Local and regional government came in as "active observers", providing data and input from scientists and even social scientists, many of whom worked for little or no pay.
Mr Bisley spoke about the background to the group's formation and the importance of working together.
There had been a recognition that it was "difficult to make policy" when groups all had different priorities, he said.
"Everything got sorted out in court, and it started getting very expensive; everybody thought, 'We need to do better'."
Water, he said, is a common pool resource, which New Zealanders have been accustomed to having in abundance.
With more intensive land use, people are "constrained in what we can take out, and what we can put back into them without ... if I can use the term, buggering them".
Since 1990, for example, New Zealand's dairy milking herd had increased from 2.6 million to 4.5 million.
"This has put much much more pressure on water bodies, streams, rivers, lakes and estuaries."
Mr Bisley spoke of the recognised need to balance economics and the environment, and to have "a good brand out there in the economy".
Collaboration involved "taking out the middle man" of government, and talking to each other, Mr Bisley said.
Opposing groups "begin to realise that people are not the villains they thought they were".
"They may also stop believing their own propaganda.
"They begin to work together and when they have to make trade-offs they make wiser trade-offs than they would otherwise have done."
Mr Bisley said sometimes the process could be "excruciatingly boring" and sometimes there was "blood on the floor", but the end result was a plan with its "tyres well and truly kicked" and supported by all sides.
"That's very freeing for Government."
The forum recommends regional objectives for water quality, supported by limits to takes and discharges, worked out in each catchment and community through collaboration.
"Without limits you cannot manage cumulative effects, because the little bit you do, and the little bit (someone else does) ... mounts up and gets out of control," Mr Bisley said.
A possible tool is "audited self-management schemes (that) may sit within a regulatory framework", and "timeframes, set by regions, through collaborative processes" would also be needed.
The next step is to achieve buy-in from the Government.
"You need to have the people who can say 'No' in the room; we don't have a democratic mandate, so we're making representations to the Government who do."
