What’s new around the Willamette Slough? Three projects designed to help habitat near the Willamette Slough and River are taking shape. Pringle Creek restoration has been completed, and we are continuing to restore Minto Brown with two more grant-funded projects scheduled to begin July 6, 2020.
Pringle Creek Restored
The design of the new channel is a riffle-pool run and includes a more natural fishway that replaced an old fish ladder. If you stand on the Commercial Street bridge overlooking the site, you will notice boulders and large natural wood structures that provide stream roughness and habitat refuge. The banks are sloped and planted with streamside native Oregon trees and shrubs along both sides to create a greenway corridor that will grow to shade the creek and help keep it cool. All these design elements provide better habitat for fish and other aquatic animals that live in the creek. The corridor will also provide the opportunity for a future pedestrian connection between Mirror Pond Park and Riverfront Park.
The project was funded with $1.3 million from the South Waterfront URA and $1.6 million from stormwater funds.
At the site of the former Boise Cascade paper mill, just upstream from where Pringle Creek meets the Willamette Slough, the City removed a concrete slab that covered the creek, many rows of concrete pilings, and a large water tank that partially blocked stream flow. The former Boise Cascade paper mill had a building that was constructed across the entire channel of Pringle Creek and hid the creek for decades. When the building was removed in 2009, those remnants remained and severely impacted the site.
Willamette Slough Habitat Restoration
Downstream of the daylighting and restoration project, in the Willamette Slough, the City of Salem and Willamette Riverkeeper are teaming up to address the spread of the invasive plant Ludwigia hexapetala. Ludwigia is a yellow-flowered plant that grows quickly and can completely cover a waterbody, degrading habitat and water quality, reducing recreation opportunities, and restricting water flow. Spread of aquatic invasive species reduces habitat for native fish, including endangered salmon runs.
Up and down the Willamette River, groups are working to stop the spread of this aquatic weed. To address the growing concern in the Willamette Slough, treatment of Ludwigia is scheduled for Monday through Friday beginning July 6, 2020 and running through July 17, 2020 as a state-licensed contractor treats the Ludwigia with an aquatic-approved herbicide. A blue dye will be used to ensure efficient application of the herbicide. This activity will run from the south end of the Willamette Slough to the mouth of the Slough, where it meets the Willamette River. Notice of the treatment and any precautions that should be taken during the treatment will be placed in parks and at boat ramps.
Funding for this project was provided to Willamette Riverkeeper by Meyer Memorial Trust and Bonneville Power Administration.
More about Ludwigia
The Willamette Slough was identified by the Willamette Aquatic Invasive Network as having a large source population of Ludwigia. Ludwigia spreads long distances through plant fragments and by seeds. During high water events the plant is most likely to move downstream with the flow of the river and establish new populations at other riverside and off-channel habitats. Due to its location, treating Ludwigia in the Willamette Slough will help prevent the downstream spread of Ludwigia.
Invasive aquatic plants and animals can also be dispersed by watercraft so it is important to clean, drain, and dry your boat before transferring it to another waterbody.
Additional restoration of the Willamette River is occurring at the Minto Island Conservation Area thanks to a grant the City of Salem received in November 2019 from Meyer Memorial Trust and Bonneville Power Administration. This grant-funded restoration project builds on the restoration work that is being done in the Willamette Slough this summer. The recently funded restoration project is taking place in the Minto Island Anchor Habitat located in, and owned by, the City of Salem. Restoration activities began in December 2019 in 48 acres of floodplain adjacent to the Willamette River.
The Willamette River needs high-quality floodplain forest; the reduced amount of historic floodplain forest is identified as a limiting factor and threat for Upper Willamette River Chinook Salmon and Steelhead. This project will focus on treating invasive weeds and planting thousands of native plants to preserve, restore, and enhance 48 acres of floodplain forest. The restoration work will continue through 2024.