As U.S. Population Rises, Groundwater Levels Fall

Published on August 10th, 2017

A new analysis by the Alexandria, Virginia-based group Negative Population Growth (NPG) finds that rapid U.S. population growth is stressing both the quantity and quality of our nation’s critical groundwater resources.
It is difficult to overstate the importance of groundwater and aquifers to America’s economy and wellbeing. As the United States Geological Survey (USGS) states:
“Ground-water use has many societal benefits. It is the source of drinking water for about half the nation and nearly all of the rural population, and it provides over 50 billion gallons per day in support of the Nation’s agricultural economy.”
Just how much water is 50 billion gallons per day to support U.S. agriculture? That volume of water would fill the enormous Vehicle Assembly Building (VAB) at the Kennedy Space Center in Florida about 54 times. The VAB – in which the colossal Saturn V rockets that carried men to the moon were assembled – is one of the largest buildings in the world by volume, with an interior space of 3,665,013 cubic meters (129,428,000 cubic feet).
Multiply this by 365 days, and the amount of groundwater used annually to irrigate our crops and feed our livestock would fill the VAB nearly 20,000 times. Now that’s a staggering quantity of water! It’s no wonder that groundwater depletion is a serious problem, one that is made worse by incessant California and U.S. population growth.  

Kennedy Space Center
The amount of groundwater used in U.S. agriculture every day would fill the
cavernous Vehicle Assembly Building at the Kennedy Space
Center in Florida about 54 times. 

Depletion happens, in essence, when the amount of water pumped out of an aquifer (which is an underground “reservoir” of water) exceeds its recharge rate, that is, the rate at which rainfall and snowmelt infiltrate the soil and seep downward to the water table below. Aquifer recharge can also occur from surface water bodies such as rivers and lakes.
Again the USGS:
“Ground-water depletion, a term often defined as long-term water-level declines caused by sustained ground-water pumping, is a key issue associated with ground-water use. Many areas of the United States are experiencing ground-water depletion.”

Aquifier system chart
Groundwater budgets in the Gulf Coastal Plain system, one now subject
to depletion from water withdrawals (pumping) under development conditions.

The new NPG Forum Paper by Christopher J. Daly examines the worrisome status of several of America’s most important aquifers in Florida, Texas, Kansas, and California, as well as the unsustainable exploitation of the “Granddaddy of America’s Aquifers”: the Ogallala.
The Ogallala/High Plains Aquifer spans parts of eight states in the center of the country. It first formed some 10 million years ago, fed by streams draining the Rocky Mountains and flowing eastward toward the Mississippi River. It is essentially a fossil aquifer; if it were drained all at once, it would take more than 6,000 years to recharge. 
Today the Ogallala is being depleted at a rate equivalent to the annual discharge of 18 Colorado Rivers. More than 90 percent of the water being pumped out of the Ogallala is used to irrigate the grains and other staple crops – wheat, corn, grain sorghum, soybeans, etc. – that feed Americans and the livestock we eat. Some of that output is also exported to a hungry world, of course. But this is an example of unsustainable agriculture, because it relies on “mining” an essentially nonrenewable water resource.  

The Ogallala Aquifer underlies portions of eight states,
including most of Nebraska.

Today, population growth and climate change (which is drying out most of the region) are subjecting the Ogallala to greater stresses than ever, according to Scientific American.
Among the appropriate responses to these grim realities are less thirsty crops such as drought-tolerant corn, dryland farming techniques, no-till agriculture, and more efficient irrigation techniques and tools. Of course, U.S. population stabilization to stop the ceaseless growth in demand from an ever-increasing number of consumers is also a must.
The Floridan Aquifer is the largest in the southeastern U.S., underlying much of Florida and parts of Georgia, Alabama, Mississippi, and South Carolina. Pumping groundwater out of it has helped enable the explosive growth of Florida’s population from just 3 million in 1950 to over 20 million today. But over-pumping of the Floridan Aquifer also contributes to saltwater intrusion along the coasts and the appearance of sinkholes in many places, which have notoriously swallowed up homes and businesses, and even tragically devoured people. 

Massive sinkhole in Winter Park, Florida
Massive sinkhole in Winter Park, Florida.

In Texas, state-wide efforts are underway to manage and conserve groundwater resources. But as Daly states:
“What is true for Texas is true for the U.S. as a whole: sustained population growth will inevitably, sooner or later, wipe out conservation and efficiency gains – triggering water shortages and/or a need for new environmentally damaging water projects. Water savings from efficiency and conservation should not be squandered to accommodate still more population growth.”

And at present, the state of Texas has the fastest population growth in the country, even faster than California or Florida.  Texas population graph
By 2070, demographers project that there will be more than 50 million Texans. And the implications for the state’s water resources – surface water and groundwater alike – will be dire.  

In Kansas, farmers are mining water from the High Plans Aquifer to boost corn yields for ethanol production due to the federal mandate. They are stealing from tomorrow’s prospects to inflate today’s. 
California has long been suffering from depletion of its critical Central Valley aquifers, a long-unfolding crisis made acute by the most recent, historically-horrific drought. With surface water so limited, farmers were pumping groundwater at unparalleled rates. For the moment, this pressure has been alleviated by last winter’s unprecedented rains and snows that broke the back of the drought. For the moment. 
Measurements made in 2015 by NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites found that in the combined Sacramento and San Joaquin River basins, at the northern and southern areas of the Central Valley, over-pumping between 2011 and 2014 amounted to 12 million acre-feet of water per year. This would almost equal the annual, natural flow of the Colorado River into the Gulf of California before massive diversions reduced it to a trickle.   
This accelerated pumping enabled agricultural operations to survive despite the drought, which curtailed deliveries of surface water for irrigation of the Central Valley’s 250 types of crops.
California’s groundwater is threatened not just by over-pumping and depletion, but by contamination. In one outrageous case, in the fall of 2014, it was reported that state officials had inadvertently allowed oil and gas companies to inject nearly 3 billion gallons of hydrofracking wastewater into aquifers that could have been used for drinking water or irrigation.
As the NPG Forum Paper by Christopher J. Daly says, we expect water to be there “24 hours a day, seven days a week, and 365 days a year – whenever we want it.” In other words, in this land blessed with abundant resources, affluence, and knowhow, we take abundant, clean water for granted.
When I was a Peace Corps Volunteer in impoverished Honduras, water was not always available at the turn of a faucet. And you had to boil or filter what came out of that faucet to kill the pathogens it might contain. Although I tried to be careful, within two weeks of arriving, I’d already had the first of many bouts of diarrhea. At least I avoided amoebic dysentery and cholera. 
Whether in the United States or Honduras, population stabilization is a key part of the solution to our groundwater conundrum: how to use this critical resource today while still preserving it for tomorrow.
And this relates to “sustainable development” as defined in the now-classic 1987 report of the World Commission on Environment and Development (aka, the Brundtland Commission), Our Common Future:
"Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”    


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