Just as the settling and development of the arid American West was fueled by harnessing its available fresh water, the growing lack of water availability may well be its undoing.
California’s epic drought is just the latest example of what is shaping up to be the new normal out west. Last year was the driest on record. This year, river flows are so low that deliveries of surface water to the southern half of the state, through California’s complex network of aqueducts and canals, were slashed to zero. Thirsty homeowners and anxious farmers have been forced to dig more and deeper wells to tap into steadily declining groundwater reserves.
Several cities and towns in California have imposed mandatory restrictions in order to curtail water use. The State Water Resources Control Board recently authorized fines of up to $500 for wasting water on washing down sidewalks or for overwatering yards. A new study from the University of California, Davis estimates that the current drought will cost the state $2.2 billion in damages, and will result in 17,000 jobs lost.
Such severe drought is becoming more commonplace across the western United States. Just a few years ago, the 2011 Texas drought was raging at full throttle. Nationwide media coverage regularly confronted us with graphic images of emaciated longhorns, desiccated fields and burning prairie grass. Stories of small towns literally running out of water made headlines.
In between California and Texas, there is scarce little green space to be had. Colorado, Utah, Nevada and Arizona are all in the grips of a multiyear ‘big dry,’ with only the last vestige of this past winter’s average snowpack in Colorado to hang their hopes on. Lake Mead, our country’s largest reservoir, is at its lowest level ever.
Can it get any worse? I’m afraid so.
Today, the journal Geophysical Research Letters published a new study from our research team on groundwater depletion in the Colorado River Basin. Quite honestly, we are alarmed and concerned about the implications of our findings. From a group that studies groundwater depletion in the hottest of the hot spots of water stress around the world — in India, the Middle East, and in California’s Central Valley – that says something.
The Colorado River Basin is the water lifeline of the western United States. It provides water to roughly 40 million people in 7 states and to Mexico. It supplies water to major metropolitan regions including several of the country’s largest and driest — Los Angeles, San Diego, Phoenix and Las Vegas — and enough water to support irrigation on 4 million acres of farmland. As the water future of the Colorado River Basin goes, so does that of the west.
In our new study, we used NASA satellites to find that between December 2004 and November 2013, the Colorado River Basin lost a total of 65 cubic kilometers of water, or roughly the equivalent of two full Lake Meads. This was a period of prolonged drought in which the water levels in Lake Mead and Lake Powell (the United States’ second largest reservoir) had fallen to dangerously low levels, and were being carefully managed to prevent further declines. Surprisingly, we found that 75% of the water lost was from the Basin’s groundwater supplies.
Such behavior is normal in times of drought. Groundwater is the strategic reserve when persistent drought limits rainfall and snowmelt that would normally feed our rivers and replenish our aquifers. It allows local water managers to bridge the shortfall between supply and demand, and farmers to secure precious irrigation water and continue to grow food to put on the nation’s tables.The map above combines data from the satellites of the NASA Gravity Recovery and Climate Experiment (GRACE) with other satellite and ground-based measurements to model the relative amount of water stored in underground aquifers in the continental United States. The wetness, or water content, is a depiction of the amount of groundwater on July 7, 2014, compared to the average from 1948 to 2009. Areas shown in blue have more abundant groundwater for this time of year than comparable weeks over the long-term, while shades of red depict deficits compared to this time of year.
The maps are an experimental product used by the U.S. Drought Monitor and supported by NASA’s Goddard Space Flight Center. The measurements are derived from observations of small changes in Earth’s mass and its gravity field—features that are affected by the movement and storage of water and ice around the planet.
From the National Drought Mitigation Center and NASA Earth Observatory.
However, in many parts of the west, groundwater is non-renewable. When we use it, it’s gone. Moreover, in most western states, in contrast to management of our surface water in rivers and reservoirs, groundwater management can be loose and difficult to enforce, and in some cases non-existent.
When it comes to groundwater, the west can truly be wild. If you own the property, the vagueries of groundwater law often mean that you can dig the wells and pump to your heart’s content. Multiply that by millions of private wells and you get the picture.
The undeniable consequence is that groundwater supplies in our major western aquifers — the Central Valley, the southern Ogallala and now those that underlie the Colorado River Basin – are disappearing. We simply pump out more water than is being naturally replenished, and as a result, groundwater levels are falling rapidly.
This is a problem if, as the best available science tells us, the frequency and severity of drought will continue to increase in the coming decades. After the groundwater is gone, there is no more backup.
The American West is running out of water.
This weekend, representatives from the 7 basin states, the Bureau of Reclamation and the Department of the Interior will meet to discuss future water management strategies for the Colorado River basin. It is important that this group recognize the following implications for this and future Basin management discussions.
First, in the western United States, we use far more water than what is renewable by natural precipitation and snowmelt. Our rivers and reservoirs are simply no longer enough. We rely on groundwater far more than we are ready to admit.
Second, groundwater is already being used to supplement declining surface water resources, and under the severe drought conditions of the past decade, the Basin has been over-allocated by a much as 30%. Groundwater has been filling the gap between supply and demand.
Third, if we expect to continue to use groundwater as a strategic reserve, then we’d better embark on some strategic management, before our aquifers drop to critically low and perhaps irrecoverable levels.
Without a regulatory framework for jointly managing surface and groundwater resources as ‘one water,’ groundwater levels will continue to fall, basin water managers will be challenged to meet future allocation commitments, and the water security of the western United States will be seriously threatened.
That could mean a far drier future with profound socioeconomic consequences for a vast swath of the western U. S. and its major urban centers. Considering the similar situations in America’s fruit bowl, California’s Central Valley, and its bread basket, the Ogallala aquifer, agriculture in the United States would be difficult to sustain.
My colleague, Bill Patzert, the oft-quoted climatologist at NASA’s Jet Propulsion Laboratory, got it right in a recent quote when he said ‘the American West is on the ropes.’ If we don’t take action soon, it will be down for the count. Sadly, there will be no water left to splash on its face to help it recover.
Jay Famiglietti is Senior Water Scientist at the NASA Jet Propulsion Laboratory of the California Institute of Technology, and a professor of Earth System Science at the University of California, Irvine. The opinions expressed here are his alone.