Canal Boat — November 2017

40 November 2017 Canal Boat canalboat.co.uk

RESERVOIRS

Dam the

water...

With lowish levels being a concern this

year on some canals the reservoirs have

come under scrutiny – but it’s not just too

little water the engineers worry about

T

he cold Pennine winter of 1830
saw a thick layer of ice cover
the surface of the Lancaster
Canal’s Killington Reservoir,
high up in the hills west of Sedburgh. But
then the weather turned milder, the ice
began to break up and thawing snow on
the surrounding hills swelled the waters.
The wind veered around to the north,
blowing the broken ice down towards the
dam, where it blocked the overflow
spillway. With nowhere else to go, the
rising waters overtopped the dam and
began cascading into the valley below...
The reservoir-keeper saw what was
happening and, showing quick-thinking
and presence of mind, grabbed a spade
and set about creating a deliberate breach
alongside the dam to get rid of the excess
water. His prompt action prevented what
would have been a major disaster if the
dam had collapsed.
Almost two centuries later, we can still
see what is probably the remains of the
channel washed out by the water as the

reservoir emptied itself through his

makeshift cut. I’m visiting the reservoir

with David Brown, a senior reservoir

engineer with the Canal & River Trust,

who is supervising work taking place at

this site as part of a regime of inspection,

maintenance and improvement work

aimed at ensuring that the events of

1830 will never be repeated at any of the

Trust’s reservoirs.

This isn’t just a CRT matter: all of

Britain’s reservoirs are subject to

statutory legal requirements – and with

good reason. Disaster may have been

averted at Killington, but the people of

Cwm Carn on the Monmouthshire Canal

weren’t so lucky in 1875, when heavy rain

caused the dam to overflow and fail,

killing 12 people.

Failures of two drinking water supply

reservoirs in the 1920s resulting in 31

deaths led to the 1930 Reservoirs Act, and

to today’s ten-yearly independent

inspections and reports by members of a

panel of qualified civil engineers – backed

out by more recent legislation, with failure

to comply being a criminal matter. And, to

date, there haven’t been any more deaths

from reservoir failures since then.

Often tucked away in valleys some

distance from the canals they serve, CRT’s

reservoirs form a part of its system that

many boaters probably rarely think about

• other than when their water stocks start
  to run low in a dry summer, as looked like
  being the case this year.
  But it’s the opposite issue that most

Good for a ‘once in 10,000 years’ flood? The 1819-built Killington dam

Repairs to Killington’s overflow spillway