Fact Sheet on the U.S. Virgin Islands 2018 Impaired Waters List
July 2019
Section 303(d) of the Clean Water Act requires states, territories and authorized tribes to develop lists of
impaired waters. Impaired waters are waters that are too polluted or otherwise degraded to meet the state
water quality standards. Federal law requires these jurisdictions establish priority rankings for waters on
the lists and develop total maximum daily loads for impaired waters. A total maximum daily load, or
TMDL, is a calculation of the maximum amount of a pollutant that a waterbody can receive and still
safely meet water quality standards. The EPA has approved the U.S. Virgin Islands 2018 list of impaired
waters requiring a TMDL. The U.S. Virgin Islands 2018 impaired waters list presents information on
impaired waters, pollutants causing the impairment and pollutant sources.
How States Report on the Quality of their Waters
The Clean Water Act requires states (Section 502 of the Act defines "state" to include the U.S. Virgin
Islands) to assess the quality of their waterbodies and to report their findings every two years to the
EPA. States adopt specific water quality standards that serve as the foundation for water quality
management. Water quality standards identify the designated uses for each body of water (such as
swimming, drinking, shellfish harvesting, etc.) and set criteria to protect those uses. During the
assessment process, states compare the collected data to the established water quality standards.
In addition to reporting on the overall quality of all waters, the Clean Water Act directs states to identify
and list specific waterbodies where water quality is impaired by pollutants. A waterbody is considered
impaired if it does not meet water quality standards. The requirement to prepare the impaired waters list
is found in section 303(d) of the Clean Water Act, and the list is often called the 303(d) list.
Each impairment reflected on the 303(d) list requires a calculation of the maximum amount of the
impairing pollutant that a waterbody can receive and still meet water quality standards. TMDLs include
reductions for pollution sources impacting the waterbody that, when achieved, will result in the
attainment of water quality standards in the waterbody.
In certain cases, impaired may not appear on a state's 303(d) list. If a TMDL has already been developed
for the water, another required control measure is expected to result in the attainment of water quality
standards within a reasonable amount of time, or the impairment is the result of pollution not caused by
a pollutant (e.g., hydrologic or habitat alteration), then the water may not be included.
Water quality monitoring data and other information must be considered by states in assessment and
reporting efforts. Monitoring may be carried out by national, state, local and tribal authorities,
universities, dischargers, volunteers and others. It can include measurements of physical and chemical
parameters (temperature, dissolved oxygen, suspended sediment, nutrients, metals, oils, and/or
pesticides, for example), examinations of stream flow, water color, condition of stream banks and lake
shores, observations of communities of aquatic wildlife, and sampling of fish tissue or sediment. Land
use data, predictive models and land surveys may also be used.
Summary of 2018 Findings
The U.S. Virgin Islands 303(d) list includes 158 instances where a pollutant is causing a designated use
impairment. The indicators/causes of impairments are:

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•	turbidity (64),
•	enterococcus (48),
•	dissolved oxygen (18),
•	pH (16),
•	phosphorus (8),
•	temperature (3), and
•	chroni c toxi city (1).
Pollutant sources include:
•	other marina/boating on-vessel discharges,
•	erosion and sedimentation,
•	source unknown,
•	other recreational pollution sources,
•	highway/road/bridge runoff (non-construction related),
•	urban runoff/storm sewers,
•	changes in tidal circulation/flushing,
•	discharges from municipal separate storm sewer systems (MS4),
•	impacts from resort areas,
•	residential districts,
•	site clearance (land development or redevelopment),
•	highways, roads, bridges, infrastructure (new construction),
•	marina boat maintenance,
•	marina/boating sanitary on-vessel discharges,
•	on-site treatment systems (septic systems and similar decentralized systems),
•	municipal point source discharges,
•	nonpoint source,
•	commercial harbor and port activities,
•	dredging (e.g., for navigation channels),
•	illegal dumps or other inappropriate waste disposal,
•	marina fueling operations,
•	other spill related impacts,
•	erosion from derelict land (barren land),
•	industrial point source discharge,
•	sanitary sewer overflows (collection system failures),
•	marina/boating pumpout releases,
•	package plant or other permitted small flows discharges,
•	internal nutrient recycling,
•	municipal point source impacts from inadequate industrial/commercial pretreatment, and
•	post-development erosion and sedimentation.
Note: a pollutant may come from more than one source.
