Starting August 10, plan for delays when biking through the area. Flaggers will be on site to control trail traffic. Users may also need to detour via nearby streets or paths. But note that the sidewalk next to 102nd Ave NE is very skinny, and there will be no temporary trail or bike lanes.
Details from Bothell (emphasis theirs):
Beginning around August 10, there will be brief trail interruptions on the Sammamish River Trail, near the pedestrian footbridge leading to downtown Bothell. The interruption will affect traffic in both directions.
The contractor will be placing sandbag protection in the Sammamish River. In order to keep the public and work crew safe, spotters will be on the trail temporarily halting pedestrian and bicycle traffic (up to 20 minutes) as equipment and sandbags are moved to the work area along the trail. Bike and pedestrian commuters please allow some additional travel time.
After moving to the Burke Gilman/West Riverside Trail, eastbound cyclists have a bike lane along E. Riverside Drive, and a pedestrian actuated crosswalk to connect back to the Sammamish River Trail. The westbound cyclists along E. Riverside Drive may use the same general route. The street is marked with sharrows in the westbound direction. Then connect to the main Burke Gilman/West Riverside Trail.
If cyclists want to connect to the bridge or the parking lot trail spur via the sidewalk, please dismount for pedestrians. It is a narrow 5-foot sidewalk and heavily used by seniors, families, and those with disabilities. Please make their safe passage your responsibility during this detour.
While I certainly agree that people biking need to make the safety of people walking their responsibility, it’s rather frustrating that Bothell has not made the safety of people biking their responsibility by creating a temporary trail or bikeway during this closure. Trails like the Sammamish River and Burke-Gilman Trails attract kids and other people who don’t feel comfortable biking on busy streets or skinny sidewalks. As a rule, all detours should be of comparable safety and comfort level to the trail.