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It’s a secondhand town. Everything has been used by somebody else before.

ANOTHER WORLD: Los Laureles Canyon, “a secondhand town,” in Tijuana.
by Sylvia Tiersten
Life’s not bad for Sergio Arreola Armenta—as long as the sun is shining. Four years ago he moved to Colonia de San Bernardo, in Tijuana’s Los Laureles Canyon. He owns his home, a 750-square-foot structure he built himself, and he owns his livelihood, a small construction materials store that extends credit to local residents. But when it rains in Tijuana, life stops in San Bernardo, a hillside neighborhood with no paved streets, no sewer, no storm drainage system and no external lighting.
Some 80,000 people—many of them squatters—live in Los Laureles, or Goat Canyon as it is known in the United States. “It’s a secondhand town. Everything has been used by somebody else before,” says Oscar Romo, a UC San Diego lecturer on urban studies and planning and the Coastal Training Program coordinator at the 2500-acre Tijuana River National Estuarine Research Reserve (TRNERR) in Imperial Beach. The National Oceanic and Atmospheric Administration administers the Coastal Training Program.

When torrential rains come—as they did in the winter of 2004-2005—mattresses, tires and other secondhand debris hurtle down the canyon’s eroded hillsides, and end up north of the border in the Tijuana River estuary. South of the border, the storms bring death and destruction to impoverished canyon residents—as improvised shacks built from tires, garage doors and other scrap materials tumble down the slopes.
Uneasy Neighbors
Culturally and economically, San Diego and Tijuana are worlds apart. But geography, globalization and runaway urban sprawl have pushed the two communities into a difficult marriage—and divorce is not an option.
“ They share a common watershed,” says Nina Jean T hurston, MPIA ’08, a former student at UCSD’s School of International Relations and Pacific Studies (IR/PS) who worked as Romo’s assistant in 2007-08. The Tijuana Reserve is the largest coastal wetland in the Southern United States, a United Nations-designated “wetland of international importance,” a living laboratory for education and research, and a paradise for birdwatchers. More than 370 varieties of migratory and native birds have been spotted in the protected marsh habitat, which is home to six threatened and endangered species.
More than 370 varieties of migratory and native birds have been spotted in the protected marsh habitat of the Tijuana River National Estuarine Research Reserve. It is also home to six threatened and endangered species.
These include: The California Least Tern, The Western Snowy Plover, The Light-Footed Clapper Rail, The Least Bell’s Vireo, The Belding’s Savannah Sparrow, and The California Gnatcatcher. The Tijuana Estuary has one endangered plant—the Salt Marsh Bird’s Beak.
The estuary’s mix of indigenous plants and silt is a last-chance filtering system for cleansing rain and floodwaters before they reach the Pacific Ocean. But raw sewage, loose soil and solid trash do not respect international borders—and the reserve is constantly under siege. Sediment from rainstorms chokes out healthy marshland, and the sediment, trash and pollution actually create opportunistic conditions for invasive (or exotic) plants to thrive. Such plants as giant reed and castor bean threaten to overrun native species—and alter local ecosystems.
In addition, pollution closes South Bay beaches about 180 days a year, affecting local health and local economies.South of the border are the ad hoc shanty towns that have sprung up in Los Laureles Canyon. “It’s an ethnic hodgepodge,” says Thurston of the residents who pour in from rural Mexico, Central America and South America in search of work and housing. Many end up in the nearby maquilas—foreign-owned factories in Mexico that take advantage of low-cost labor and easy access to U.S. markets. By U.S. standards the wages are meager—between $2 and $3 an hour, with exposure to toxic factory wastes as an unwelcome fringe benefit.
Students learn that by building pervious pavers in Tijuana, they’re saving wetlands in the United States.

UNWELCOME EXPORT: Sediment and pollution from ad hoc shanty towns in the canyons around Tijuana are slowly choking the salt marches of Tijuana River estuary north of the border.

Hands-On Learning

“The current situation harms Tijuana and it harms us,” says Anastasiya Plotina, ’10, who belongs to UCSD’s Urban Studies and Planning (USP) Club. It’s a balmy Saturday afternoon in San Bernardo, and club members are busily constructing pervious pavers for the colonia’s dirt roads. They are pouring a mixture of water, gravel and cement into hexagonal wooden frames to make the foot-wide blocks.

UC San Diego students, work with Los Laureles residents installing pavers.

PAVERS— A SIMPLE SOLUTION: Gravel is first laid on the soil and then the pavers are set on the gravel. The pollution collects in this sub base of gravel, between the soil and the pavers, and naturally occurring aerobic bacteria breaks down any pollution. The sub base and the pavers also help to harvest the water, which in turn helps to maintain native sediment at the site.

