12th Ave. NW Drainage Improvement Project Update

Dear neighbor,

This is an update on the 12th Ave NW Basin Drainage Improvement project.

Natural drainage systems

Last October, we announced that we were proposing to narrow down the potential blocks for natural drainage systems to:

• The south side NW 127^th St between 1^st Ave NW and 3^rd Ave NW
• The west side of 1^st Ave NW between NW 127 St and NW 130^th St near the intersections
• The north side NW 130^th St between 1^st Ave NW and 3^rd Ave NW

Since then, our design time has been working on selecting the final proposed locations of natural drainage systems and new trees that will be installed as part of this project. See a map of the natural drainage systems and trees on our website.

The natural drainage systems are sited in areas where they will provide the biggest drainage benefit while still being cost-efficient. Additionally, the selected locations avoid existing underground utilities and other significant structures.

New trees may be planted inside the natural drainage systems and as stand-alone improvements. The tree locations avoid overhead utilities, maintain sightlines for pedestrians and drivers and allow trees to be clustered for ease of maintenance and tree health. You’ll also see areas of new lawn or sod that may or may not be accompanied by trees. These areas will provide additional drainage capacity. Lawn soaks up stormwater better than hardscape or gravel.

Please note:

• Every tree that is removed as part of this project will be replaced with two new trees. Trees that are marked for removal were either deemed hazardous, or we cannot safely construct around them.
• Maintenance of new natural drainage systems and street trees will be performed by the City. New lawn areas will be maintained by the City for the first three years of growth.

Looking ahead

• The project is moving toward 60% design. In addition to the natural drainage systems design, our project team continues to refine the design of the new drainage pipes that will be located further south in the neighborhood along NW 125th St, 10th Ave NW and 11th Ave NW. 
• Later this year, the team plans to issue our Washington State Environmental Policy Act (SEPA) Checklist. SEPA Checklists are used by agencies to evaluate and plan for any environmental impacts associated with a project. We’ll post the Checklist on our website so the community can review it.
• At this time, construction is anticipated to begin in mid-2021. We will update the community if there are any significant impacts to schedule.
• Additional outreach will be conducted closer to the start of construction, but we’re available to have one-on-one conversations (by phone, email or virtual meetings) with homeowners any time in the meantime to answer questions.

Direct replies to GovDelivery email messages will not be received by the project team. As always, if you have a question about the project, please feel free to contact us directly by emailing SPU_BroadviewProjects@seattle.gov. 

Best,

Broadview Project Team

Visit the project website