A natural hot pool is created whenever rainwater reaches the earths hot zone deep below the surface and then rises again heated. It blows up to the surface to form a pool, containing minerals dissolved from the rocks. These hot springs are found all over New Zealand but mainly near volcanic zones or alpine faults and water temperature varies from location to location. The most famous hot pools are situated in the volcanic zone of Taupo in the centre of the North Island. Others are formed deep in native bush, while others may be hand-made when digging out a hot pool at a beach.
Maori were first to have used such pools to wash, cure and relax and gave them spiritual attributes in important warm-water ritual. Some hotter pools were even used for cooking and weaving purposes. As European settlers arrived, they took over and commercialised these waters. Today, several springs have been turned into luxurious spas, while others remain untreated and are open to any public explorer.
Deaths through bathing have been reported throughout the 20th century. They were caused by carbon dioxide poisoning at Kami, hydrogen sulphide gas intoxication near Rotorua as well as cases of amoebic meningitis. The latter is caused by the amoeba called Naegleria fowleri, a parasite that may enter the body through the mucous membrane and cause brain fever. Experts recommend to avoid diving in such natural pools since these organisms prefer to live in wet and warm grounds surrounding the pools.
Westland has three main sources of hot pools throughout the park. The most famous are the springs at the Welcome Flat Hut, four pools that reward hikers on the Copland Track. Other waters include the Fox River Warm Spring and the Glacier Hot Pools in the north of the park.