Frequently Asked Questions

MAR is not a new concept and has been used extensively overseas. Managed aquifer recharge in our context refers to the intentional recharge (infiltration) of clean water to aquifers for environmental benefit. Near River Recharge is a form of MAR occurring in river floodplains where benefits affect the river system and connected aquifers.

The process uses infiltration basins filled with high-quality water that seeps down to recharge groundwater. Clean alpine water from the Rangitata River is delivered to the MAR/NRR sites via irrigation races and pipes. Water passes through a forebay (silt trap) before flowing through the main infiltration basin, where it seeps down to recharge the groundwater system. Benefits include natural water treatment and aquifer replenishment.

Most nitrates take many decades to travel through Hekeao/Hinds aquifers. These nitrates will continue to emerge in lowland springs for generations to come. These structures manage nitrates in spring water while requiring significantly less land than traditional wetlands.

Water quality issues exist due to nitrate levels that exceed the New Zealand drinking water maximum acceptable value. The region must reduce on-farm nitrogen losses by 36% by 2035 per Plan Change 2. Nutrients from land use activities take a very long time (decades to centuries) to travel through the groundwater system. A combination approach addressing both legacy and current nutrient leaching is required.

Although other industrial practices and leaky septic tanks negatively impact water quality, nitrates in Hekeao/Hinds waterways largely come from farming. The farming community must reduce nutrient/nitrate leaching by 36% by 2035.

The project uses repurposed Rangitata River water from existing consents. It is important to note MAR and NRR do not use any additional water resource or consents. Water filters through alluvial material before mixing with other groundwater.

The Hekeao / Hinds Water Enhancement Trust (HHWET) governs the projects.

Trustees: Peter Lowe (Chair), Alister Argyle, Neil Brown, Craig Fleming, Vince Lobb, Ian Mackenzie, Rab McDowell, Marcus Murdoch, Fleur Tompsett, Carolyn Cameron, Evan Chisnall

Observer and Advisor: Mark Webb

Executive Director: Dr Brett Painter

Projects have achieved positive results. The governance group is confident they will make a difference, though these projects are not the only solution. Farmers must maintain independently audited Farm Environment Plans and farm to good management practice standards.

If we don't reduce nitrate levels to those required by Environment Canterbury, then more drastic measures will need to be taken.