Update on the City of Seattle Stormwater Regulations

Prepared by Christie Coxley, with additional materials from City of Seattle

The stormwater code is designed to protect people, property, and the environment by controlling how rainwater runs off of streets, buildings, and parking lots. Stormwater runoff can cause flooding, landslides, and erosion, which in turn can damage homes, businesses, and property. It also carries oil and grease, fertilizers, pesticides and other toxic chemicals to creeks, lakes, bays, rivers and other waterways.

Some examples of storm water mitigation techniques. Some examples of storm water mitigation techniques.
Image Courtesy of the City of Seattle

Cistern system overflow into raingarden. Cistern system overflow into raingarden.
Image Courtesy of C2 Urban Garden Design

Raingarden captures runoff from driveway and hardscaping. Raingarden captures runoff from driveway and hardscaping.
Image Courtesy of C2 Urban Garden Design

Front yard bioswale garden. Front yard bioswale garden.
Image Courtesy of C2 Urban Garden Design

Raingarden and overflow facility captures stormwater from public sidewalk. Raingarden and overflow facility captures stormwater from public sidewalk.
Photo Courtesy of the City of Seattle
Most APLDWA members practicing in Seattle, and other Western Washington jurisdictions, will be affected by new regulations on single-family and small multi-family projects. As these new codes are implemented in Western Washington over the next several years, APLDWA members are encouraged to seek out training opportunities on stormwater management and LID techniques in order to stay abreast of the current technology and requirements.

For example, in Seattle, some type of stormwater management technique will soon be required for any new single-family residential construction [or remodel] of over 2,000 square feet of impervious surface. There will be a stepped checklist of preferred remediations. The following methods of onsite stormwater management must be evaluated for feasibility in order by category. Category One includes: 1] full dispersion, 2] infiltration trenches, and 3] dry wells. If none of these is feasible then the next category must be evaluated, and so on through the four categories (total of 17 options).

Municipalities that collect stormwater runoff in municipal storm sewers and discharge it to surface waters must have a permit under the Federal Clean Water Act. The City of Seattle is updating its current Stormwater regulations, as mandated by Federal Law to meet the standards of the Department of Ecology’s (DOE’s) 2012 Stormwater Management Manual. The City is revising the format and language of its regulations to conform to that of the DOE manual. The new codes will be evaluated by the DOE for minimum compliance, and will address the following topics:

  • Improve stormwater management for new development in Seattle, including Green Stormwater Infrastructure
  • Improve Construction Site Stormwater Runoff Controls requirements
  • Clarify Pollution Prevention, Good Housekeeping, and Operation and Maintenance
  • Update the Source Control and Water Quality Treatment Practices
The City is now in an informal comment period on the initial draft. After this informal comment period closes at the end of July, the City will revise the initial draft and submit it to the DOE. After its review the final drafts will be available for formal public comment, anticipated in the winter of 2015.

Members of the Advocacy Committee have attended informal presentation and feedback-gathering meetings hosted by the City of Seattle. We are monitoring Seattle’s process and providing feedback when necessary. And, Vanessa Gardner Nagel, APLD, has been attending pubic hearings and providing feedback for over a year on the process in Cowlitz County.

Stormwater management is a hot topic in many regions of the nation (Midwest, California and Eastern seaboard) and in other areas in Washington State. It will continue to impact our designs—whether mandated by code or by us as we create designs that result in more sustainable landscapes. I encourage members who encounter an unfamiliar code pertaining to stormwater to inform the Advocacy Committee so that we can continue to monitor changes throughout the region.

The website for Seattle’s update is http://www.seattle.gov/dpd/codesrules/changestocode/stormwatercode/whatwhy.

 

Why become a member?
Watch this short video

Why be certified? If you’ve ever wondered, watch this excellent video, authored and produced by Pat Wagner, APLD, member California Chapter of APLD.

Contact Barbara Lycett, APLD at blycettlandscapes@gmail.com. Or call her at 206-784-2521 to discuss how you can become certified.

Advantages of Joining

  • Become part of a professional network
  • Quality continued education
  • International Design Conferences
  • Be creative at the Northwest Flower & Garden Show
  • Visibility
  • Design Professionalism
  • Certification
  • Legislative advocacy
click here to read more...

Contact us today at contactus@apldwa.org for more info.


Top

Why become a member?
Watch this short video

Why be certified? If you’ve ever wondered, watch this excellent video, authored and produced by Pat Wagner, APLD, member California Chapter of APLD.

Contact Barbara Lycett, APLD at blycettlandscapes@gmail.com. Or call her at 206-784-2521 to discuss how you can become certified.

Advantages of Joining

  • Become part of a professional network
  • Quality continued education
  • International Design Conferences
  • Be creative at the Northwest Flower & Garden Show
  • Visibility
  • Design Professionalism
  • Certification
  • Legislative advocacy
click here to read more...

Contact us today at contactus@apldwa.org for more info.