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NONPOINT SOIREE SICEESS STORY
Island
Reducing Bacteria Led to the Reopening of a Conditionally Approved
Shellfishing Area in Greenwich Bay
Waterbody Improved Atsunriseon Se»tember2- the Rhode lsland Department
of Environmental Management (RIDEM) opened 180 acres of
conditionally approved shellfishing area in the Nausauket area of Greenwich Bay, just southeast of
the mouth of Apponaug Cove in the city of Warwick, Rhode Island. This section had been closed to
shellfishing for 20 years due to elevated fecal coliform levels, and its opening increased Greenwich
Bay's conditionally approved shellfish area by 10%. The shellfish classification upgrade was possible
due to water quality improvement efforts, including the passage of Rhode Island's Cesspool Phaseout
Act in 2007, state and local actions to strengthen stormwater controls (particularly in the Hardig
Brook subwatershed), and a substantial increase in sewering in the area around Apponaug Cove.
Problem
Greenwich Bay is on the western side of Narragansett
Bay. The Apponaug Cove subwatershed of Greenwich
Bay is within Warwick in east-central Rhode Island
(Figure 1). High- to medium-density residential land use
covers almost one-third of the 17.5-square-kilometer
watershed. Another 18% of the land is in commercial
and industrial use, mainly along high-traffic roads. For
years, most homes around Apponaug Cove used cess-
pools and septic systems for onsite wastewater disposal,
with large neighborhood areas remaining unsewered.
in addition, untreated stormwater regularly caused
closures of shellfish beds and the three bathing
beaches in Greenwich Bay, which iasted up to a week
after as little as 0.5 inches of rain. The primary driver
in determining the classification of shellfishing waters
is the level of fecal coliform, as determined by compli-
ance with the U.S. Food and Drug Administration (FDA)
National Shellfish Sanitation Program (NSSP). Shellfish
harvesting waters must exhibit geometric means of
less than 14 colony-forming units (CFU) per 100 mil-
liliters (mL), with no more than 10% of the most recent
15 samples exceeding 31 CFU/100 ml. in 1992, a large
rain and snow event caused weeks of violations of this
standard in all of Greenwich Bay, leading to its perma-
nent shellfishing closure shortly afterward. Although a
1993 RIDEM/FDA classification study allowed condi-
tional openings of certain areas depending on rainfall
conditions, this area just southeast of the mouth of
Apponaug Cove remained closed until September 2022.
Figure 1. Hardig Brook basin (outline) and Apponaug
Cove-area homes sewered 1980-present (shaded).
Story Highlights
Commercial shellfishing is an important economic
driver in Rhode Island. NOAA data place Rhode Island's
commercial shellfish catch (scallops, quahogs/clams,
and Jonah crabs) at $20 million annually, comprising
roughly 20% of the state's commercial shellfish catch
(not including lobster). During the winter, when rough
seas may prevent shellfishing in the remainder of
Narragansett Bay, the relatively sheltered Greenwich Bay
has served as a highly valuable harvesting alternative
and has been a priority for restoration and protection.
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Proposed
closure option 1
(CedarTree Pt.)
9
Station 8-7
Period
100%
90%
80% |
jg
70% |
O
60% |
5OT4 f "U
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