The two- to three-mile loop trail for hiking and bicycling is expected to open next spring on Bangert Island. The county is working with the Missouri Department of Conservation, which owns the island just south of Interstate 70.

Spring Bend Park will be created through a donation of the property by the family of William and Nancy Knowles of Chesterfield. However, the “botanical preserve park” won’t open as long as William and Nancy Knowles are living and their longtime property manager lives on site.

Under a “park in reserve” agreement approved by the council, the county will work with family members on a master plan over the next year.

County officials say the two projects will provide unusual public access to natural areas close to heavily populated suburban neighborhoods.

Under the Bangert Island deal, which was revised in recent weeks, the county and the state will share the cost of creating the trail estimated at less than $5,000.