Shoreline's Green Street Project

Monday, December 6, 2010

by Janet Way, originally published in Of Paramount Importance
City Experiments with "Low Impact Development" Street Treatment Project

17th NE. Photo by Janet Way
On a small neighborhood street between NE 145th and NE 150th on 17th Ave NE, an extraordinary experiment is underway. This is the "Green Streets" project undertaken by Shoreline's Public Works and Surface Water and Environmental Services. 

Permeable Asphalt Pavement Medium 
creates new sidewalk
Photo by Janet Way
Green Streets is a Capital Improvement Project approved by the City Council in 2009, and implemented by the need to comply with the NPDES II (National Pollution Discharge Elimination  Standard) Permit required by the WA Department of Ecology.  

This permit allows municipalities to operate their drainage systems. The latest permit is providing a very high standard that now surpasses the stormwater requirements of DOE, because City Council approved this newest Stormwater Code in 2009.

It is partially inspired by the now well known SEA streets (Street Edge Alternative) project in Seattle's Greenwood Neighborhood. 

That original project was created in 2003, and has now achieved acclaim nationwide for its effectiveness in infiltrating stormwater, slowing traffic and providing an attractive neighborhood environment. 


These photos show 17th NE while the project was underway
Photos courtesy City of Shoreline

Now the Shoreline 17th Street Project is nearly completed. It features bioswales planted with native plantings in the Right of Way, "pervious" asphalt sidewalks and driveways, and an attractive "meandering" design which slows traffic. The pervious asphalt is underlain with a bed of prepared soil, as are the swales which absorb a large quantity of stormwater which would otherwise run quickly into the local stream. In this case it is Hamlin Creek, a tributary of Thornton Creek, which is already greatly stressed as an urban stream.  When the stormwater percolates into the ground in the bioswales or through the asphalt, it is cleaned naturally by the soils and plantings. 

Here are some before and after shots provided by the Surface Water Environmental Services.

17th NE before the project
Photo courtesy City of Shoreline
Street Edges shown before the project.
Photo courtesy City of Shoreline
Planted swale next to sidewalk section before permeable asphalt applied.  Photo courtesy City of Shoreline

One feature of the project was that some of the existing trees have been preserved, though some were too impacted to be saved. The City met frequently with the neighborhood to address their concerns. 

This huge Madrone tree was protected and reserved next to the sidewalk. It had previously had a circular bed surrounding it that covered part of the trunk. Hopefully now it has more breathing room .
Photo by Janet Way

One neighbor I spoke to said she was happy with the sidewalks and the fact that traffic is now lessened and slowed down, but she was surprised how much of the area she'd thought was her yard was impacted. She also said she felt the project came out much differently than she'd expected. But, she also said that the stormwater DOES seem to be infiltrating well into the pavement and swales

Section of 17th NE project adjacent to the VFW Hall. This sidewalk appears to be the typical concrete material.
Photo by Janet Way

Here's hoping that this magnificent Madrone which is watching over the project will thrive and the neighbors will as well! We look forward to the completion and the plantings growing into their true potential to do their "water quality work".

Giant Madrone on 17th NE
Photo by Janet Way

11 comments:

Anonymous,  December 7, 2010 at 8:11 AM  

I live on one of these streets. The new sidewalk is a nice touch and was needed (I walk 17th NE daily, the concrete section of the sidewalk by the VFW hall was there prior to the project). But I'm also a driver and for drivers what this has done is to constrict 17th Ave NE into a one lane street. If the purpose of this project was to make driving to my house into a difficult obstacle course and to deter me from driving in the first place I say mission accomplished.

Janet Way December 7, 2010 at 10:03 AM  

Hello,
As the author of this article I just wanted to respond.

As I stated above, folks do seem to like the sidewalk and the "permeable" pavement which is slowing runoff onto driveways and other problems. There does seem to be a concern with less parking space. But, there also seems to be appreciation of the slowdown of cut-thru traffic, etc.

