Between Wednesday and Saturday, it received 127.6mm of rain - almost 150% of the November average of 86.49mm.
Graeme Stephen, Senior Treatment Operator at Ballater Water Treatment Works, said the floods on 19 November were ‘the worst he’s seen’, as the River Gairn breached the site and forced its shutdown.
A tankering operation swung into action, moving 32 loads of water each day from the Friday until Tuesday, to ensure customers in Ballater and the surrounding area retained access to fresh drinking water.
Having spent 22 years at the Ballater site, Graeme knew early on there was likely to be an issue: “I could tell from the colour of the raw water when sampling in the morning that there was a quality issue; it was well above our parameters – which wasn’t a surprise given the amount of rain we’d been having.
“The river runs high several times a year, but this time it wasn’t long before we were flooded. It was worse than Storm Frank; it was the worst I’ve seen it. I had to shut down the site as the well had flooded and the pumps were under water. We tried to save them, but it was beyond our control.”
Power had to be shut down across the station for safety reasons, while the on-site team battled 24/7 to pump out the water. More than a dozen pumps were knocked out of action as they became submerged under the floodwater, including those for servicing, sampling and treatment. Each has had to be kiln-dried and reinstated, work which is still ongoing.
Elsewhere, at Inchgarth Reservoir in Aberdeen the water overtopped for the second time in seven years as the River Dee, which flows next to the site, rose 5.5 metres in just 12.5 hours. When it was built, it was said to have a one in 200-year chance of overtopping. Flood mitigations installed after Storm Frank prevented its pumping station from being flooded from the outside, but internal flooding in the basement saw the team rush to respond to the emergency.
Aimee Kent, Water Treatment Operator, was on standby and called out to support the efforts on-site.
She said: “After Storm Frank the compressors and motors were moved to protect them from future flooding, and that has proved successful during these latest floods.
“We know that we’ll continue to face this as we get hotter summers and wetter winters. I can definitely see us being flooded again. But we will pull together like we did this time and work hard to get the site up and running as soon as possible.”
Kes Juskowiak, Water Operations General Manager, praised the early intervention of Scottish Water staff in responding to the severe weather: “The actions they took in the early stages protected our customers and, had they not taken the action they did, we could have faced very significant longer-term problems.”