Source/Archive record SEM8361 - Archaeological survey of the weir and leat system at Dulverton, West Somerset

The report outlines the results of an archaeological survey carried out in March 2016 of the wear and leat system in Dulverton. The weir is 65 metres in length and several metres wide, diverting some of the water from the River Barle into the leat north of the town. The leat is over half a kilometre long and channels water through the town before returning it to the river. During the medieval period and up to the 19th Century it provided the energy to drive several mills, the buildings of which (largely rebuilt in the post-medieval period) survive as standing structures. The aims of the survey were tightly focused on measuring water levels along the leat relative to water levels in the river, and to see what the results might reveal about why the weir and leat were laid out the way they were, perhaps shedding light on the rationales of the original builders of these structures. The total fall from inlet to outlet of the leat is 6.40 metres. It was noted that the system allowed gravitational pull on the flow of water at certain vertical 'falls' or 'drops' into wheel pits to be used to drive mill wheels. This was achieved by carrying the water (at height) through the town and it is the latter part of the structure where the levels drop steeply and most of the water mills are placed. The lay-out of such a highly functional weir-and-leat system must have been surveyed in prior to construction, albeit using more basic techniques than GPS. Those who built it had a deep practical understanding of how water moves in relation to gravity, and how the energy of the river can be effectively channelled, tapped into and utilised.