New Bridge Over Creek Open; Students A No Show

P9020659The new pedestrian bridge over Thornton Creek at the Knickerbocker Natural Area (20th Avenue NE) was open for business this morning but no students heading towards Sacajawea Elementary School turned up. As construction crews paused for an hour for the scheduled 8 AM – 9 AM opening, with a flagger standing by, the first people to use the new 85 foot bridge instead were three dog walkers.

The bridge will reopen this afternoon between 2:45 and 3:30 PM when school lets out. Even if you aren’t a student, this is an excellent chance to get a close-up view of the work that continues to be done to the creek.

Last night’s huge rainstorm left standing water around the construction area which was still cleaning up after Monday’s storm. But things were expected to get back on schedule within a day.

The bridge will continue to be open weekday mornings between 8 – 9 AM and again in the afternoons 2:45 – 3:30 PM until the project is completed sometime in October.

Knickerbocker Project Brings More Truck Traffic

The Knickerbocker Floodplains Project off NE 100th Street will be bringing more truck traffic to the neighborhood in the next few weeks. Construction began last week on the project which so far has cleared the land in preparation for the relocation of Thornton Creek (see photo comparing the site over the past four weeks):
Knickerbocker02

In an e-mail to residents Seattle Public Utilities (SPU) said,

We’ve heard concerns about truck traffic in the neighborhood. Because of the nature of the neighborhood streets, our contractor carefully considered pedestrian and traffic safety when they chose a route for trucks to enter and exit the site. All delivery trucks larger than a pickup will follow the directions below.

-Exit I-5 Northgate Way and travel East on NE Northgate Way
-Turn right going South on 23rd Ave NE.
-Turn right going West on NE 102nd St.
-Turn left going South on 21st Ave NE
-Turn left [sic] going East on NE 100th St.
-Back down into site.

We have implemented the following safety procedures for all truck deliveries:
• All deliveries are required to call Project Superintendent 10-15 minutes before entering the neighborhood.
• The contractor will provide flaggers throughout the route for all semi-tractor trailer trucks.
• The contractor will place “No Parking” signs 24 hours in advance for semi-tractor trailer truck deliveries.
• Flaggers and drivers will not allow truck staging or idling on 21st Ave NE.

Why they don’t just go down Lake City Way and then straight up NE 100th Street from Summa is a mystery. It would be a much shorter and direct route rather than through the entire neighborhood. I guess that’s “carefully considered” for you (or a cheap-ass Google Maps route search).

As for the project itself:

Anticipated work during the week ahead
The contractor will:
• Prepare equipment that will divert the creek through flexible pipes while they construct the new creek bed and floodplain.
• Remove the steel frame of the current pedestrian bridge.
• Begin work in the creek July 1 and continue through the fish window.

If you would like to receive e-mail updates about the project from SPU, subscribe to this listserve.

Knickerbocker Floodplain Work Begins July 1st

The Knickerbocker Natural Area as seen in May 2014. In three months time, it will look much different.

The Knickerbocker Natural Area as seen in May 2014. In three months time, it will look much different.

Construction work on the long-planned Knickerbocker Floodplain Restoration Project will begin in July on Thornton Creek. Last night at the Knickerbocker Natural Area (NE 100th Street and 20th Avenue NE), staff at Seattle Public Utilities (SPU) and the Parks Department met with neighbors to update them on the work. The project will relocate about 600 feet of Thornton Creek, create a 1.5 acre vegetated floodplain, and upgrade the pedestrian bridge over the creek. The new floodplain will store more water, wood, and sediment during storms and provide benefits to properties further down the creek (e.g. less flooding). It will also improve the habitat for fish and wildlife in the creek.

Related: Knickerbocker Restoration Would Be First In the NationKnickerbockerPlans

Some construction work will begin in June, while work in the creek will take place during July 1st and August 31st in an effort to protect fish populations. During that time, the creek will be diverted into two 12″ pipes, and the pedestrian path across the area will be closed for those two months. Once the new 80 foot bridge is installed, access will be reopened in time for the school year to begin.

The two and half million dollar project is a joint effort between the two Seattle departments (SPU & Parks) that have purchased parcels over the past several years. Some of the wetlands creation is being paid by Sound Transit as mitigation for construction at Northgate of the Link Light Rail station. After the contractors finish their work this summer, both departments will be responsible for maintaining the floodplain.

Just a mile east of Knickerbocker, another section of Thornton Creek is being updated when 35th Avenue NE is closed at Meadowbrook beginning Monday to install a larger bridge over the creek. The Seattle Times describes the project.

Visit the SPU website about the Knickerbocker project.

 

Knickerbocker Invasive Plant Removal To Start

Seattle Public Utilities announced that work is expected to begin this month to remove invasive plant species at the Knickerbocker Floodplain Reconnection site (aka Thornton Creek at the bottom of 20th Avenue NE at NE 100th Street). The Seattle-based non-profit group EarthCorps will be performing this work.  It will include both physical removal and treatment with an “eco-friendly” herbicide application, which will be reapplied in the spring.

