NONPOINT SOIREE SICCESS STOIY
Septic Tank Effluent Pumping Project Improves King Branch
Waterbody Improved
Since 1993 King Branch has been posted with signs for water contact
avoidance due to high Escherichia coli (E. coli) levels from failing septic
systems. In 1998 the Tennessee Department of Environment and Conservation (TDEC) added the entire
West Prong Little Pigeon River watershed to the Clean Water Act (CWA) section 303(d) list; King Branch
was added to the 303(d) list as an individual segment in 2002. The Tennessee Nonpoint Source Program, in
conjunction with the Sevier County Environmental Health Department and using partial funding support
through CWA section 319 grant funding, installed a septic tank effluent pump (STEP) sewer system to treat
sewage that had been impacting both surface and groundwater. In April 2014 the water contact advisory
was lifted due to improved water quality and decreased E. coli. TDEC removed the 2.5-mile segment of
King Branch from Tennessee's CWA section 303(d) list in 2014.
Problem
King Branch is within the West Prong Little Pigeon
River-Upper watershed (060101070206) near Pigeon
Forge in central Sevier County, Tennessee (Figure 1).
King Branch flows generally east/northeast into the
West Prong Little Pigeon River, which is part of the
Lower French Broad River watershed.
In the early 1990s TDEC conducted an intensive
bacteriological study of the West Prong Little Pigeon
River to determine if the river met bacteriological
standards for body contact recreation during recre-
ational seasons. The sampling results showed that King
Branch exceeded regulatory bacterial limits, and the
stream was deemed unsafe for contact recreation. The
primary cause of impairment was identified as failing
septic systems (chiefly for homes and businesses
along King Branch Road). In 1993 a public advisory was
issued and warning signs were posted. In 1998 and
1999 TDEC tested samples from King Branch for E. coli;
the sample concentrations ranged from 1,553 counts
(cts) per 100 milliliter (ml) to over 2,419 cts/100 mL
(i.e., above the test method's detection limit). In 1998
TDEC added the entire West Prong Little Pigeon River
watershed to the Clean CWA section 303(d) list; King
Branch was added to the 303(d) list as an individual
segment (TN06010107010JD200) in 2002.
A total maximum daily load (TMDL) for pathogens in
the Lower French Broad River was developed by TDEC
and approved by the U.S. Environmental Protection
Agency in December 2005. The goal of the TMDL was
LEGEND
^—King Branch
OWest Prong Little
Pigeon River
Location of STEP System
A TDEC Monitoring Station
TDEC Stream Assessment
Fully Supporting
Not Supporting
Not Assessed
Figure 1. The King Branch Road STEP project was implemented
in the West Prong Little Pigeon River watershed in Sevier
County, Tennessee. The locations of King Branch, the STEP
system, and the nearest TDEC monitoring station are shown in
the lower watershed.
to have King Branch meet the Tennessee criteria/
standard for E. coli, which states that the concentration
of a fecal coliform group shall not exceed 200 colony
forming units (cfu) per 100 mL nor shall the concentra-
tion of the E. coli group exceed 126 cfu/100 mL as a
-------
Figure 2. Maneuvering the new STEP system equipment into
place was challenging because of tight working conditions alon£
King Branch Road.
geometric mean based on a minimum of 10 samples
collected from a given sampling site over a period of
not more than 30 consecutive days, with individual
samples being collected at intervals of not less than
12 hours; and, the concentration of the fecal coli-
form group in any individual sample shall not exceed
1,000 cfu/100 ml.
Project Highlights
Planning and design for restoring King Branch began
in 2001. In 2006 the Sevier County Environmental
Health Department approved the construction of a
STEP sewer system in this area because of an immedi-
ate threat to public health from failing septic systems.
STEP systems collect sewage from the customers on
the system and route it to a recirculating sand filter
with drip irrigation lines for disposal. Previously exist-
ing septic leach lines are removed from service, which
prevents sewage from reaching the soil surface and
contaminating runoff. In 2007 a STEP system capable
of treating up to 11,000 gallons of effluent per day was
constructed to service over 30 homes and businesses
along King Branch Road (Figure 2).
Results
Removing septic-related pollution sources reduced
bacteria levels in King Branch. Sampling conducted
by TDEC in 2013 showed that the E. coli levels within
the stream had improved and met water quality
standards for all designated uses. Observations from
June to August 2013 indicated E. coli had decreased to a
Average E. co//Concentrations in
King Branch, 1999-2013
1000
o
Approximate date of
STEP system completion
*<*.
7/24/1998 1/14/2004 7/6/2009
Date
12/27/2014
Figure 3. E. coli levels consistently met standards after the
STEP system was installed.
range of 62.2 most probable number (MPN) per 100 ml
to 112.4 MPN/100 ml (this is approximately equal to a
range of 62.2-112.4 cfu/100 ml), which is well below the
126 cfu/100 ml required by state standards (Figure 3). In
2014 TDEC lifted the contact advisory and removed King
Branch from the impaired waters list for bacteria.
Partners and Funding
The Sevier County Environmental Health Department
served as the lead organization for the STEP proj-
ect. Other cooperating organizations included the
Sevier County Soil Conservation District, Smokey
Mountain Resource Conservation and Development
Council, Tennessee Department of Agriculture, TDEC,
Tennessee Department of Health - Division of Lab
Services, and the U.S. Department of Agriculture -
Natural Resources Conservation Service.
Sevier County was the recipient of two CWA section
319 grants (2001 and 2005) for a total of $334,425.
Partial funding through the CWA section 319 program
assisted in the purchase of the STEP system itself,
along with the accompanying packed bed trickling
filter/drip effluent dispersal system. Matching funds for
the project were supplied by Sevier County. The sys-
tem is owned and operated by Tennessee Wastewater
Systems and is inspected twice a month. The system
serves approximately 35 homes under Permit No. SOP-
05043; the permit must be renewed every 5 years (the
current permit expires August 31, 2017).
U.S. Environmental Protection Agency
Office of Water
% Washington, DC
^ EPA841-F-16-001R
August 2016
For additional information contact:
Sam Marshall
Tennessee Department of Agriculture
615-837-5306 • Sam.Marshall@tn.gov
------- |