Environmental Services is designing a project in the Hollywood, Grant Park and Rose City Park neighborhoods to repair the public sewer system and to reduce stormwater flow into the system. The Hollywood-Grant Park Sewer and Stormwater Project will repair or replace about 38,500 feet of public sewer pipes that are between 75 and 110 years old and deteriorating due to age. The project will also install 12 green street planters and six sumps to remove about 203,000 gallons of stormwater from the sewer system annually.
Together these improvements will increase public sewer capacity, reduce the amount of sewage flowing into the Sullivan Gulch Trunk Sewer, protect public health, property and the environment, and reduce the risks of street flooding and sewage releases to homes, businesses and streets.
Construction could begin as early as September 2015 and last 18 months.
The city installed the 72-inch diameter Sullivan Gulch Trunk Sewer in 1911. It's a combined sewer that carries both stormwater runoff and sanitary sewage from northeast Portland neighborhoods to the Columbia Boulevard Wastewater Treatment Plant. Construction of more streets and buildings since 1911 has increased the volume of combined sewage flowing into the trunk line. Keeping stormwater runoff out of the sewer can help avoid a costly project to replace the Sullivan Gulch Trunk Sewer with a larger pipe.
Construction Locations and Methods
The current project design includes construction only on the streets where work is indicated on the project area map. There may be traffic control, construction signage or increased traffic volume on nearby streets.
The construction contractor may repair some pipes with new linings or replace pipes, depending on their condition and location. The objective is to improve the public sewer system with minimal disruption to the neighborhoods.
The project includes replacing manholes, storm drains sewer service branches that connect homes and businesses to the public sewer in the street to the curb. The project also includes installing green street planters and sumps to remove stormwater from the sewer system. See proposed stormwater facilities locations.
Stormwater Design Information
In addition to public sewer system repairs, the project will also install 12 green street planters and six sumps to remove 203,000 gallons of stormwater from the sewer system annually. This is equivalent to more than five railroad tank cars of stormwater.
The stormwater facilities locations map shows the current project design with potential locations of stormwater management facilities.
What is a Sump?
A sump is a perforated pipe installed vertically underground. Sumps collect stormwater runoff and allow the water to soak into the ground. Sumps are also known as underground injection controls, or UICs. The sumps in this project will be connected to green street planters that will collect and filter stormwater runoff from the street. Soil in the green street planters will absorb much of the runoff. Overflow from the planters will flow into the sumps and slowly soak into the ground.
Rain Garden Partnerships
As part of this project, Environmental Services worked with six homeowners on NE 46th and NE 49th avenues to construct rain gardens on their properties to manage stormwater. These projects keep over 160,000 gallons of stormwater out of the combined sewer system. That's equivalent to four railroad tank cars of stormwater. The rain gardens are all visible from the sidewalk and marked with small blue and green signs.
Street Trees Manage Stormwater
Environmental Services is also working with Friends of Trees to plant street trees in the project area. Trees absorb rain to reduce stormwater runoof, cool the air, provide habitat and beautify neighborhoods. If you'd like to plant a street tree, please contact Naomi Tsurumi at firstname.lastname@example.org or 503-823-4886.
For More Information
Throughout the Hollywood-Grant Park Sewer and Stormwater Project, we will be sending periodic email updates on the schedule, possible traffic detours, delays and lane restrictions. Please sign up now to receive updates by emailing Rhetta.Drennan@portlandoregon.gov with “HGP” in the subject line.
Please let us know if you have concerns such as business operations, disability issues or medical or business deliveries.
Contact Rhetta Drennan with questions and concerns by email or by phone at 503-823-6006.