Portage Bay 138 Gate Retrofit & Pump Station 20 Improvement Project

Project Description

Improving Service Reliability in Your Neighborhood
Portage Bay 138 is a combined sewer basin, where combined sewage and stormwater flows to Pump Station 20 at the street end of E Shelby St and is pumped to a treatment plant.

During heavy rain events, high volumes of stormwater can overwhelm the sewer system causing a combined sewage overflow (CSO) into Portage Bay. The combined mixture of raw sewage and polluted stormwater can be harmful to humans, aquatic life, and other wildlife.
 
For this project, Seattle Public Utilities (SPU) will be modernizing the way our existing infrastructure manages high flows during rainstorms. To accomplish this, SPU will remove the existing flow restriction device attached to the buried storage tanks beneath the northern sidewalk on E Shelby St and replace it with an automated gate. This will allow SPU to optimally manage flows in the storage tanks in real time.
 
SPU is also making improvements to Pump Station 20, which is also located at the street end of E Shelby St, to help us continue to provide reliable sewer services to the community.
 
Because of the proximity of the work on Pump Station 20 to the Portage Bay Gate Retrofit project and the above-ground impacts, SPU will perform this work at the same time. This will help reduce the duration of construction in the area and other construction impacts on the community as well as minimize restoration costs.

Location

Construction will take place at the street end of E Shelby Street near Fuhrman Ave E and Boyer Ave E (link to project area map).  

What & Why

Portage Bay 138 is a combined sewer basin, where combined sewage and stormwater flows to Pump Station 20 at the street end of E Shelby St and is pumped to a treatment plant.

During heavy rain events, high volumes of stormwater can overwhelm the sewer system causing a combined sewage overflow (CSO) into Portage Bay. The combined mixture of raw sewage and polluted stormwater can be harmful to humans, aquatic life, and other wildlife.

For this project, Seattle Public Utilities (SPU) will be modernizing the way our existing infrastructure manages high flows during rainstorms. To accomplish this, SPU will remove the existing flow restriction device attached to the buried storage tanks beneath the northern sidewalk on E Shelby St and replace it with an automated gate. This will allow SPU to optimally manage flows in the storage tanks in real time.

SPU is also making improvements to Pump Station 20, which is also located at the street end of E Shelby St, to help us continue to provide reliable sewer services to the community.

Because of the proximity of the work on Pump Station 20 to the Portage Bay Gate Retrofit project and the above-ground impacts, SPU will perform this work at the same time. This will help reduce the duration of construction in the area and other construction impacts on the community as well as minimize restoration costs.

What's Happening Now?

The Gate Retrofit work, which will close vehicle access 24hr/day to the driveways on the north side of E Shelby St for about 6-8 weeks is currently scheduled to begin mid- to late May. Please sign-up for the project email list to get the most up to date construction information.

The SPU contractor is conducting site preparation and working to install a sewer bypass system, which will continue through mid-May.

Some construction activities will have significant impacts to street end access and may block driveways during working hours. We cannot guarantee the timely flagging of residents in and out of the driveway between 8 a.m. and 4 p.m. when crews are working, but the contractor will provide driveway access whenever it is safe and feasible. Pavement restoration, which will close access to the street end 24hr/day for less than 1 week is scheduled for late 2020. Additional notice will be sent to adjacent residents in advance of the closures.

Please review the Project Fact Sheet and FAQs for more information and sign-up for the project email list to receive updates throughout construction.

Community Benefits

The Portage Bay 138 Gate Retrofit & Pump Station 20 Improvement Project will improve water quality and public health by reducing the number of CSOs into Portage Bay. This work will reduce the risk of pump station failure and maintain safe working conditions for SPU crews within the pump station, in addition to helping SPU comply with industry standards and regulations.

Anticipated Impacts

We understand that this project is highly impactful, and our team has been working hard to find solutions and ease the stress of construction.

Throughout the project, work will take place at the end of E Shelby St. The gate retrofit work will involve digging a large trench on the north side of E Shelby to access a greater than 10-foot diameter underground maintenance access structure that connects to the storage pipes. Much of the pump station work will take place within the pump station, but there will be additional aboveground work to install a temporary bypass system, remove and replace the pumps, as well as trenching and installation of electrical conduit.

