Last Sunday, 22nd March, one of the largest water mains feeding Derby – a 30 inch main under Mansfield Road by Chester Green burst. Flooding was dramatic, as pictures from Derby Telegraph show.
This is one of the main supplies into Derby, feeding from the Little Eaton water treatment works. The pipe is old – 30 inch pipes are no longer a standard size which makes getting a replacement section and fittings more difficult. The repair has been on-going all week, so how has the waater supply network coped?
If water was delivered across Derby through a simple branching nework like a tree and its branches, this would be like chopping through the trunk. Many people would be left without a water supply. Luckily this is not the case. Water pipes form a linked network under the city’s roads, with several supplies from different directions. The main ones here are from the landmark water tower beyond Mackworth and the more hidden reservoir at Constable Drive, in Littleover as well as from ? in the east and ? in the south of the city.
By closing valves to isolate the broken pipe, and opening others to allow more water to flow from other areas of the network, Severn Trent have been able to keep people across Derby supplied with water – so far.
The water use from Constable Drive and Mackworth is obviously much higher than usual. So much so that the supplies feeding these reservoirs are insufficient. Using their usual routes they can not be filled up as fast as water is wanted. Severn Trent has therefore been tankering water across Derby, pumping water into these reservoirs to increase the water supply from them. Even so water supply pressures have been low, as complaint incidents logged on their website indicate – ironically close to the reservoir in Littleover – near the top of the hill!
This morning I phoned Severn Trent as their live updates map doesn’t mention the incident in Chester Green at all. However, their helpful switchboard team had been briefed, and warned that water supplies in Derby are becoming more critical. Low pressure is likely to be a problem to more people later today. But as members of the public we’re not even being asked to help by not wasting water.
The repair Severn Trent hoped to make last night unfortunately failed, but generally their technical teams seem to be managing the situation well. A major supply incident has made barely a ripple in the lives of most of Derby.
But for me, this is also an opportunity for people to be reminded about how smoothly our basic services like water supply work, day in day out. It helps us to appreciate what we have, not take it for granted. If that includes using a little less water for a few days while the repair is completed, we should. That way no one will be left without an essential supply.
More pictures and background at: www.lucycare.mycouncillor.org.uk