Groundwater Declines Seen, Even in Wet Climates: Studies

By Amena H. Saiyid

Aug. 22 — Water availability in the U.S. characterized by four years of drought in the West and more rainfall in the East reflects the nation's geographic extremes from deserts and mountains to low-lying swamplands. Even where water seems abundant, rising demand is stressing the ability to re-charge groundwater supplies everywhere.

From all appearances, the West Coast in 2015 was thirsting for more water with its parched lands and dried up lakes and rivers, while most of the Southeast was wetter than average, according to the National Oceanic and Atmospheric Administration.

Regardless of how much rainfall the different regions received, the reality is that groundwater, held in vast aquifers—sponge-like porous rocks or gravel and sand-filled underground reservoirs—is declining on both coasts. That is because either there isn’t enough rain or snow to replenish aquifers or too much groundwater is being pumped nonstop to supply a rapidly growing population that has grown to expect water to be supplied 24 hours a day, seven days a week, and 365 days a year.

Groundwater in any country is a valuable, yet hidden, resource. It is responsible for half of this nation’s drinking water supply, according to the U.S. Geological Survey. Globally, it accounts for 99 percent of the unfrozen freshwater, according to UNESCO. This source of freshwater is used in some way by about 75 percent of cities and in most industrial processes. The largest use of groundwater is to irrigate crops.

Keeping groundwater recharged is essential for maintaining sufficient water levels in lakes, rivers and streams; protecting water quality, especially in streams where groundwater and surface water meet; and preventing land subsidence that can occur with a sudden drop in the underlying water table.

Take Florida and Nevada as examples of climates at either end of the spectrum: one is lush with vegetation while the other is a desert. Yet, both grapple with dwindling groundwater supplies because the demand for freshwater exceeds what the states' aquifers can support.

In Nevada, evidence of groundwater depletion can be seen in the low water levels of the Colorado River Basin. The drought has led to a shrinking Lake Mead and caused water levels to drop in many of the aquifers underlying the basin, which in turn reduces the base flow in the river feeding the lake.

Subtle Effects of Groundwater Scarcity

Paddling down the Ichetucknee River in North Central Florida under the overhang of the ancient cypresses and hardwoods, it is hard to imagine that the Sunshine State is hurting for water. This part of the state receives about 55 inches of rain a year, providing no reason for water shortages to occur here, yet they do.

“To you it looks incredibly abundant, but if you go by the historical baseline, then river flows are about 25-30 percent lower than the flows in the 1960s,” Cynthia Barnett, an author and visiting professor of environmental journalism at the University of Florida in Gainesville, told Bloomberg BNA, as she paddled her kayak down the river.

North Florida is home to the greatest concentration of freshwater springs in the world. They are fed by the Floridan Aquifer, which provides 90 percent of Florida's drinking water and underlies most of the state, about half of Georgia, parts of Mississippi and Alabama and a little bit of South Carolina, according to Barnett.


A Bloomberg BNA slideshow showing declines in groundwater aquifers is available at

Barnett, whose book, “Rain: A Natural and Cultural History,” was longlisted for the National Book Award, took a gaggle of reporters and Leonard Konikow, an emeritus scientist with the U.S. Geological Survey who specializes in groundwater, kayaking down the river for a close-up look at how climate change and human activity are adversely affecting not only water quantity, but its quality.

The trip was part of the McCormick Specialized Reporting Institute in November to educate environmental reporters about U.S. water issues, now exacerbated by the changes in climate that swing from prolonged droughts in the West to incessant rains in the East.

A native of Florida, Barnett has seen changes in the quality of Florida’s pristine freshwater resources—its rivers, springs and swampy areas. As the group silently paddled past turtles sunbathing in threes and fours on logs along the river banks, Barnett quoted the 19th-century naturalist and artist William Bartram whose descriptions of Florida’s waters in the late 18th century include fast-bubbling springs, “something we never see now.”

“Florida has so over-pumped its once abundant groundwater that the hundred-thousand-square-mile sponge known as the Floridan Aquifer, one of the most productive aquifers in the world, can no longer supply the state's drinking water needs,” Barnett wrote in her 2011 book, “Blue Revolution: Unmasking America's Water Crisis.”

Florida's population has soared over time. In 1950, it was home to 2.8 million. The U.S. Census Bureau estimates that number grew to 20.3 million by 2015.

Algae Blooms: Foreshadowing Changing Climate

She pointed to the black algae hanging from the banks and clouding the shallow water. “This is where we see the signs of our indelible connections between human activities and water,” Barnett said.

Excess nitrogen and phosphorus in stormwater and agricultural runoff as well as discharges from septic tanks and municipal-owned wastewater utilities have fueled a growth in various forms of algae, some harmful for humans and others to fish populations. Nine pristine springs bubbling out of the karst topography of limestone caves serve as the link between the groundwater reserves in the Floridan Aquifer and the Ichetucknee River.