You can expect:

  • Construction noise, dust, dirt, vibrations, and increased construction traffic
  • Pedestrian access to homes will be maintained throughout construction
  • Slowed vehicle traffic and partial road closure near the construction area
  • Equipment, signage, and materials will be staged in or near the work area
  • Parking on the E Shelby St street end will be prohibited 24-hr a day throughout construction
  • Vehicular access to the street end will be maintained from 4 p.m. to 8 a.m. on work days to allow for easy travel to/from work and school
  • During working hours in and out access may be blocked for indefinite periods of time to facilitate work and to move equipment and materials in and out of the street end
  • Driveway access on the north side of E Shelby St to be restricted for approximately 6-8 weeks while the contractor performs the gate retrofit work. This work is currently scheduled to begin in mid-April. Additional notice will be provided in advance of this closure.
  • 24-hr a day vehicle access restrictions to repave the street end. Pavement work should take less than a week to complete and will likely occur in late 2020.

To help ease the impacts of construction, you can expect:

  • For the duration of the project, there will be a 15-min loading zone on Boyer Ave E near E Shelby St to allow residents to pick-up and drop-off items close to their home.
  • Pickup for garbage, recycling, and compost for houses located at the street end of E Shelby St will be consolidated so that it is all picked up on Wednesdays. You will be able to bring your garbage/recycling/compost to the same location as you do currently by collection day on Wednesdays. Our contractor will work to accommodate pickup, which could include moving bins outside of the construction area for residents on the north side of E Shelby St and providing truck access to the southern Fuhrman Ave "alley" and ensuring that cans are moved to a location where the truck is able to pick them up.
  • We have worked with the Seattle Fire Department on an emergency services plan for our construction. Emergency services will be able to reach residents during construction.
  • We have coordinated with USPS to ensure they are aware of this project. We will ensure that pedestrian access is maintained at all times and may have to temporarily relocate mailboxes in order to maintain access.

Community Engagement

Please subscribe to the project email list to receive up-to-date information throughout construction.

Schedule

high level chart illustrations of project timeline milestones

Schedule is subject to change due to weather and other factors

Chart text:

  • Task "Construction and Mobilization Bypass" represents March - mid May
  • Task "Gate Retrofit" mid-May through early July
  • Task "Pump Station" spans July through October
  • Task "Restoration and Demobilization" from nearly mid-October through December

Early 2019

  • Project design continues
  • Engagement with the community

Late 2019

  • Finalize project design
  • Continue to engage the community

Early 2020

  • Pre-construction activities and community outreach including February 27 drop-in session from 4 to 6:30 p.m. at project site
  • Construction work begins in early March, and it is expected to take 7-9 months
  • Gate Retrofit work is tentatively scheduled for mid-May and take about 6-8 weeks. During this time, vehicles access to driveways on the north side of E Shelby St will be prohibited

Late 2020

  • Pavement restoration, which will close vehicle access to the street end for less than 1 week is scheduled to occur in late 2020
  • Construction scheduled for completion
  • Construction updates, as needed, via website and email lists

* Tentative schedule as of April 2020 and is subject to change due to weather or other factors.

Background

In some areas of the City of Seattle, sewage and stormwater runoff are collected in the same pipes, known as combined sewers. During heavy storm events, sometimes the flow in these pipes exceeds the sewer system capacity. 

When this occurs, the system overflows at an outfall structure designed for this purpose. This is called a combined sewer overflow (CSO). There are currently 84 outfalls in the City of Seattle where CSOs can occur.
 
To comply with State and Federal requirements, SPU must limit the number of CSOs at each outfall around the city of Seattle to an average of no more than one per year based on a 20-year moving average.
 
Portage Bay's basin 138 currently exceeds this standard at almost twice the required limit. The goal of this project is to reduce the number of CSOs in order to protect the environment and public health.
Following this work, SPU will continue to monitor performance and identify if additional action is needed to limit CSOs to less than 1 per year on average.