Lewis and Clark County commissioners on Tuesday unanimously agreed to put a $10 million, county-wide open-space bond on the Nov. 4 ballot.

If approved, the money would mostly be used to pay landowners to put their properties in conservation easements, which protect lands in perpetuity from subdivision. The funds could be used to purchase tracts of land, but bond supporters have said they’ll focus on easements. They money also could be used to garner grant funding.

The main goal is to protect riparian areas and water resources, supporters have said.

Commission Chairman Ed Tinsley said he wanted to let voters have their say on the issue, and he plans to vote for it this fall.

“As an individual citizen, I absolutely support the idea,” he said Tuesday. “People are moving here because they like open space, free-flowing rivers … and the more we do to protect these assets, the better we’re all going to be.”

The proposal came from the Heritage Land Committee, a relatively new group formed last year to focus on the need to protect open spaces throughout the county.

Committee members plan to set up an advisory board to manage the money if it’s approved. The new group would evaluate projects, seek grant funding and prioritize purchases and easement work.

Paul Putz, the city-county historic preservation officer, asked commissioners Tuesday to add wording to their resolution that would allow the money to also be used to protect historically significant sites, such as historic ranches or fields with teepee rings or other artifacts.

Commissioners tentatively agreed to the change. A bond attorney must give final blessing before the ballots can be printed.

The bond would cost $16.77 per $100,000 in assessed property value.

The state Department of Revenue’s land valuations often differ from market values, so landowners should check their latest tax bill to learn their property’s value and how the bond would affect them. City and county residents would be assessed.

The committee chose the bond amount based on support voiced in a phone survey conducted this spring.

A professional pollster called 400 registered county voters in May and found 70 percent would support a $10 million bond, with 26 percent opposed and the remaining 4 percent undecided.

Water protection was rated as the highest priority in the survey, with 75 percent calling the protection of drinking water sources “extremely” important.

Groundwater protection had 73 percent support, and protecting water quality in rivers and streams was extremely important to 68 percent of responders.

Reporter Larry Kline: 447-4075 or larry.kline@helenair.com