Ōkaro is a small lake with very high productivity and is classed as super-trophic. It is subject to frequent and severe blooms of cyanobacteria (blue-green algae) during summer. It has been the focus of an extensive water quality management programme, including land-based interventions such as agricultural detention bunds, wetlands and in-lake remediation (flocculation and sediment capping) (source www.lawa.co.nz).
