Update 12th Ave NW Basin Drainage Improvement Project

Dear neighbors,

This is an update on the 12^th Ave NW Basin Drainage Improvement project. Last November, we held a drop-in session in your community to present natural drainage system concepts that we were considering and the feasible blocks where they could be located. We received a lot of thoughtful feedback at that event and would like to thank everyone for their input!

Since November, we’ve been doing several things to narrow down the blocks we’re considering for natural drainage systems, such as:

• Listening to community preferences and concerns regarding natural drainage system locations.
• Conducting hydraulic modeling to figure out the amount of natural drainage systems we need to meet our project goals.
• Looking into where we can design and construct natural drainage systems cost-efficiently.
• Evaluating the impacts to existing underground utilities (such as gas lines or water mains) to ensure we protect existing infrastructure.

Based on the above considerations, we’re proposing to narrow down the potential blocks for natural drainage systems to:

• The southside NW 127^th St between 1^st Ave NW and 3^rd Ave NW
• 1^st Ave NW between NW 127 St and NW 130^th St near the intersections
• The northside NW 130^th St between 1^st Ave NW and 3^rd Ave NW

See graphic for details.

Important things to keep in mind at this point in the siting process

• Natural drainage systems will be located on one side of each block, but the opposite side of the block may require some improving as well, such as a thickened edge or berm to help convey stormwater into the natural drainage systems.
• Natural drainage systems will be located along specific sections of the block.

What are our next steps?

We’ll be hosting an open house on Nov. 7 to present the block proposal, answer questions and seek community feedback. We’ll also share an update on the current design of the new underground drainage pipes that will be located farther south in the basin.

When: 5:30 – 7 pm on Thursday, Nov. 7

Where: Broadview Community United Church of Christ, 325 N 125^th St, Seattle, WA 98133

Format: This will be a drop-in style open house with no formal presentation. Stop by any time to visit with the project team.

If you have questions or comments in the meantime, please don’t hesitate to reach out to the project team by emailing SPU_BroadviewProjects@seattle.gov or calling 206-233-1534.

Grace Manzano

Project Manager

Project Delivery & Engineering Branch | Seattle Public Utilities

700 Fifth Avenue, Suite 4500

PO Box 34018 | Seattle, WA 98124

Tel: (206) 233-1534 | Email: grace.manzano@seattle.gov