Water Quality Improvement Project
Pipers Creek Area:
Fecal Coliform

Pipers Creek, Washington State.  Photo courtesy of Blue Canon, Wikipedia.


Pipers Creek is a 1.4-mile long urban stream located in Seattle, Washington. Most of the creek is contained within the boundaries of Carkeek Park, and empties into Puget Sound. Upper tributaries to the creek are located in residential neighborhoods of Seattle and include Venema and Mohlendorph creeks.

Water quality issues

Pipers Creek was found to be impaired with fecal coliform bacteria. Monitoring showed that the potential sources of bacterial contamination to the creek are typical of urban watersheds in the area. They were identified as pet wastes; combined sewer overflows at the treatment facility and North Beach Pump Station; leaking sewer pipes; failing septic tank systems; and a local duck pond.

Status of the project

Ecology, along with local citizens, agencies, and special interest groups, developed a total maximum daily load (TMDL) that detailed the sources of the fecal coliform bacteria, and contained a plan to reduce the fecal coliform inputs into Pipers Creek. The Environmental Protection Agency (EPA) approved the TMDL in March 1993.

A watershed action plan was developed for Pipers Creek. Its purpose was to formulate a coordinated program of effective actions to prevent and decrease nonpoint source pollution in the watershed. It detailed activities aimed at public education; improving the regulatory program; the operations and maintenance program; and the public works program. Difficulties in dealing with nonpoint source pollution resulted in public education as an early implementation element from the Watershed Action Plan.

In June 2003, Ecology published the results of effectiveness monitoring done on Pipers Creek. The TMDL required that adequate monitoring be conducted to assess progress in achieving both the TMDL and Watershed Action Plan’s goals. Water quality sampling was conducted bi-weekly or monthly by both City of Seattle and King County in the Pipers Creek watershed from 1993 to the present. The data indicated that fecal coliform concentrations continue to exceed both parts of the water quality criterion at all Pipers Creek sites.

Ecology currently funds the Venema Natural Drainage System project with Seattle Public Utilities (SPU). The project is located in the upper Venema Creek basin in a dense urban neighborhood in North Seattle, tributary to Piper’s Creek. Both Venema and Piper’s Creek are impacted by high stormwater flows, and Venema Creek is particularly sensitive to stormwater impacts due to its underlying geology and lack of grade controls. Both creeks are 303(d) listed for fecal coliform bacteria. Seattle will construct a series of bioretention and conveyance swales with underlying pipes, and use underground injection control for some stormwater. The project will provide flow control and water quality treatment for the approximately 81-acre Venema Creek basin draining to Venema Creek by 2015, meeting water quality goals of 80% total suspended solids removal and 78% annual runoff volume reduction.

Technical information

Pipers Creek Fecal Coliform Bacteria Total Maximum Daily Load (Ecology publication)

Effectiveness Monitoring for Fecal Coliform Total Maximum Daily Loads in Pipers Creek (Ecology publication)

Related information

WRIA 8: Cedar-Sammamish-Lake Washington Watershed Information (Environmental Assessment Program website)

Back to top of page

Last updated March 2012
  Water resource inventory area (WRIA) 8 map, Washington State.


WRIA: #8 (Cedar-Sammamish)

Water-body Names:
Pipers Creek

Fecal Coliform

# of TMDLs:
Fecal Coliform - 1

TMDL approved by EPA

Contact Info:
Joan Nolan
Phone: 425-649-4425
Email: Joan.Nolan@ecy.wa.gov

Northwest Region
Department of Ecology
3190 160th Ave. SE
Bellevue, WA 98008-5452