‘We need to pull every lever’: Water review suggests 25 million cubic-metre shortage by 2040

Dry hills and vines on Ngatarawa Rd during the 2020 drought. Photo / Warren Buckland

An updated draft of the Hawke’s Bay Regional Council’s (HBRC) Regional Water Assessment (RWA) says it needs to “pull every lever” to reduce demand for water.

While data from an earlier draft of the Regional Water Assessment predicted an annual 32 million cubic metre shortage of water in the region by 2040, the figure has been amended in a newer draft of the RWA supplied to Hawke’s Bay Today, to a still-significant 25 million cubic metre shortage by 2040 and nearly 33 million cubic metre shortage by 2060.

According to Hinewai Ormsby, chairperson of HBRC, the release of the Regional Water Assessment report, due in March, has been delayed and is now set down for late June due to the impact of Cyclone Gabrielle.

“The report is the first of its kind in New Zealand, providing a region-wide stocktake of how much water we had (based on the 2019/2020 year), how much water we used and what that might look like in future, given climate change,” Ormsby said.

Hawke’s Bay had severe droughts from 2019 to 2020, while 2022 was one of the wettest years the region has ever recorded.

“We’ve faced two years of severe drought and now the devastating cyclone during our wettest year on record,” Ormsby said.

“The immediate focus for our region and Hawke’s Bay Regional Council needs to be on recovery, but we also have our eye firmly on building our resilience to climate change - to the increasing volatility of both too much water and not enough.

“We need to pull all the levers we have to both reduce how much water we use and, where possible and supported by the community, to increase supply. It will use every practical tool we have to ensure Hawke’s Bay has long-term, climate-resilient and secure supplies of freshwater, for all.”

The draft RWA heavily references Te Mana O Te Wai, which prioritises the environment first and then human health before other uses.

As of 2020, the report notes that about 64 per cent of all the water use in Hawke’s Bay was for agriculture and horticulture, notably higher than the provisional figure of 54.9 per cent reported from the earlier draft.

The adjustment could be due to the exclusion of water used for hydroelectricity generation at the Waikaremoana Power Scheme from the measurements, because that water is nearly instantly returned to the system rather than “used”.

Both supply and demand are seen as areas where improvements can be made and solutions can be found.

“We need to pull every lever we have to radically reduce our demand for freshwater - through technology, behaviour and allocation,” the updated RWA draft reads.

“We need to investigate all practical options available for increasing freshwater supplies in Hawke’s Bay to hold the line for the environment, human health and our community.”

Potential solutions on the supply side of the water issue focus on “slowing water down”, which the draft report says is the key to holding more water in the environment and supplementing the supply during dry summers.

Options to retain water that the HBRC identified in the report draft so far include restoring and improving wetlands, encouraging natural aquifer recharge, water reuse technology or building community-scale water storage such as dams or managed aquifer recharge.