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Mercer Corridor Project Update: What’s happening on Roy St.?

Stormwater Detention System (not like in “The Breakfast Club”) is helping protect Seattle’s Waterways!

If you’ve traveled along Roy St. lately, you’ve probably come across a closure between 4th Ave. N and 5th Ave. N. Crews have dug a large hole in the north side of Roy St., and are placing some huge structures in there. But what exactly are they doing?
Mercer Update

As part of a collaboration between SDOT’s Mercer Corridor Project and WSDOT’s North Portal tunnel project, crews are installing a stormwater detention system under Roy St. What does that mean? Here’s a bit of background: Every year, rain washes untreated sewage and stormwater into the city’s waterways during storms. On average, more than 300 sewage overflows per year send millions of gallons of raw sewage and stormwater into Seattle’s creeks, lakes, the Ship Canal, the Duwamish River, and Elliott Bay. Not good!

These combined sewage overflows create significant health and environmental risks, but the City of Seattle has a plan to protect Seattle’s Waterways. Installing detention facilities, such as the one on Roy Street, reduces the likelihood of an overflow surge in the downstream system that can lead to a combined sewage overflow into Lake Washington or the Ship Canal. The detention facility on Roy St. will provide the required capacity for the State’s projects on the SR 99 Bored Tunnel and the Aurora Street Grid connections north of Denny Way, thus reducing the chance of overflows in our city’s waterways. You can find out more about the City’s Plan to protect Seattle’s Waterways on the Seattle Public Utilities website.

So, if you’re walking down Roy St. in the next few weeks, be sure to take a look at the progress! Businesses along Roy St. are still open. People walking can still use the south sidewalk on Roy St., but people driving and riding bicycles are detoured south to Mercer St. This work is expected to wrap up in early November, and is one of the last closures for the Mercer Corridor Project.

For more details on protecting the areas waterways: