Region may reap millions through aquifer recharge

Kiwifruit could be one of the crops to benefit and expand in this region from a successful aquifer recharge. File picture

MORE kiwifruit and other high-value crops could cover the Poverty Bay Flats if a recharge of the Makauri aquifer proves successful, bringing in a bounty for the horticulture and fruit-growing sectors.

Economic modelling suggests a 30 percent increase in irrigated land would boost the sector by 122 percent ($27 million) and provide 77 percent more jobs.

This would mean a $61m increase in value to the Gisborne economy and 959 extra jobs.

Conversely, if the aquifer recharge fails and water use is cut by 60 percent, it would slash the sector by $7m, dropping $29m from the Gisborne economy and costing 434 jobs.

The Managed Aquifer Recharge Economic Study will be presented to Gisborne District Council on Thursday.

With funding from the Ministry for the Environment, the council engaged Lewis Wright Consultants in Gisborne, Waikato University and Market Economics to develop an economic model to understand the costs and benefits, at a farm scale and whole Gisborne economy level, of both a full aquifer recharge and also potential reductions in water allocation from the aquifer.

The aquifer recharge trial began in May by injecting water from the Waipaoa River into the Makauri aquifer through bores on Kaiaponi Farm. This is to learn if the depleted water resource, essential for irrigating crops on the Flats, could be recharged long-term.

If successful, the aquifer could be replenished using high winter flows from the Waipaoa River.

Aquifer over-allocated

GDC said the aquifer was over-allocated by about two-thirds of actual use and, with water levels declining by two centimetres a year, a 60 to 70 percent reduction in irrigation of 60 to 70 percent would be required for a natural recharge.

The economic study looks at five scenarios, based on increases in irrigation from a successful aquifer recharge, and declining aquifer levels if it fails.

With the aquifer recharge it found the greatest benefit was not from an increase in irrigation volume but an increase in actual irrigated area.

The increase in irrigated area would allow more high-value permanent crops to be grown, such as kiwifruit, apples, persimmon and feijoa, which are more labour-intensive and have higher returns.

Scenarios without the aquifer recharge all show significant cuts to the economy and employment as there would be a corresponding drop in high-value permanent and annual crops.

With cuts to water allocation, there would likely be a large increase in low- value annual crops such as sweet corn, maize, seed maize and squash, and a small increase in low-value permanent crops such as grapes and citrus.

The study recommends more research into the scope for more high-value permanent crops on the Flats, the risks for such crops and ways to manage them, and ways to reduce nitrogen loss under vegetables.

The study confirms the benefits would substantially outweigh the economic costs of the aquifer recharge.

Assuming a total capital cost of $3m, with $615,000 to $740,000 a year operating costs, a full aquifer recharge would need to increase in capital cost 33 times and operating costs 21 times before the benefits reduced to “break-even”.

A council report on the study notes the economic benefits of a full recharge of the aquifer would largely be felt in the horticulture sector rather than the wider Gisborne economy.

“This gives clear direction that any funding of a managed aquifer recharge scheme should come from those beneficiaries,” the report says.

Potential funding could come through a targeted rate.

The council report also notes the significance of the aquifer recharge, a key plank in the Regional Economic Development Strategy, and lack of other options.

“At the moment all the ‘eggs are in one basket’. Should a managed aquifer recharge not be able to proceed, this research indicates the impacts will be very significant. Without a managed aquifer recharge scheme, cuts in Makauri aquifer water use are ultimately the only option available to the council.”

MORE kiwifruit and other high-value crops could cover the Poverty Bay Flats if a recharge of the Makauri aquifer proves successful, bringing in a bounty for the horticulture and fruit-growing sectors.

Economic modelling suggests a 30 percent increase in irrigated land would boost the sector by 122 percent ($27 million) and provide 77 percent more jobs.

This would mean a $61m increase in value to the Gisborne economy and 959 extra jobs.

Conversely, if the aquifer recharge fails and water use is cut by 60 percent, it would slash the sector by $7m, dropping $29m from the Gisborne economy and costing 434 jobs.

The Managed Aquifer Recharge Economic Study will be presented to Gisborne District Council on Thursday.

With funding from the Ministry for the Environment, the council engaged Lewis Wright Consultants in Gisborne, Waikato University and Market Economics to develop an economic model to understand the costs and benefits, at a farm scale and whole Gisborne economy level, of both a full aquifer recharge and also potential reductions in water allocation from the aquifer.

The aquifer recharge trial began in May by injecting water from the Waipaoa River into the Makauri aquifer through bores on Kaiaponi Farm. This is to learn if the depleted water resource, essential for irrigating crops on the Flats, could be recharged long-term.

If successful, the aquifer could be replenished using high winter flows from the Waipaoa River.

Aquifer over-allocated

GDC said the aquifer was over-allocated by about two-thirds of actual use and, with water levels declining by two centimetres a year, a 60 to 70 percent reduction in irrigation of 60 to 70 percent would be required for a natural recharge.

The economic study looks at five scenarios, based on increases in irrigation from a successful aquifer recharge, and declining aquifer levels if it fails.

With the aquifer recharge it found the greatest benefit was not from an increase in irrigation volume but an increase in actual irrigated area.

The increase in irrigated area would allow more high-value permanent crops to be grown, such as kiwifruit, apples, persimmon and feijoa, which are more labour-intensive and have higher returns.

Scenarios without the aquifer recharge all show significant cuts to the economy and employment as there would be a corresponding drop in high-value permanent and annual crops.

With cuts to water allocation, there would likely be a large increase in low- value annual crops such as sweet corn, maize, seed maize and squash, and a small increase in low-value permanent crops such as grapes and citrus.

The study recommends more research into the scope for more high-value permanent crops on the Flats, the risks for such crops and ways to manage them, and ways to reduce nitrogen loss under vegetables.

The study confirms the benefits would substantially outweigh the economic costs of the aquifer recharge.

Assuming a total capital cost of $3m, with $615,000 to $740,000 a year operating costs, a full aquifer recharge would need to increase in capital cost 33 times and operating costs 21 times before the benefits reduced to “break-even”.

A council report on the study notes the economic benefits of a full recharge of the aquifer would largely be felt in the horticulture sector rather than the wider Gisborne economy.

“This gives clear direction that any funding of a managed aquifer recharge scheme should come from those beneficiaries,” the report says.

Potential funding could come through a targeted rate.

The council report also notes the significance of the aquifer recharge, a key plank in the Regional Economic Development Strategy, and lack of other options.

“At the moment all the ‘eggs are in one basket’. Should a managed aquifer recharge not be able to proceed, this research indicates the impacts will be very significant. Without a managed aquifer recharge scheme, cuts in Makauri aquifer water use are ultimately the only option available to the council.”

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