Global Rundown
- Japanese officials are raising concerns over worsening water quality near Mt. Fuji, where thousands of coins thrown by tourists are sullying the health of sacred ponds.
- Nearly one-in-five Americans relied on water containing elevated levels of nitrates between 2021 and 2023, according to a new analysis.
- The amount of time snow remains on the ground in the Himalayas fell to a 20-year low this winter, resulting in reduced inflows to major rivers including the Mekong.
- Flooding could be more detrimental than drought for certain crops in the Great Plains and Midwest, according to a newly published model.
The Lead
Roughly two billion people living in the vicinity of the Hindu Kush Himalaya (HKH) mountain range — a topography that spans parts of Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal, and Pakistan — depend on alpine snowfall and snowmelt for their freshwater needs, a reliance that has earned the region the moniker “Asia’s Water Tower.”
But the springtime replenishing of the area’s twelve major river basins has declined precipitously in recent years. A quarter of those basins are fed solely by runoff from HKH snowmelt.
Between 2003 and 2026, 14 winters were marked by below-average snow persistence, which is defined as the amount of time snow remains on the ground after snowfall. According to a new report from the International Centre for Integrated Mountain Development, 2025-26 was the fourth consecutive winter of below-average snow persistence, falling to 27.8 percent below the historic average and setting a new two-decade low.
These seasonal anomalies have had outsize impacts in several major river basins. Snow persistence fell to 59.5 percent below normal in the Mekong basin this year, the lowest recorded in the river since 2003; 47.4 percent below normal in the Tibetan Plateau; 41.8 percent below normal in the Salween basin; and 35.9 percent below average in the Yellow River basin.
According to the Nepal Climate Hub, the HKH region is expected to lose one-third of its glacial mass by century’s end if global warming is limited to 1.5 degrees Celsius, and up to 80 percent of glacial mass under higher-emission scenarios. Regional drinking water access, energy reliability, infrastructure stability, and global wheat and rice supplies are all threatened by short-term flooding and long-term drought scenarios.
Recent WaterNews from Circle of Blue
- Stalled Farm Bill, Slashed Grants Undercut Farmers’ Water Protection Efforts — Ahead of a new growing season, canceled federal grants and policy gridlock threaten progress on flooding, runoff, and water pollution.
- U.S. Government Orders Emergency Actions to Protect Glen Canyon Dam — Extraordinary moves in the struggling Colorado River basin could prompt historic lawsuits.
This Week’s Top Water Stories, Told In Numbers
Roughly 18 percent of Americans — 62.1 million people — received water with elevated levels of nitrates from community water systems between 2021 and 2023, according to a new analysis from the Environmental Working Group, a nonprofit research and advocacy organization that focuses on agriculture and pollution in the United States.
More than 6,000 drinking water systems in that three-year span were tested at least once to contain nitrates above the 3 milligram/liter threshold, indicating human-caused contamination.
The U.S. EPA’s maximum legal contamination limit is currently set at 10 milligrams/liter, “but more recent research shows strong evidence of an increased risk of colorectal and other cancers, thyroid disease and birth defects at 5 mg/L and smaller levels far below the legal limit,” the analysis reads.
Thousands of coins apparently thrown by tourists into the Oshino Hakkai hot springs near Mt. Fuji has raised water quality concerns in one of Japan’s most-visited UNESCO World Heritage sites. The Straits Times reports that more than 50,000 coins — tossed for luck — have been recovered over the past decade from the pools, which are known for their clarity and are fed by underground channels of water originating at Mt. Fuji. The coins’ corrosion has sullied the pond’s typically pristine cleanliness, with the largest pool, Wakuike Pond, receiving particular attention. More than 18,000 coins were removed from the water body, where inflows are the strongest, in 2016. Officials are aiming to put a stop to the practice before nearby rivers — which thus far have not been affected by corrosive coins, according to recent testing — are impacted.
On the Radar
A study published this month in the journal Science Advances introduces a new model to better quantify how flooding might lead to agricultural losses across the United States, in an effort to prepare communities for possible food crises.
According to the researchers, most current models that examine the impact of natural disasters on crop yields focus on drought and heatwaves, but do not fully factor in flooding. This stems from the fact that most crop-growth models fail to incorporate robust hydrological parameters, such as how waterlogging or flooding might alter a plant’s ability to photosynthesize, absorb nutrients, or grow roots.
After bridging this gap and developing a framework to estimate global crop losses due to floods, the researchers assessed the risks to maize, soybean, and wheat in the continental United States.
They found that between 2015 and 2100, under a high-emissions climate scenario, average annual losses for maize, soybean, and wheat caused by flooding would reach roughly $287 million, $234 million, and $212 million, respectively.
The researchers also found that flood-induced losses surpassed drought-induced losses in 26 percent, 19 percent, and 62 percent of states for maize, soybean, and wheat, respectively. The highest-risk states for these flood indemnities were Illinois, Indiana, Iowa, Kansas, Minnesota, Mississippi, Missouri, and Nebraska.
