Construction will close part of the Rillito River Path and Camino de la Tierra this week.
Crews will be setting up a crane to place girders on the new bridge across Camino de la Tierra on Tuesday and Wednesday.
The parking area and bike path along the Rillito River will be closed to all traffic in the area on those days.
Crews will be working from 7 am to 5 pm.
Camino de la Tierra will be closed Wednesday, and Pima County Sheriff's deputies will be directing traffic, from 8:30 am to 3 pm.
Drivers, bicyclists and pedestrians should find alternate routes while construction is ongoing.
The project is expected to be complete by the fall of 2017.