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.

The 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.