Bikers and walkers should take note: A Boise State University geothermal construction project will temporarily close a Greenbelt tunnel on the north side of the Boise River under Capitol Boulevard.

The closure, which starts Thursday, is expected to last several weeks.

Signs mark a detour from the 8th Street pedestrian bridge to the Bob Gibb Friendship Bridge linking Boise State University and Julia Davis Park.

The Capitol Boulevard pedestrian tunnel on the south side of the Boise River will be closed intermittently in 10 to 15 minute increments. Flaggers will direct pedestrians.

Construction crews are installing a geothermal pipeline on the underside of the Capitol Boulevard Bridge in order to connect Boise State to the City of Boise’s historic geothermal heating system. The first phase of the project should be completed by January 2012.

The Morrison Center, the Multipurpose Classroom Building, the Interactive Learning Center and the Math/Geosciences Building are connecting as part of the first phase. The Administration Building, Student Union Building and Environmental Research Building will connect when phase two begins in summer 2012. When completed, approximately 625,000 square feet of building space will be heated using geothermal energy.

For information about the geothermal project, contact Vince Trimboli, Community Relations Supervisor, Boise Public Works Department, at 384-3927.