An aerial view of the shocking water level at Whau Valley Dam which will be shut down if insufficient rain fell in winter.
Photo / Supplied
An aerial view of the shocking water level at Whau Valley Dam which will be shut down if insufficient rain fell in winter.
Photo / Supplied
Whangārei's main water dam will be shut down and users supplied through Hatea River, if inadequate rain falls during winter.
Recent rain has lifted river levels across Northland only slightly and worst-hit areas like Whangārei are praying for much-needed winter rain to provide respite from the present situation.
The 15mmof rain Whangārei received on Sunday was enough to last only a week of reticulated water supply and another plea has gone out for people to reduce water use as much as possible.
Figures from MetService and Niwa show just 21.2mm fell in Whangārei between Friday and Tuesday, 21.6mm in Kaikohe, 55.8mm in Kerikeri, and 20.6mm in Dargaville.
Niwa has two stations in Kaitaia. The one at the airport recorded 15.8mm and 18.2mm fell at another site.
Water level at the Whau Valley dam that supplies the city has plummeted to a record 44 per cent and Whangārei District Council water services manager Andrew Venmore said the situation was concerning.
"If it drops down to 15 per cent or thereabouts, we'll stop using Whau Valley Dam. We need 8000 to 9000 cu m of water from that dam daily, which we can then take from the Hatea River.
"Normally we expect about 50mm of rain in 24 hours but we haven't had that for a year and a half and the long-range forecast from Niwa isn't that great, either. They are forecasting average or below-average rainfall for the next three months," Venmore said.
Andrew Venmore at the Whau Valley dam about an year ago when water level started falling and now sits at 44 percent.
Photo / John Stone
Hatea River and other water sources falling too low to take any water, as well as limits on how much could be drawn, have compounded water woes.
Level 2 restrictions have been in force in Whangārei since February 26 while much tighter limits on water take are in place in the Far North and Kaipara districts. Whangārei went into level 3 restrictions on April 16.
The whole of the Kaipara region has level 4 restrictions that allow for household use only while Kaitaia, Kaikohe, Kawakawa-Moerewa and Rawene-Omanaia in the Far North face similar prohibitions.
Residents connected to the Kerikeri-Waipapa, Paihia-Waitangi-Opua and Opononi-Omapere town supplies are subject to level 3 restrictions which ban the use of garden hoses and sprinklers. In Okaihau (level 2), only sprinklers are banned.
With winter rain hopefully coming, Venmore said dam levels should be able to be maintained over the next few months.
He said everyone needed to save water, whether they were at work or at home.
Since January last year, Whangārei has had 1000mm less rain than usual or just 58 per cent of the norm and will head into summer this year with far lower groundwater levels than usual.
Water level at Whau Valley Dam presently is less than half of what it looks like in this aerial photo taken in early 2016.
Photo / Tania Whyte
Venmore said without significant rain over winter, dam and aquifer levels would not recover before next summer.
"It is therefore critical that we reduce the demand on our dams as much as possible until they have fully recovered."
The Northland Regional Council catchments recorded between 30mm and 50mm of rain last weekend and its rainfall record differs from that of Niwa and MetService because it has more testing stations across the region.
In the Far North, the top three rainfall amounts NRC recorded on Tuesday and yesterday were in Taheke (19mm), Takahue (12.5mm), and Rorkakahi and Hokianga (12mm)
In Whangārei, the Opouteke station had 21mm, Otaika 15mm, and Waiarohia 14mm. Tutumoe Ranges in Kaipara recorded 27mm, Kai Iwi Lakes 19mm, and Pouto Pt 14.5mm. NRC river stations indicate only four rivers are currently are below drought flows.
They are Hikurangi, Mangahahuru, Whakapara and Victoria.