Related: Knickerbocker Restoration Would Be First In The Nation
Related: Knickerbocker Site History

Actual reconstruction of the upland areas in now scheduled to begin in early June of 2014.  The work in the creek itself, the “floodplain reconnection” portion, can only be done during the “fish window” of July 1 – August 30, as determined by Washington State Department of Fish & Wildlife. Visit the SPU Kickerbocker site for more information.

Knickerbocker Restoration Moved To 2014

KnickerbockerThe Seattle Public Utility (SPU) project to restore the Knickerbocker site of Thornton Creek (at the foot of 20th Avenue NE at NE 100th Street) has been rescheduled to  May 2014.

SPU announced in a letter to residents that,

Construction is planned to begin in late May of 2014 and be complete by October, 2014. City contractors will be on site early this summer to begin preparation for construction next year. They will treat and remove some invasive weeds to reduce re-growth following construction…. Crews will be making follow-up trips to the site in fall of 2013 and next spring.

Related: Knickerbocker Restoration Would Be First In The Nation
Related: Knickerbocker Site History

Originally the project had been announced to be done during summer 2013 but SPU is still working to obtain the completed environmental and building permits by late summer/early fall. Due to impact on fish and foot traffic during the school year, it can only be worked on during the summer months.

In addition, cedar trees in the north end of the project site will be removed, despite requests from the community that they be relocated. The city couldn’t afford to do so because of poor access and the low feasibility of their survival. But they wanted to note:

The project will incorporate the removed trees into the project design as in-stream structure, and more than 500 trees will be planted on the project site, including 265 cedar trees.

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Knickerbocker Site History

floodplain1960

Knickerbocker Floodplain site circa 1960. Photo courtesy Jay Amena.

Seattle Public Utilities (SPU) has created a page detailing the history of the Knickerbocker Floodplain site (aka Thornton Creek at NE 100th Street and 20th Avenue NE).  Resident Jay Amena has provided a number of historic photographs that show the houses that once existed on NE 100th, the soon-to-be site of the Floodplain Restoration Project that begins works this summer.

Related articles: Knickerbocker Restoration Would be First In The Nation

SPU Outlines Knickerbocker Project Status

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The River Wild

After a weekend of solid rain, Thornton Creek swelled to nearly overflow its banks at the Knickerbocker site (20th Avenue NE) as seen here at 9 AM on Monday, November 19th. The Floodplain project (see previous article here) to be done next summer will lessen the effects of torrential rain by storing the water and slowing the creek.

 

 

 

Watch a YouTube video:

Knickerbocker Restoration Would be “First In The Nation”

Mike “Rocky” Mrachovec of SPU outlined the Knickerbocker Floodplain project Thursday.

The Knickerbocker Floodplain Project on Thornton Creek will include innovative subsurface restoration techniques that would be the first of its kind in the nation and part of a studied, living laboratory, according to Mike Hrachovec of Seattle Public Utilities (SPU).  Mike, known to everyone as “Rocky,” is a SPU engineer who has been designing the floodplain restoration on and off for seven years as funding came in leaps and starts. He gave an enthusiastic talk Thursday night at Sacawajea Elementary School as part of SPU presentation for local residents about the project which is planned to begin construction next summer.

Nearly two dozen members of the public attended including the original Knickerbocker family the site is named after (they sold the first parcel to SPU and the Parks Department including their house just south of NE 100th which has since been demolished). Cheryl Eastberg with the Parks Department began the meeting by describing the history of the project and acquisitions of property around Thornton Creek including the Rossi property on the south side of Thornton Creek that was accessed via the wooden bridge at the end of NE 100th Street (which will be replaced by a rock ford once the project is done).

Katherine Lynch then talked about the funding that made the project happen. Although the city has been interested in creating the floodplain for the past seven years, funding had all but dried up two years ago just as plans had finally been developed. A grant from the King County Conservation District helped move the project forward, while the Thornton Creek Watershed Oversight Committee sought out further funding which finally came from the Washington State Department of Ecology, the EPA, and most importantly Sound Transit which kicked in for floodplain mitigation as part of its Northgate Light Rail station project.

The main goals of the Knickerbocker project are 1) improve instream and riparian habitat, 2) optimize floodplain storage and slow peak flows, and 3) serve as a demonstration project. “Rocky” then began describing the process of engineering which he called, “an incredibly complex design.” Using the area of the creek just west of NE 102nd as a model for what the Knickerbocker site should look like (though with more large wood), he said the city needed to correct what been engineering dogma throughout the 50s and 60s, namely taking out any large trees and installing retaining walls.  “We shattered the habitat in the process,” he said. The Knickerbocker project will rip out the rockeries and retaining walls, remove 9,000 yards of dirt and replace it with logs (mainly under the surface) and create a floodplain.  Restoration will not only occur on the surface (with indigenous plants and rerouting and widening the creek), but under the surface as well by rebuilding the entire subsurface, a first-in-the-nation effort.  He admitted it would be “a radical experiment in stream ecology,” and “we’re just making educated guesses,” but as part of an ongoing plan the area would be monitored and studied extensively with adjustments made where needed. If you would like to see an extensive 30-page technical drawing of the project, check out this pdf from the city.

