Hydrology

Millions of Californians were under flood alerts as a powerful atmospheric river brought heavy rain to the West Coast in early February 2024. Los Angeles saw one of its wettest days on record with over 4 inches of rain on Feb. 4. Other communities were hit by more than 12 inches of rain and reported widespread flooding. Debris and mudslides shut down sections of highways and roads into Malibu. It was the latest in a series of atmospheric rivers to bring extreme rainfall to the West Coast. While these storms are dreaded for the damage they can cause, they are also essential to the region’s water supply, particularly in California, as Qian Cao, a hydrologist at the University of California, San Diego, explains. What are atmospheric rivers? An atmospheric river is a narrow corridor or filament of concentrated water vapor transported in the atmosphere. It’s like a river in the sky that can be 1,000 miles long. On average, atmospheric rivers have about twice the regul...

As renewable energy production expands across the U.S., the environmental impacts of these new sources are receiving increased attention. In a recent report, the National Academies of Sciences, Engineering, and Medicine examined whether and how constructing offshore wind farms in the Nantucket Shoals region, southeast of Massachusetts, could affect critically endangered North Atlantic right whales. The Conversation asked marine scientists Erin L. Meyer-Gutbrod, Douglas Nowacek, Eileen E. Hofmann and Josh Kohut, all of whom served on the study committee, to explain the report’s key findings. Why did this study focus on such a specific site? The Bureau of Ocean Energy Management, which is part of the U.S. Department of the Interior and regulates offshore energy production, asked the National Academies to conduct this study. Regulators wanted to better understand how installing and operating offshore, fixed-bottom wind turbine generators would affect physical oceanographic pr...

Seawater intrusion is the movement of saline water from the ocean or estuaries into freshwater systems. The seawater that has crept up the Mississippi River in the summer and early fall of 2023 is a reminder that coastal communities teeter in a fragile land-sea balance. Fresh water is essential for drinking, irrigation and healthy ecosystems. When seawater moves inland, the salt it contains can wreak havoc on farmlands, ecosystems, lives and livelihoods. I am a coastal hydrogeologist and have studied water across the land-sea interface for 25 years. I think of seawater intrusion as being like a seesaw: The place where fresh water and salt water meet is the balance point between forces from land and forces from the sea. A push from the land side, such as heavy rainfall or high river flows, moves the balance point seaward. A push from the sea side – whether it’s sea-level rise, storm surge or high tides – moves the balance point landward. Droughts or heavy us...

Open Access Government takes a closer look at the hydrology and surficial geology in Alaska to illustrate the broader picture of geology in the region, primarily focusing on Permafrost and Periglacial Studies From reporting on oil and mineral finds to helping in the aftermath of deadly mudslides, the Division of Geological & Geophysical Surveys (DGGS) in Alaska staff tirelessly put effort into growing the economy and safeguarding their communities. Investing in geology is essential for commercializing and discovering Alaska’s untapped gas, oil, coal, and mineral resources and preventing geologic risks to Alaskans. Under the banner of the Director’s Office, the DGGS consists of five sections: the Geologic Materials Center and the Alaska Geospatial Office. The Director’s Office oversees strategic planning for the Division’s programs to ensure DGGS serves the community’s needs, oversees the Division’s financi...

Rivers are critical corridors that connect cities and ecosystems alike. When drought develops, water levels fall, making river navigation harder and more expensive. In 2022, water levels in some of the world’s largest rivers, including the Rhine in Europe and the Yangtze in China, fell to historically low levels. The Mississippi River fell so low in Memphis, Tennessee, in mid-October that barges were unable to float, requiring dredging and special water releases from upstream reservoirs to keep channels navigable. Conditions on the lower Mississippi may be easing somewhat, thanks to early winter rains. But as Earth scientists at the University of Memphis, we see this year’s dramatic plunge in water levels as a preview of a climate-altered future. River barges are an efficient way to transport bulk commodities, such as grain shipments, and heavy equipment over long distances. But that’s true only for normal water conditions. Increased swings between extreme low...