1120 SW 5th Avenue, Room 1000, Portland, OR 97204
Work has begun on a damaged section of the Inverness Force Main suspended under the Columbia Slough pedestrian bridge over the Columbia Slough. Repairing this pipe is essential for protecting water quality and public health.
The 11-mile force main carries flow from the Inverness Pump Station east of I-205 to the Columbia Boulevard Wastewater Treatment Plant. A 36-inch pipe splits into a 20-inch and a 30-inch main two miles from the treatment plant and both pipes run under the pedestrian bridge.
When maintenance crews discovered the corrosion-caused leak in the 30-inch pipe, BES transferred flow to the 20-inch pipe. The project will insert a 24-inch HDPE pipe into the damaged main and connect to the existing pipe at both ends of the bridge. Repairs will close the bridge to pedestrians and bicyclists for up to 90 days.
There are more than 500 cliff swallow nests under the Columbia Slough Trail Bridge.
To avoid conflicts between nesting season and work to repair the section under the bridge, Environmental Services’ biologists will remove about half of the nests and drop them into the slough. Cliff swallows return to the nest colony each spring on about April 1 and nesting season lasts until around August 1. The nests need to be removed before swallows occupy them to avoid harm to nesting birds during construction.
Cliff swallows are not an endangered or threatened species, but they are a protected migratory bird species. The U.S. Fish and Wildlife Services, Audubon Society, and Oregon Office of U.S. Department of Agriculture – Wildlife Services have been fully apprised and have endorsed the management plan. During next year’s nesting season, the swallows will likely rebuild the nests removed this year.