Myrtle Reservoir retrofitting going out to bid, likely to start in fall

(West side of Myrtle Reservoir site, where work is likely to be staged)
By Tracy Record
West Seattle Blog editor

Nine months after Seattle Public Utilities discussed the earthquake-resistance retrofit needed for West Seattle Reservoir in Highland Park, we know what’s in store for our area’s other underground water facility, Myrtle Reservoir.

Myrtle was covered in 2008, West Seattle in 2010. Then in 2012, their designer, MWH, told the city about “possible seismic deficiencies” in their work – not potentially catastrophic, but not something that could be ignored, either. Analysis and testing ensued, and in June of last year, we reported on the retrofit/strengthening plan for WS Reservoir, interviewing reps from SPU and its consultants.

At the time, they didn’t know exactly what would need to be done to Myrtle Reservoir, a relatively small reservoir (5 million gallons) at the city’s highest point on the east side of the Gatewood neighborhood. Now they do.

We contacted SPU after spotting a bid-solicitation notice this past week for the work that’s ahead at Myrtle and at Maple Leaf in North Seattle, and have since spoken with project manager Stephanie Murphy, to find out what will be done and what Myrtle neighbors and users of the nearby park will see.

It’s not as extensive as the work that had to be done at the much-larger West Seattle Reservoir in Highland Park, but from above ground, it’ll be more noticeable, since there’s no other work ongoing at Myrtle, unlike the other reservoir, where park-building has been continuing.

SPU has stressed that even with the design flaw, the reservoirs were/are not in danger of failing during an earthquake – but, as Murphy said in the case of West Seattle, could have been at risk of “extensive leakage.” (Our report from last June contained a fair amount of technical detail, if you’re interested.)

Murphy explained that they’ll be adding more steel and concrete to reinforce one row of the underground columns in Myrtle, compared to two rows of reinforcement in the Highland Park reservoir plus extra concrete in its columns. The price tag for the Myrtle work is $700,000, less than a tenth of what SPU said last year that the West Seattle Reservoir work would cost (they were “collaborating” with the designer about covering that cost, given that it wouldn’t have been necessary if the design hadn’t been flawed).

What will neighbors and park users see when the work is under way?

You might not notice much from the surface aside from staging; Murphy said the work will be mostly on the west side, accessing from Willow to the north, going around the treatment building, and staging on the flat grassy area west of the reservoir. She says they won’t have to dig it up – the existing stairwell into the reservoir is what they’ll use for all types of access throughout the project, whether it’s dropping in materials or pouring the concrete. The construction trailer will be relatively small, Murphy expects, because the job will be managed from the Maple Leaf site.


Myrtle is packaged for bidding with Maple Leaf (which is projected to cost more than $5 million) because SPU expects the same contractor to do both jobs, one “cell” at a time – the Maple Leaf reservoir has two cells, Myrtle one, so after getting going on the first cell at Maple Leaf, the contractor would embark on the Myrtle work, and then return to Maple Leaf. So the Myrtle timeline is likely mid-October through January, according to Murphy, assuming Maple Leaf starts in June. The reservoir will be out of service for a few weeks before the work and a few weeks after, since they’ll have to drain and rinse it, but that doesn’t mean a change in water service – they’ll route the supply from somewhere else.

Bids are due April 1st, so we’ll find out sometime next month who will be handling the work.

2 Replies to "Myrtle Reservoir retrofitting going out to bid, likely to start in fall"

  • Pibal March 23, 2015 (11:06 am)

    So I guess the question to ask is: Why?

    Have design standards become more stringent or were there errors made by the design team?

    If the latter, how do we keep this from happening again?

  • Rick March 24, 2015 (9:14 am)

    Just how do you stop a revenue stream?

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