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Documents prepared by Outram and Brown for the construction
of the canal were restricted to the minimum then required
by law. These comprised a plan of the canal with a book of
reference as to land occupation, a rudimentary bill of quantities
and an estimate of costs.
The plan, an early example of Brown's work, was an inaccurate
plot, probably of magnetic compass and chain survey. It was
of limited value for engineering purposes, but served as a
useful illustration for the parliamentary procedures and for
potential investors.
Outram recommended a route from Sir John Ramsden's Canal
in Huddersfield to follow the Colne Valley to Marsden, climbing
436 feet to the summit level at 649 feet above sea level then,
by tunnelling over three miles through Standedge, to emerge
in Brunn Clough, from where the canal pursued the Tame Valley
on the Lancashire side, descending via Stalybridge to the
Ashton Canal some 334 feet, with a tunnel of 200 yards at
Scout Mill.
The Engineer did not refer to another tunnel near Ashton
which, though finished, was opened up in later years. He intended
to leave the numbers and locations of locks to be decided
at the construction stage and in fact, forty-two were built
in Yorkshire and thirty-two on the Lancashire side, the average
fall being to 10 feet 6 inches per lock. The total length
of canal was given as 19 3/4 miles.
Outram stressed that the route was 'the shortest communication
yet between Manchester and the eastern navigations and it
will pass through a country full of manufacturers…and
by the vicinity of the proposed canal to the river the mills
will receive their articles free from land carriage to the
canal'.
This was true; the numerous mills shown on the survey were
located close to the canal because of the narrow valley floors.
Moreover, the Engineer was aware of the millowners' fears
for their water supplies, hence reservoirs to feed the canal
were to be situated only in large and deep valleys where 'collected
waters frequently produced torrents of floods'. He intended
taking no water from the rivers, hence the canal's operation
would not interfere with the thirty six waterwheels on which
the mill depended for their power.
The engineer did not see fit to mention the difficulties,
forseen by some of his critics at the time, of linking his
narrow canal between broad navigations at Huddersfield and
Manchester. That certainly was a defect in the design but,
had the route been built with the generous dimensions of a
broad navigation, it is certain that the costs would have
been prohibitive and unlikely to attract investors.
In any event, the estimate was pared down to less than a
desirable minimum in spite of what must have been obvious
at the start, that this was going to be a difficult project
fraught with imponderables created by its remoteness, climate
and uncertain ground conditions.
The major engineering task was the great tunnel at Standedge,
for which Outram envisaged a five-year programme with costs
of £55,187. He stated that the tunnel 'appears favourable,
the strata consists of gritstone and strong shale and the
low ground in the centre near Red Brook will afford the opportunity
of opening works by steam engines so as to greatly facilitate
completion'. The shafts for £2,767 10s. and lesser sums
for steam engine operations.
Unwisely, he did not include costs for lining and arching
sections of the tunnel, assuming that even the shale strata
required no support. He was to be proved incorrect at that
assumption.
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