Drought fears as Bay of Plenty 'severely dry', rainfall well below average ahead of summer

Focus: Global Warming and Climate Change causes and effects. Video / AP / NASA

The Bay of Plenty has only received 60 to 80 per cent of usual rainfall so far this year.

While this week's rain has been welcomed as a short-term salve, it's not enough to address the long-term impact of this year's big dry.

And residents can also expect to see situations like this more regularly in years to come, according to a recently published government climate report.

Niwa's drought index for the past 60 days deemed the Rotorua area and coastal Bay of Plenty, from Waihī to Te Kaha, "severely dry" with an even worse situation at the easternmost tip of the Bay of Plenty, which is "extremely dry".

When an area goes beyond being "extremely dry" it is in drought, according to the index.

NIWA drought index map for the past 60 days. Source / NIWA

Nowhere in the region is "near normal" and even the mountainous pockets that are faring best are still "moderately dry".

Exceptionally dry weather also put some Western Bay of Plenty stream levels at record lows from March to May this year, leading some councils to start a pre-summer push for water conservation earlier than in past years.

The Government's Our Atmosphere and Climate 2020 report, published last month, cites Niwa data showed a trend towards rising temperatures and less rainfall in the Bay of Plenty.

Tauranga's annual average temperature increased consistently each decade, from 14.53C in 1972 to 16.02C last year. In Rotorua it went from 12.53C to 13.47C over 47 years.

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Meanwhile, average annual rainfall decreased by an average of 3.2 per cent per decade in Tauranga, between 1972 and 2019.

Rotorua's annual rainfall is also "very likely decreasing", Niwa states.

The city got 1462mm in 1960, 1294mm in 2000 and just 944mm last year.

The Bay of Plenty Regional Council has never had to issue a water shortage direction before, but if it does, it would involve staggering times to take water, reducing the amount of water each property could take and reducing the purposes residents could use water for.

Bay of Plenty Regional Council water shortage event manager Steve Pickles. Photo / Supplied

The council came close to having to issue a direction earlier this year, water shortage event manager Steve Pickles told the Bay of Plenty Times last month.

"Preparing now by planning for periods of potential water restrictions is critical."

Rotorua-Taupō Federated Farmers president Colin Guyton, a dairy farmer in Reporoa, said yesterday

the low rainfall this year caused drought concerns on properties like his.

Federated Farmers Rotorua - Taupō president Colin Guyton. Photo / File

He said a few days' rain "makes a difference in the short term but if we go into a prolonged dry period after this rain then it won't take too long for things to dry out".

"The water table is quite low.

"The last few summers have been quite tough," Guyton said.

"And it does add a bit of pressure to a farming job that's already got quite a lot of pressures in it."

Dry rural land in the Bay of Plenty in January 2020. Photo / File

He said farmers prepare where they can.

"For example I have just planted 15ha of turnips ... They are quite a good supplement for the cows."

Bay of Plenty Federated Farmers president Darryl Jensen said his Paengaroa property needed "a lot more rain" to improve soil moisture going into summer from spring.

Federated Farmers Bay of Plenty president Darryl Jensen. Photo / File

"I've noticed pasture growth rates are slowing down."

He has also noticed the changes in weather patterns over decades.

"In my childhood, I used to ride out to the school bus, over puddles that had frosted over. That kind of frost doesn't happen anymore here."

The primary climate change threat for his property was droughts that were "a lot harder and harsher than they used to be".

Nearly half (48 per cent) of New Zealand's gross emissions in 2018 came from agriculture.

Jensen said farmers like him were putting in a lot of work to reduce emissions and respond to the Government's new freshwater rules.

"We are trying to grapple with how to keep our methane emissions down ... There are a lot of farmers out there tinkering with their system. I am doing the same. I have cut my cow numbers back to reduce my methane emissions and putting a proportion of my farm into crops."

New Zealand Kiwifruit Growers chief executive Nikki Johnson. Photo / File

For Bay kiwifruit growers, warmer temperatures and less rain can affect crop loads, yields, and fruit skins.

New Zealand Kiwifruit Growers chief executive Nikki Johnson said climate change may also influence the development of pests and diseases.

Major companies such as Zespri are investing heavily in developing products that "tread lightly on the environment" to reduce their footprint, she said.

"Operating in a sustainable manner will be critical for growers."

Freshwater ecosystems can also be affected by low rainfalls - shrinking habitats for fish and other freshwater species.

When taonga species and mahinga kai (food gathering sites) deteriorate due to drought, that hurts the relationships of tangata whenua with natural resources, too.

Department of Conservation ecology adviser Paul Cashmore (front). Photo / File

The Department of Conservation expects climate change will alter the distribution of plant species in the Bay of Plenty.

Coastal species that prefer warm temperatures and don't tolerate heavy frosts, such as kauri and nīkau, will likely be able to spread more widely.

But it could also help weeds flourish, Bay of Plenty-based ecology adviser Paul Cashmore said.

"Tropical and sub-tropical weeds such as pampas, lantana, banana passionfruit and blue morning glory can be anticipated in areas where it is currently too cold for them."

A plantation of nīkau palms. Photo / File

Many native plants have low drought resistance.

The Bay of Plenty Regional Council declared a climate change emergency last year and has developed a Climate Change Action Plan.

Catchments manager Chris Ingle said climate change would make the management of all natural hazards, such as drought and fire risks, even more important because it will "increase the risk".

A kauri tree in the North Island of New Zealand. Photo / File