Section 319
NDNPDINT SUWSEE PROGRAM SUCCESS STDRY
Outhouse Removal Eliminates Source of Bacteria
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Rnocle lslancl placed Gilbert Stuart Stream on its 2000 303(d)
list of impaired waters because it did not meet the state's
fecal coliform bacteria water quality standard. The bacteria impairment was caused by an
outhouse near the shore of a pond that serves as the stream's source. After removing the
outhouse, bacterial levels dropped, and the segment now meets water quality standards.
Rhode Island removed the stream from its list of impaired waterbodies in 2008.
Problem
Gilbert Stuart Stream is the largest freshwater
tributary to Narrow River and an important
anadromous fish run. Narrow River is in
southern Rhode Island, west of Narragansett
Bay. Its watershed lies within the towns of
North Kingstown, Narragansett and South
Kingstown. Gilbert Stuart Stream originates
at the discharge spillway of Carr Pond at the
Gilbert Stuart Museum historical site in North
Kingstown, travels approximately 0.3 km
through hardwood wetlands and terminates
at the northern end of Upper Pond, which is
the beginning of the Narrow River (Figure 1).
The surrounding watershed is sparsely settled
with several camps and low-density residen-
tial development. Local organizations and
the general public enjoy hiking, camping and
canoeing in the watershed.
Water quality monitoring data collected dur-
ing the development of the Narrow River Total
Maximum Daily Load (TMDL) for pathogen
impairments indicated that Gilbert Stuart
Stream's fecal coliform (FC) levels were
sporadically very elevated and consistently
violated the state's bacteria water quality
standards. Rhode Island classifies Gilbert
Stuart Stream as a Class A waterbody. The
water quality standard for fecal coliform (an
indicator of pathogen contamination) in Class
A waters requires that concentrations do not
exceed a geometric mean value of 200 MPN
(per 100 milliliters (ml), and not more than
Figure 1. An aerial view of the project location. Inset pictures
show a fish ladder at the Carr Pond Dam (top left) and two views
of the Gilbert Stuart Museum site (right).
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10 percent of the total samples shall exceed a
value of 400 MPN/100 ml, where MPN is the
most probable number.
Rhode Island Department of Environmental
Management's (OEM's) 1999 water qual-
ity data showed that, at a sampling station
immediately downstream of the Gilbert Stuart
Museum, the dry-weather geometric mean of
the stream was 182 FC/100 ml, while the wet-
weather geometric mean was 573 FC/100 ml.
The calculated weighted-geometric mean for
the segment was 290 FC/100 ml, and the
90th percentile value was 4,320 FC/100ml_.
DEM determined that Gilbert Stuart Stream
did not meet standards necessary to support
its designated use (primary recreation) and
added the stream to its 2000 303(d) list of
impaired waters.
Project Highlights
DEM determined that human activity was
likely the dominant source of fecal coliform
bacteria. A failing septic system at the Gilbert
Stuart Museum (at the headwaters of the
stream) was replaced around 1997; however,
fecal coliform concentrations in the stream
remained elevated. During the 1999 sampling
effort, the primary source of fecal coliform
contamination to the stream was localized to
the Gilbert Stuart Museum property (Figure 2).
DEM identified an outhouse within 35 feet of
Carr Pond as the probable source. Museum
curators agreed to replace the outhouse with
a portable toilet in 1999. Removal of this
outhouse was the only remedial measure
deemed necessary for Gilbert Stuart Stream
in the Narrow River TMDL report.
Figure 2. The Gilbert Stuart Museum and
waterwheel.
Results
Data indicate that Gilbert Stuart Stream water
quality has improved significantly. Project part-
ners collected and analyzed 29 water samples
from 2000 to 2005. Results show a geometric
mean of 45.75 FC/100 ml with only 2 of the 29
samples exceeding 400—a drastic decrease in
fecal coliform levels. The stream now meets the
state's Class A water quality standard and sup-
ports its designated use for primary recreation.
Therefore, Rhode Island removed the stream
from its303(d) list in 2008.
Partners and Funding
University of Rhode Island Watershed Watch
volunteers contributed to the water quality
monitoring effort. Rhode Island DEM used
Clean Water Act section 319 funding to develop
the Narrow River TMDL.
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-08-001J
August 2008
For additional information contact:
Ernie Panciera
Office of Water Resources, Rhode Island
Department of Environmental Management
401-222-4700x7603
ernie.panciera@dem.ri.gov
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