The impact on animal husbandry was significant, especially in Downland areas such as ours, allowing an increase in flock or herd size. Watermeadows survived until the mid 20th C when the effect of the introduction of artificial fertilisers and changed farming practices rendered them obsolete. In the Og valley there were Watermeadows to the north of St Andrew and the south of Maisey; indeed the water control south to Bay Bridge was remarkably complex.
The course of the River Og to the north of St Andrew was substantially altered when the Marlborough to Swindon road was turnpiked in the late 18th C, allowing for the creation of a watermeadow fed by a leat which had been cut into the contours above the meadow:
The leat took water from further upstream, near Hallam, and followed the contour line to just above Wetpit. At various points along its length there were sluices which allowed a controlled flooding of the meadow below during the late winter and early spring. The water was naturally oxygenated and carried sediment and nutrients to feed the grass. The meadows to the south of Maisey also had complicated sluices to control the water flooding them.
It seems hard in the 21st C to conceive of a water mill on the River Og, but in 1086 one of the most valuable mills in Wiltshire was sited here. It was owned by Miles Crispin whose wife was Maud of Wallingford. There are references in the 13th C to a water mill and in 1296 two tenants were fined for having millstones in their house "to the detriment of the lord’s mill" and in 1316 the miller was charged with grinding additional corn without a licence. By the 16th C the water levels had dropped to such an extent that a windmill was recorded in the village "at the east end of the churchyard". It has been suggested, with no evidence, that it was situated on top of the mound but any trace would have been removed when the latter was cut open in the late 19th C.
What the Victorian leat detailed in the watermeadows section above shows, however, is that it was possible to draw water from higher upstream and at Wetpit there would have been a ten foot or so head of water, more than adequate to drive a mediaeval water mill. Whether it would be possible to find any trace of the original leat or mill is unlikely, given the land changes over the centuries.