te maire: we claim a kinship with the environment, and it takes a lot of time for people to understand that. yaara: dr. te maire tauhip over freshwater. te maire: we've made it clear that rangatiratanga is more than ownership. this isn't specifically for ownership, this claim to water, it's a claim for rangatiratanga. so, in a sense, what maori are claiming is, and what this tribe is claiming, is authority and autonomy over water. yaara: a ngai tahu historian and community leader, dr. tau says their authority over water is not just enshrined in the treaty but comes from a more spiritual source. te maire: the stories we have are the canoes and our ancestors, our gods. our ancestors came here on canoes as well. so they turned into the mountains and the lakes. so you won't get a waterway around here that we don't claim descent from. for maori, water is an ancestor, what's our obligations to it? yaara: the poor state of the country's freshwater is dominating the day's discussions. gabrielle huria: new zealand has an image of itself that it is wonderful and green. but underneath the thin facade are filthy waterways-- ya