Shallow water that is easily warmed by the sun has also fueled the algal growth. Forty years ago, this water was crystal clear enough to wash fruit brought on picnics, recalls Alison Adams, chief technical officer for Tampa Bay Water who was a local resident of this area.

As the group kayaked downstream, Konikow said the Ichetucknee River gradually became wider and deeper, fed by the groundwater seeping from the limestone caves that characterize the state's karst topography.

“If development remains unchecked, the environmental impacts will be felt in Florida with a decline in groundwater levels causing reduced flows at springs,” Konikow said.

In fact, Florida’s groundwater regulations were born in the early 1970s after over-pumping began to dry up springs, lakes and other natural waterbodies, Barnett said. Drought had also settled on the state, and in South Florida, the Everglades burned ominously, she said.

 Disappearing Groundwater in U.S.

Kissengen Spring was a popular spot for swimming in Central Florida’s Polk County and dried up from overzealous pumping to feed the phosphate industry in the 1950s.

Two decades later, White Springs in North Florida experienced a similar fate.

The average spring water flow in North Florida alone has declined by 21 percent compared with pre-development conditions, according to a 2014 study by Robert Knight, environmental scientist and founder of the Gainesville-based nonprofit Howard T. Odum Florida Springs Institute, and Scott Knight, of the University of Florida.

Declines in groundwater levels can lead to salt-water intrusion into aquifers and can also negatively affect native plants and wildlife.

Most importantly, though, excessive pumping of groundwater can lead to lower aquifer levels that in turn cause sinkholes to form, according to a presentation by Robert Knight.

Correlation With Population Increase

Meanwhile, on the West Coast, changes in climate have wrought an extended drought, curtailing snowfall that creates frozen stores of water that melt and feed the Colorado River and other river systems which are important sources of freshwater.

Inadequate snow melt translates to insufficient groundwater recharge. Nationwide, groundwater use increased steadily between 1945 and 1980 before leveling off and then decreasing through 2000, Konikow said, citing his own May 2013 study that was published as a U.S. Geological Survey report, and updated in January 2015 in an article in the National Groundwater Association's Groundwater journal. Konikow presented these findings in Florida to news reporters as well.

At the local level, particularly in Las Vegas, the same trend can be observed with exponential increases in population between 1950 and 2010 prompting the need for more groundwater to meet the city's needs. Nevada, for example, grew from about 160,100 people in 1950 to 2.9 million in 2015, according to the U.S. Census Bureau.

“Simultaneously, water levels in some wells dropped more than 100 feet because of overpumping,” Konikow said, adding “the correlation is hard to miss.”

According to the USGS, the growing demand for freshwater means groundwater is being withdrawn at a faster rate than aquifers can replace it. Konikow said more wells and deeper wells are being drilled to meet this demand. The phenomenon of pumping out groundwater from the Earth, he said, is akin to a person using a straw to sip Coke out of a glass filled with ice.

“Except in this case, there are thousands upon thousands of wells,” Konikow said.

The situation is reminiscent of Daniel Day Lewis’s Oscar-winning portrayal of Daniel Plainview, the hard-scrabble oilman, in the film “There Will be Blood.” Plainview drills wells to extract oil trapped underneath his property, but also from the reserves underlying the land of his neighbor who refused to sell him the rights initially. The neighbor discovers there is no oil left under his land because it all has been sucked out by Plainview's wells.

The oil, like groundwater, is a finite quantity that can be overdrawn. The key lies in management, according to scientists and policymakers well versed in groundwater issues.

“We take water for granted,” said Patricia Mulroy, a senior fellow with the Metropolitan Policy Program at Brookings and a senior fellow for climate adaptation and environmental policy at University of Nevada, Las Vegas Brookings Mountain West. “Ben Franklin was right. You learn the value of water when the well runs dry, and human behavior has replicated that time after time after time,” Mulroy said, in a video posted on the Brookings Institute website on water scarcity and climate change. Mulroy is the former general manager of the Southern Nevada Water Authority, the water utility serving Las Vegas.

The driest state in the U.S. and its wet counterpart 2,000 miles away are employing similar solutions to help the aquifers recover. These involve better groundwater stewardship from the state level down to farms and individual yards. Amid very different groundwater laws that are driven by the geology and climate, regulators in Nevada and Florida also face pressure to permit more groundwater pumping for those who would put the water to “beneficial use.”

Both states also have seen per-capita and overall water use decline but not enough to reverse the steady depletion that marked the second half of the 20th Century and has been aggravated by the current drought. NASA satellite imagery that reveals moisture underground shows severe hotspots in the arid West and North Florida alike.

For instance, Florida with its tropical, lush vegetation is looking to grow more native plants that will retain water in the soil to compensate for over-pumping. Drought-stricken Nevada is paying homeowners to remove water-hungry grass from their yards.

