The April 23, 2021 issue of Science Magazine showed up in my mailbox over the weekend. I was excited to see that the mainstream of science has finally recognized the importance and the building crisis in groundwater! The cover (as clipped below) was a picture of an agricultural water well in India and a barren and dry land. The title of the issue was “DRY WELLS” with a subtitle “Falling groundwater levels threaten wells globally.” There are two articles in this issue addressing the building groundwater crisis and both are very worthwhile reading -free access is available through the public library.
Rodell,
M., and J. S. Famiglietti. 2002. "The potential for satellite-based
monitoring of groundwater storage changes using GRACE: The High Plains aquifer,
central U.S." J. Hydrology, 263: 245-256.
Below are quoted and paraphrased some of the key points made
by Drs. Jay Famiglietti and Grant Ferguson and Drs. Scott Jasechko and Debra
Perrone in last weeks Science Magazine.
Water is at the core of a sustainable earth and is critical not only for economic development and healthy ecosystems, but for human survival itself. Ninety-six percent of the earth’s non-frozen freshwater is groundwater, fresh water (from rain or melting ice and snow) that soaks into the soil and is stored in the tiny spaces between rocks and particles of soil. Groundwater is the primary water source for billions of people and nearly half of irrigated agriculture. Groundwater is also an essential component of the baseflow of our rivers, streams and creeks. Because groundwater is unseen, mankind has been using it unsustainably. More than half of the world’s major aquifers are being depleted.
Using the well construction data for 39 million groundwater wells in 40 different countries along with available monitoring data Drs. Jasechko and Perrone found that from India to the United States groundwater wells are already running dry from groundwater level declines. Because they are only a few meters below the water table, from 6%-20% of groundwater wells are in danger of running dry from declining groundwater levels, seasonality and drawdown. Though, newer wells tend to be deeper than older wells, it provides only short-term reprieve from declining water levels and increases the cost to construct and operate a well.
Groundwater depletion is projected to continue in the areas
where it is already occurring and expand into new areas not yet experiencing depletion.
Millions of wells are at risk of running dry. Despite this not all areas and countries
are engaged in long term groundwater monitoring. Here in Prince William County,
Virginia we do not have a groundwater monitoring program. There is an
opportunity right now with the county awash in stimulus money to establish a
groundwater monitoring network within the county to develop the relationship to
land use, weather and water use to sustainable water.
As the authors point out, existing groundwater wells are
vulnerable to groundwater depletion because many wells are not much deeper than
the local water table, making them likely to run dry with even modest declines
in groundwater levels. Maintaining the water level above the well pump intake
is critical to sustainable water use but has been ignored in favor of recording recharge
rates in our own well completion reports. Predicting changes to water level requires
that measurements be taken and the hydraulic properties of the subsurface be
studied. Drs. Famiglietti and Ferguson
point out to ensure that groundwater remains a reliable component of water
supplies new networks must be fostered to raise awareness of the urgency of the
situation and encourage and coordinate stakeholder participation and help our
local and state governments build the political will to protect groundwater as
a key element of water security and sustainability.
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