yaara: a ngai tahu historian and community leader, dr.rce. 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-- yaara: gabrielle huria, the head of the tribe's freshwater unit, says the high court claim is capturing the public's imagination. gabrielle: and i knew that we had hit on a zeitgeist when i received letters and they would tell us stories of they used to take their son fishing in such and such a river. now their son can't do it with his muckel because you can't fish in it anymore. yaara: back in canterbury, dr. te maire tau is taking me to the ashley river, a plac