The parched state of the Ladybower Reservoir outside Sheffield – where water levels are seriously low and the lost Derwent village has surfaced again, hitting the national headlines by attracting vandals – is a stark reminder of just how dry this year's scorching summer was.
Rainfall completely flatlined in the long heatwave and has only just begun to pick up again, which explains why Ladybower and its two sister reservoirs were merely a little over 40 per cent full as of December 3.
Companies are taking action in a bid to make sure the situation does not worsen. Severn Trent Water, which looks after the three Derwent Valley sites, has put measures in place and Yorkshire Water has applied to the Environment Agency for six drought permits on the River Don catchment which flows through Sheffield, to stave off the threat of a serious water shortage.
If approved, these permits would run until the end of March, meaning the firm could draw more supplies from the river or cut the amount it sends into the Don from places like Damflask and Rivelin as part of an agreement to boost water quality and top up levels downstream.
“During the heatwave this summer, we saw demand for water increase by up to 200 million litres per day, more than the daily demand of a city the size of Leeds," says Matt Diner, of Yorkshire Water.
“The weather has also been unusually dry, with some areas of Yorkshire seeing the driest period on record through the summer and autumn. This has meant that not only have we needed to take more water from our reservoirs to meet demand, but there also hasn’t been the rainfall to replenish stocks.”
Reducing the flow into the Don – known as ‘compensation releases’ – will ‘help preserve reservoir stocks and help them to replenish as much as possible over the winter,’ says Matt.
“The variations are temporary and we will return to our normal permitted levels on March 31, or sooner if we receive sufficient rainfall.”
Chris Firth, trustee of the Don Catchment Rivers Trust charity, worked on behalf of the Environment Agency in 1995 during the hot summer of the hosepipe ban, when multiple requests for drought orders were in place.
“My experience was that the river was generally more resilient than we had anticipated, we didn't experience any serious fish kills,” says Chris, who was made an MBE in 2000 after a long career in fishery management.
He supports the present application. “From the trust’s point of view, our view is that Yorkshire Water needs to be precautionary. We would hope the drought orders will be short-lived and heavy rainfall or snow over the winter period will fill the reservoirs and everything will be OK by next spring. It's a necessary evil, unfortunately. We have to recognise drinking water is paramount.”
Taking a careful approach now reduces the risk to the river next spring or summer, he thinks. “If nothing was done and we got to early summer 2019 and we had not had rain to refill reservoirs then we would be in a potentially serious situation.”
Chris says it is ‘unlikely’ levels will noticeably drop in the Don, where salmon have finally returned. He adds: “The likelihood of compensation flows having a significant impact on water quality is fairly low. Generally speaking, quality is better than it has been for many generations.”
Ladybower and the neighbouring Howden and Derwent reservoirs are connected, so Severn Trent can move water between the repositories if it chooses.
“One of the reasons why Ladybower is so lacking water is we're keeping it in the other two,” says Jonathan Smith of the firm. “If we wanted to we could flood Derwent village again, but we don't want to at the moment, we'd rather the rain did the job for us.”
There has been less reliance on Bamford Treatment Works – ‘a site of national infrastructure importance’ – where supplies from Ladybower are converted into drinkable water.
“We move treated water around our network of pipes - it might be that people normally getting water from Ladybower, Derwent or Howden are going to get it from a different source,” Jonathan says. “It's still treated in the same way and I'm sure most people won't be able to taste the difference.”
The River Noe, which feeds the River Derwent, has been de-silted to offer another way of refilling the reservoirs.
“You're not going to find it on a map,” says Jonathan of the obscure Noe. “It's kind of marshland that masquerades as a river when it rains a lot.”
So, should people be worried about going thirsty?
“No,” Jonathan states.
“What we'd say is that it's always helpful if people are 'water wise'.”
People are advised to take more showers than baths, and to consider buying a discounted water butt for their garden.
“Stuff like that is helpful regardless of whether it was a hot summer,” Jonathan says.
“We're looking at the reservoirs recharging as they would normally, it's just they're starting from a lower level than last year. Hopefully we'll have a very wet winter.”
‘Refilling a reservoir doesn’t happen overnight’
Heavy rain fell in Sheffield this week, ‘which is a very good thing indeed’, says Jonathan Smith of Severn Trent Water which maintains the depleted Ladybower Reservoir.
“To refill a reservoir takes months, it doesn't happen overnight. It's not unexpected that it's taking a long time. What was unexpected was quite how high demand was and quite how hot the summer was, basically. We always view autumn, winter and a bit of early spring as the time we get the reservoirs back to the level they should be. Going into this summer the reservoirs were on average 98 per cent full, but when you've got increased demand of 22 per cent, that goes - it barely rained in the summer. In actual fact, it's not been wildly wet until November. It's taking longer than normal to get reservoirs back to very high levels but we've got months left of - hopefully - more rain.”
The village of Derwent was submerged when the Ladybower was filled in the 1940s. Dry weather caused it to be exposed in 1976, 1995 and this summer.