Revised on 7 July 1989. Westhay Moor forms part of the nationally important grazing march and ditch systems of the Somerset Levels and Moors. In the basin of the River Brue at the foot of the Lias limestone slopes of the Wedmore Ridge. The soils are principally of the Turbary Series acid peats modified in parts by cutting.
Altcar series reed peat occurs on the fringes of the site.
Over much of the moor. Water tables in the peat excavations are artificially lowered during active working. The Moor is a former raised bog. A wide range of sward types has developed due to variation in soils and in management practice. 136 aquatic and bankside vascular plant species have been recorded from the field ditches, IDB-maintained rhynes.