Project manager Arnel Valmonte talked about scheduling. Right now the project is at “90% design.” If any changes are to be made, now is the time. They hope to finish the design work by May 2013 and have all the permitting done. The earliest they could begin is June 2013 and wrapped up by the end of October.  They need to work around the fish window giving them between July 1st and August 30th as the creek is diverted into pipes while the construction goes on. An 80 foot bridge will replace the current one over Thornton Creek (part of the 20th Ave NE walkway), and they are timing it not to interfere with the school year as many students use it to access Sacawajea from Victory Heights.

Contractors in theory work from 8 AM to 5 PM Monday through Friday but have the discretion to work past those hours and on weekends. Neighbors will be kept informed of activity if it impacts them. There will be noise and vibrations associated with the work, and the city will attempt to deal with problems with nearby residents.

Finally, Deb Hayden talked about the future of the site after construction is completed. “Our intention is to let the site grow naturally,” she said, but other than noxious weeds and invasive species being managed they want to remain hands-off. Sound Transit would assume responsibility for managing and maintaining the site (i.e. be paying the bills) for the first five years, after which it would be the domain of the Parks Department. “We’re open to feedback,” was the message.

Visit the City’s official Knickerbocker Floodplain website.

Knickerbocker Floodplain Project Meeting November 15

The next in a series of community meetings (read about the first here) about the Knickerbocker (Thornton Creek) Floodplain Project will be held Thursday, November 15th at Sacajawea Elementary School beginning at 6:30 PM. Seattle Public Utilities (SPU) and Seattle Parks & Recreation are restoring several hundred feet of the south branch of Thornton Creek at the downstream end of the Kingfisher Natural Area, now dubbed the Knickerbocker site (where the 20th Ave NE footpath crosses Thornton Creek just south of NE 100th Street). This project also will create a 1.5 acre vegetated flood plain and replace the pedestrian bridge across the creek.

SPU and Parks will review the project designs and timeline at this meeting, and invite you to express your concerns, ask questions and make suggestions. Visit their official website for more details.

Sacajawea Elementary School is located at 9501 20th Avenue NE, the meeting will be held in the school’s lunchroom between 6:30 PM and 8 PM.

SPU Outlines Knickerbocker Project Status

Click for larger image

Tuesday night, employees of Seattle Public Utilities (SPU) met with local residents to discuss the status of the Knickerbocker Floodplain Restoration Project at the site location (the walkway at 20th Ave NE and NE 100th Street). They outlined the funding, construction timeline, work, and goals of the project.

Contrary to what Sound Transit officials said last month, funding for the project is coming from a Capital Improvement Project grant of SPU that will be voted on in November 2012. Sound Transit’s interest is to increase the wetlands area as mitigation for the work at the Northgate Link Light Rail station, but the Knickerbocker project is not dependent on that money.

Construction would need to be done between July 1, 2013 and August 31st, 2013 due to impact to fish migration. During the work, Thornton Creek would be diverted into pipes via pumps (possibly generating some noise, although the possibility of using quieter electric pumps was mentioned). As can be seen in the map above, the channel of the creek would be moved slightly north with a much wider floodplain added to collect runoff during storms.The pedestrian bridge that is part of the 20th Ave NE walkway would be replaced by a larger prefabricated bridge 80 feet long and five feet wide just west of where the current one is located. The existing bridge at the west end of NE 100th Street would be replaced with a rock crossing similar to the one on the 17th Ave NE trail.

The main objectives of the project are flooding and fish (less of the former, more of the latter). The project is of scientific interest as well and will be studied to see if the Hyporheic Zone (an aquatic environment that exists within the stream bed sediment) can be improved in an urban area.  The test wells that were sunk last month were the first part of that study.

Invasive plants within the project zone (the dotted line on the map) such as ivy and blackberries would be removed and replaced by native plants and trees.  When completed, only two parking spots will be at the location. SPU was worried garbage trucks might lose their turn-around area but were reassured that those vehicles always back down the many dead-end streets of Victory Heights so they can easily access bins and then drive straight out.

Residents seemed mostly positive about the project, the only hesitation was about the name. Apparently “Knickerbocker” was a woman who owned part of the property for only a year, never built on it, and then sold to the city. SPU seemed amenable to a name change although there was no consensus on a better one. (For my money, I say keep it unique. If you do a search online or call up SPU and say “Knickerbocker” they instantly know what you are talking about; a more generic name runs the risk of obscurity. Feel free to discuss this in the comments section.)

Curiously, nobody at SPU has the least idea what was going on near the Les Schwab on Lake City Way on Tuesday as dozens of trees were removed on the south side of Thornton Creek by a large crane (a small bulldozer was also spotted on the north side across from Summa).

Further public meetings will be scheduled in the autumn to discuss the final design stages of the Knickerbocker Project. Stay tuned for announcements when it happens.