He said a complete draft statement could be finished by the first part of 2013.
The plan is to divert a portion of the Provo River northward toward Powell Slough to create a delta. The shallow, meandering streams of the delta would create a habitat for the young June sucker to mature. As it is now, the river channel at the mouth is too cold and lacks food and cover for the fish, an endangered species.
But the plan has unleashed a flood of controversy, as critics say the project would close off the current Provo River channel or reduce it to an unnavigable trickle.
In a letter to The Salt Lake Tribune, Salem resident Donald Cole said the plan was a "fantasy" that would damage businesses and farms that rely on the river.
Ben Allen, owner of CLAS Ropes Course on the Provo River, echoed Cole's complaint that the delta would make it easier for non-native fish to prey on June sucker, which are found only in Utah Lake.
"I wish they'd take about 50 years or more," Allen said.
He said the commission appeared to be trying to rush the project despite objections.
But Weland said no plans are set for the fate of the lower river. He said the agency wants to meet with landowners to discuss their concerns, as well as quash some misinformation that has surfaced.
The commission has also conducted public meetings to discuss the plans and get public input.
Weland dismissed the predator argument, noting that native fish in healthy fisheries are also prey for other fish.