Rain brings limited relief as Northland continues to dry out

This week’s storm brought highly variable rainfall across Northland and resulted in this flooding in Whakapara, north of Whangārei. Photo / Denise Piper

The storm that brought heavy rain across parts of Northland early this week has done little to ease dry conditions facing the region’s west. More than 100mm of rain fell on parts of Northland’s east coast in the storm.

But Northland’s west coast received half that or less, with Kaipara missing out and places including its Pouto Peninsula, getting barely a few sprinkles.

Northland Regional Council (NRC) natural resources monitoring manager Jason Donaghy said the storm’s rainfall had been variable.

“The recent rain has provided some relief to the east coast, with rainfall exceeding 100mm in some places. The west coast did not receive a lot of rain,” Donaghy said.

The rain came just as NRC’s drought risk assessment for the region was released, highlighting increasingly dry conditions in a December climate report.

Monday’s rain made little change to its situation outline.

Its drought risk assessment is based on Northland’s rainfall, river flows and groundwater data, as well as its water resources.

Donaghy said there was limited rain on the horizon so Northlanders should still be conserving water, in spite of Monday’s rainfall.

“We’re not out of the woods yet,” he said.

“People still need to keep up to date with any water restrictions and conserve water where possible.”

The report said the Far North was worst hit and classified as extremely dry, while the rest of the region was classified as very dry.

About 37% of NRC’s 51 monitored river sites were below their long-term mean annual low flow. Of the region’s nine key aquifers, 30% were at low or very low levels – at Poroti, Whangārei and Ruakākā.

The report said limited rain over an extended time had resulted in a moderate meterological drought. The region’s rivers and groundwater levels were also in a slight hydrological drought.

Donaghy said many of east coast rivers water flows increased with Monday’s rain and would take a week or two to return to pre-Christmas flow levels.

West coast rivers would however be back to low flows within days.

The west coast’s Kaihu River provides drinking water for Dargaville and Baylys Beach, where water use has been limited to the basic necessities of life since before Christmas, in the earliest Kaipara District Council (KDC) restriction introduction of its type in recent memory.

Dargaville's water use has been restricted to life's basic necessities since before Christmas

And KDC chief executive Jason Marris said further water restrictions were likely in the near future.

“Basically, we need more rain in the streams and rivers to increase the flow and allow us to ease restrictions – until that happens, we need to continue to reduce our water use immediately, to make sure we all have enough for our basic needs,” Marris said.

Monday’s rain has made no difference for Kaipara’s west, where lower-than-expected rain and extremely low river flows are edging it closer to drought.

Northland Civil Defence ranks agricultural and water supply drought among Te Tai Tokerau’s top 10 hazards.

Federated Farmers Northland president Colin Hannah on his Te Kamo farm in less dry times.

Federated Farmers Northland president Colin Hannah said the overnight rain had been beneficial but time would tell how much impact it would have, depending on the coming weeks’ weather.

“One swallow doesn’t make a summer,” Hannah said.

“In fact, we could do with more rain around Whangārei district and south,” Hannah said.

However, the rain would have some postive impacts on areas including Kaipara’s Dargaville and Mititai, as well as the Kaitāia sand country and around Whangārei district’s Pipiwai, where ground had browned off before the precipitation fell.

While areas such as Whangārei district’s Ngunguru and the Bay of Islands were not as dry beforehand, they would, however, be better off as a result of the rain.

Conditions had been dry on Hannah’s Te Kamo farm for some time.

Monday’s 90mm of rain hadn’t made much difference to the fertiliser spread on his property in October, some of which still hadn’t fully dissolved into the ground because of the dry conditions.

Wangārei's Whau Valley city water supply dam in February 2020 amid one of the region's worst droughts.

Meanwhile, NRC’s Donaghy said Northland’s increasingly dry conditions does not mean the region is currently facing the prospect of another serious drought of the type suffered in 2020.

This summer’s dry conditions were different from those leading into that drought.

Rivers were tracking at similar flow levels as 2020 but Northland’s water reserves for summer and into autumn were in better shape due to normal to above-normal rainfall ahead of the 2024/2025 summer.

Northland had experienced its driest year on record leading into the 2020 drought.

■ LDR is local body journalism co-funded by RNZ and NZ On Air.