Reasons for Designation
An essential part of the infrastructure required to support a medieval
monastic community was a reliable supply of water. The smallest
establishments, cells for perhaps one or two, could manage with just a well,
but the more populous houses required an ample and accessible source. Rivers
and streams were often instrumental in deciding the precise location of
monastic houses, especially in the countryside. When a religious house was
planned, great care was taken to channel clean water from upstream so that it
supplied the kitchen, lavatorium, infirmary and brewhouse with potable
supplies. Water was also extensively used in the industrial processes carried
out within many monastic precincts. If the volume of water was sufficient,
its final duty was to provide a continuous flow to clean the reredorter drain.
Monastic communities established in or near to towns had the same requirements
for water. Local streams or rivers would be used where possible, but if these
were heavily polluted the only alternative was to pipe in clean water from a
spring or springs. Such arrangements, using pipes made from lead or hollowed
tree trunks, were well known in the medieval period. Probably the most famous
record of such a water supply is provided by the mid-12th century drawing of
Prior Gilbert's piped supply for Christchurch, Canterbury.
The use of gravity was esential to obtain a continuous supply of piped water.
This meant tapping into sources of water located at a higher level than the
recipient community and here building covered collecting and settling tanks at
the spring source. From this point, clear water was piped to its destination,
often through further settling tanks. Such spring head structures, usually
called conduit houses, may originally have been as numerous as the monastic
houses which they served, but surviving examples are now comparatively rare.
Some still retain their early cover building, while others have been
extensively restored in recent centuries.
Due to their comparative rarity, all medieval monastic conduit houses which
exhibit significant surviving archaeological remains are considered to be of
national importance and worthy of protection.
The conduit house for St Augustine's Abbey at Canterbury is, despite the loss
of its covering structure, a well preserved example of its class. Excavations
carried out in 1988 revealed the extent of the survival of the medieval
structure and provided evidence of major phases of repair in the 18th and 19th
centuries. These clearly demonstrated the continuing importance of the
original monastic water supply both to the buildings of the abbey after the
dissolution and to the town itself.
Details
The monument includes a medieval conduit house, situated on a steep west
facing natural hillside to the east of Canterbury.
The conduit house, part of the water supply for the Abbey of St Augustine,
comprises a roughly octagonal masonry collecting and settling tank, divided by
an 18th century chalk block and brick wall and now entered by a later doorway
on the west side. Into the tank lead four tunnelled openings and three smaller
ducts which collect water from springs which issue from the aquifer. Water was
delivered to the abbey by means of a three inch diameter lead pipe running out
from the downslope (western) side of the structure. The tank measures a
maximum of 7m (north east-south west) by 4.75m internally. The walls, which
survive to a height of approximately 3m, are built of flint and chalk block on
substantial chalk block foundations. Their well dressed external faces
indicate that they were built free standing while the internal wall faces are
of coursed flint and were originally rendered. The bed of the reservoir is of
natural brickearth.
The four tunnels which lead into the tank are fed by a number of subsidiary
ducts and have openings approximately 1.3m high and 1m wide. Each opening is
dressed with lower Greensand quoins, with larger blocks set at the point of
springing for the arches. The tunnels have original fabric surviving to spring
level above which each has a covering barrel vaulted roof of later flintwork.
Each tunnel is blocked with brickwork some way back from its opening, beyond
which lie circular dome topped brick chambers.
The conduit house dates from the mid-12th century and appears to post date and
lie on the south east edge of a large artificial catchment pond recorded
during recent construction work. The pond has largely been destroyed and is
not included within the scheduling.
The reservoir of the conduit house was probably divided in the 18th century at
which time a new covering of two irregular shallow barrel vaults, resting on
the dividing wall, was provided. This was then covered with a thick slab of
mortared brick, chalk and flint. Other repairs to the structure were carried
out at this time together with the addition of two ducts and the construction
of a brick filter tank. This phase of refurbishment may have been the work of
Sir John Hales who, in 1733, allowed Canterbury the use of the reservoir,
which he owned, to supplement its water supply. Another major phase of repair
and refurbishment occurred in the 19th century when the tunnel roofs were
rebuilt and the external steps and doorway were probably provided.
In February 1988 the roof of the conduit house collapsed. Subsequent part
excavations, carried out later that year by the Canterbury Archaeological
Trust, revealed details of construction and sequence.
The monument is in the care of the Secretary of State. All fence posts,
scaffolding and services are excluded from the scheduling, although the ground
beneath 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.
