Approximately 20 community members attended the open house on Thursday, Jan. 30, at the Elliott Bay Marina to learn more about King County Wastewater Treatment Division’s (WTD) SouthMagnolia Combined Sewer Overflow (CSO) Control Project.
The project will include a new tank and storage facility next to Smith Cove Park and a new pipeline under the bluff to get water there during storms. The tank will collect overflow water and store it until the storm has passed. Then it will release the water back into the existing WTD system. The whole system is automated, and the tanks are underground.
The design team made the facility as compact as possible, with a 50-by-45-foot building above ground. It chose this location because it was close to the Magnolia Bridge but away from activities and the waterfront, said WTD community relations planner Monica Van der Vieren.
Parts of the project will have pervious pavement and as much grass as possible. Trees will screen the building. WTD is also installing an osprey pole and native plants.
“We figured this was going to be easier to blend into a future park if we put softer vegetation and wildlife habitats,” Van der Vieren said.
The underground tanks will be on a three-tier system — that way, WTD won’t need to use and maintain the entire system all year long. Odor-control systems will also be installed, Van der Vieren said.
Potential overflows throughout the tiers will be monitored both locally and remotely, with gates available to shut off access, said project engineer and design consultant Grizelda Sarria.
The outfalls into Puget Sound will be limited to one per year — fewer than the 19 average WTD has had or the record 36 overflows it had last year.
WTD doesn’t want to completely block the overflow off because it is a relief point. Overflows have increased over the past few years. Those increases could be due to weather, but Seattle also has problem with aging sewers that leak and increase inflow during storms, Van der Vieren said.
“It’s not good to go in the sound, but it’s terrible to go into homes and parks and stuff,” she said.
The outfalls are about 90-percent stormwater and 10-percent sewage, Van der Vieren said. WTD was under a federal consent decree to get the improvements done so they had to complete the design while Seattle Parks and Recreation was still in negotiation about the surrounding area. Parks has since bought the land, with hopes to turn it into a waterfront park. The site will be fully fenced until the park is created.
Even though the city owns the surrounding area, it doesn’t have money to develop the property, said Parks real property agent Louis Webster. A funding option may be presented to voters next November.
Carla Kotila, a Magnolia resident and district council member, attended the meeting. She didn’t have any problems with the construction but wanted Parks to “move forward on this to make it a park as quickly as possible, and not try and landbank it. That would be unacceptable.”
The north end of Smith Cove Park will stay operational during construction, and the parking area will get about 2 inches of new gravel. One resident asked for improved drainage function to be installed as the park is repaired from construction.
One of the first priorities of construction will be to get power from near Palisade Restaurant (2601 W. Marina Place) to the site. That will include trenching down West Marina Place to 23rd Avenue West.
Stellar J Construction is the team building the facility. Representative Tom Williams said crews will start working on the site in mid-February. They need to get power to the site by May 1 so they’ll start that construction no later than March 1.
After the shoreline plan is approved, excavation can start to build the tanks. Williams estimates that work will go March to September.
“Construction schedules are all very fluid early on until we start things going and we can plan a little better,” he warned.
Once the tank is done, Stellar J will construct the building and install all of the amenities, including landscaping. The project is slated to wrap up by the end of 2015.
Noise impacts will be relatively mild for this project, Williams said, but there will be early noise when they prepare for excavation.
Traffic impacts are a little more complicated, he said, with materials entering and leaving the site in a steady stream of trucks. The crew will do some work at night, when there is less traffic.
Some concerns, like odor, have already been addressed, Van der Vieren said. Marina events have also been taken into account, and construction will work around that.
Nearby residents have been concerned about lights at night, but Van der Vieren said the no-glare lights will be trained downward.
Marina boat owners have also shared their concerns about dust, so they’ll control dust on the site, as well as wash tires to make sure mud isn’t getting tracked off-site.
Stellar J expects there to be contaminated soil on the eastern side of the project site, Williams said. They already have a contaminated-soil plan in place that will identify any contaminates and treat the soil properly.
The bid for the pipeline portion of the project opened last week, and right now, Stellar J is the apparent low bidder for that project, too. The pipeline portion of the project will be 150 feet deep under the bluff and 15 to 20 feet deep in other places. There will be a pit and open cut across 23rd Avenue to the tank, Sarria said.
Stellar J would need to use a subcontractor for much of the pipeline project, but it would save money and resources to have the same team working on both parts of the project, Williams said.
On Thursday, Jan. 30, that project had five bidders, said project manager Shahrzad Namini. Bidding will stay open for three months and will go to the lowest, qualified response bidder.
Construction for the pipeline hasn’t been set, Van der Vieren said. WTD is having a formal meeting in March to address community concerns about the process.
There’s an eagles’ nest in Magnolia Boulevard Park, and “tunneling obviously has renewed interest,” she said, alluding to Bertha’s series of problems on the Alaskan Way Viaduct replacement project.
WTD has a 24-hour hotline to call if you experience problems during construction. To report problems, call (206) 205-9196.
To comment on this story, write to QAMagNews@nwlink.com.