Sunday, May 10, 2009

SEAing Green Streets

Probably a case of green streets on the brain - but a current pro-bono project has inspired me do some looking back at a range of innovative stormwater projects using the street rights-of-way. One of the best is Seattle's SEA Street project. SEA stands for 'Street Edge Alternatives' and is part of the Natural Drainage Systems program - synonymous to green streets but regionally specific to the Seattle area. The interesting part of the project is the integrated nature of the streetscape, stormwater infrastructure, and residential character.

Check out some slides from a 'virtual tour' of the project for some info and visuals of this simple yet effective solution...

:: image via Seattle Public Utilities

From the tour text: "The drainage goals for this project include conveyance, flood control, and minimizing the flow of stormwater off-site. The project team sculpted the project area to move water away from the roadway and homes and into planted swales along both sides of the road."

:: image via Seattle Public Utilities

A series of additional images and text includes some details, including the residential landscape character, pollution reduction items, plantings, and maintenance. A big issue is the transportation aspects - which are definitely a challenge to engineering status quo... narrow, multi-modal, slow, and non-linear. The fact that the combination of factors for the this project was built, and is successful, is testament to the potential transferability to other locales.

And interesting to see if there have been other versions of this approach, particularly retrofit versions in a residential context. A final image shows the before and after shots...

:: image via Seattle Public Utilities

Stay tuned for another precedent study, the award-winning Pringle Creek Community in Salem, Oregon that uses curbless 'gravel verges' along the roadway to allow for soft, pervious edges - inspired by the work of Patrick Condon at UBC. Any other ideas of curbless, gravel verge streets incorporating stormwater and natural drainage that others know of, let me know.


  1. City of Vancouver (BC) did a similar project a few years back, but from what I understand costs ballooned somewhat and it's seen as a one-off. Pity, because it's a nice street.

    See for more...

  2. Very nice. I wonder what maintenance on a system like this is though. With any luck it can take care of its self.

  3. Thanks for the info Desmond... great to see some other examples - and the similarities with the Seattle project are telling.


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