Ten years ago, World Bank VP Ismail Serageldin said "If the wars of this century were fought over oil, the wars of the next century will be fought over water." Though some people at the UN disagree, there is no question that water scarcity is a looming problem of our time.
What many urban greens don't know is that solving the world's water problem requires solving the irrigation problem. Both in the developed and undeveloped world, irrigation is a boon to agriculture, and in some ways a boon to sustainability, allowing farmers to increase production of their land without having to convert more forests or other wild areas into cropland. However, inefficient irrigation wastes more water than all the people of the world use (efficiently or inefficiently) for all their drinking, bathing, manufacturing, and industry. By a long shot. Worldwide, 70% of all water use is agricultural irrigation, according to the UN World Water Development Report. (22-23% is used for industry, and the remaining 7-8% is domestic use.) In the US, irrigation uses 80%, and in the dry western states 90%, according to the USDA. What's more, the UN's World Water Assessment Program says that almost 60% of irrigation water is wasted. (These and many other impressive statistics at International Water Management Institute and Earth Policy Institute.) Usage and efficiency differs from country to country, but to give you an idea of scale, the unit of measure for irrigation in the US is an acre-foot: the amount of water required to fill an acre of land one foot deep. (That's about 1.2 million liters.)
Why does all this irrigation water get squandered, and how can it be fixed?
For poor farmers, irrigation water is usually squandered by lack of infrastructure--bringing water from river or dam to field using canals without linings or covers, which would prevent water soaking into unfarmed soil or evaporating into the air. Since most of the world's poorest people are farmers, they are also the people who suffer the most from inefficient water use, because they are the last ones to get clean safe drinking water. The solution to this is smart investment, which some government programs and micro-credit organizations and are making possible, but funding is wanting. India was the cradle of modern irrigation technology while under British rule, with a mix of public and private funding for waterworks projects (as well as a mix of success and failure, according to a nice paper on the history & its lessons for today). India could now become the cradle for the next generation of water-efficient micro-scale irrigation if they put their minds to it.
For rich farmers, water is usually squandered by the tragedy of the commons. Most countries--including developed ones--lack water-rights laws that charge for water usage. In fact, most rich countries have laws that say "use it or lose it" and "first in time, first in right", which actually encourage farmers to use as much water as they can, even when they don't need it. City dwellers are used to paying for water, but they are paying for their water delivery, not their actual water consumption; irrigators do not pay by the liter as urbanites do. Changing water rights laws, or shifting taxes to charge for water consumption, would help align price incentives with resource scarcity. The Canadian government's Policy Research Initiative found that simply measuring irrigators' water usage (no fees, just metering) caused them to reduce usage by 10%, and introducing a price penalty for exceeding water allotments caused an additional 22% reduction. Aggressive price changes (which could include rebates for low-volume users as well as fees for high-volume users) could easily cause much larger changes in usage.
The irrigation problem will become bigger in coming decades: the World Bank estimates that population growth will require global agriculture to double its production in the next thirty years, and as developing countries lift themselves out of poverty, consumers' appetite for water-intensive foods like meat tend to skyrocket. But with clever policy incentives and infrastructure improvements, the world could double irrigation without using any more water than today. We might even be able to use less. According to the Pacific Institute, California used less water in 2001 than it did in 1975, despite population growth of 60% and a 2.5x increase of gross state product. The "soft path" to avoid catastrophe in water supply is not only possible, it is already being done in some places.
How can farmers reduce water usage? The first part of the solution is to choose crops and animals that require less water (for instance, raising 1kg of beef uses 15 to 30 times as much water as growing 1kg of grain). But the real burden here is on consumers making their food choices. Farmers need to grow what sells, or they go out of business; consumers ultimately decide what crops are grown.
Assuming that farmers are growing what they need to grow, agricultural water use can still be cut in half or better by choosing the right irrigation system.
Drip irrigation, first tried in Germany in the 1800's and then brought to its modern incarnation in Israel in the 1960's, is the most efficient method of delivering water to a plant's roots. Running water through open ditches or canals (called "surface irrigation") allows water to evaporate into the air and soak into the ground; spraying water through the air with sprinklers is effective in humid climates, but can cause up to 45% evaporative loss in desert climates. Drip irrigation instead uses pipes with tiny holes or channels in them (or pipes of porous material) that let a controlled amount of water drip from the pipes in certain places directly onto the ground. Some systems are even buried below ground to prevent any evaporation. Drip irrigation is especially good for trees and shrubs that don't require tilling of the soil, but the system can be used anywhere. Though it can be more expensive to use than sprinklers or surface irrigation, it can also improve uniformity of water distribution, which keeps crop quality high.
