vvEPA
U.S. Environmental Protection Agency
Pacific Southwest / Region 9
Serving Arizona, California, Haioaii, Nevada, the Pacific Islands and 148 tribes
Water Division	75 Hawthorne Street, San Francisco, CA 94105
August 2019	866-EPA-WEST • www.epa.gov/region9
23 Years of Investing n a
Clear, Healthy Lake Tahoe
Lake Tahoe is an EPA Priority Watershed, in part
because of its iconic clarity and beauty. But climate
change and human disturbance of the watershed
threaten this national treasure. Lake clarity recov-
ered from the impacts of extensive logging in the
19th century, but rapid, unregulated development
following the 1960 Winter Olympics again in-
creased fine sediment and nutrients flowing into
the lake. Between 1968 and 1997, annual average
clarity fell dramatically from around 100 feet to
64 feet (Figure 1).
ANNUAL AVERAGE SECCHI DEPTH
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020
YEAR
Figure 1. Source: UC Davis TERC (terc.ucdavis.edu)
A new era of ecosystem and watershed restoration
began in 1997 with the visit of President Clinton to
Lake Tahoe, where he helped launch the Environ-
mental Improvement Program. This $2.3 billion
effort has helped achieve Tahoe Basin improve-
ments for air and water quality, soil conservation,
forest health, wildlife and fisheries, and scenic and
recreational resources. The decline in annual aver-
age lake clarity halted in recent years, with 2018
seeing a rebound to 70.9 feet after 2017's extreme
winter and the worst annual average Secchi depth
ever recorded: 60.4 feet. Past improvements may be
attributed in part to local management of urban
runoff guided by innovative decision-making tools.
Continued progress as we face growing challenges
of climate change, like increasing tree mortality,
forest fires, warmer lake temperatures and prolif-
eration of invasive species, will require constant
vigilance and dedicated resources.
What Is EPA Doing to Protect Lake Tahoe?
EPA has been charged with protection of the Tahoe
Basin ever since Section 114 of the 1972 Clean
Water Act required implementation of a study to
.preserve the fragile ecology of Lake Tahoe."
EPA's involvement accelerated sharply after the
1997 Presidential Forum, where President Clinton
announced a number of air- and water-quality goals,
as well as a full-time, on-site EPA Lake Tahoe Basin
Coordinator. Since then, EPA has invested over
$47 million, including $9 million for a lake clarity
restoration plan, known as a Total Maximum Daily
Load (TMDL). EPA also oversees implementation
of the Clean Water Act, Safe Drinking Water Act,
Clean Air Act and other statutory requirements by
our partner agencies in California and Nevada, and
by local partners.
What Is the Lake Tahoe Total Maximum
Daily Load (TMDL) and What Does It Do?
The Lake Tahoe TMDL is the centerpiece of efforts
to reverse the decline in the lake's deep-water
clarity and restore it to historic levels. The TMDL
and its Implementation Plan were adopted by
California and Nevada, and approved by EPA in
2011 following a 10-year, $10 million development
effort funded by state and federal agencies. Both the
scientific research and stakeholder input that under-
pin the final restoration plan are among the most
advanced ever applied to a TMDL in the Clean
Water Act's 47-year history. Key elements include:
• Understanding Pollutant Sources: Quantified
relative amounts of fine sediment, phosphorus
and nitrogen inputs to Lake Tahoe from major
pollutant sources including urban and forest
stormwater runoff, stream channel erosion, and
atmospheric deposition.

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Targeting Load Reductions: Calculated
needed load reductions for the largest pollutant
sources in order to achieve the interim "Clarity
Challenge" target of 78 feet by 2026 and the
long-term TMDL numeric clarity goal of 97 feet
by 2076 (Figure 2).
Load Reduction Milestones to meet TMDL Goal
2016 2021 2026 2031 2036 2041 2046 2051 2056 2061 2066 2071 2076
Years
~ Fine Sediment Particles ~Total Phosphorus ~ Total Nitrogen I
Figure 2. Source: U.S. EPA
•	Creating and Implementing a Strategy:
Developed a strategy to achieve pollutant load
reductions through many possible actions,
including improved roadway operations and
maintenance, targeted street sweeping programs,
infiltration basins to capture and treat urban
stormwater, stabilization and revegetation of
eroding slopes, removal of impervious cover
and restoration of soil infiltration, and numerous
non-urban source control and reduction mea-
sures, including reconnecting streams with their
fioodplains.
•	Tracking and Reporting Results: The TMDL
included development of the Lake Clarity
Crediting Program (claritv.laketahoeinfo.
org), an innovative, comprehensive accounting
system that measures the amount of key urban
stormwater pollutants entering the lake and sets
load reduction targets, or "Lake Clarity Cred-
its," that city, county and highway agencies
must achieve. The program enables greater
transparency and accountability for expenditures
on water quality improvement projects and is a
model for other urban stormwater programs
confronting similar issues. Adaptive TMDL
Management System procedures enable TMDL
program managers to report on accomplish-
ments, better identify and respond to challenges,
and make adjustments to ensure that the TMDL
is working. Results show that the TMDL
achieved 2016 fine sediment load reduction
goals and currently is on track to achieve the
2021 milestone of 21% load reductions.
What Are EPA's Priorities for Lake Tahoe?
EPA will continue to work with our federal, state
and local partners, and the Washoe Tribe to support
the TMDL planning and implementation needed to
restore deep water clarity, improve nearshore water
quality, and protect Lake Tahoe as a drinking water
source. EPA will continue to support projects with
multiple and sustainable benefits, especially to
improve watershed resilience to the effects of
climate change. We will also continue to invest in
applying and improving scientific tools to predict
and measure project benefits.
What Can YOU Do to Protect Lake Tahoe?
Visit the Tahoe Regional Planning Agency website
and find "10 WAYS TO SAVE LAKE TAHOE"
(www.trpa.org/get-involved/10-wavs-to-save-
lake-tahoe)
Choose native plants: to reduce
water, fertilizer and pesticides.
Use phosphorus-free fertilizer:
to reduce algae growth.
Adopt a storm drain:
to keep sediment and
other pollutants out.
Bike, walk, or catch the bus:
to reduce air pollution.
Don't litter, pick up trash:
to keep trash out.
Replace old woodstoves:
to reduce air pollution.
Install and maintain Best
Management Practices:
to keep sediment and other pollutants i^P*
from flowing off your property.
Volunteer: to help clean
up and get involved.
Clean, drain, & dry:
to prevent invasive
aquatic species.
Become a Tahoe Keeper:
learn to spot invasive species
on your paddle crafts.
Pick up after your pet:
to keep bacteria and
nutrients out.
Get defensive!:
defensible space reduces
wildfire risk.
Support restoration efforts:
to improve Lake Tahoe's
ecosystem and water quality.
Lai<; Tahoe
Developed through a collaboration between Tahoe
Regional Planning Agency, Nevada Division of
Environmental Protection, Lahontan Water Board
and Environmental Protection Agency
April 2014
For more information:
Jacques Landy, U.S. EPA
Lake Tahoe Basin Coordinator
Tel: (775) 589-5248
Email: landv.iacaues@epa.gov
Learn more about the activities of EPA and partner
agencies at EPA's Lake Tahoe website at
www.eDa.aov/lake-tahoe

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