The environmentally friendly pavers let rainwater drain through and slowly percolate into the soil. The process prevents erosion and reduces flooding hazards, as well as providing water for nearby plant life, before finally ending up adding to the underground aquifers.
With support from the Mexican and U.S. governments, the students are helping canyon residents—mostly women—build and install 70,000 of these handmade pavers to prevent runoff from flowing into the Tijuana River Estuary and adjacent San Diego Bay. Armenta’s shop is providing the materials at a discounted price. The city of Tijuana has agreed to install a sewer system once the pavers are laid.

But the work is proceeding at a snail’s pace. “In a first-world country you would lay a big sheet of permeable asphalt in a parking lot and get the job done quickly,” says Adam Krohn, ’08, who founded the USP club. “In a way, it’s frustrating that the money is not there.”

However, the good part about having canyon residents do it themselves, he reckons, is that “they learn why they’re doing it, how their actions affect the environment and gain a sense of ownership.” As for the student volunteers, “we’re learning about watersheds and wetlands and why the estuary is important.”

Pilot projects such as the paver activity are scientifically based and empower local people, says Romo. He hopes that in a year or two, Tijuana officials will install pervious pavers elsewhere in the city, since it is also a sustainable model for roads, parking lots, sidewalks and driveways in San Diego. The U.S. Environmental Protection Agency (EPA) has designated use of pervious, or porous, concrete as a Best Management Practice for pollution control and storm water management.

The paver project is one of several efforts by Romo and his USP students to improve canyon life and save the U.S. wetlands. UCSD is contributing technical assistance and funding for the bi-national activities, which include educating Los Laureles canyon residents, engaging with local officials in California and Baja, building environmentally friendly homes in San Bernardo, and creating nurseries for native plants in San Bernardo and in Tijuana’s Parque Moreles, near the Tijuana River Channel.

Romo is an ardent environmentalist, who has been trying for many years to educate people on both sides of the border about the perils of unsustainable development. He hosts a Spanish-language talk show in Mexico titled “Ocean Without Borders.” In July, he received the 2008 Smart Growth for Excellence Award from the Urban Land Institute for his work with students in the barrios of the Tijuana River watershed.

Born and raised in Aguascalientes in central Mexico, Romo carries a binational Rolodex in his head that helps him tweak the system. In 2007, he obtained permission from Tijuana Mayor Jorge Hank Rhon to perform restoration projects on San Bernardo land. Rhon and Director of California State Parks Ruth Coleman signed the agreement, which includes building houses, laying pervious pavers and developing a plant nursery.

Going Abroad in Your Own Backyard
One of the benefits of a UCSD education is “You can travel for half an hour and see the developing world,” says Romo. By participating in the paver project, “Students get hands-on experience in urban systems, globalization and sustainable development.”

Enlightened self interest also comes into play. “Students learn that by building pervious pavers in Tijuana, they’re saving wetlands in the United States,” says Romo.
Some of the lessons are not so comfortable. “In order to enjoy affordable prices on our products, we have to rely on people who earn too little,” says Romo of the maquila-based economy. “Sometimes globalization translates into poverty and lack of access to a higher standard of living.”

Unplanned growth strains social and natural systems, as rural populations across the developing world migrate to urban areas. This year, for the first time in human history, more than half the human population will live in cities, according to UN projections.

Tijuana, with nearly 2 million residents, is the fastest-growing city in North America. But its hillside slums, despite their lack of basic security and sanitation, have some redeeming features. “They’re self-organized and organic,” says Romo. “To some extent, common sense substitutes for the lack of planning.” The residents are creating their own city—and that’s a model his students won’t easily find stateside.

For example, since loans are unavailable, people build their homes with out-of-pocket cash. Los Laureles dwellings are clustered near maquilas, so that residents can walk to work. Because water is expensive, people gather rainwater for recycling purposes.

The Coastal Training Program conducted 70 public meetings and workshops in Los Laureles to promote conservation practices. Funded by the California Conservancy, the workshops “gave scientists a chance to meet with residents, learn from them, share results of studies and invite them to participate in pilot projects,” says Romo. In exchange for attending, people received food and services at affordable prices.

And how successful are such efforts? Residents are responsive, Romo says, once they see the link between protecting the estuary and improving their health and safety.
Sylvia Tiersten is a freelance writer based in San Diego. She acknowledges extra reporting assistance from Carmen Romo, of the Propuesta Design Group.