Water recharge progress
by Ann van Engelen
Selwyn District Council, Environment Canterbury, Central Plains Water and DOC staff joined Corban Te Aika from Te Taumutu on Monday, July 1 at a land blessing ceremony before construction starts on a project to recharge groundwater in the Selwyn Waihora zone.
The Hororata Recharge Basin will use water from Selwyn District Council and Central Plains Water consents and an off-take from the recently completed stage two of the Central Plains Water scheme will pour up to 3.5 cumecs of Rakaia River water into the basin when groundwater levels are low. This water will percolate into the groundwater system beneath, recharging the aquifer and feeding springs that are the source of streams where mudfish live.
“During the last century, all major droughts in this catchment have occurred during extreme El Nino or La Nina climate events. These climate events have become more regular in recent decades, and this trend is expected to continue,” says Environment Canterbury project leader Dr Brett Painter.
The $2.8-million project is being funded by the government’s Freshwater Improvement Fund and Environment Canterbury, with in-kind support provided by CPW.
The basin will be in the middle of a pine plantation, and the project should improve the health of the Selwyn River / Waikirikiri and its catchment. The location has been assessed as ideal for enhanced lizard habitat and the re-establishment of native dryland species in clearings.
When completed, the system will only operate when the nearby Selwyn River / Waikirikiri is not flowing naturally and will not mix at the surface with natural river water. It will primarily operate during winter to compensate for dry winters that result in low river flows the following summer. Construction is set for winter and spring this year, with full commissioning to follow once sufficient water and pipe capacity are available.