David Hamilton is the Environment Bay of Plenty Chair in Lakes Management and Restoration at the University of Waikato. In his role, David studies 12 lakes in the Rotorua region to better understand how land use affects water quality and what might be done to preserve or restore water quality in the lakes.

David explains that the lakes in this region are highly interesting and very important. Not only are they extremely beautiful and we enjoy them for recreational purposes, they act as freshwater storage and are important for plants and animals living in and around them. They also provide a recreational resource for the people of Rotorua, other New Zealanders and overseas tourists. The Rotorua lakes are mostly volcanic lakes, which means that they were formed directly or indirectly through volcanic activity. This also explains why some of them are affected by geothermal activity, with geothermally heated springs that directly feed into some of the lakes.

What’s happening to the lakes?

Over many decades, human activities – like settlements with septic tanks and farming – have taken a heavy toll. Wastewater from septic tanks and run-off from farming has added a heavy load of nutrients and bacteria to some of the lakes. This has resulted in a deterioration of lake water quality, which sometimes shows up as short-term events like algal blooms when nutrient pressure is particularly high.

David Hamilton’s work involves intensive studies of these lakes. Some lakes have data collected in real time, at intervals of 15 minutes, on factors like water and air temperaturepH levels, concentrations of dissolved oxygen in the water and light penetration. A further activity is to produce computer models to help inform and predict ongoing management of the lakes with the ultimate goal of increasing biodiversity and reducing human impacts on the lakes.

nature of science

Social and cultural elements play a part in the direction and funding of science research. The Rotorua lakes are culturally significant to local iwi and are highly regarded as recreational resources.

Useful links

See the information that David Hamilton and his research group collect on the Lake Ecosystem Restoration New Zealand website.

    Published 28 May 2009