Lake Grassmere sits in the region known to local Maori as Kapara Te Hau or “wind blown waters”. It has been described by many visitors as an “alien landscape”. The large lake has many ponds that turn a deep pink colour as the summer months pass.
Algae that changes from green to a vibrant pink when exposed to high levels of salt create this alien vista. Sitting near these blushing ponds are piles of white, naturally formed salt. Seawater from the Pacific Ocean enters the lake, while a warm breeze blows across its shallow surface. Water evaporates, leaving behind unrefined salt.
Pumped into holding ponds, the salt concentrates further and crusts on the bottom of crystallization ponds. Eventually this process creates the famous Marlborough sea salt, used all over the world. Dominion Salt are the operators of the Lake Grassmere refinery, which provides around half of New Zealand’s domestic salt requirements. This makes it a critical location and economic hub.
A great place to stop and take pictures of the fascinating process of commercial salt manufacturing, this is also an area steeped in local history. The lake was the site of a great battle fought between invading North Island Maori, (Ngāti Toa) and local Iwi, (Ngāi Tahu). In 1832, famous North Island Maori Chief Te Rauparaha was surprised and sustained heavy casualties while trying to gather moulting ducks to be used for winter food from the lake.