Reasons for Designation
A watermill uses the gravitational force of water to turn a paddled or bucket
wheel, the energy thus generated in the axle of the wheel enabling the
operation of varying kinds of machinery. The waterwheel can be set directly
into a stream, with a simple 'shut' to control water flow, or may be spring
fed or use tidal waters. More usually, however, an artificial channel, goit
or leat, is diverted from the main watercourse and its flow to the wheel
regulated by sluices. The spent water returns to the main stream via a
tailrace which may be straightened to increase efficiency. Where the natural
flow of water is inadequate, a millpond may be constructed to increase the
body of water (and thus the flow) behind the wheel. During the medieval
period, mills, usually used for corn grinding, were a sign of status, and an
important source of income to the lord of the manor who usually leased the
mill and its land to the miller. With technological improvements, an
increasing range of equipment including fulling stocks, tilt hammers,
bellows, and textile machinery could be powered by watermills, and they
became increasingly important to urban and rural life and industry. With the
advent of steam power and the introduction of iron gears in the 18th century,
waterpower eventually became obsolete for major industry, although many
smaller rural mills continued in use until well into the C20. As a common
feature of the rural and urban landscape, watermills played an important role
in the development of technology and economy. Many of those retaining
significant original features or of particularly early date will merit
protection.
The weir and water management system of Calver Weir are a well preserved
group of features representing several phases of the mill's development. They
represent a major historic engineering enterprise, necessary to harness the
power of one of the region's largest rivers, much of the course of which is
included in a World Heritage Site which takes its name from the River
Derwent. Features relating to early phases of the mill such as redundant
sluice gates and a weir provide evidence of the changing technological
developments necessary in the cotton industry as a whole and specifically at
Calver. Buried archaeological deposits both within and below the earthwork
banks running parallel to the goit will provide important details relating to
the construction of the goit as well as palaeoenvironmental evidence relating
to the natural landscape at the time the mill was built.
The combination of structural evidence, archaeological deposits, documentary
and map evidence provides this monument with a rare opportunity to enhance
our understanding of the social and economic place the mill held in the
wider landscape.
Details
The monument includes the remains of Calver weir, goit and the water
management system associated with Calver Mill. The mill itself is a Grade II
listed building (LB 81617) and not included in the scheduling. The existing
mill building represents the latest phase of the cotton mill but earlier mill
buildings on the site are documented and mapped from at least 1752.
The weir is situated in the River Derwent approximately three quarters of a
kilometre downstream from the mill. The goit (water channel) runs almost
parallel to the Derwent from New Bridge in the north, to the wheel house in
the south.
The weir was built in the first half of the 19th century by the family of Sir
William Heygate, to serve Calver cotton mill. It is built of large squared
grit stone blocks and forms an elongated reversed S, a shape designed to
minimise the impact of flood waters. This weir replaced an earlier one close
to the current site. A retaining wall, also of gritstone blocks, survives
along the western bank of the river and would have served to prevent the
erosion of the bank from the water as it flowed, at an angle, from the weir.
A small quarry evident in the hill side to the west of the Shuttle House may
have provided at least some of the stone used in the project.
The goit provided a managed flow of water that enabled the amount of water
which reached the mill wheel to be controlled, reducing the impact of
flooding on the operation of the mill. The original goit appears to have been
cut sometime between 1799 and 1804. In the 1830s or early 1840s, the southern
stretch of the goit was diverted around the main mill building to a new wheel
house to its south. The wheel house is a Grade II Listed Building (LB 81618)
and is not included in the scheduling. Map evidence shows clearly the changes
in the water management system over time. Such changes would have been
essential to the running of the developing mill technology.
The goit survives as a clay lined channel with linear banks following its
contours on the eastern bank of the goit. Banks on the western side are also
visible just north east of Stocking Farm and continue to immediately north
west of the mill building. The banks survive up to 0.75m in height and
approximately 2m wide. At its most northern point the goit flows through a
tunnel under the garden of the Shuttle House, and emerges through a low grit
stone arch about 80m south of the house. Originally the flow was regulated
by gates beneath the Shuttle House but it is understood that the gates no
longer survive. The tunnel and arch are included in the scheduling although
the ground above these structures as well as Shuttle House are excluded from
the scheduling. The remains of a sluice gate survive approximately 10m south
of the edge of the Shuttle House garden.
As the goit continues south it is crossed by two low arched bridges, which
would have originally given private access to the riverside. Further south
another bridge gives access to the mill complex but this is excluded from the
scheduling, although the ground beneath it is included. East of Stocking Farm
on the east side of the goit the scheduling extends slightly to include the
visible and buried remains of an earlier weir and sluice. This is the point
at which the original goit flowed into the northern side of the mill complex
to turn wheels within the mill building. When the goit was rerouted is
unclear but Ordnance Survey maps show the new line of the goit in place by
1840/41.
As well as the built structures mentioned earlier all modern paths, fences
and gates are excluded from the scheduling, although the ground beneath all
these features is included.
MAP EXTRACT
The site of the monument is shown on the attached map extract.
It includes a 2 metre boundary around the archaeological features,
considered to be essential for the monument's support and preservation.
