&EPA
San Juan Watershed:
Water Quality and Recreation
Under the, Clean Water Act (CWA), EPA regulates the quality of and discharges of pollutants into our nation's surface
waters. States: and tribes ffegularly monitor and assess surface water quality, communicate water quality conditions
to the public, and work to address natural and human-caused water quality issues. The San Juan Watershed in the
southwestern United States comprises: the San Juan and Animas Rivers and their tributaries. The headwaters of the:
Animas River lie in a naturally ore-rich mineral belt that was the site of significant historical mining activity. While some
metals in the waters of the upper Animas River are naturally occurring, many come from acid mine drainage and
runoff from mining disposal piles.
The lower Animas River is diluted by incoming waters with lower levels of metals as the Animas flows southward
through Durango, CO to Farmington, NM where: it joins the' San Juan Rivet: The Animas is the largest free-flowing
perennial tributary to the San Juan and can have an important influence on San Juan water quality.
The San Juan River is a source of water and power for over 4 million people. The river crosses diverse landscapes
and receives waters from multiple tributaries before it reaches Lake Powell and converges with the Colorado River.
STATE AND TRIBAL ASSESSMENTS1
Animas River
Lake Powell
Durango
San Juan River
armington
Waterbody Status
| Not Supporting Recreation Use
| Fully Supporting Recreation Use
¦ Other Assessment Status

Data Sources: EPA ATTAINS, USGS, Esri
This map presents state and tribal assessments of water quality relative to the standards they established under
the CWA for recreational uses such as swimming, boating;, and fishing. These standards ensure that the waters are
safe for recreation and protect people from illnesses associated with ingesting or being in the water and
consuming fish caught in these waters. Grain segments of the waterbody are meeting: established standards for
recreational uses. Red segments are not meeting established standards for recreational uses. Bf«bsegments were
not assessed or not reported or are in the process of being assessed.
' This map diOes.:not include information for Ute Mountain Utfi: or Southern UtQ Indian Tribes. The'Southern Ute was authorized, as treatment in a
¦similar manner as a slate (TAS) for CWA Section 303(e); and aisf July 2020, is in the process of preparing tfieirwatenquality standards package
for EPA review and approval The Ute Mountain U{8 hay? tilbally-adopted and federally-apprqsed water quality standards and are fn tire process;
of developing an assessment methodology Thetrtbssscan be contacted directly with any questions related to water quality.

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&EPA
San Juan Watershed:
Water Quality and Recreation
KEY POINTS
EPA, states, tribes, and other federal, non-profit, and local entities have conducted extensive monitoring to
evaluate watershed condition. For recreational use, water samples are analyzed for metals and bacteria such
as E. coli. Fish tissue may be analyzed for mercury and other pollutants that could pose a human health risk if
consumed in high guantities.
The states and tribes in the watershed have assessed surface water guality based on their respective
standards under the CWA. Assessments are updated periodically in accordance with established state and
tribal assessment cycles.
According to CWA reporting for 2020, Colorado determined that assessed waters in the upper Animas
River are meeting established State Standards for recreational uses.
According to CWA reporting for 2018 to 2020, New Mexico determined that the Animas River and middle:
and lower San Juan Riverin New Mexico were not meeting state surface water guality standards for
recreational uses, due to high levels of E. coli bacteria.
According to CWA reporting for 2011 to 2017, Navajo Nation determined that portions of the San Juan River
and certain tributaries to the San Juan River were, not meeting established tribal standards for recreational
use due to levels of certain metalS in the watts*.
According to CWA reporting for 2016, Utah determined that assessed waters in the lower San Juan River
and Lake Powell were, meeting established state standards for recreational uses.
A study to identify the sources of bacterial pollutants in this area of the watershed determined that human and
ruminant (e.g., cattlf, sheep, d®r) bacteria were significant contributors to bacterial levels at most sampling
sites, particularly in the San Juan River? Additional research is needed to better identify and manage the major
sources of bacteria, such as stormwater runoff and direct discharges into the rivers.
A 2018 EPA report found that contaminant levels in fish tissue do not exceed recommended consumption
concentrations;!
A 2017 Navajo Nation EPA report found that contaminant levels in fish tissue do not exceed recommended
consumption concentrations!
From 2018 through 2021, EPA is working in collaboration with states and tribes to: collect water guality and
Sediment samples at 39 locations across the watershed. These samples are-analyzed for metals and other
parameters,
• Metals in the Animas and San Juan Rivers are generally well below guidelines for recreational exposure.
Some metals, including nickel and copper, are prevalent in higher concentrations in the upper Animas due
to mining activities, but diminish further downstream.
All available data from these monitoring efforts can be found on ERAs San Juan Watershed website.
®.San Juan Basin Bacteria Source Tracking Project San Juan Watershed Group,
San Juan Soil & Water Cptjsajfation District, and Animas Watfttshefl Partnership.
Sampling conducted 2013-2014.
* U.S. EPA. Nevarntaj 2018. Analysis ,©f Biological Data Coltecteil from	EPA 840-F-20-001
the Animasand San Juan Rivers Following the Sold King Mifte Releasa	August 2020
EPA/830/R-18/003,
Navajo Nation epa. November20i7. San Juan River Fish Contaminant study.	https://www.epa.gov/san-iuan-watershed

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