The Washington State Department of Transportation and Seattle Parks and Recreation are working on a project to winterize the irrigation line from the Foster Island Bridge to the Washington Park Arboretum.

A three-week construction period that starts Monday, Oct. 1, will require temporary closures of the north entry to Broadmoor at Foster Island Road, the Arboretum maintenance parking lot and the trail at the Foster Island Bridge, according to a Seattle Parks and Recreation news release.

The maintenance lot will be closed Oct. 4-8, and the north entry to Broadmoor will be narrowed to one lane from Oct. 8-12. Work on the trail is set for Oct. 15-19.

Winterizing the pipeline will allow for year-round irrigation under the new State Route 520 bridge, and includes running an electrical line in the same trench as the water line; this will prevent the line from freezing in the winter.