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Waterbody Names Green River
Newaukum Creek
Soos CreekWRIA 9 County King Parameters Dissolved Oxygen
TemperatureCurrent Status TMDLs under development TMDL Approval Date --- # of TMDLs --- TMDL Lead(s) Sinang H. Lee
Located in western Washington State, the Green River basin drains about 484 square miles of land area and includes portions of King County and the cities of Auburn, Black Diamond, Covington, Enumclaw, Kent, Maple Valley, Renton, Sea-Tac, and Tukwila. The Green River flows for over 93 miles from the Cascade Mountains to Elliott Bay.
The TMDL study focuses on the Middle-Lower Green River which flows about 54 miles from the outlet of the Howard Hanson Dam to the confluence with the Duwamish Waterway at river mile 11 in the City of Tukwila. Land use in the study area varies considerably from a mix of residential, commercial forestry and agricultural land uses around the Middle Green River, to residential, industrial, and commercial land uses near the Lower Green River.
Major streams draining to the Green River include Newaukum, Soos, Springbrook, and Mill Creeks. Newaukum Creek and Soos Creek are the two major subbasins targeted for their own TMDL studies on temperature and dissolved oxygen. Newaukum Creek runs about 14 miles from its headwaters (3,000 ft above sea level) to the confluence with the Green River near river mile 40.7 (elevation of 180 ft). The Soos Creek System consists of mainstem Big Soos Creek and the major tributaries: Soosette, Jenkins, Covington, and Little Soos Creeks.
Warm Temperatures and Low Oxygen in the Water
Portions of the Green River, Newaukum Creek, and Soos Creek System exhibit unhealthy temperature and oxygen conditions that cause them to fail Washington State water quality standards. Fish breathe oxygen in the water (dissolved oxygen). Cooler water holds more oxygen. Warmer water results in less oxygen for fish and other aquatic organisms. When water has too little oxygen or is too warm, local fish can face thermal stress and harm. These streams serve as important migration corridors and spawning and rearing areas for several salmon species, including Puget Sound Chinook, bull trout, coho, chum, pink, sockeye, kokanee, steelhead/rainbow, and cutthroat trout. These species all need cold waters for optimum health during various stages of their lives.
To address the water quality issues, in 2006 Ecology initiated the Water Quality Improvement (TMDL) Projects for temperature and dissolved oxygen in Green River and Newaukum Creek. Ecology, King County, and others cooperated in a summer field study to collect data for the temperature and dissolved oxygen TMDL studies. In 2007, Ecology and its local partners initiated a similar effort for the Soos Creek System which includes Covington, Jenkins, Big Soos, Little Soos, and Soosette Creeks.
As part of the TMDL study, Ecology identifies the pollution problems and specifies how much pollution needs to be reduced to achieve clean water. As a follow-up to the TMDL study, Ecology works with the local community to prepare a Water Quality Implementation Plan (WQIP) that details the specific actions needed to improve water quality in the basin. The plan describes management roles, activities, and schedules for partners.
Many local partners are involved in this effort, including the Muckleshoot Indian Tribe; King County; U.S. Army Corps of Engineers; State Department of Agriculture; Tacoma Public Utilities; and the Cities of Auburn, Black Diamond, Kent, Tukwila, Renton, Covington, Maple Valley, Enumclaw, and others. Most importantly, volunteer groups, such as Middle Green River Coalition and Midsound Fisheries Enhancement Group, watershed residents, and local businesses play important roles as well in improving water quality.
Green River and Newaukum Creek TMDL Project Timeline:
| Spring 2006 | Ecology initiated TMDL studies in the Green River and Newaukum Creek. |
| June - September 2006 | Ecology, King County Department of Natural Resources, and others participated in a cooperative effort to collect field water quality data in the Green River and Newaukum Creek. |
| Winter 2007 - Spring 2008 | Ecology, with assistance from King County, developed computer models to simulate water quality conditions of the Green River and Newaukum Creek. |
| July 31, 2008 |
MeetingEcology shared updates on the modeling of the Green River and Newaukum Creek. |
Soos Creek System TMDL Project Timeline:
| July 2007 | Ecology initiated TMDL study in the Soos Creek System sub-basin. |
| July to September 2007 | Ecology, King County Department of Natural Resources, and others participated in a cooperative effort to collect field water quality data in the Soos Creek System. Data Summary Report underway. |
| January 21, 2009 | Ecology held a TMDL advisory meeting. They reviewed the summary of water quality data collected in the Soos Creek System during summer 2007 and obtain local input. |
Quality Assurance Project Plan for the Temperature and Dissolved Oxygen TMDL
in the Green River and Newaukum Creek (Ecology Publication)
www.ecy.wa.gov/biblio/0603110.html
Green River and Newaukum Creek Temperature and Dissolved Oxygen Total Maximum
Daily Load Study: Data Summary Report (Ecology Publication)
www.ecy.wa.gov/biblio/0703001.html
Soos Creek Watershed Temperature and Dissolved Oxygen Total Maximum Daily Load Study Sampling and Analysis Plan
http://your.kingcounty.gov/dnrp/library/2009/kcr2022/SAP.pdf
Focus on Soos Creek Watershed
(Ecology Publication)
www.ecy.wa.gov/biblio/0910003.html
Focus on temperature and dissolved oxygen in the Green River and Newaukum
Creek (Ecology Publication)
www.ecy.wa.gov/biblio/0610061.html
Overview of Ecology's TMDL process
www.ecy.wa.gov/programs/wq/tmdl/overview.html
WRIA 9: Duwamish-Green Watershed Information (Environmental Assessment
Program website)
www.ecy.wa.gov/apps/watersheds/wriapages/09.html
Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.html.