Over-allocated Basin

Nevada has been drawing less water from the Colorado River than it is allowed under allocations set through an agreement with six other western states. It has taken steps to ensure that the hotels along the Las Vegas strip reuse every drop of water and has placed communities on a watering schedule. But those measures haven’t been enough either, partly because the surrounding states have not cut back on their water use, according to Konikow.

The Southern Nevada Water Authority for instance has prohibited turf in the front yards of new development since 2003 and limited turf to 50 percent of the area that can be landscaped in the back yards. Golf courses are allocated an annual amount of water annually and residents are banned from watering during the hottest times of the day, which run from 11 a.m. to 7 p.m., according to the authority, which represents seven wastewater utilities and water agencies and serves 2 million residents in the cities of Boulder, Henderson, Las Vegas, North Las Vegas and areas of unincorporated Clark County in Nevada.

The Colorado River Basin, which supplies water to 50 million people and irrigates nearly 5.5 million acres of land in seven states, is losing water at rates far exceeding how quickly it can be replenished. Water is over-allocated in this basin partly because the amounts each state could receive under the agreement were set in 1922 at a time when the average flow levels were above the 100-year norm.

Lake Mead, which is the largest surface water reservoir in the U.S., is showing the effects of over-allocation and over-usage of water in the Colorado River Basin that in turn are over-amplified by the effects of drought. The level of Lake Mead has steadily dropped to its lowest level of 1,080 feet, a level not seen since 1937 after the completion of the Hoover Dam.

The white perimeter along Lake Mead is a giveaway of the drop in water levels.

A recent study, published this May in the American Geophysical Union journal Water Resources Research, shows that more than half, or 56 percent, of the streamflow in the Upper Colorado River Basin originates as groundwater, and about 80 percent of this flow is lost when it reaches the lower basin by evapotranspiration or water diversion for irrigation.

Need for Overarching Measurements

With groundwater management left in the hands of states, Sandra Postel, director and founder of the Global Water Policy Project, observed in a June 2014 blog that there has been no overarching assessment of groundwater resources until NASA used data from its Gravity Recovery and Climate Experiment (GRACE) satellites to measure groundwater depletion. Now more studies are coming out of the USGS, the University of California, Irvine, and the University of Texas at Austin showing the indelible connections between groundwater levels and declining surface water linked with increased development.

From a regulatory perspective, managing this critical resource is problematic because “groundwater is treated separate from surface water when both are linked through hydrology and ecology.”

There has to be an integrated solution, Postel said.

However, neither Konikow nor Postel advocate for a federal solution, but instead call for strategies that are tailored to the hydrology of the region.

The issue of water scarcity has grown in prominence at the global and domestic level. Water stress was identified as a source of regional instability by a 2012 Intelligence Community Assessment on Global Water Security. From the historic drought in California to serious water quality issues in China, water has emerged as a topic of growing concern for businesses and investors. Water topped the World Economic Forum’s annual risk ranking this year, and it is making its way into analysts’ recommendations to buy and sell stocks.

Recognizing the importance of water, the White House in March held a summit on World Water Day, and released a document listing commitments made across the nation by universities, municipalities and companies to develop sustainable uses for water.

One of these programs included the University of California's Water Security and Sustainability Research Initiative. The university system has committed to develop an integrated water-accounting system that will combine conventional groundwater-level monitoring data with modeling tools. The idea is to disseminate this system to hundreds of water managers by 2017, including those in 127 California state-defined groundwater basins.

At this summit, Richael Young, president and co-founder of Nebraska-based Mammoth Trading, announced the launch of a trading program for farmers that rely on groundwater pumped from the stressed Ogalalla Aquifer to irrigate their crops. Under this program, farmers would be able to trade rights for conserving groundwater with those users who need it.

“We don't need more water. We need to be better stewards of water,” Young told the gathered audience of policy makers, scientists and engineers at the White House summit, as she explained the company's trading programs.

Postel recommends that states develop incentive-based programs. She points to the “cash-for-grass” initiative in Las Vegas where homeowners are paid not to grow grass in their yards that require extensive watering. She encourages the use of water banking, where farmers who conserve water can trade some of their rights to municipal and industrial users in the West.

She said the current water allocation system for the Colorado River Basin is too fixed and stuck. Instead of allocating water to the states based on a system that everyone knows is not reflective of current conditions, a new compact should be developed that would allocate water based on the percentage of total supply available.

“At this moment, we as a society are like the frog that chooses to stay in a warming pot of water as the heat is gradually turned up—unable to grasp the dire consequences of incremental change. Inch by inch, the water tables drop. Mile by mile, the rivers run dry. The trends are not good. Yet we stay the course, refusing to recognize that, for safety’s sake—for survival itself—a big change is necessary. We pretend not to know. Denial, as has been said, is not just a river in Egypt. It flows in every one of us,” says Postel on the website of the Global Water Policy Project.

To contact the reporter on this story: Amena H. Saiyid in Washington at

To contact the editor responsible for this story: Larry Pearl at

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