FORUM: "Strengthening Global Cooperation for Sustainable Lake Management." World Lake Day 2026. Lakes and reservoirs contain more than 90% of the world's liquid surface freshwater. They
are the lifeblood of ecosystems, driving local economies, securing food and drinking water
for billions , and regulating local climates. Despite their critical importance, lakes globally face unprecedented threats from pollution, agricultural runoff, climate-induced evaporation,
and rapid biodiversity loss. The observance of the World Lake Day serves as an opportunity to reaffirm the importance of lakes, while also
providing an international platform for countries and diverse stakeholders to collaborate in
advancing their conservation and sustainable use. Recognizing the critical importance and
compounding crises faced by lakes, a special event to commemorate World Lake Day is
being organized to elevate the global political and technical profile of sustainable lakemanagement. Specifically, the event aims to:
• Showcase good practices and lessons learned.
• Mobilize support: Highlight Global Wetland Watch as one of the global Earth
observation initiatives that provides standardized information on inland water and
wetland ecosystems, supporting improved lake monitoring, policy development, and
international reporting.
• Catalyse Science-to-Policy Action: Convene a multi-stakeholder panel of experts ,
policymakers , and UN representatives to propose actionable pathways for integratinglake protection into national strategies, including on climate and biodivers ity.
• Bridge to the upcoming World Lake Conference: Build momentum toward the WorldLake Conference (WLC21) schedule to take place in June 2027 in Dares Salaam,
Tanzania. Follow the conversations with the hashtags: #worldlakeday, #lakemanagement, #naturallakes, #artificiallakes, #27August, #GenerationRestoration.
EVENTS: On August 27th 2026 from 10:00 to 11:30 am (TBC) at United Nations Headquarters Conference Room 11 will be held an in-person event to mark the World Lake Day 2026. Read the concept note, the agenda programme and Register to participate!
- Preliminary Programme -
This programme assumes a 90-minute event.
10’ Opening
session:
- Opening remarks -Tentative speakers Rafael Peralta (Director
of NY Office) Japan
- Indonesia.
10’ Technical
Showcase:
Earth
Observation for
Lake
Monitoring
- Demonstration of Global
Wetland Watch and how
satellite-bas ed monitoring
supports lake extent,
wetland monitoring,
national reporting, and
evidence-based
management. Tentative speakers - UNEP – GWW (Stuart
Crane, remotely)
30’ MultiStakeholder
Panel
Discussion:
From Science
to Policy.
Suggested guiding questions :
• How can lake conservation be
better integrated into national
climate and biodiversity
strategies?
• What lessons can countries
s hare through South-South and
triangular cooperation?
• What technical and financial
support is needed to accelerate
action?
• How can momentum be
sustained toward the 21st
World Lake Conference?
30’ Interactive
Discussion /
Q&A
-Tentative speakers: Audience.
5’ Closing
Remarks
- Key takeaways
- Invitation to the 21st World
Lake Conference (WLC21)
- Clos ing
-Tentative speakers: Tanzania.
Recognizing the critical importance and compounding crises faced by lakes, a special event to commemorate World Lake Day is being organized to elevate the global political and technical profile of sustainable lake management. Lakes and reservoirs contain more than 90% of the world's liquid surface freshwater. They are the lifeblood of ecosystems, driving local economies, securing food and drinking water for billions, and regulating local climates. Despite their critical importance, lakes globally face unprecedented threats from pollution, agricultural runoff, climate-induced evaporation, and rapid biodiversity loss.
Related Sites and Documents: Draft Concept Note & Website.
PUBLICATION: America’s Cleanest and Dirtiest Lakes: 2026 Report on Lake Pollution and Water Quality. Lake has released our 2026 report ranking the cleanest and dirtiest lakes in the United States. Discover why Lake Chelan ranks #1 on the cleanest lakes list, and get acquainted with the factors that influence a lake’s position on the cleanest list and the dirtiest list. Download the Report as PDF
- Lake Chelan is the cleanest lake in America, due to its low mineral levels and low turbidity.
- The Great Salt Lake is the dirtiest lake in the US right now, with by far the heaviest mineral load of any ranked lake (134,500 mg/L Total Dissolved Solids), as well as the lowest dissolved oxygen levels (3.65 mg/L) and the highest ammonia levels of any lake in the top ten dirtiest (0.92 mg/L).
- Over 60 major lakes in America were assessed across eight different categories.
