|Green Streets Plan, Portland OR|
Stormwater seems like a pretty banal issue but it's actually very important in cities because they contain a lot of impervious, impermeable surfaces (i.e. streets). When it rains, the water runs off, collects and needs to be drained into our storm sewer system which then leads to our waterways (streams, rivers, etc.). Stormwater can pick up pollutants, dirt, and other contaminants and it can also cause flooding and erosion which destroys habitat and contributes to combined sewer overflows (CSOs).
In Portland, they've opted for a fantastic approach to these problems. They believe that:
Stormwater management systems that mimic nature by integrating stormwater into building and site development can reduce the damaging effects of urbanization on rivers and streams. Disconnecting the flow from storm sewers and directing runoff to natural systems like landscaped planters, swales and rain gardens or implementing an ecoroof reduces and filters stormwater runoff. [City of Portland, Sustainable Stormwater Management]Portland defines a 'Green Street' as one that uses these measures. In all, their comprehensive Green Street strategy aims to:
- Reduce polluted stormwater entering Portland’s rivers and streams;
- Improve pedestrian and bicycle safety;
- Divert stormwater from the sewer system and reduce basement flooding, sewer backups and combined sewer overflows (CSOs) to the Willamette River;
- Reduce impervious surface so stormwater can infiltrate to recharge groundwater and surface water;
- Increase urban green space;
- Improve air quality and reduce air temperatures;
- Reduce demand on the city’s sewer collection system and the cost of constructing expensive pipe systems;
- Address requirements of federal and state regulations to protect public health and restore and protect watershed health; and
- Increase opportunities for industry professionals [City of Portland, Green Streets]
|A typical greenstreet facility in Portland, Oregon. This one compines a stormwater treatment facility with a bulbout to reduce pedestrian crossing distances. Photos: Portland BES.|
|This facility treats the cascade that used to come off Mt. Tabor during a strong storm. It also rationalized a difficult intersection and shortened pedestrian crossing distance by more than 50 feet.|
|SE Clay Street, Portland @ Portland Online|
You can read the Water Environment Research Foundation's (WERF) case study on Portland here.
According to the WERF case study, Portland staff emphasized that that right-of-ways are already within a city's authority which makes Green Streets projects fairly easy to implement. However, planners should still consult with stakeholders (homeowners, businesses) about their aesthetic preferences and expectations to ensure community acceptance.
Also, they stress that:
a successful sustainable stormwater program requires a multi-disciplinary approach that involves landscape architects, engineers, planners, reviewers, department heads, and watershed managers.They knew they needed the participation of all these groups in discussions and planning for individual projects as well as Citywide initiatives. This type of collaboration can also bring more resources to the table where funding for a project or initiative might be limited. [WERF, Portland Case Study]There wasn't too much about this on the City of Vancouver website but I did manage to find this. It doesn't seem to as much a priority or practice as it is in Portland. Vancouver, like Portland, receives its fair share of rain and I'd like to see these gems all over the place.