Freshwater

In the popular imagination, the Caribbean is paradise, an exotic place to escape to. But behind the images of balmy beaches and lush hotel grounds lies a crisis, the likes of which its residents have never experienced. Caribbean islands are in a water crisis, and their governments have warned that water scarcity may become the new norm. Within the past five years, every island in the region has experienced some sort of water scarcity. For example, Trinidad is experiencing its worst drought in recent memory, and residents are under water restrictions through at least the end of June 2024, with fines for anyone who violates the rules. Dominica, considered the nature island of the Caribbean for its mountain rain forests, is seeing a significant decrease in freshwater resources and increasingly frequent water shortages. In Grenada, known as the spice isle, drought has affected water systems throughout the island. Apartments in Havana, Cuba,...

A lot can go wrong in a large urban water system. Pumps malfunction. Valves break. Pipes leak. Even when the system is functioning properly, water can sit in pipes for long periods of time. Water shortages are also a growing problem in a warming world, as communities across the Southwestern U.S. and in many developing nations are discovering. That’s why cities have started experimenting with small-scale alternatives – including wastewater recycling and localized water treatment strategies known as decentralized or distributed systems. I study large- and small-scale water systems, focusing on innovative system designs that allow local use of water sources that might otherwise go to waste. As technology improves, cities are discovering something that rural communities have long known: Small-scale water treatment, properly engineered, can be cheaper and easier to maintain than a centralized system, and it can improve water security and even the environment. Cleaning w...

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...

Rivers are awash with excess nutrients, chemicals, and other pollutants, including sewage. Globally, roughly 50% of wastewater is treated at facilities before being released into nearby bodies of water. But new research shows that even advanced treatment might not be enough to safeguard the health of freshwater ecosystems. Researchers released dilute, treated wastewater into an unpolluted stream in northern Spain and made a before and after comparison of energy flows through the ecosystem. “We found subtle yet fundamental shifts in ecosystem function.” “We found subtle yet fundamental shifts in ecosystem function after adding wastewater,” said Ioar de Guzman, a freshwater ecologist at the University of the Basque Country in Spain and lead author of the study. By manipulating a pristine ecosystem, she and her colleagues could isolate the effects of wastewater, which can be masked in streams that contain other types of...

California has seen so much rain over the past few weeks that farm fields are inundated and normally dry creeks and drainage ditches have become torrents of water racing toward the ocean. Yet, most of the state remains in drought. All that runoff in the middle of a drought begs the question — why can’t more rainwater be collected and stored for the long, dry spring and summer when it’s needed? As a hydrogeologist at the University of California at Santa Cruz, I’m interested in what can be done to collect runoff from storms like this on a large scale. There are two primary sources of large-scale water storage that could help make a dent in the drought: holding that water behind dams and putting it in the ground. Why isn’t California capturing more runoff now? When California gets storms like the atmospheric rivers that hit in December 2022 and January 2023, water managers around the state probably shake their heads and ask why they can’t hold...