2 8
REPORTS OF MEETINGS
GEOLOGY FIELD MEETING TO LEWES AND EAST
GRINSTEAD, 12TH MAY, 1985
Soil erosion on the South Downs and in Ash-
down Forest
Highdown, Lewes
On 27th November, 1982, the first of a series
of floods affected the Highdown Road area of
Lewes. Flood water and soil passed through
allotments and gardens, then through a number
of houses and so into the road, where the
drains were quickly choked up with debris.
Although this was the flood that had the
greatest effect in human terms in that area
that winter, it was not isolated. In a
limited study of 50 km2 by Dr. J. Boardman
of Brighton Polytechnic, 66 sites of erosion
were found.
The situation was brought about partly by
the weather, though that was by no means
exceptional as rainfall is at its greatest
in autumn and early winter in the area, and
partly by changes in agricultural practice,
largely in response to E.E.C. farming subsidy
policies.
The autumn of that year was wet and it was
not until early November that the large slop-
ing field behind Highdown Road could be
ploughed and winter wheat sown. The field
was then free of surface vegetation and had
been ploughed up and down the slope. The
rains started again, one effect of which was
to cause silt in the soil to slake, to form
a relatively impervious crust at the surface.