The U.S. Virgin Islands added 40 new waterbody/pollutant combinations to the 2018 303(d) list. The
new combinations are summarized below:
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•	31 assessment units impaired for enterococcus,
•	3 assessment units impaired for turbidity,
•	2 assessment units impaired for dissolved oxygen,
•	2 assessment units impaired for phosphorus, and
•	2 assessment unit impaired for temperature.
The 2018 303(d) list also reflects waterbody/pollutant combinations that no longer require listing.
Removal of a waterbody/pollutant combination from the 303(d) list, called delisting, may indicate that
the water is restored, a TMDL was developed, the water is receiving management attention that is
expected to result in the attainment of water quality standards, or other factors (including errors). The
U.S. Virgin Islands delisted 89 waterbody/pollutant combinations for the 2018 cycle, including:
•	61 waterbody/pollutant combinations where water quality standards are now met, based on new
water quality data, including:
o 32 waterbody/pollutant combinations for dissolved oxygen,
o 11 waterbody/pollutant combinations for enterococcus,
o 6 waterbody/pollutant combinations for phosphorus,
o 2 waterbody/pollutant combinations for temperature,
o 3 waterbody/pollutant combinations for transparency/clarity, and
o 7 waterbody/pollutant combinations for turbidity.
•	23 waterbody/pollutant combinations were delisted for fecal coliform because the water quality
criterion is no longer applicable.
•	3 waterbody/pollutant combinations covered under a TMDL that was developed prior to the
approval of the 2016 303(d) list.
•	2 waterbody/pollutant combinations where the original basis for listing was incorrect.
How the Water Quality Sampling and Reporting Process Works
The waters in and around the U.S. Virgin Islands are divided into 177 assessment units. The DPNR
evaluates and assesses data gathered through its surface and groundwater monitoring programs. Under
the U.S. Virgin Islands coastal water quality monitoring program, ambient water quality is monitored on
a quarterly basis. Ambient monitoring currently includes sampling and analysis of water quality at 55
near-shore sites around St. Croix and 83 near-shore sites around St. Thomas and St. John. The coastal
water quality monitoring program also monitors designated recreational beaches on a weekly basis
during the summer season, with some beaches also sampled from April to May and October to
December. To ensure that the U.S. Virgin Islands considers all readily available data, on January 25,
2018, the DPNR solicited water quality data for the 2018 303(d) list through a notice in the St. Croix
Source. In addition to the data solicitation request, the DPNR contacted government and non-
governmental organizations to solicit data.
The U.S. Virgin Islands uses the data collected through its monitoring program to determine the health
of its waters by comparing the data to its water quality standards. Impaired waters are those waters that
do not meet water quality standards even after limits based on treatment technology are applied, such as
technology requirements at publicly-owned wastewater treatment facilities. For the waters listed as
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impaired, the U.S. Virgin Islands must develop loading limits to restore the waterbody. The list must
include a priority ranking for each segment and the U.S. Virgin Islands must document its decisions on
which waterbodies to include on the list. The documentation includes a description of the methodology
used to develop the list. The DPNR printed a notice regarding the draft list and assessment methodology
in The Virgin Islands Daily News on October 25, 2018. The U.S. Virgin Islands allowed a 30-day period
for the public to comment on the draft list and assessment methodology.
How to Get Involved
Recognizing that stakeholders throughout the U.S. Virgin Islands collect valuable water quality data, the
DPNR has established a process that allows groups and individuals to submit information for use in the
territory's assessment work. To submit data for consideration during future 303(d) assessment cycles,
submissions (data, photographs, etc.) must be sent to the DPNR and include a quality assurance project
plan. Parties submitting information should send materials to:
Department of Planning and Natural Resources
Division of Environmental Protection
45 Mars Hill
Frederiksted, U.S. Virgin Islands 00841
Alternatively, information can be sent via email to: benjamin.keularts@dpnr.vi.gov. If you have
questions or would like to speak directly with a DPNR representative, call (340) 773-1082.
The DPNR also provides the opportunity for formal public comment on its draft 303(d) list. The public
comment period for the draft 303(d) list is typically announced in even-numbered years on the DPNR
website. Comments are accepted during a 30-day period.
The EPA Contact for the U.S. Virgin Islands 303(d) List
If you have questions or concerns, contact Jacqueline Rios by phone at (212) 637-3859 or by email at
rios.iacqiieline@epa.gov.
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