/ Floating Wetlands Return to Stormwater Pond
June 22, 2026
Tucked into one of the port’s stormwater retention ponds, a familiar nature-based stormwater treatment feature is back at work.
Earlier this month, port staff installed a new floating treatment wetland system, replacing the original floating treatment wetland system that began as a pilot program to improve water quality in 2014.
The previous floating wetland platforms had reached the end of their useful lifespan and were removed during stormwater pond maintenance work completed in 2024.
In early June, employees planted approximately 800 native sedges and rushes into 10 new floating platforms. The bare-root plants were placed into planting pockets and secured with hydrated coconut coir, a natural material that helps retain moisture while allowing roots to establish and grow.
Over time, the plants’ roots will extend through the floating platforms and into the water below, creating habitat for aquatic life while helping remove algae, heavy metals, and suspended solids from stormwater.
The growing vegetation also provides shade across portions of the pond, creating a unique environment and cooling water temperatures beneath the floating wetlands, supporting the pond’s ecological health.
The floating treatment wetlands cover approximately 500 square feet and work continuously, using natural processes to improve water quality before stormwater leaves the retention pond. As the new system becomes established over the coming months, it will continue the work begun by the original wetlands more than 10 years ago.
The wetlands are just one component of the port’s broader stormwater management program. Along with other treatment systems, including the port-developed Grattix boxes, they help form a multipronged approach to protecting water quality and supporting environmental stewardship along the Columbia River.
