Water Quality Improvement Project
Wildcat Creek is a small stream within the Chehalis River Basin. The
stream is made up of three forks: the East, Middle and West forks. The
East Fork originates several miles northeast of McCleary, Washington,
entering Cloquallum Creek nine miles to the southwest. Wildcat Creek is
particularly significant to salmon fisheries, with chum and coho
utilizing the stream for spawning and rearing.
Water quality issues
In response to two significant fish kills in Wildcat Creek that occurred
in 1970, several water quality studies of Wildcat Creek near McCleary
found that improvements at the McCleary sewage treatment plant (STP) were
needed to improve water quality in Wildcat Creek. Improvements to the
STP were made in the 1980s, and a 1987 study to evaluate the effects of
the STP improvements established total maximum daily load (TMDL)
allocations for the STP, which were incorporated into their permit
limits. This TMDL set load and wasteload allocations for ammonia-N and
biological oxygen demand (BOD) in order to improve dissolved oxygen
levels in the creek.
The 1987 study concluded that the STP upgrade considerably improved water
quality in Wildcat Creek, despite a 50% decline in the creek stream
flows measured during the study, compared to the 1977 study period.
Ammonia (NH4+) is one measure of nitrogen, a nutrient that can
increase the growth of plants and algae in water. Large
concentrations of ammonia in a stream or lake can create a large oxygen
demand. This demand is caused by the conversion of ammonia to nitrate,
called "nitrification". High concentrations of nitrate in wastewater
treatment plant effluent can cause algae to grow in large quantities.
Dead and decaying algae can cause oxygen depletion problems, which in
turn can kill fish and other aquatic organisms in streams.
Higher-than-normal levels of nutrients in the water can lead to
changes in the water’s pH and clarity. In addition, increased algae and
plants can be ugly, create odor problems when they die and decompose, and
interfere with recreational activities like boating and swimming.
Biological Oxygen Demand (BOD) is the amount of oxygen required by
aerobic microorganisms (organisms that need oxygen to survive) to break down
organic matter in water. It can be used to measure the amount of water pollution
in a water body.
Allocations for fecal coliform bacteria were also established by this TMDL to
improve water quality in Wildcat Creek and protect people that recreate in and
around the creek. Fecal coliform is a type of “bacteria” common in human and animal
waste. It can make people sick and cause the closure of shellfish harvesting
beds. Bacteria can get into our waters from untreated or partially treated
discharges from wastewater treatment plants, from improperly functioning septic
systems, and from livestock, pets and wildlife.
People can help keep bacteria out of the water. Properly collect, bag, and
trash dog poop. Check your on-site sewage system to make sure it is maintained
and working properly.
TMDL implementation: getting to clean water
The McCleary STP (National Pollutant Discharge Elimination System [NPDES] Permit #WA0024040) was upgraded to the advanced
secondary level in the winter of 1980-81. Subsequent monitoring found that the
previous pollutions problems, except for temperature, were improved.
TMDL reports are submitted to the U.S. EPA for approval. These documents are
also called WQ Improvement Reports (WQIRs). Sometimes the study on which these
reports are based is published separately as a TMDL study, or technical report,
that describes the results and analysis of the study. The precursor to a study
is a Quality Assurance Project Plan (QAPP). The QAPP describes the study design,
data collection and data quality objectives. Important follow-up studies to a
TMDL are also included in the following table. Unless otherwise specified the following documents are Ecology publications.
Biological Oxygen Demand (BOD)
Wildcat Creek Ammonia-N, BOD, Total Residual
Chlorine, and Fecal Coliform TMDL
||Effects of McCleary Wastewater
Treatment Plant Effluent on Water Quality and Macroinvertebrate
Community Structure in Wildcat Creek, Washington
Water Quality Studies of Wildcat Creek near
WRIA 22 Watershed Information (Water web site)
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WRIA: #22 (Lower Chehalis)
County: Grays Harbor
# of TMDLs: 4
TMDL approved by EPA
Department of Ecology
P.O. Box 47775
Olympia, WA 98504 -7775