The alluvial fringes of the Somerset Levels.
Using core lithology and palaeoecological analyses, the vegetational and landscape development
and local hydrological conditions since c. 6000 BP in two areas of the Somerset Levels has been
studied. Focusing on the former characteristics of the river Brue, the floodplain upstream from
Glastonbury and the area near Panborough Gap in Wedmore Ridge were investigated. In the latter
area a distinct palaeochannel thought to be the prehistoric course of the Brue is present.
Both areas show a similar development with saltmarsh and lagoonal environments until 6000 BP,
followed by a prolonged period of Alnus - Salix carr and sedge fens. In the Panborough area
freshwater deposition was interrupted by distal saltmarsh and lagoon sedimentation between 2900
BP and 2200 BP. This marine incursion caused stagnation of river discharge upstream which led to
the growth of Cladium-rich "tloodinq layers" in the central raised bog area. After embankment of the
rivers in the Middle Ages the changed hydrological conditions caused deposition of the upper
Until medieval embankment and canalisation determined its present day course, the river Brue did
not have a fixed course but consisted of several small short-lived channels. The palaeochannel in
the Panborough area is filled with sediment from the Sheppey while its course is inherited from a
tidal channel that was incised between 2900 BP and 2200 BP. Blocked by the raised bog in the
west the Brue water took a northerly drainage route, and it seems likely that it contributed to this
palaeochannel system. The Brue sediment however was deposited as floodplain and backswamp
clays in the Glastonbury area, and the long-held opinion that the palaeochannel is the 'Old river
Brue' therefore cannot be maintained.
Processes in the coastal region have been inferred from the local hydrological changes and these
inferences have partly been verified with a simplified, two-dimensional hydrogeological model.