- The Cleanest and Dirtiest Lakes at a Glance
A new report has revealed the cleanest and dirtiest lakes in America, with Lake Chelan ranking as the cleanest, while the Great Salt Lake in Utah ranks as the dirtiest due to its saline levels. The study, conducted by vacation rental platform Lake.com, analyzed all the available chemical data from the National Water Quality Monitoring Council (NWQMC) for 100 of America’s largest lakes, sampled from January 1st, 2021, until July 30th, 2026. The study evaluated eight of the most commonly measured characteristics that can indicate a lake’s cleanliness level:
- Dissolved oxygen
- Ammonia
- Lead
- Phosphorus
- Sulfate
- Total dissolved solids
- Turbidity
- pH levels
A total of 67 lakes reported at least three of these pollution factors and therefore qualified for the study. The findings were put into an index to produce a pollution score out of 10 to determine the safest and most dangerous lakes based on hygiene, pollution and more.
At the other end of the scale, Lake Chelan in Washington state is the cleanest lake in America. Lake Chelan has turbidity of just 2.00 NTU, meaning it’s extremely clear, and one of the lowest TDS levels at 30.25 mg/L. Lake Chelan also experiences low sulfate levels of 3.65 mg/L.
However, Lake Superior, which was the cleanest lake in last year’s report, ranks a close second with the lowest turbidity of any lake (0.54 NTU), low TDS levels (74 mg/L), and high oxygen levels (10.58 mg/L).
The Great Salt Lake in Utah is America’s dirtiest lake. Its water carries an extremely high mineral load, with total dissolved solids (TDS) of 134,500 mg/L, which is much more than any other lake in the study. TDS refers to the total minerals within water, including sulfates, chlorides, calcium, magnesium, potassium, bicarbonates and sodium, and indicates the general quality of water. While not necessarily a direct indicator of pollution itself, the levels highlight how dangerous it could be to ingest any water from the Great Salt Lake due to its extreme chemistry.
The Great Salt Lake is also the most poorly oxygenated lake in the ranking, with dissolved oxygen of just 3.65 mg/L. If this level were to drop below 2, the lake would become hypoxic, meaning fish would suffocate. It also reports the highest ammonia of any lake in the top ten dirtiest ranking at 0.92 mg/L, along with elevated lead at 2.09 µg/L. The Great Salt Lake is not a freshwater lake and is a terminal lake; therefore, there is no outlet for any mineral or chemical buildup.
Lake McConaughy in Nebraska and Lake Winnebago in Wisconsin rank second and third dirtiest, respectively. Lake McConaughy has turbidity levels of 5.50 NTU, while Lake Winnebago, Wisconsin’s largest inland lake, is ranked so low due to its high levels of phosphorus, which are 0.09 mg/L, along with a pH deviation of 1.58.
The fourth dirtiest lake in America is Lake Vermilion in Minnesota. Lake Vermilion is the second least oxygenated lake, behind the Great Salt Lake, with dissolved oxygen of just 3.90 mg/L.
Devils Lake in North Dakota is the fifth dirtiest lake in the country and is likely to be the smelliest of all, as it has the highest levels of sulfate (639 mg/L) due to no natural outlet to dilute sulfates over time. The smell of sulfate is often described as similar to ‘rotten egg’.
Despite ranking as the eighteenth dirtiest lake overall, Lake Moultrie in South Carolina is the most lead-contaminated lake included in the study, with samples detecting lead at 17.2 µg/L. There is no safe level of lead.
Lake Mattamuskeet in North Carolina shows the highest ammonia of any freshwater lake in the top ten, estimated at 0.67 mg/L. Ammonia should not be present at all in clean water, and when levels reach 0.53 mg/L, the water begins to become harmful to fish.
“America’s largest lakes remain, on the whole, clean and pleasant to swim in. Even the lakes at the top of our dirtiest table sit within the range you would expect for large natural bodies of water, which shows that there is good maintenance and care for them.
“However, with that in mind, some monitoring of lakes throughout the country is uneven from one lake to the next, so anyone looking to visit a lake, particularly swimmers, needs to check any signage near their local swimming spot and follow the advice given to them. No lake in the ranking is inherently dangerous, but you could be at risk of a stomach bug.” David Ciccarelli, CEO of Lake.com
Other publications: Research papers of the International Lake Environment committee Foundation (ILEC)
