The Tasman District Council is a unitary authority which combines the functions of both a city council and a regional council. Its region has more than 9,000 kilometres of rivers and streams, a coastline stretching for 817 kilometres, and two moderately large pristine alpine lakes. This district is also home to Te Waikoropupu Springs, the largest cold water springs and clearest water in the Southern Hemisphere. These waterways provide valued places for swimming, boating and other recreation, a home for aquatic plants and animals, a source of food, water for drinking, hydroelectricity, and irrigation for horticulture and agriculture.