Other techniques are also important. Scheduling, for instance: watering more or less in different parts of the season, compensating for weather; and if evaporation is an issue, watering at night to reduce losses from the heat of the day. While use of greywater for irrigation is only an option for urban gardens and landscaping, cropland irrigation systems could return runoff from the bottom of a sloped field to the top to be used again. This would also lessen the runoff of fertilizers or pesticides into rivers and groundwater. Mulching and other techniques can also reduce evaporation.
Paying For Water
With drip irrigation, we know that the technology exists for saving water. Since it hasn't been used much, clearly we also need some incentives. The most obvious is making water cost money.
British Columbia taxes water consumption at varying rates, as low as $20 per acre-foot (about 1.6 cents per 1000 liters). According to Sightline Institute's book Tax Shift, if the US state of Idaho (a particularly dry state) enacted a similar tax, it could cut its sales tax in half, and even if all the farmers' additional costs were passed on to consumers, the reduction in sales tax would decrease food prices more than water taxes would increase them. If monitoring agricultural water usage were seen as too burdensome, the tax could be placed on water rights instead, giving farmers an incentive to use less water so they can sell the remaining rights to others. Another possible incentive structure would be water markets, where the government decrees a certain amount of water use is allowed annually, and the right to use it is bought and sold among users. Such markets have proven very effective incentives for carbon emission reductions, and many policymakers argue that they work better than taxes.
Most small farmers today, even in rich nations, are barely making ends meet, and thus lack the cash to invest in infrastructure such as drip irrigation. At the same time, some green office buildings spend significant amounts of money putting in rainwater catchment systems, low-flow toilets and other fixtures, etc. What if, instead, a building developer bought a farm a drip irrigation system (and perhaps even provided for its maintenance & upkeep with an endowment or other service contract)? An entire subdivision may use 8000 gallons per day, and making all the houses super-water-efficient like BedZED might reduce that to 2600 gallons per day; but a California farm may use 2.6 acre-feet per acre per year (over 2300 gallons per day, per acre). So a hundred-acre farm (the size of about four city blocks on a side, square; roughly as big as a small subdivision) would use 230,000 gallons per day. Even reducing that farm's water use by 3% causes more water savings than reducing a normal subdivision's water use by 60%. Installing a state-of-the-art drip irrigation to reduce the farm's water use by 50% would save 115,000 gallons per day, which is over 19 times what the BedZED-style water saving would achieve in the subdivision.
William McDonough once told a building developer to plant ten square miles of forest to offset greenhouse emissions for the building being built. It's time for an architect to tell the developer they're buying drip irrigation for ten square miles of California farmland. Assuming that reduced water use by 50%, it would save almost 7.4 million gallons per day--enough LEED credits to last the rest of their career.
I think all calls to conserve, whether it be water, energy, food, or other resources, is a good thing. However, it is in the nature of things that whenever we expand a resource by conservation or production, we just push the ultimate result of overpopulation down the road. If it weren't for our ever increasing population, we probably wouldn't even be talking about these issues. Until we find a way to permanently reduce our population and keep it there, all calls for more efficiency or more production are ultimately fruitless and just makes the ultimate result even more miserable.
Regardless, I conserve. But I have this nagging feeling that there will just be additional population and growth that will just take up the slack.
A couple of observations:
- water conservation can be as simple as placing a stone next to the plant to provide a condensation trap.
- the Regent Honeyeater Project is a program in NE Victoria that, each August/September (sprout time), uses seed gathered from indigenous vegetation to create habitat links between isolated bits of bushland for endangered species. The point being that, when planting, they don't water the seedlings at all! They have a remarkable strike rate of over 90%, even in drought years. While wattles etc. aren't an intensive agricultural crop, it does demonstrate the advantages of not just native, but local, vegetation in adapting to local conditions.
Population growth is of concern, but the scenarios are looking far less malthusian than they were a couple of decades ago. When I last checked, the world population was estimated to peak in 2030? at ~10 billion (Scientific American had an excellent report in September, 2005)
Regardless, the next few decades are going to be 'interesting times'.
It's good to see recognition that the typical sprinkler system of irrigation results in massive water loss through evaporation - as temperatures continue to rise and desertification continues to advance globally this is likely to become an worsening problem unless an incentive for drip irrigation is found.
