The Geology of Sutton
The village of Sutton, and the whole Isle of Ely of which it is
a part, stands on soil described as gravel over a bed of clay. Ancient seashells
and fossils are still often dug up in gardens. The Fenland which surrounds
the Isle comprises a mixture of much softer soils including silt, clay and
black peat.
The natural interaction between the land and its weather
had resulted in a regular winter flooding and summer drying. The beneficial
effects of revitalising the summer farmland and grazing areas through the
deposition of alluvial silt was even noticed after the 1947 floods. The farmers
then working the land thought they had lost everything; in fact, the crops
grew better than before. The land's steady annual drop in ground level had
been a very gradual affair until Vermuyden's dramatic restructuring by earthworks
in the 17th century started that process which has since been greatly accelerated
by applying modern sophisticated technology to the business of land
drainage.
Over at least 6,000 years, the gradual gradient of water flow from
the Bedford levels through this area has meant that adverse tides and/or
winds, often combined with periods of heavy rain or melting ice and/or snow
can result in a back pressure sufficient to stay the river flows and flood
the adjacent plains with fresh water. Salt or brackish water flooding was
always a very rare event around Sutton. Also the lack of "scouring" which
is usually part of the cleansing process in faster flowing waterways, means
silt builds up in the water channels and further reduces their efficiency
at getting the water away. The more the land has fallen towards sea level
through draining and consequent shrinkage, the worse these problems have
(and will) become.
The great floods of 1947 resulted in the most recent radical upgrading
of flood prevention measures, but it seems reasonable to assume that it is
only a matter of time before another slip of the defences allows another
crisis of flooding to afflict the area surrounding the village.
To put off that day, it has been suggested that leaving the farmland
wetter for longer might provide a cost-effective solution. As well as requiring
less running of the drainage equipment with those consequent cost savings
and addressing the land shrinkage problem, it would be using the ground as
a natural reservoir of water for periods of shortage. The clay below the
fen topsoil forms a natural basin. Water is now a valuable commodity and
despite Sutton being in the driest part of Britain, it is still self-sufficient
in its water use. With a little further good husbandry it could become a
model example for others to follow.
A summer phenomenon afflifting the area is the "Fen Blow", when windy
days lift the dusty topsoil and deposit it on roofs, window sills and washing.
A slightly moister soil would be far less inclined to take to the air.