Waikoropupu Springs is the clearest water I have ever seen. It's of significance to the Maori people with the following legend:
Waikoropupu is the legendary home of the female taniwha, Huriawa, one of the three main taniwha of Aotearoa. She is a diver of land and sea, travelling deep beneath the earth to clear blocked waterways. She is brave and wise and believed to still rest in the waters of Waikoropupu, when she is not away attending to business.