Where is the project site?
The project site is on 10 acres located along Johnson Creek and adjacent to the Springwater Corridor Trail near SE 72nd Avenue and Luther Road.
Why are so many agencies involved, and what are their roles?
The site is in Clackamas County and is part of the Metro region. The City of Portland owns the Lents Interceptor Sewer Line, which crosses the property and was the focus of the project’s repair work. In 2009, Environmental Services, the North Clackamas Parks and Recreation District (NCPRD) and Metro together purchased the 10-acre property. NCPRD is the title holder of the property and maintains it. Environmental Services repaired the sewer pipe and relocated and restored the creek channel and floodplain. NCPRD plans to create a community park at the site. Metro’s role is to protect regional open spaces and natural areas. Six of the 10 acres on the project site will remain natural area. The NCPRD will convert four acres into a park.
What problems did the project address?
The 76-inch Lents Interceptor Sewer, constructed in the early 1920s, crosses Johnson Creek at the project site. Erosion in the creek bed and banks had exposed portions of the pipe and a nearby manhole, increasing the risk of damage to the sewer line and creating a barrier for fish. During a typical dry summer day, the Lents Trunk sewer carries about 4.2 million gallons of wastewater. During heavy rainstorms, the trunk sewer can carry over 15 million gallons per day. A break in the pipe would have released a significant amount of sewage, threatening public health and wildlife.
The project protected and improved fish and wildlife habitat by burying the pipe and establishing a new more stable Johnson Creek crossing point.
Were there other environmental and habitat improvements?
This project enhances water quality and improved streamside natural areas. Burying the sewer pipe crossing Johnson Creek created opportunities to move the creek and reshape it in ways that help restore natural stream function. To create a better habitat for fish, Environmental Services placed woody material in the new stream and created backwater areas that provide refuge for juvenile salmon and trout species during high flows. Along the stream banks and in the open spaces of the property, Environmental Services removed non-native vegetation and installed plants that fit with the area’s natural environment.
Does the project have any flood benefits?
The project provides local flood benefits to some of some neighbors to the south by relocating the creek and its floodplain to the north. However, the creek in this location is too steep to slow the flow of flood waters and allow water to spread over the new floodplain, so the project does not provide additional flood benefits to areas downstream.
How much did this project cost and what was the funding source?
Funding for the pipe repair and creek restoration work came from the Environmental Services Capital Improvement Program (CIP). The project cost about $4 million.
What’s the project timeline?
Environmental Services started construction in July 2014, completed it in late 2014 and planted the site in 2015.
What are the benefits for site neighbors and the wider community?
Relocating and restoring Johnson Creek in the project area created greater separation between local businesses and the stream and reduces erosion and flooding on private property. Stabilizing the trunk sewer crossing Johnson Creek reduced the likelihood of sewer failure in the area and removed an obstacle to fish passage.
Site neighbors, trail users and the wider community will benefit from the restored creek habitat, which will attract a greater variety of native fish and wildlife, including Chinook and coho salmon and steelhead trout that are listed as threatened under the Endangered Species Act. The future addition of a community park at the site will provide a much-needed area for neighborhood recreation.
About a community park at this site, what’s the timing and process for that?
The Southgate/Town Center neighborhood is severely deficient in parkland and natural area. The neighborhood is densely populated and there are few large vacant parcels available for park development. With this in mind, community members suggested creating a park on this property due to its size and proximity to the Springwater Trail and Johnson Creek.
The North Clackamas Parks and Recreation District will work with the public to help determine future park uses and site amenities. Public input will be combined with environmental site conditions to establish a conceptual park development plan. Ultimately, the construction of a park will be contingent upon both funding availability and approval of all necessary local, state and federal permits.