Lake Ōmāpere

Lake Ōmāpere is located north of Kaikohe and feeds the Utakura River, which flows into the Hokianga Harbour. It is a large, shallow nutrient-rich lake which is prone to blooms of toxic algae, which affect downstream water quality.

The Council and the local community have been working closely together for the last two decades to improve water quality in the lake, through active management and regular monitoring.

Over the last year there have been positive signs that the lake may be improving. The TLI grade for Lake Ōmāpere was 5.06, an encouraging result considering the previous year's grade was 5.32 which decreased from 5.98 the year before.

Blue-green algae levels also remained low during 2009/10 with peaks in November 2009 (684 cells/mL) and February 2010 (235 cells/mL), which coincided with peaks in total phosphorus. There has also been a considerable drop in total nitrogen concentration in the lake over the last year.

It is still too early to tell if these changes are due to improvements in water quality, or as a result of climatic conditions and natural nutrient cycles. The Council will continue to monitor the water quality of Lake Ōmāpere and also carry out monitoring of freshwater mussels and aquatic plants.

Graph of nutrient concentration in Lake Omapere. 

Lake Ōmāpere.

Photo: Lake Ōmāpere