Harnessing rainwater to slake Mexico's thirst
By Nancy Flores Original Print Publication: May, 2008
- Baja California is one of the dryest states in Mexico receiving only 7.8" of rainfall a year. Tabasco by comparison receives an average of 102".
- 67% of the rain in Mexico falls between June and September.
- 457 billion - Mexico’s total available internal renewable water resources in cubic meters (m3)
- 3069 billion, 3300 billion m3 total available internal renewable water resources of the US and Canada, respectively.
- 78 billion m3 water used in Mexico each year
- 78, 17, 5 percentages used for agriculture, residences, and industry respectively
- 55% of Mexican households don't have reliable piped water
- 30% of Mexico City’s water is piped in from surrounding states
- 55.5 m3/second - rate at which Mexico City’s aquifer is being drained
- 28 m3/second - rate at which it is being replenished
- 4 - number of Mexico’s 13 hydrological regions where groundwater use exceeds replenishment
- 85% of Mexico is classified as arid or semi-arid
- 32% of Mexico’s water resources are in the north and center of the country
- 77% of Mexico’s population is in the north and center of the country
- 20 - percentage of average monthly income that went to pay for water in Cochabamba, Bolivia after
- 6 deaths resulting from protests before privatization was canceled
Sources: World Resources InstituteMexico, CONAGUA, INEGI, LEADInternational, Counterpunch, CBC, CIA
SAN FELIPE DEL PROGRESO, Estado de México - The first time Celia Cayo's six-year-old son asked for purified water instead of Coca-Cola, she couldn't stop smiling. In the northwestern corner of the Estado de México, where the Mazahua people live without potable water, soft drinks mean survival. Like other mothers here, Cayo fears her three children will become sick with the gastrointestinal diseases that plague the region if they drink contaminated water from the tap or a nearby polluted river.
Residents of San Felipe del Progreso resort to bathing and washing clothes in the nearby San Antonio River. The contamination has made the water undrinkable.
Turning to soda isn't a healthy solution either. Doctors have diagnosed Cayo's elderly mother, Gloria, with a kidney infection and gastritis because she relies too much on sweetened sodas for nourishment.
When a rainwater purification plant was built in the arid, mountainous Mazahua region in 2006, mothers felt a burden lifted.
"We suffer so much without water," Cayo, 31, says. "At least now we have some, and I notice a difference in the health of my children. They want to drink water now, and that's how I know things are going to be different for them."
Today, the $1.5 million USD rainwater harvesting and purification plant supplies drinking water for 6,000 residents and twenty area schools. For the Mazahua, who believe water is sacred and honor it with traditional ceremonies, the plant is especially significant since rivers that once provided them with water were diverted years ago to supply a thirsty Mexico City.
Rainwater -- a possible solution?
The Mazahua's predicament is not unusual. In Mexico, an estimated 11 million people live without access to drinking water and another 25 million have only limited access. That's despite the fact that an estimated 1,500 cubic kilometers of rain pours across the country annually.
It's no wonder then that rainwater collection and purification projects like the one in San Felipe are now in growing demand throughout the country. The International Center for Demonstration and Training in Rainwater (CIDECALLI) has 1,800 similar projects planned this year for marginalized cities across Oaxaca, Guerrero, Puebla, Chiapas, Sinaloa, Nuevo León, and Veracruz, according to a Rainwater Harvesting report by Fulbright scholar Femke Oldham.
"We've already contaminated our rivers, depleted our aquifers," says CIDECALLI coordinator Manuel Anaya Garduño. "Now we have to stop looking down for a solution and start looking up."
According to CIDECALLI, just 3% of Mexico's annual rainfall could supply 13 million people with clean water and irrigate 18 million hectares of crops.
Rainfall both savior and enemy in Mexico City
Mexico City gets almost thirty inches of rain each year, enough to supply its own needs and ship the rest to other states. Yet water shortages have become critical, since most of the rainfall is funneled out of the city and into the ocean through massive drainage systems.
Meanwhile, the city spends millions on an elaborate network of pumps and treatment plants to import water from other states. Water from the mountainous forests of Michoacán, for example, is pushed for miles uphill. Pumping this water into Mexico City eats up as much energy as the cities of Querétaro or Puebla use annually, according to a report by Ilán Adler, general director for the International Renewable Resources Institute (IRRI-Mexico). Even with this complex process, 40% of this water is reportedly lost along the way because of leaky pipes.
"We do not have the ethical or moral right to ask other zones for their water until we have repaired every leak...captured every raindrop and recycled 100% of our city water," Adler's report concludes.
While some see rainfall as a possible salvation for the city's water woes, rainfall in the megalopolis is often portrayed as an enemy because it floods streets and adds pressure to an already weak drainage system.
The situation has become so dire in the capital that the National Water Commission warns that a catastrophic flood could submerge the city under five meters of water for several weeks. The city has had several close calls as heavy rainfalls caused the drainage system to almost overflow.
Mexico City's main water supply -- about 70% -- comes from pumping underground aquifers that are not refilling fast enough to keep the water supply at a constant level. At this rate, experts have said they don't expect the city's aquifers to last more than fifty years. The result? The sponge-like clay underneath the megalopolis dries out and sinks.