Upper Nihotupu Dam. Photo: Watercare / Supplied
The Upper Nihotupu Dam, Auckland's second-oldest water supply dam, celebrated its 100th birthday on Friday.
The dam, in the Waitakere Ranges, is one of five in the area and one of four that feeds the Huia Treatment Plant.
It is also one of two gravity-fed dams, making it one of the most sustainable water sources for Auckland, supplying 22 million litres of water a day.
Watercare environmental assets manager James Talbot said it plays a pivotal part in water supply in the Waitakere Ranges district.
"The main factor being that since it's a gravity-fed dam, we don't have to use electricity to supply water through the pumps to the plant.
"The characteristics of the dam makes it quite resilient to high rain events in terms of water quality - we find the water quality stays a bit cleaner in that dam."
Upper Nihotupu Dam in 1923. Photo: Watercare / Supplied
But the dam has spent its 100th birthday out of commission, suffering damages in the significant weather events In January and February.
Fortunately, Talbot said there will be no major impact on the rest of Auckland's water supply, as other sources in the ranges would still be capable of supplying the plant.
"The dam itself during the weather events held up very well - there has been no concern of the safety of the structural elements of the dam.
"But the water main that travels six or seven kilometres, that's taken some severe damage in a number of locations that will take some time to work through."
Talbot said the dam is expected to be fully running by summer, but an exact timeline is still unknown.
Due to the age of the dam, it receives a full medical every year.
Upper Nihotupu Dam. Photo: Watercare / Supplied
The dam's construction began during World War I, taking eight years and facing various challenges brought on from the war, with labour and material shortages.
Watercare hopes to hold a celebration for the dam's birthday later in the year, offering tours for the public.