GSNZ Auckland branch meeting

The Waikato Regional Council (Hamilton) is in the process of publishing a book, comprising 20 chapters, on the region’s lakes entitled “The hidden gems of the Waikato – the history, ecology and management of the Waikato lakes.” David’s task was to document the occurrence, origins, and ages of lakes (defined as ≥1 ha in area) in the Waikato region, which stretches from the Bombays and Coromandel through the Hauraki Plains and the three Waikato basins to the King Country, Lake Taupo area, and Tongariro National Park. Although the topic initially seemed to be comparatively straight forward, David and co-author Dr John Green were surprised to find many more lakes and lake types than reported previously, and that many lakes of the past, namely paleolakes, had been remarkably extensive. They discovered that the Waikato region has around 330 lakes ≥1 ha in size (previously only 96 had been reported) including representatives of eight out of ten lake classes based on lake origin. Around 50% are riverine lakes including cut-off lakes and ~20,000-year-old blocked-valley riverine-phytogenic lakes (“peat lakes”). The latter provide a unique and valuable archive for studying past environments, including past climates as well as volcanic and earthquake records, through paleolimnology based on analyses of lake cores.