City Clears Seabed Tests for Winslow Wastewater Outfall Extension

Bainbridge Island has approved two seabed test holes off Wing Point to help design a wastewater outfall extension intended to reduce nearby shellfish-harvest closure areas. The approval limits the drilling season and requires measures to keep fuel, drilling fluids, and waste out of Puget Sound.

The City’s October 29 shoreline decision covers geotechnical exploration—collecting soil samples to help engineers design the project. It does not authorize construction of the outfall extension.

The Army Corps of Engineers authorized the exploratory drilling in March; the City’s October decisions add local shoreline approval and environmental conditions.

In a January 23, 2026, email to the Army Corps, NOAA Fisheries confirmed that the sediment borings are consistent with the Salish Sea Nearshore Programmatic biological opinion and essential fish habitat consultation. The email also requires the Corps to follow the program’s monitoring and reporting provisions. If the project changes, the applicant must notify the Corps and NOAA Fisheries so they can determine whether another verification is needed.

An outfall is the pipe that carries treated wastewater from the treatment plant to its discharge point. The City’s larger project would move that discharge farther offshore, away from commercial shellfish beds. State health protections require precautionary harvest closures near wastewater outfalls even when a plant meets its discharge requirements, according to the Puget Sound National Estuary Program’s shellfish strategy. The drilling approval itself does not close or reopen any harvest area.

A barge-mounted drill rig would take samples at two locations approximately 700 feet and 925 feet offshore from the Wing Point Road area. The work is expected to take eight working days, during daylight hours. The Army Corps of Engineers authorization included in the City’s exhibits allows the investigations between July 1 and August 31, 2027. That is an “authorized work window,” not an announced start date. The timing is intended to reduce risks to fish and avoid the Suquamish Tribe’s fishing season. The City requires at least two weeks’ notice to the Tribe before work begins.

Drilling waste must be removed for disposal off-site, the holes must be filled, and equipment must be checked daily for leaks. Work must stop and Ecology must be notified if a spill or oil sheen is observed.

The City granted a shoreline substantial development exemption for the testing. That category allows qualifying preliminary investigations without a substantial development permit when they meet requirements such as avoiding significant environmental harm, preserving normal public use of the water, and restoring the site. Other environmental rules and permit conditions still apply. The application anticipates temporarily keeping recreational boats away from the immediate work-barge area.

The City also issued a mitigated determination of nonsignificance: its finding that the testing does not require a full State Environmental Policy Act (SEPA) environmental impact statement if the required protections are implemented. The notice sets a deadline of 4 p.m. Pacific on November 12, 2026, to file a written appeal with the City Clerk at 280 Madison Avenue North and pay the $530 appeal fee.

The outfall design work is a separate project from the urgent discharge-pump replacement previously reported by Bainbridge Environmental News.