Te Awa O Te Atua / Matatā Lagoon water quality, ecology and management

Te Awa o te atua / Matata Lagoon, May 2024.

Te Awa o te Atua /Matatā lagoon is an outstanding example of a complex dune land-wetland-open-water system on a freshwater-saltwater interface. It has high botanical values and provides high value breeding and feeding habitat for a large number of water birds.

The western lagoon was remediated in about 2010, however the width of aquatic emergent wetland vegetation on the margin of the western lagoon remains considerably less than what was intended to regenerate into shallow wetland habitat following the post-flood remediation.

River Lake Ltd and Place Group undertook water quality, fish and vegetation surveys to assess the ecological health of Te Awa O Te Atua / Matatā Lagoon and identify ways to improve its values.

The report for Whakatane District Council can be found here:

Sullivan Lake water quality and management

Sullivan Lake, Whakatane, May 2022.

Sullivan Lake is a small (2.7ha), shallow, urban lake located in Whakatāne which has had persistently poor water quality. River Lake has undertook monitoring and a series of investigations to characterise the water quality of Sullivan Lake and identify practical options for improvement.

The report for Whakatāne District Council can be found here:

Manawatū River Mixing Study

RWT dye released from the Mangaone Stream to the Manawatū River, 2024.

Palmerston North City Council is in the process of substantially upgrading the treated water that is currently discharged to the Manawatū River. One option being considered as part of the upgrade is to shift the discharge location further downstream.

River Lake undertook a series of mixing studies to assess the mixing characteristics of the Manawatū River at multiple locations downstream of Palmerston North. This was done by: 1) releasing a bolus of Rhodamine WT (RWT) dye in to the river and using drone imagery to map its dispersion across the river as it moves downstream; 2) slowly releasing RWT dye into the river to achieve a steady state and using a fluorometer to measure its concentration at along cross-sections downstream.