As one who approved this project on the Council at the time, I can say that there was not a specific desire to prevent anyone from driving, who lives there, but encouraging walking on sidewalks....for sure that was a goal.

It is definitely a multi-purpose type of project. More neighborhood walking, slower traffic and especially drainage benefits.

I hope folks in the neighborhood will find the street more beneficial as it is completed and the plants enhance the overall feeling.

Your neighborhood is contributing a great benefit to the larger City and watershed, and I really appreciate it!

Best Wishes!

Janet Way

Travis December 7, 2010 at 10:14 AM  

The pictures of the trees called Madrone don't look like Madrone to me.

Anonymous,  December 7, 2010 at 10:23 AM  

It IS a giant Madrone tree. There are several in that neighborhood.

Anonymous,  December 7, 2010 at 1:13 PM  

Hi Janet,
The sidewalks, permeable or otherwise, are needed and a nice addition to my neighborhood. But cutting the width of 17th NE to only one lane (not one in each direction) in strategic pinch points strikes me as urban planning run amok.

Janet Way December 7, 2010 at 1:38 PM  

Dear Anonymous,
Just my understanding of the process.... the ROW (Right of Way), which is publicly owned, is the area they could work with. In order to install the sidewalk and swales and get the most out of the LID drainage concept, they needed to use a "flexible" meandering design. This provides other benefits. The "pinch points" you mention were not an end in themselves but are a traffic moderating concept. The traffic curves and meanders provide that flexible design to fit in the swales. This was the reason for funding the project.

While some people would prefer "nothing in there way" and want to zip through there faster, that is a family and pedestrian neighborhood, which needs some protections from speeders and opportunists who want to cut through.

If the City wanted to simply put in a sidewalk, it would have been cheaper, but there is no more capital funding available now for just sidewalks. By addressing the drainage issue the City was able to get a sidewalk project done AND meet the drainage objectives.

So, I hope that answers some of your concerns.

Anonymous,  December 7, 2010 at 8:34 PM  

I wish Lake Forest Park would build some sidewalks. The traffic cameras don't help much when the kids have to walk in the street since there aren't any sidewalks.

Anonymous,  December 8, 2010 at 2:46 PM  

As someone who frequently walks this neighborhood, I'm extremely happy with this project. It satisfies 3 needs: the need for sidewalks, the need for traffic calming, and the need for better management of surface water. This kind of design will probably take a period of adjustment for resident drivers, and we may have some lessons learned after this first project, but I hope we will have more projects like this in the city.

Wendy DiPeso,  December 8, 2010 at 2:56 PM  

There is a trade off at work here. If the road was kept straight it would make it easier for those living there to drive quickly,..but also increases cut through traffic.
Creating a meandering design might be felt as a hinderance to those living there when in a hurry to be elsewhere,..but it also means less traffic over all in the neighborhood and greater pedestrian safety.
The changes made to increase permeability will benefit everyone in reduced pollution running into the creeks, streams and Puget Sound. It also makes for a healthier tree canopy and is pleasing to the eye. If residents can plan ahead, be less in a hurry and enjoy the scenery as they walk or drive they will benefit the most from the change.

Chuck Dolan,  December 8, 2010 at 9:42 PM  

I ride my bike on this street and enjoy the sway of the curves and the slowing of the traffic.

I appreciate the drainage benefits! Hamlin Creek south of the street is a typical channelized urban creek. Most would call it that deep, dangerous ditch on the west side of 20th Avenue NE but it is an important tributary to the North Branch of Thornton Creek and the infiltration and slowed runoff for this project will help reduce the furious flows.

Anonymous,  December 22, 2010 at 7:20 PM  

The shoulder of the road is a hazard to public safety. Numerous vehicles have been swallowed by what was and currently still looks like a shoulder. Furthermore pedestrians and children playing will fall victim to the poor under footing causing injury. The environment is important and I believe in projects that are sustainable, however the city has failed to recognize that public safety and traffic are part of being sustainably responsible.

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