An expert on the advisory panel for the recently announced plans for freshwater quality improvement has acknowledged it will be difficult to achieve swimmable rivers by 2020.
Yesterday Environment Minister David Parker unveiled a blueprint of plans for environmental change, which included new rules by 2020 around freshwater quality.
Environment Minister David Parker said he would change the Resource Management Act within a year to amend consenting processes and ensure stronger environmental enforcement.
However, none of the planned changes will be made just yet.
Freshwater ecologist Mike Joy, a member of the new advisory group announced along with the plan, has been a strong critic of the country's water quality.
He told Morning Report the plans outlined a change in systems.
"There's going to be some inclusion of the ecosystem health, so a redo of the national policy statement, which is one of the big failings in the last seven or eight years... it had no way of measuring [ecosystem health] or making it happen."
Under this process the national policy statement and environmental standards would clarify that they way to improve ecosystems was via intensity reduction and change of land use practices, Dr Joy said.
The changes would bring benefits to a whole list of groups and communities, he said.
"The only losers are the big guys - the fertiliser companies and mainly Fonterra - they're going to have to change what they're doing to make the difference."
He said he was content the plan had "good goals that force change in a hurry" but acknowledged they would be difficult to achieve within five years as outlined.
"That's a very optimistic one... we've gone backwards for so long and we do know about lag effects of nitrate..." he said.
"It'll be extremely difficult, [but] we can make short-term changes in swimmability by getting fences up and then stopping point source discharges."
Federated Farmers water spokesperson Chris Allen also said five years was ambitious, but farmers had already started the process.
"There's a huge amount of work going on. We've just got to identify where those catchments are that have really got water quality issues," he said.
"Not saying every farmer has picked up those signals, but most have, and there's a lot of really neat stuff happening. We've just got to stop some of the really dumb stuff going on as that's what effects our water quality."