During a visit to North Otago on Saturday, Mr Norman looked at one river neighbours believe is suffering - the Waianakarua - before a public meeting in Oamaru that night at which he highlighted the parlous state of New Zealand's waterways.
Lyn and Kim Simpson have owned the Olive Grove Lodge, a former Scout camp on the north branch of the Waianakarua River, for seven years.
They have turned it into a lodge, backpackers' accommodation and camping ground.
They are worried about the state of the river and a proposal from the Otago Regional Council for a minimum flow, and they outlined their concerns to Mr Norman.
They view themselves as guardians of the river, but Mrs Simpson said their fight to improve it had had a major impact on them.
"We are trying so hard, but it is emotionally draining to see the destruction," she said.
The couple have been involved in preliminary community consultation carried out by the regional council to see if agreement can be reached on a minimum flow for the river.
They would have preferred a minimum flow of 0.4cumecs, but have accepted a general agreement for 0.3cumecs, even though that would not ensure the river reached the sea.
However, they fear there is a push by farming interests for 0.15cumecs, which they say would ruin the river.
They are also upset by the effects of land-clearing, farming and other activities along the river, which have lowered water quality, they say.
A group from Kakanui raised similar concerns about the state of the Kakanui River, and demands from farmers for water.
Mr Norman said the same thing was happening to rivers and lakes all over New Zealand.
He said they were the "last wild places" and had to be looked after.
He said all rivers and lakes should have a minimum standard of being safe to swim in.
"No-one [in government] has yet had the guts to do that."
