A comprehensive new study led by the University of Texas at Austin provides an overview of the world’s freshwater supplies as well as solutions for their sustainable management. The study, published in Nature Reviews Earth & Environment, highlights the links between surface and groundwater and argues for different ways of managing the two.
“I like to highlight a lot of solutions and how they can be optimized,” said lead author Bridget Scanlon, a senior researcher at the UT Bureau of Economic Geology, a research unit of the Jackson School of Geosciences.
The study draws on data from satellites, climate models, monitoring networks and nearly 200 scientific papers to analyze the Earth’s water supply, how it is changing in different regions, and what is driving those changes. The co-authors of the study include almost two dozen water experts from around the world.
According to research, humans are primarily dependent on surface water. Globally, it accounts for 75 percent of irrigation and 83 percent of municipal and industrial supplies annually. However, what we see on the surface is closely related to the flow of groundwater. In the United States, about 50 percent of annual flow begins as groundwater. And globally, surface water that seeps into the ground accounts for about 30 percent of annual groundwater supplies.
Human intervention can strongly affect the exchange of water between surface and underground water sources. About 85 percent of groundwater pumped by people in the U.S. is considered “captured” from surface water, leading to a decline in flow. At the same time, irrigation from surface water can increase groundwater recharge as irrigation water seeps through the ground back into aquifers.
The study provides numerous examples of human activity affecting this flow between surface and groundwater supplies. For example, surface water irrigation recharged aquifers in the early to mid-20th century in the US Northwest on the Columbia Plateau and the Snake River Plain, while global models show that groundwater pumping greatly reduced the volume of water flowing into streams, with 15–21 per cent global watersheds threatened due to reduced flows.
Despite their natural interconnectedness, surface and groundwater are often regulated and managed as separate resources. According to the researchers, future water resilience depends on recognizing that surface water and groundwater behave as one resource—and building on that knowledge.
The study describes different ways to manage water through natural and man-made solutions that can help increase water supplies, reduce demand, store and transport water. According to Scanlon, one of the best ways to adapt to increasing climate extremes is to store water during the wet season and pump it out during the dry season.
Read Now :<strong>Indian startups have deposits of about $1 billion in Silicon Valley Bank</strong>
