Enhancement of Willamette Slough: Phase 2
Status: : In progress. The project is in the second of three years of treatment for aquatic weeds. This year's treatments are tentatively scheduled for the end of July and mid-September 2021.
Recreationists who enjoy paddling and fishing in the Willamette Slough are finding it more difficult to do so due the fast-spreading aquatic weed, Ludwigia hexapetala, also known as creeping or Uruguay water primrose.
Teaming up against creeping water primrose (Ludwigia hexapetalal)
Members of the Willamette Aquatic Invasive Network (WAIN) have been treating and removing invasive Ludwigia from numerous locations along the Willamette River. With funding from the Bonneville Power Administration and Meyer Memorial Trust, Willamette Riverkeeper and the City of Salem are working together to use effective treatment methods that provide the greatest benefits and the least harm to the native ecosystems. Ludwigia will be treated with an aquatic-approved herbicide by state-licensed applicators. Ludwigia control efforts in the Willamette Slough complements the City of Salem's other restoration efforts occurring at Minto Island Conservation Area and Willamette Riverkeeper's and WAIN's efforts within the Willamette River Watershed.
Problems caused by creeping water primrose
Ludwigia forms dense mats that choke entire waterways and that lead to significant impacts, such as:
- Reducing recreation opportunities,
- Reducing vital habitat for turtles, frogs, waterbirds, fish, and other wildlife,
- Impeding water movement (affecting both water quality and flooding potential),
- Blocking the growth of native plants,
- Reducing dissolved oxygen, which can lead to fish kills, and
- Catching a ride on boats, kayaks, and other watercraft and quickly spreading into new places.
The off-channel habitat provided by Willamette Slough is critical habitat for migrating and resident Chinook salmon and winter steelhead trout, which are listed as threatened under the Endangered Species Act. For these sensitive species, as well as a diversity of other fish and wildlife, it is vital to keep this slough open.