What bothers me is the idea of forcing payment for water...we saw some consequences of such an idea in Cochabamba, Bolivia in 2000 (http://www.democracyctr.org/waterwar/#war) when privatization of water set off shockwaves across the nation, especially among urban dwellers and small farmers.
That access to potable water is a basic human right is affirmed in the 1948 U.N. Universal Declaration; however, Cochabamba proved that this right can be negated by price-gouging (which is all but guaranteed as water supplies dwindle).
The question is - what incentive can spur farmers to irrigate sustainably, that will *not* make water inaccessible to the small or subsistence farmer?
WE AGREE WITH THIS ARTICLE 100%. IN NYE COUNTY NEVADA, THE COUNTY COMMISSION THAT CONTROLS THE GROWTH THINKS THAT THE WATER WILL MATERIALIZE (MAGICALY) WHEN THEY VOTE TO ALLOW MORE DEVELOPEMENTS, EVEN THO WE HAVE HAD ONLY .75 OF AN INCH RAINFALL THIS YEAR AND ONLY 5.4 INCHES ON RAINFALL IN THE PAST 3-4 YEARS. WE HAVE HAD OVER 40 DOMESTIC WELLS GO DRY IN THE PAST 6 MONTHS. OUR WELLS ARE DROPPING AN AVERAGE OF 2 FEET PER YEAR AND WILL DROP FASTER AS THE POPULATIION INCREASES. AN EXPECTED INCREASE OF 50,000 IN THE NEXT 4-5 YEARS. AN ENGINEER HAS ESTIMATED THAT OUR WATER WILL BE GONE OR UNDRINKABLE DUE TO CONTAMINATION IN 10 YEARS WITH THE CURRENT POPULATION EXPLOSION. THE COUNTY PLANNERS ARE LOOKING AT A FIGURE OF 150,000 INCREASE IN 10 YEARS. THIS VALLEY WILL BE A GHOST TOWN BY THEN. THREE YEARS AGO THE VALLEY POPULATION WAS NEARLY 22,000 WITH 10,000 WELLS AND NOW HAS A POPULATION OF 40,OOO AND GROWING DAILY. 8,000 HOMES ARE CURRENTLY UNDER CONSTRUCTION AND 15,000 MORE ARE APPROVED, CONSTRUCTION PENDING. WELLS HAVE INCREASED ONLY 200 AND MOST ARE COMMERCIAL WELLS. THIS USED TO BE A AGRICULTURAL VALLEY AND NOW IS ONLY A BED AND BREAKFAST FOR LAS VEGAS. THE FARMS ARE GONE. LETS FACE IT THE REALESTATE BUSINESS DOES NOT MAKE MONEY ON FOOD ONLY ON WATER RIGHTS AND LAND TO GO WITH IT.
In Denver, where I live, Mayor Hickenlooper has made water conservation one of the keystones of the Greenprint Denver program. I think they plan on REDUCING water usage by 20% by 2015, although I'm sure that the reduction is offset by growth. I'd probably tell Hick to get the city workers off their butts and fix the broken sprinkers that I pass when I bike to work. I estimate that a gallon pours out of those large broken heads at the rate of 1 for every 2 seconds. The zone is on for about 10 minutes - maybe more. 600 seconds = 300 gallons shot.
I use a drip system in my garden, and while it requires a lot of maintenance, it's the only reason I can have a garden in this hot, dry climate. I'd have to water every day otherwise.
we all live on a very dry continent.we need to
help save this world by saving our water!!!
we cant afford to let our taps drip and drip cuz if we all do it the world will go dry to quick.
Nice work Jeremy. Now, how about something on cotton and cane alternatives?
Great piece on water something Australia has been struggling with for ages now. The crisis doesn't seem to abate the Queensland government recently declared an 'emergency' to sieze regulatory control over water infrastructure and planning in South-east Queensland becuase of the drought induced water shortage there.
And Daniel's points on cotton and cane are worth taking up it is not just how we irrigate our crops that should matter, but also what, where and how we grow in relation to water, climate, land and energy that must be considered as well. Recently, I found out that the latest Australian statistics show that "while [Australian] farmers of other crops had reduced their water use in 20042005, that same year cotton farmers had increased their water irrigation use by 570 gigalitres from the previous year." Hemp is suggested by some as a water-efficient alternative to cotton.
The same stats also found that water wasting irrigation systems such as those you discuss are still being used in some parts of Australia. We should know better.
Good overview, Jeremy!
The policy levers of tax-shifting and "irrigation offsets" are intriguing.