National Geographic
Menu

Short on Water? Don’t Blame it on the Rain

Colorado River Delta
The Colorado River now dries up completely in the sands of its delta, breaking its fluid connection with the Gulf of California in Mexico. Can a river still be a river when the water is all gone? (Photograph by Pete McBride)

The common refrain in media stories about water shortages is that they are caused by droughts.  Don’t believe them.

Droughts don’t cause water shortages.  People do.

The water shortages appearing with increasing frequency and intensity around the globe are, regretfully, poignant signs of our society’s woeful inability to govern itself within limits, or to plan adequately for the resources essential to our future.

We really do need to come to grips with these failings.  Right now.

As I explain in my new book Chasing Water, the communities using the waters of the Central Valley of California, the Colorado River of the American Southwest, the Ogallala Aquifer of the Midwestern US, the Jordan River of the Middle East, the Cauvery River of India, and hundreds of other overtaxed rivers and aquifers around the world are in serious trouble for three simple reasons: (1) they have been consuming their available water faster than it can be regularly replenished with rain and snow, (2) they lack sufficient restraint or regulatory controls to keep this from happening, and (3) resource limitations or political lethargy cause reaction time to be too slow to avoid disaster.

Taking Stock of our Water Accounts

Your personal bank account offers a near-perfect analogy for understanding the physical cause of water shortages.  If you spend more than you deposit you go bankrupt.  It is as simple as that.

One telling measure of our water bankruptcy here in the United States is our overdraft of groundwater from aquifers like the High Plains (Ogallala), or the Central Valley Aquifer in California.  When you pump water out of an aquifer faster than it is being recharged with percolating rain or snow, the volume of the aquifer is depleted.  Since 1900, we’ve drained U.S. aquifers by a volume equal to two Lake Eries.

What this means in water budget terms is that the communities drawing water from those aquifers are not only overspending their liquid income (percolating rain and snow are the deposits that recharge our aquifers), they’re now raiding their savings to near exhaustion.

In many aquifers, those water assets had been accruing for millennia.  Prior to the mid-20th century we didn’t have the keys to the planet’s underground water vaults because our pumps and wells couldn’t pull water from great depths to the surface.  The industrial-scale pumps that became available following World War II opened access to seemingly unlimited water supplies underground.  This access to abundant groundwater resources enabled agriculture to flourish in otherwise water-limited growing regions like the American Midwest (High Plains/Ogallala Aquifer), the Central Valley of California, and the North China Plain.

But these withdrawals of water quickly exceeded the natural rates of replenishment, in places by more than 10-fold.  The water level is now dropping by more than 10 meters each year in many aquifers.  Today, at the global scale, our collective overdraft is greater than the volume of Lake Tahoe in California or the Dead Sea.  Every year.

In contrast with aquifers – where you can continue to chase water to ever-greater depths if your well pipe is long enough and you can afford the electricity to suck the water from deep in the earth – our overuse of rivers shrivels them in size.  Eventually, we hit an ultimate limit in our exploitation of a river: a dry bed.  The Colorado River Delta is a stark portrait of a river now perpetually devoid of water.  And life.

Increase the Supply or Reduce the Demand?

As with a bank account, there are two general ways to rebalance an overdrawn water account: you can look for ways to increase your deposits (water supply) or you can reduce your expenditures (demand management).

For example, you can import additional water using long-distance pipelines and canals.  The State Water Project in California, the Central Arizona Project, or the new South-North Water Transfer Project in China are grand examples of this approach.  A major obstacle of water importation is its cost; water is heavy, and it takes a lot of electricity to move it over long distances or uphill.  That’s why the State Water Project and the Central Arizona Project are the two biggest electricity hogs in their respective states of California and Arizona.

The electricity cost – which translates into higher water costs – is the primary reason why we are not seeing more large-scale water-moving schemes being proposed in water-scarce regions.

Alternatively, we can remove salt from ocean water and transform it into freshwater supply.  This can be a particularly attractive option for cities near coasts.  But again, the huge limitation of desalination is its cost, again due to the electricity required.  The Saudi Arabians are the global kings of desalination, made possible in that country because of the availability of oil to generate electricity.  The Saudis burn through one-and-a-half million barrels of oil every day to power their 30 desalination plants.  When other countries or communities have to pay the full cost of that electricity, the price can be quite prohibitive.

There is a Better Way

Before pursuing expensive new options for bolstering water supplies, it is critically important to minimize the amount of water needed in our homes, industries, and on farms.  When viewed as a water budget-balancing strategy, water conservation – both in cities and on farms – typically costs one-third to one-tenth of the expense of developing new water supplies, such as by importing water or desalting ocean water.

No water supply option should be pursued until we have trimmed our water expenditures to a minimum.

