[6]: 527 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 6,000 acres (2,400 ha) belonging to Thomas Bruce (1831–1908) who began farming there in 1872.

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.

[10] In New Zealand kōtuku have a population of roughly 200 at any one time, breeding only at Ōkārito on the West Coast, and are symbols of beauty and rarity in Māori culture.

[5] Fortified settlements were built at Pah Point on the eastern side of the lake, and on nearby Takataka Island, with terraces, stockades, and gardens.

There is evidence of pounamu working taking place at Pah Point and Takakataka Island at the lake, and Kotuku up the Arnold Valley.

[5] Brunner, who in the 1840s had undertaken several journeys to and from the West Coast alone or in the company of Charles Heaphy—but always led, provisioned, and hosted by local Māori—spent Christmas of 1847 at the settlement of Māwhera at the mouth of the Māwheranui (Grey River).

The resident Poutini Ngāi Tahu told him about a lake upriver, and Brunner was keen to explore the area inland.

After a three-week delay while his guides went on a fishing trip, and ten days of provisioning, Brunner and twenty Māori set off upriver in four canoes on 26 January 1848.

They camped on Takataka (later known as the Refuge Islands) near the mouth of the Crooked River, where they ate kākahi and raupō root, and Brunner smoked the last of his tobacco.

[14]: 11  His guides told Brunner there was an overland route across the mountains near the Taramakau River, but the group turned back and headed to the Grey and the Inangahua Valley.

[6]: 45–46  In February 1859 surveyor John Rochfort followed the same route down the Taramakau, but after camping below its junction with the Ōtira, east of Mount Turiwhate, he headed north through the low gap that led to the lake.

On the shore the party made a canoe from a kahikatea log and crossed the lake, which Rochfort named after Thomas Brunner, and exited by the river he dubbed the "Arnould".

On 27 June, Howitt and two of his party set off across the lake by canoe to fish for eels and retrieve stores from their camp at the Arnold River outlet, and were never seen again.

The canoe, which sat only three inches above the water when laden, was presumably swamped in a storm, and the three men drowned;[15] numerous subsequent searches turned up only his tent and some eel lines at the lake shore.

[6]: 89–90 In December 1865, during the West Coast gold rush, word got around that a group of prospectors, known as the "Kangaroo party", had lodged a claim on land to the north-east of Lake Brunner.

[6]: 173–175 By 1867 the Canterbury provincial government had built a bush track along the south bank of the Grey and Arnold rivers, and along the south-west shore of the lake to Natural Paddock.

Materials were then conveyed by the steam launch Little Tay across the lake and up the Orangipuku River to Inchbonnie, and during 1893 construction continued in both directions up to Rotomanu and down to Jacksons.

All trains stopped at Moana for water, and the settlement quickly grew: by 1906 it had four shops and a billiard room, and in 1907 a grand hall opened, hosting bachelor dances for the timber workers.

[14]: 7  United Mills operated in Te Kinga, using timber felled in a logging camp across the lake at Bain Bay.

[7] After native timber forestry had ceased on the West Coast, a business sprang up using divers and chains to salvage logs from the lake bottom for milling.

[16] Logs that had sunk to the lake floor a century ago remained perfectly preserved, with axe marks still visible.

Kahikatea is able to tolerate submergence of its roots, and when lake levels are high it is possible to travel by kayak through forests of 30 m trees, one of the few places on the West Coast where this is easily done.

[2]: 52–53  The lakeside kahikatea and flax (Phormium tenax) community includes small-leaved divaricating shrubs like mingimingi and Coprosma rhamnoides, and the trees rimu and kamahi.

[2]: 224–226  In the understory can be found wheki-ponga (Dicksonia fibrosa), distinguished by its skirt of dead fronds, marble-leaf (Carpodetus serratus), and the climbing rātā Metrosideros perforata.

[8]: 187–188 Both the white-faced heron (Egretta novaehollandiae) and the white heron / kōtuku (Ardea modesta) occur at Lake Brunner, and waterfowl include black swans (Cygnus atratus), Canada geese (Branta canadensis), scaup (Aythya novaeseelandiae), paradise shelducks (Tadorna variegata), grey ducks (Anas superciliosa), mallards (A. platyrhynchos), and coots (Fulica atra).

Today, though, Lake Brunner is one of New Zealand's most significant brown trout (Salmo trutta) fisheries, and is often referred to as "the place where fish die of old age".

[9] The temperate West Coast climate means trout can still be caught in winter, when in the cooler eastern South Island lakes they are much less active.

[27] Dairy farmers responded to the concerns about deteriorating water quality by investing in riparian planting, improved fencing of waterways and bridging of streams on their properties.

The group comprised around 60 individuals, and had support from regional and local councils, NZ Landcare Trust, Te Rūnanga o Ngāti Waewae, Fish & Game, the Brunner Residents Association, and representatives of the dairy industry, including Westland Milk Products.