OLYMPIA — Gov. Jay Inslee’s salmon adviser Friday outlined for the Washington Fish and Wildlife Commission a proposal to require riparian buffers, which one commissioner called heavy-handed.

Conservation programs that rely on willing landowners have been successful, Commissioner Kim Thorburn of Spokane said. The governor’s proposed Lorraine Loomis Act depends on rules, she said.

“It seems pretty onerous really,” Thorburn told the governor’s adviser, Erik Neatherlin.

“Why the heavy hand in the Lorraine Loomis Act when we have a lot of experience with how beneficial incentive programs are?” she asked.

Neatherlin agreed habitat restoration “through grants and programs and incentives has been really effective.”

“I think on the flip side, Are we losing habitat more quickly than we’re restoring it? So that’s what this act tries to address,” he said.

The governor’s office and tribes drew up the proposal, named for the late chairwoman of the Northwest Indian Fisheries Commission.

Landowners could be fined up to $10,000 a day for not planting and maintaining “riparian management zones” along waterways crossing their property. The act has been introduced by Democrats in the House and Senate.

The House Rural Development, Agriculture and Natural Resources Committee is hearing the legislation, House Bill 1838.

The width of the buffers would be equal to the height of 200-year-old trees growing in the area. In some places, old-growth canopies reach 245 feet, according to the Department of Fish and Wildlife.

The buffer mandate would not apply to land with buildings, but it would apply to farmland.

“Nobody in Western Washington could economically operate” a farm, Washington Farm Bureau CEO John Stuhlmiller said in an interview Friday. “All eyes are on this one. It’s a big deal.”

Farm groups have been through buffer wars before. In 2011, lawmakers created the Voluntary Stewardship Program as an option to large and uniform buffers.

The program was slow to develop because after creating it, lawmakers didn’t fund it for several years. The State Conservation Commission has now approved VSP plans in 27 counties for enhancing fish habitat through projects by willing farmers.

Several Puget Sound counties, including King County, stayed out of VSP.

Inslee’s salmon plans calls for “leveraging” the Growth Management Act and Shoreline Management Act to enforce a “statewide riparian standard.”

“I’m afraid it might just gut VSP,” Stuhlmiller said. “How do you have a voluntary program when you have mandatory buffers that big?”

The governor’s office cites a Fish and Wildlife 2020 report on riparian ecosystems as the “best science available.”

Riparian buffers stabilize banks, provide shade, filter pollutants and contribute wood to waterways, the report states.

To get the full benefit, buffers may need to be as wide as the tallest trees, though the report notes ecosystems are complex. “Managers should adopt an attitude of humility,” according to the report.

The report also says “management decisions should integrate ecological, economic and social perspectives.”

“We hope this volume can help inform that process,” the report stated.

In drawing up its salmon plan, the governor’s office talked to tribes and some agencies, Neatherlin said. The salmon plan followed a task force report on orca recovery, but was “less of a big-table exercise,” he said.

Fish and Wildlife Commission Chairman Larry Carpenter asked the governor’s office to send more details on who it consulted — “just so we can have a flavor of how this came about.”

“I don’t know a single sole that I’ve known or met over the course of my career that was involved in this,” he said.

The state Department of Agriculture was aware the proposal was coming, but was not involved in drafting the bill, a department spokesman said.