The Rotorua Te Arawa Lakes are central to the identity of their region, of immense historical and cultural importance, and provide ecosystem services that underpin biodiversity, conservation and socioeconomic aspirations of the community. The diversity of water quality in the lakes reflects their catchments, which are diverse in topography, hydrogeology and intensity of land use, ranging from the largely undeveloped land around lakes Tikitapu and Okataina, to highly developed forestry and pastoral land around lakes Rerewhakaaitu, Rotorua and Okaro. Lake water quality is strongly linked to nutrients received by each lake from surface flows and groundwater springs. It therefore follows that management of lake water quality requires a good understanding of nutrient loads derived from the landscape, as does the assessment or prediction of the in-lake effects of catchment-based management initiatives aimed at improving lake water quality.