In addition to cost savings, water conservation is highly preferable to water supply projects from an environmental perspective.  Water importation can disrupt existing land uses or natural landscapes, or block animal migration routes as pipelines or canals are constructed across the landscape.  These projects can also displace people or entire towns and villages located along the pipeline or canal route.  Generating the electricity needed to power a water importation or desalination project likely also produces undesirable carbon emissions that are driving climate changes.  Also problematic in desalination is the need to safely dispose of highly salt-concentrated brine water, the spoils of the desalting process.

The Central Arizona Project canal
The Central Arizona Project canal brings water from the Colorado River across most of the arid expanse of the state of Arizona, supplying water to large cities including Phoenix and Tucson. (Photograph by Brian Richter)

By contrast, water conservation lightens our touch on freshwater ecosystems and species.  Or at the very least, it can help us avoid further impact.

Fortunately, there is great potential for using water more efficiently, both in our homes and on farms.  The average rate of water use in Australian cities, for example, is less than half the volume used in cities in the western U.S.  Much of that difference comes from the Aussies’ landscape aesthetic.  In their urban landscapes, they plant native species or other vegetation well-suited to their climate, thereby requiring little to no outdoor watering.

Much greater water savings are possible in irrigated agriculture, simply because of the gigantic volumes of water used in growing crops.  While squeezing true water savings out of an irrigation system can be tricky, a tiny bit of improved efficiency here will result in a very large volume of savings.  With more than a half-century of experience in pushing irrigation efficiencies higher, there is much to be learned from Israeli farmers.

Living Within Our Water Budgets

The single most important way to avoid a water shortage is to begin living within the limits of nature’s water budgets.  We need to stop overspending the rain.

To do this well, our water managers need to carefully estimate the likely volume of water that will be available in each water source that we rely upon – not just the average amount of water likely to be available over the decades, but instead, how much we can count on during droughts, or during a future when less water could be available as a result of climate changes.

We don’t have to always constrain our water appetite to the worst-case scenario, but we must be ready for it when it arrives.  When more is available, an adaptive water allocation system should be able to optimize water usage to take advantage of greater abundance, but not become addicted to it.  In Chasing Water I offer an illustration of such an adaptive allocation approach, which I’ve called “cap-and-flex.”

Is a River Still a River When the Water’s All Gone?

Lastly and of utmost importance, we must begin questioning the wisdom of taking all that a river or aquifer has to give.  We possess the means to wring every last drop from the planet’s rivers and lakes, or to suck its aquifers dry, but is that what we really want to do?  Don’t we instead want to leave some water alone, enough to fuel the biological engines of our planet, or to serve as a hedge against dry times and an uncertain future, or simply to irrigate our souls with the intrinsic beauty of flowing water?

Drying our planet’s rivers and lakes is not a foregone conclusion.  We can find the water we need without destroying natural freshwater systems in our wake.

As with monetary inheritance, our children will surely thank us for all that we save today.

Brian Richter’s new book, Chasing Water: A Guide for Moving from Scarcity to Sustainability, will be available from Island Press in June.

Comments

  1. Paul Heymann
    Roanoke, VA
    April 11, 10:22 am

    Another issue is that pumped water from aquifers usually contains minerals, including salt. When that water is used for irrigation, these minerals can get concentrated in the top soil. Eventually the soil can get too salty for plant growith. Rainwater, by contrast, was “distilled” from ocean evaporation and does not contain minerals.

  2. Tim Town
    San Jose, CA
    March 8, 4:33 am

    The author ignorantly (or purposely) omits a great option for increasing availability of water…namely, storage reservoirs. These can be located and constructed with sensitivity to the environment, and can capture water during heavy rain years for use during light rain years. This is a better option than over-pumping the aquifers. The current water shortage situation is due to an increasing population without the corresponding increase in water storage reservoirs. The solution is to increase water storage reservoirs to keep up with population growth.

    • Brian Richter
      March 8, 5:30 pm

      Storage reservoirs can be a very sensible way of storing water during a wetter time of the year, for use during a drier season But they really don’t help much in multi-year dry periods or prolonged droughts, as currently in evidence in California, Texas, and the Colorado River basin. You can’t hold onto water forever. They can also be substantial water “consumers” themselves, as evaporative losses from reservoirs can be quite high, particularly in more arid regions. For example, nearly 15% of the water in the Colorado River ends up evaporating from the large storage reservoirs in that basin.

  3. Greg Koch
    Atlanta
    March 7, 9:48 am

    You hit the nail on the head, Bryan. The bank account analogy is perfect — governments are quick to borrow more money (or create more) running a deficitt and huge debt. This obviously doesn’t work with water.

  4. Wade Peerman
    Portland
    March 5, 4:42 pm

    It’s not just our freshwater ecosystems that suffer from over use, but also our seas. The lack of any flow from the Colorado River has changed the Sea of Cortez as highlighted in this Harper’s magazine piece by Erik Vance, http://harpers.org/archive/2013/08/emptying-the-worlds-aquarium/