AUCKLAND, NZ — Divers have made sure that Birkenhead’s drinking water remains at its finest.
For the first time, water treatment reservoir number two – Birkenhead’s largest, has been cleaned by divers using vacuum hoses to suck sediment from the reservoir floor.
The new process involving divers means reservoirs in the Auckland region, including all 10 in North Shore, can be monitored and cleaned more frequently, Watercare water quality and contract controller Chris Watson says.
“It’s been quite a long time and a lot of stuff had settled into the bottom,” Mr Watson says of the Birkenhead reservoir.
Iron, manganese and sand sediment was found at the bottom which could have discoloured water, making it brown or black if a pipe burst in the water network.
It would have been safe to drink but not met aesthetic tests, Mr. Watson says.
He says the dive cleaning process is new in New Zealand, Britain and Australia where water must be well-conserved.
In the past reservoirs have been emptied, cleaned using high pressure hoses, sanitised, refilled and tested in a process which can take up to two months.
Watercare says there are a number of reservoirs in the Auckland region that cannot be taken out of service for that long.
“We’ll hopefully get them on a five-year rolling programme. It only takes a couple of hours for a diver to look and see if it needs a clean,” Mr. Watson says.
Another bonus is the significant amount of water being saved by not having to empty reservoirs, he says.
“It’s quite an impressive feat. It’s going to save us money in the long run because it takes less time.”