Water Quality Improvement Project
Skokomish River Basin:
Fecal Coliform Bacteria
The Skokomish River drains a basin of about 247 square miles.
It empties into Annas Bay in southern Hood Canal near Potlatch,
Washington. Major sub-basins include the North Fork Skokomish River (118
square miles), South Fork Skokomish River (104 square miles), and Vance
Creek (25 square miles).
The upper reaches of the Skokomish River lie
within the Olympic National Park. The North Fork basin includes Lake
Cushman, a reservoir maintained for hydroelectric power generation whose
shores include residential development. The basin is sparsely
populated and rural. The Skokomish Indian Reservation is located at the
mouth of the basin and contains low-density residential development.
Commercial and noncommercial agricultural activities occur in the lower
river valley and include cattle and other livestock culture, hay and
Christmas tree production, and some vegetable cropping. Silviculture on
U.S. Forest Service and privately-owned lands dominate the upper basins.
The Annas Bay estuary contains a rich shellfish resource that is used by
Tribal, commercial, and recreational harvesters. Recreational shellfish
beds are located within, and to the south of, Potlatch State Park.
Potlatch State Park is also a center of primary contact recreation,
being used by swimmers and scuba divers. The mainstem Skokomish River
and lower Vance Creek are also used by swimmers and waders during the
summer months. The Skokomish River valley provides important habitat to
a variety of terrestrial wildlife such as elk, deer, beaver, and
waterfowl. Wildlife, shellfish, and finfish are important cultural and
economic resources for the Tribe. The Skokomish River system provides
valuable habitat for important species of fish such as chinook, coho,
and chum salmon; steelhead; and various trout.
The lower Skokomish Valley has several streams crossing it, the
largest of which are Purdy Creek, Weaver Creek, and Hunter Creek.
Streams and springs in the valley contribute to several large wetland
areas, which drain to the mainstem of the Skokomish River mostly
downstream of Highway 101. The river then discharges to the tidal
estuary of Annas Bay and Hood Canal. Rainfall in the basin varies
from 75 inches per year near the mouth to 230 inches per year at the
crest of the Olympic Mountains near 6,000 ft. elevation. Winter
precipitation in the mountains, mainly in the form of snow, provides
runoff in the North and South Forks through the spring and early summer
months. The dry season runs from July into September, followed by an
October through March wet season in which more than 75% of the annual
precipitation occurs. The courses of these streams seem to have changed
over the years due to flood activity, wetland dynamics, and human
Innovative partnerships have been formed to preserve and protect this watershed. See video “Coming Back: Restoring the Skokomish Watershed."
Water quality issues
Human activities altered the natural hydrologic regime in the entire
Skokomish basin. Sedimentation in the lower river channel due to
forestry, road building, dikes, levies, and other land use practices
have resulted in an increase in the frequency and intensity of flood
events, higher basin groundwater levels, and subsequent septic system
A study (TMDL) for fecal coliform bacteria (FC) for the Skokomish River
found that FC levels were not meeting fresh water
quality standards due to nonpoint source pollution. The study found that concentrations of fecal coliform bacteria
in the lower river valley exceed state water quality standards.
The 2000 study area included the south and north forks of the
Skokomish River, as well as Purdy Creek, Weaver Creek, Ten-Acre Creek,
Vance Creek and Hunter Creek. The Department of Ecology conducted the
study with the cooperation of the Skokomish Tribe, whose reservation
includes part of the watershed.
Why this matters
Fecal coliform bacteria are found in the waste of warm-blooded animals. They
are a major concern in the river because they indicate that people may be
exposed to a variety of harmful bacteria and viruses. In downstream Annas Bay,
too much bacteria may cause shellfish harvesting to be restricted or closed.
Status of the project
EPA approved the Total Maximum Daily Load (TMDL) submittal for fecal
coliform bacteria in 2001.
The submittal included a study of the water quality issues and
recommendations based on the results of the study. The submittal
also included a strategy on how to carry out the recommended actions in
Following the study, responsible agencies, the Tribe, and local
landowners developed a
implementation cleanup plan. That plan was completed in February
2003. Many actions have been taken to improve water quality. Monitoring
continues to measure progress towards cleanup goals.
In January 2005, Mason Conservation District began monitoring in the
Skokomish valley. The data was to be used to:
- Evaluate progress towards water quality goals.
- Help identify current source areas (after several years of
apparent improvement, bacteria concentrations suddenly began
increasing in the spring of 2004 – the data may help us to
- Help focus cleanup actions.
We identified four main sampling locations from the
2000 water quality
study. These are the places where bacteria concentrations need to be
reduced – Weaver, Purdy, and Ten Acre Creeks, and at the Highway 106
Bridge. The Conservation District monitored each of these stations, plus
one “background” station (called mid-Skokomish) that is located above
most of the development in the lower valley. Monitoring is planned every
two weeks through November 2006, totaling 46 sampling events. The
Conservation District monitored according to a
Project Plan developed by the Department of Ecology.
Unless otherwise specified, the following documents are Ecology publications.
Washington: Skokomish River - Watershed-scale Effort Removes Bacteria
Sources (EPA web site)
Cleaning up bacteria in the Skokomish Watershed Newsletter:
Skokomish River TMDL
Cleans Up Bacteria (Ecology water
Section 319 - Nonpoint Source Program Success Story:
Watershed-scale Effort Removes Bacteria Sources (EPA)
Weaver Creek (Mason County) Fecal Coliform
Attainment Monitoring (Ecology publication)
WRIA 16: Skokomish-Dosewallips Watershed Information (Water web site)
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