Lake Grassmere
- 41.720591666667174.1642Koordinaten: 41 ° 43 ' 14 " S, 174 ° 9' 51" E
Lake Grassmere is a lagoon at the Clifford Bay near the Cook Strait in the north east of the South Island of New Zealand
Geography
The Lake Grassmere is located about 30 km south of Blenheim and 11 km south of the mouth of the Awatere River. It I is a shallow lagoon that is separated from the Clifford Bay by a narrow, covered by sand dunes barrier. It is the most north-eastern part of the Ward Valley.
The area of the lake fluctuates 14 to 17 km ², the last value is reached only on rare floods. He has no natural inflow. The water is due to the proximity to the sea a high salt content.
The lake area has only a low annual rainfall of 585 mm. The prevailing strong, warm northwest winds favor the evaporation.
Until the 1940s, the lake in winter was a mud surface in summer dried up the sea, with occasional natural salt deposits formed. Because of the geography of the lake is ideal for the plant of salt marshes. The lake has been divided into evaporation ponds.
Towards the end of the summer are the bright white salt mountains of the Lake Grassmere from State Highway 1 visible and form a strong contrast to the brown of the Marlborough Hills.
Lakeside are the small towns Lake Grassmere and Hauwai. The Blind River flows about three miles south in the Clifford Bay.
Early history
The name of the Māori for the lake is Kaparatehau ( "wind blown lake "). Early whalers botched this to " Cobblers ' Hole".
According to legend, Māori were at the place of the lake earlier plantings that have been doused by the legendary navigator Kupe with salt water, causing the lake was created. Before the discovery by Europeans, the lake was used by the inhabitants on the hunting of the numerous water birds.
1832/33, a year after the Ngāti Toa had defeated under the leadership of Te Rauparaha Ngai Tahu at the Kaiapoi and on the Banks Peninsula, visited the Ngāti Toa the lake to hunt ducks. A Force of Ngai Tahu learned of the planned visit and set an ambush. Scouts of Te Rauparaha found the place seems to leave before, so they brought the canoe to shore. On landing they were attacked surprise and suffered heavy losses. Te Rauparaha was captured by Tuhawaiki who wanted him absolutely alive. The prisoner was found seemingly to his fate and was less strictly guarded, so that he was able to escape and swim to one of the canoes and escaped.
Salt industry
The salt industry started at the lake in 1943 and now occupies a third of the lake surface. 1960 17.000 tons of salt have been produced, the total consumption of salt for industrial and domestic purposes in New Zealand that year was about 61,000 tons. 1964/65 reached to 30,000 tons. The maximum possible annual production of the lake is estimated at 50,000 tons. 2005, the lake covered about half of the salt requirement of New Zealand.
In 1970 the harvest almost 52,000 tons, but could not keep up with the growing demand of the industry step. They began to build a salt refinery in Mount Maunganui, is processed in the salt from Australia and the Caribbean to high-purity salt for the food and pharmaceutical industries. A second smaller refinery was built in Grassmere.
In the mid-1960s, a new type of evaporation basins was introduced, which allowed it to drain rain water before it has time to mix with the brine.
Sea water is pumped into the tank and pumped for several months between the basins, its salinity increases even further. Finally, the salt crystallizes and is harvested.
At Lake Grassmere a variety of salt products with slightly different chemical composition, particle size and shape is made. The entire edible salt in New Zealand is obtained in salt pans. It is partially iodinated and treated as a flow with silica. In Grassmere also Licks for agriculture are produced.
In addition to the salt smaller amounts of sodium hydroxide and gypsum are produced.