The Big Promise of the Small

Water projects have been some of the largest engineering feats of humankind. But these projects came at a price many now think was too high. Where do we turn for water solutions?

In the 20th century, humanity achieved huge feats of water engineering, taming wild rivers, redesigning entire watersheds, and creating farmland from desert. But evidence has begun to mount that massive manipulations of water are not worth their costs. Huge dams have destroyed ecosystems and human communities, often waste as much water as they gather, put countries in unsustainable debt, and inevitably silt up, becoming useless, often before they have even been paid for. Other massive schemes have their own problems; desalination plants are expensive and produce toxic byproducts, while big pumping projects deplete aquifers.

Is human ingenuity useless in solving water shortages? Those who study the issue think there is still hope. The problem may be in scale; it was the mega-projects that failed. The most exciting solutions are small. All over the world, engineers, potters, and even children are coming up with inventions that are cheap, simple, locally attuned, and sustainable.

One of the more elegant human inventions is drip irrigation, invented by the Israelis to make the desert bloom. Seventy percent of the water used by humans goes to agriculture, and irrigation has been one of the prime factors in boosting world food production. But flood irrigation, the usual way of delivering water to crops, wastes huge amounts of water and can damage the land over time. So irrigation is a crucial target for water conservation.

Drip irrigation systems deliver small amounts of water directly to plant roots, wasting little to evaporation or runoff and avoiding the soil salination that flood irrigation creates. The drip systems marketed commercially are too expensive and too large for most Third World farmers. So in Nepal the nonprofit International Development Enterprises (IDE) worked with farmers to develop an ultra-cheap, ultra-simple version using parts widely available in the Third World: PVC pipes, a 20-liter bucket attached to a pole at shoulder height, and a simple cloth filter. The system costs $5. IDE also developed three larger and more elaborate systems, from a drum kit for $25 on up to a micro-tube system for $250. As a farmer profits from selling the produce grown with drip irrigation, she can scale up easily to a larger system. IDE has developed different versions of its kits for the needs, climates, and available parts in different countries. With these systems, farmers in India were able to raise their crop yields by as much as 50 percent while lowering their water use by as much as 60 percent.

Where water is available, it is often contaminated with disease-causing bacteria or other pathogens. When Potters for Peace, a group of ceramic artists from the U.S., traveled to Nicaragua in the 1980s to exchange skills with potters, they saw children dying from diarrhea caused by contaminated drinking water—the leading cause of child mortality in the Third World—and decided to work with local potters to help solve the problem. The result was ingenious—a filter that consists of a simple clay pot lined with colloidal silver, placed inside another clay or plastic vessel to hold the clean water. Water seeps through the porous clay and passes through the silver, which kills pathogens but isn't harmful to humans. Any local potter can be trained to make a pot of the right porousness, and they cost only $10. IDE and UNICEF both distribute the filter pots; there are now 36,000 in use in Nicaragua and Guatemala.

Ultraviolet (UV) light is one of the most effective and economical methods available for making contaminated water safe to drink, and it leaves no chemical residue. The ClearWater Project has used this technology for water system installations at two schools in Mexico and India, and at the Gangchen monastery and villages in Tibet. A simple UV system uses a lamp powered by a car battery or a 60-watt solar cell and can provide clean drinking water for up to 4,000 people for as little as 4 cents a ton.
Transporting water to where it can be used is usually an arduous task, certainly not child's play. Yet some thoughtful engineers are turning toys into water pumps. Engineers in the visionary community of Gaviotas, Colombia (see YES!, Summer 1998 and Fall 1998), redesigned the traditional pump to require much less force to lift water from wells. When engineer Luis Robles explained the design to Gaviotas schoolchildren, one of them told him that it was like half a seesaw. Robles then built a seesaw and attached it to a pump outside the kindergarten so that when children played on the seesaw, they also pumped water for the school. Because Gaviotas does not patent any of the community's inventions, these pumps and methods are now in use around the world.

Many desert countries lie on coasts, surrounded by unusable salt water. A beetle in desertous Namibia has come up with one way to satisfy thirst: Every morning it climbs to the top of a sand dune, where it turns its body into the wind, straightens its rear legs, and lowers its head. Fog rolling in from the sea gradually collects on its back, forming droplets of water, which slide down into the insect's mouthparts.

Humans can mimic this technique using simple nylon nets stretched on posts so that they run athwart the prevailing wind. Water droplets in the fog precipitate out of the air when they hit the net, then run down the net into a trough and from there into pipes or storage tanks. The nets range in size from one square meter on up. This system is being developed in Namibia, Peru, Ecuador, and Mexico, but it has been used most extensively in Chile. There, researchers have found that fog can also be harvested away from the coast, in mountainous areas where clouds gather on the slopes.

Cost and output of the fog nets varies, but a system used in Chile cost less than $400 and produced 144 liters of water per day. The Chilean village of Chungungo, which has no water supply and once relied on trucked-in water, now harvests enough fog to supply the town's homes and grow crops.

For more on small-scale solutions to water needs, see

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