Sustainable lake management in the face of climate change, land-use intensification, and shifting societal expectations requires a long-term, integrated, and adaptive science programme. We present an example of such a programme through the partnership between the University of Waikato and Toi Moana Bay of Plenty Regional Council in Aotearoa New Zealand. This collaboration, under the Toihuarewa – Waimāori Chair in Lake and Freshwater Science, has developed and implemented a cohesive and responsive research approach that directly supports the restoration and management of the Rotorua Te Arawa lakes and beyond.
Our research activities span ecosystem modelling, analysis of long-term water quality monitoring data, laboratory and in-situ experimentation, cultural and community engagement, and collaborative restoration science. For example, recent questions about the ongoing effectiveness of aluminium sulphate dosing to reduce phosphorus availability in Lake Rotorua after nearly two decades triggered a detailed post-dosing assessment using comprehensive analyses of long-term datasets. Similarly, the effectiveness of the Ōhau Channel diversion wall, which redirects nutrient-laden inflows from Lake Rotorua away from Lake Rotoiti, was re-evaluated using a coupled data analysis and complex 3D hydrodynamic–water quality modelling approach. This confirmed the critical role of the inflow diversion in improving water quality in Lake Rotoiti but also highlighted the need for ongoing maintenance and scenario testing under future climate.
Furthermore, the consistent and long-term water quality monitoring programme across 12 of the Rotorua Te Arawa lakes over more than two decades has enabled a robust understanding of both long-term trends and short-term shifts. Using novel statistical approaches such as moving window analyses, we have demonstrated how the influence of key drivers (e.g., temperature, water level, internal loading) on water quality can change over time and differ between lakes depending on mixing regime and trophic state. These insights are essential for interpreting the effectiveness and relative contribution of management actions to observed improvements in water quality.
We will present a series of applied science projects to illustrate how this integrated approach can bridge regulatory frameworks, cultural aspirations, and ecological complexity. By embedding research within regional partnerships, incorporating cultural values and knowledge, and fostering the training of the next generation of lake scientists and managers, our programme is supporting both immediate restoration actions and long-term stewardship of these lakes.