The Rotorua lakes occupy a catchment area of 110,000ha. The diversity of water quality in the lakes reflects their varying catchments and depth, and the extent of development and human impact on the landscape. The lakes range from oligotrophic (very high water quality) to super-trophic (low water quality). Phytoplankton communities are typically dominated by green algae and diatoms, although surface blooms of blue-green algae (cyanobacteria) have become an increasing concern in some of the lakes over recent decades.
Bay of Plenty Regional Council (BOPRC) manages water quality in the region's lakes and has been monitoring them since 1990. In 2000 the council, in partnership with Rotorua District Council and Te Arawa Māori Trust Board, initiated a lakes strategy in response to the decline in water quality in many of the lakes. The Rotorua Te Arawa Lakes Programme (RTALP) is a $230-million programme of protection and restoration for the 12 Rotorua Te Arawa lakes. For more information visit www.rotorualakes.co.nz