Geoscience Reference
In-Depth Information
erlands and died in London, having introduced Dutch land reclamation methods to
the flatlands of England. His first major drainage projects were primarily funded by
Charles I and the Earl of Bedford, along with a group of other English and Dutch in-
vestors (then known as Adventurers). His first campaign in the Fens involved the dig-
ging of the Old Bedford River (
c4
) and the Forty Foot Drain (
c5
), completed in 1637.
During the Civil War, Parliament ordered the dykes to be broken in order to hinder
the royalist advance. After the war, work continued, using the labour of prisoners of
war, and the New Bedford Level was cut by 1652, completing the remarkably long and
straight dual-river stretch of the Great Ouse that is so obvious on maps.
Vermuyden's strategy was to straighten the large rivers in order to speed up the
water flow, resulting in the rapid passing of floods and avoiding the plugging of the
channels by silt. In more recent times, attention has also been paid to widening and
deepening rivers for navigation, and gates have been installed to help control river
depth and flooding.
Water was initially lifted from low-lying areas by large numbers of windmills
(Fig. 278). Later more efficient drainage was achieved by a succession of different
types of drainage engines, firstly powered by steam, then diesel and now electricity.
The Fens have rapidly become the most engineered landscape in Britain. This increas-
ingly vigorous drainage of the Fenland fields has caused the surface blanket to shrink
and its surface to be lowered. Intensive ploughing of the land has also caused lowering
of the surface due to oxidation of carbon-rich peats (generating carbon dioxide), and
the removal of the dry soil by the wind during storms.
Because of this general lowering of the ground surface, Fenland rivers now run
between flood embankments that are generally much higher than the river surface. This
may often be several metres above the level of the surrounding fields, which may lie
well below sea level. Rainwater on the fields seeps downwards into their drains. The
water is then pumped up into rivers, and the water of these is eventually released into
the sea at low tide (Fig. 279).
After disastrous flooding of the Fens in 1947, it was decided to construct yet more
components that would improve the major drainage scheme. Part of this involved dig-
ging the Flood Relief Channel, the larger and straighter of the channels shown in Fig-
ure 280. This greatly increased the floodwater storage capacity in this area, which had
previously consisted only of the tidal Great Ouse channel (seen to the left of the Re-
lief Channel in the photograph, winding its way towards King's Lynn and the sea).
Through the last 50 years, the engineering of the Fen rivers has successfully avoided
any serious flooding. There are current proposals to carry out more engineering work
on this river system, and one of these is to allow better recreational navigation between
the Fenland rivers and those of the Thames and the Midlands.
