Water temperature and turbidity in glacially fed Lake Tekapo

Abstract

Abstract Inflow into Lake Tekapo is dominated by the glacially‐fed headwater Godley River. Measurements of water temperature and transmissivity at periods of seasonal maxima and minima provide data on dispersion of river water entering the lake. During spring, lake waters warming from isothermal winter conditions receive turbid cold meltwater which interflows or underflows down‐slope to the deepest basin to pond against the rising lake floor. Waters stratify weakly in summer, and turbid inflowing water interflows. In winter, near isothermal lake water receives cold clear water underflowing to the deepest basin. In all seasons inflowing water is deflected towards the eastern side of the lake by Coriolis force. Diurnal changes in inflow across the Godley delta in spring are complex, with interflow and overflow influenced by heating of waters flowing over wide, braided river channels. In winter, underflows are strongest in early morning when inflows are coldest, and they weaken through the day as river water...