Reservoir feeders
There are two kinds of feeders; the well known ones that take
water from a reservoir to the canal, and the lesser known feeders
that transport water from the streams in the valleys to the
reservoir. Most reservoirs are filled directly from natural
water courses but on the Macclesfield the lay of the land means
that this far up the hillsides (the top level is 520 feet up)
the natural streams are all very small and none of them would
be capable of filling a reservoir the size of Bosley on its
own.
This is one reason why five reservoirs were planned - five
catchments for the five biggest streams (see
below). The canal company were unable to obtain rights
to extract water from the biggest of the streams crossing the
canal, the River Dane. Its waters were already committed to
the Trent & Mersey Canal Company via the Caldon Canal -
its waters had to cross the Mersey/Trent watershed for the
purpose. But they did manage to extract from a tributary of
the Dane, the Shell Brook, and carry it round to Bosley in
a feeder, and this is discussed below
It was recognised that it would be just as effective (and
I dare say it was cheaper too) if a large number of streams
could be brought together and fed into the one large reservoir.
As a result several miles of small feeder channels were built
around the hillsides. There were thirteen extraction points
in all. Most of these feed into Bosley, just one into Sutton,
and a couple fed directly into the canal. I say fed because
they are no longer in use due to subsidence. One can be seen
beside the road that goes under Red Acre aqueduct at Pott Shrigley.
Every one of the collection points had a structure to separate
water from the stream for the canal while ensuring that the
stream did not go dry. A unique gauging plate was installed
at each one to measure and guarantee the occupier's water in
the stream. These plates are cast iron and contain a slot which
is of a specific size depending on the size of the stream.
The size of each slot is specified in the 1825 Macclesfield
Canal Act authorising construction of the canal.
In two places the collected water, after crossing from one
valley to another, had to be taken to a lower elevation. If
you cascade water down a steep hill it gains speed and force
and is difficult to contain at the bottom so appropriate devices
are needed to control the water. In one place the falling water
is contained at the bottom of a stone chute by well built up
stonework with an inward curve on the top and drained out along
a further feeder. In another place, now regrettably destroyed,
the water was fed down a series of, about seven, stone scallops,
each slowing the water, changing its direction and feeding
it to the next. This must have been a remarkable sight and
its loss is an enormous shame. We are not aware of any similar
structure elsewhere. We have never found any picture of the
device and the description is based on verbal description from
one who saw it before it was bulldozed. |
This
small reservoir is located south of Macclesfield and its waters
enter the canal just north of bridge 48A. The reservoir itself
is a couple of hundred metres away across the other side of
the main road. It can be approached from the canal by crossing
bridge 48A and walking up the road until the pavement runs
out then crossing over and going through the gate. The dam
can be seen in front of you.