Groundwater has been attracting considerable interest in 2013, sparked by concerns over supplies and increased consumption, contamination, property damage, and collateral effects of climate change. People dig wells, local governments supply water from underground aquifers, and businesses like carwashes and industry applications such as agriculture and natural gas drilling consume large amounts of our fresh reserves.
Businesspeople, scientists, government officials, and the public generally consider groundwater renewable because it is replenished naturally and deeper wells can often access further supplies. However, like the rest of the world, the U.S. is overusing groundwater at an alarming rate. Here are three important groundwater studies released in the first two months of this year.
"Out of sight, out of mind"
The 2013 American Association for the Advancement of Science annual meeting in Boston last month gathered scientists and enthusiasts from about 60 countries to celebrate recent research about the natural world. At the science society meeting, Dr. Henry Lin pointed out that about 60% of the world's annual precipitation ends up as groundwater, much more than the so-called "blue waters" (lakes and rivers) contain.
"We look at nature and we see all the beauty and all the prosperity around us. But most people don't know or tend to forget that the key to sustainability is right underground."
Lin is Associate Professor of Hydropedology/Soil Hydrology at Penn State. He says that groundwater is currently under threat from poor land management practices like new building projects, underground storage, and agricultural operations that fail to take it into account. Lin's conclusion: "Without water there is no life. Without groundwater, there is no clean water."
Global groundwater patterns
In last week's issue of Science magazine, earth scientists reported on global patterns of water table depth and the areas where shallow groundwater provides vital support for land ecosystems. With geophysicist Gonzalo Miguez-Macho of the University of Santiago, Yihui Fan and Haibin Li of Rutgers found that water table depth explains both global wetland patterns and regional and local vegetation gradients. Overall, shallow groundwater influences up to a third of the earth's land area.
Uncertain geohazards with water and exploratory well monitoring
In the January-February issue of Groundwater magazine, geologist/engineer J. David Rogers, a Berkeley graduate and professor at Missouri University of Science & Technology, and Dr. Jae-Won Chung, a post-doctoral fellow there, raise disturbing technical questions about the accuracy of recorded groundwater levels.
These levels are important factors in assessing geoenvironmental, geotechnical, and hydrogeologic conditions for well drilling, whether the target of exploration is water, hydrocarbons, or something else. The authors call the uncertainties of groundwater levels "pervasive." They cite three confounding variables:
- measurement error in the monitoring system,
- vagueness (confined or unconfined water conditions, uncertainties about the saturated zone, and misinterpretations of flow analyses), and
- natural variability over time and space (e.g., quantity and timing of precipitation).
Conclusion: "These uncertainties can easily lead to erroneous evaluations of environmental and geohazards, such as water contamination, landslides, and ground failure (subsidence and liquefaction, as seen in sinkholes)." Reading between the lines, the implications for hydraulic fracturing may be substantial.
Award-winning science writer Sandy Dechert covers developments and environmental issues in conventional, solar, wind, biomass, large and small hydroelectric, and geothermal energy. She detailed events and policy at last fall's 18th UN climate change summit meeting in Doha, Qatar. Sandy has also reported on extreme weather disasters, including superstorm Sandy, winter storm Nemo, and the massive summer wildfires of the past decade.
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