point, the lake would have been larger and deeper than today, with several outflows, but the Arnold River eventually became the main one, cutting through the moraine ridges to drain the lake to its present level. The same process of moraine deposition and glacial retreat created nearby Kangaroo Lake, Lady Lake, and Lake Haupiri. To the south of the lake, linking it to the Taramakau River valley, is a stretch of flat land known in the 1860s as the "Natural Paddock" or "Bruce's Paddock". The term "paddock" referred on the Coast to any treeless expanse, and Natural Paddock was mostly pakihi swamp. The lake is large enough that it can be subject to severe weather, including a powerful easterly wind known as the "Brucer", which blows up the valley from Inchbonnie, once belonging to Thomas Bruce (1831–1908) who began farming there in 1872. Lake Brunner has a maximum depth of 109 m, but local stories claimed that the lake was bottomless, or that it was connected with the sea and rose and fell with the tides. A naval survey after WWII established its deepest part, near the Takataka islands by the mouth of the Crooked River, at around 335 feet. Like Lake Kaniere, the other large glacial lake on the West Coast, Lake Brunner is in a deeply-scoured basin and drops off quite rapidly around most of its shoreline. Its water is stained the colour of tea, sometimes appearing almost black, by the tannins—organic and humic acids—leached into its tributaries: a consequence of high rainfall in a catchment that is almost entirely forested. The lake waters are acidic, with a low pH and low oxygen levels compared to lakes on the eastern side of the main divide. The soils in its catchment are derived from greywacke, granite, and schist, and are low in nutrients, but unlike many other West Coast glacial lake, Lake Brunner has significant alluvial soils on its margin. The lake has less thermal stratification than other West Coast lakes, as it is subject to strong winds, and its level fluctuates significantly following heavy rain, sometimes covering the jetty at Moana. Name Although the Māori name for the lake is often given as just "Moana", two names for the lake are recorded. The first, Kōtuku moana, translates as "sea of herons", referencing the white heron (Ardea alba modesta), known to Māori as kōtuku. In New Zealand kōtuku have