Blocking changes to the Murray-Darling Basin Plan would have caused "carnage" at the bottom end of the River Murray, Member for Hammond Adrian Pederick says.
As South Australia's Parliament sat for the first time this year, the Murraylands' MP praised federal Labor MP Tony Burke for helping get the basin plan changes across the line in Canberra.
A series of changes will reduce the total amount of water to be recovered from irrigators, for the environment, by 225 gigalitres; basin authorities believe they can achieve the same environmental goals with less water.
"What we saw was people saying, 'oh, if this 70 gigalitres come out, that just destroys all the environmental outcomes'," Mr Pederick said last week.
"Well, I have got news for them.
"What would have happened if New South Wales and Victoria had pulled out of this plan?
"We would have lost 1090 gigalitres of water.
"To put that into context, think of Sydney Harbour and double it – that is that amount of water.
"Thankfully, common sense has prevailed in Canberra, and we will see the basin plan delivered in full and on time."
He said more efficient infrastructure would be installed in the upstream states, compliance measures would tighten and transparency would increase.
Mr Pederick will have more say on such matters during the life of the current parliament.
He was recently elected the presiding member of its six-member environment, resources and development committee.