BikePortland

SW infra update: Capitol Hwy stormwater basin, Bertha Blvd updates, and progress on Red Electric bridge!


The SW 42nd St Stormwater Basin. It has three chambers with sediment basin on the right, and outflow to the left.

I have been wanting to learn more about stormwater management, keeping an eye on the progress of one of the four stormwater detention and treatment basins that are being built for the SW Capitol Highway project seemed like a fun way to do it. So let’s go!

The 42nd/Woods Creek Stormwater Facility is off of SW Alice St, at the end of 42nd Ave. It is the lower left basin in the illustration below.

Illustrations of the four stormwater detention and treatment facilities required by the SW Capitol Highway project. (Source: PBOT presentation)

The water will flow from this basin into Woods Creek, downhill from the facility (below, right photo).

Bulldozing the structured pit for the basin.

Newly constructed footbridge over Woods Creek.

I took the photos above on September 26. When I returned three days later, there was a crane on site installing the pre-formed concrete walls of the basin.

Each wall has a weir which drains the sediment and gunk-free water into the lower chamber.

Streets are dirty, and the stormwater that runs off them carries pollutants generated by cars. The purpose of the basin is to filter that water, and to manage its flow.

The final chamber drains out to Woods Creek through the pipe in the corner. It is mounted into a silo with a catch basin on top.

A foreman explained to me that the basin is divided into four chambers, the stormwater runoff from Capitol Highway will enter the first chamber, the sediment forebay, where most of the sediment will fall to the bottom. The progressively cleaner water spills over the weirs into the next lower chamber. The sediment forebay is serviced to clean out accumulating gunk.

The cleaned water exits at bottom through the pipe in the lowest chamber. It is mounted on a catch basin which collects any debris which accumulates near the facility site.

According to the bi-weekly Capitol Highway project update, “The 42nd/Woods Creek stormwater facility and surrounding land will get “buttoned up” over the next two to three weeks, with installation of soil and drainage features, hyrdroseeding of bare dirt, restoration of adjacent disturbed property, and opening of the replaced Alice Trail bridge.”

I don’t know how the top of this basin will be finished. Does it get a cover of some sort? Will it look like a pond, or get plantings? We will know in a couple of weeks.

Bertha and SW and Beaverton-Hillsdale Hwy

A couple of commenters alerted me to further work that happened at this location over the weekend. Since BikePortland last reported on it, PBOT has installed curbs and candles on the buffer between right-turning cars and the eastbound bike lane. The project still awaits its final feature, a bicycle sensor which will trigger a signal. Across the highway, PBOT is installing concrete curbs to protect the westbound bike lane.

The buffer at intersection of SW Bertha Blvd and Beaveron-Hillsdale Hwy has new curbs and candles.

The Red Electric Trail Bridge

And since I was in the area … the platform of the Red Electric Trail bridge waiting to be set atop the pillars in the gulch.

Lisa Caballero

That’s all folks!

— Lisa Caballero, lisacaballero853@gmail.com
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