MSO12577 - Medieval or post-medieval mill leat northwest of Tarr Steps (Monument)

A water meadow of probable 19th Century date is visible on aerial photographs as earthworks on the western slopes of the Barle valley, in an area enclosed by North Barton Wood centred at circa SS 8617 3247. This is a type of water meadow known as catchwork or field gutter system, commonly found on combe or hill slopes and designed to irrigate pasture by diverting water from a spring or stream. The water is carried along the valley sides via one or more channels or gutters and when irrigation was required the gutters were blocked, causing water to overflow from gutter to gutter, thereby irrigating the slopes. This film of water prevented the ground freezing during the winter and raised the temperature of the grass in the spring, thereby encouraging early growth, particularly important during the hungry gap of March and April. One gutter is clearly visible, roughly following the contours of the east-facing combe slope, although it now appears to be in use as a footpath as marked on the current Ordnance Survey base map. A second gutter may be located downslope but was not clear enough to be transcribed. The marked course of footpath, continuing through the woodland to north-west and south-east, may reflect the course of the original gutter. [1-3] The remains of a contour leat are followed by the footpath on the west bank of the Barle at this location. [4] A contour leat runs from North Barton Wood nearly as far as Tarr Steps. It comprises a well defined channel 1.2 metres wide and 0.4 metres deep. Close to Tarr Steps the leat meets the top of a rock outcrop at SS 8672 3215. Water within the leat was clearly intended to issue over this outcrop in a cascade before continuing at a lower level to meet a second outcrop a little to the south. A similar arrangement exists here. After the second outcrop the leat is visible as a shallow channel running along the valley side only 2 or 3 metres above the river level. It ends in a quarried area beside Tarr Steps. The date of the leats and cascades is uncertain. Part of the leat is depicted on 1st Edition Ordnance Survey mapping of 1890 [2], but local information (Josie Floyd, Brendon parish) recalls the leats having been dug (or possibly cleaned out) in the 1920s or 1930s (pers comm). [5,6] A weir is indicated at the take off point for the leat on the 1st Edition Ordnance Survey mapping of 1890. [2] The circular footpath from Tarr Steps to foot bridge across the Barle near Westwater Copse crosses the leat in a number of places and runs above it in sections from SS 8595 3258 to about SS 8645 3239. [7] A study of Tarr Steps and its environs in 2013 suggested that the leat supplied a grist mill for the local population. It is described as taking water from West Water, 100 metres above its confluence with the Barle (and a more stable supply), and running for some 1.5 kilometres. It can be traced as an infilled channel, 0.8 metres wide, with evidence of a stone lining along much of its course, cut into the hillside to a depth of 1.3 metres, with a substantial revetment bank, 0.8 metres wide, on its downslope side. The resulting height of the leat ensures that it is above the floods but also means it has to flow down two large rock outcrops that are unusual features. Field evidence suggests it was constructed prior to a boundary bank constructed between 1841 and 1882-88. [8]