Using Trash to Clean Up Trash

Alter Terra

In Tijuana, trash is a major problem. Government garbage trucks are in disrepair, public collection services are irregular to say the least, and few people can afford to pay for private collection. At the same time, Tijuana is still growing. All of which means that trash piles up outside of homes and businesses, lining streets, blocking sidewalks, and spilling out of dumpsters. When it gets to be too much — the physical quantity, the rodents, the smell — the waste often ends up in the dozens of illegal dumping sites dotting the coastal canyons around the city.

In the wet winter months — particularly during heavy storms — rainwater picks up trash scattered throughout the watershed. Everything from car parts to animal carcasses to plastic bags and bottles gets swept into various channels that drain into the Tijuana River National Estuarine Research Reserve, which lies just north of the border in San Diego. The Ramsar designated wetland is among the 5 percent of California estuaries that haven’t been lost to development. It provides essential habitat to more than 300 species of migratory birds, along with other wildlife. From the estuary, much of the trash moves on to the ocean.

No one is happy with the situation. Residents in Tijuana have been pushing for better trash service for decades. Across the border in San Diego, clean water advocates have been agitating for local government to address the cross-border flow of sewage and trash polluting US waterways. Recently, a coalition of local government and nonprofit groups have even sued the US federal government over this. Their goal is to compel the International Boundary and Water Commission — which addresses issues arising under US-Mexico treaties — to take action with respect to the sewage issue.

Nonprofits on the Mexican side are also working hard to address the pollution problem.

One of them is Alter Terra, a coastal and marine conservation organization. We have been studying the flow of sediment and solid waste from higher elevation regions around Tijuana into US waterbodies for more than a decade. This has involved mapping dump sites throughout the Tijuana watershed, and using strategically placed transmitters to track that trash as it moved from dump sites into waterways. The research has provided essential information about where trash is originating, how it’s moving, and where it ends up.

Next comes the difficult work of stemming the flow. Ideas abound. Cleaning up the dump sites seems like an obvious solution, but it doesn’t really work — new trash appears seemingly overnight. Improving trash collection is another appealing option, and one the city is pursuing. But it’s costly, and all signs point to the likelihood that illegal dumping will persist in the watershed for some time. So that leaves extraction — accepting that some trash is going to flow into the region’s rivers and creeks, and that we need to fish that trash out once it gets there.

That’s how Alter Terra settled on upcycled trash booms, a full-circle solution to the transboundary waste problem.

Trash booms are essentially massive strainers deployed across rivers to catch trash and prevent it from flowing further downstream. At Alter Terra, we consulted with experts in glacial movements to perfect our design — flowing trash does, after all, share some common ground with flowing ice. Then we found experts to create our hardware and perfect our design. Last year, we developed a 120-yard prototype to test our design. So far, it’s passed with flying colors. It has successfully caught everything from a bathtub, to car parts, to tires, all flowing at high speeds. All that’s left now is to deploy the first booms.

We have decided to locate our first trio of trash collectors in Smuggler’s Gulch, one of the major “rivers” flowing through the Tijuana River Watershed into the United States. Smuggler’s Gulch used to be a natural valley running roughly parallel to the Pacific Ocean. Today, the gulch is filled with nearly 2 million cubic yards of dirt, the result of an expensive effort to fence and patrol the US-Mexico border, a project with plenty of its own environmental repercussions. The water that used to run along the canyon floor now passes through a concrete culvert. Trash that used to meander through the natural waterway moves more quickly through the concrete substitute, and as a result, gets pushed faster and farther into the Tijuana River Estuary.

With our permits now in place, we will be deploying the first three booms on a section of the Smuggler’s Gulch culvert this summer. They’ll face their first field test during the next rainy season.

Once in place, the metal mesh screening on the booms will capture floating trash, which will then be collected for removal. The booms are wildlife friendly —gaps in the mesh are large enough to prevent animals like lizards and birds from getting caught. What’s more, they are part pollution-mitigation-measure and part art installation — the booms look and move like a snake.

Learn more about this Earth Island project at alterterra.org

As for the trash we remove from the waterway? We’re working to repurpose as much as we can. Some may go to creating new booms. The booms we’ve constructed so far are made of high-density plastic collected from throughout the watershed, that’s ground into flakes and melted into panels for use. As I like to say, we are technically and philosophically using Mexican trash to stem the flow of Mexican trash into the United States. In the process, we are also creating jobs in low-income communities and cleaning up the watershed. In other words, everybody wins.

Plastic that can’t be made into booms will go towards other uses. Alter Terra has used tires as alternative building materials to create functional and beautiful structures in public parks, for example, and we’re currently creating a technical manual about building with trash. We’ve also used repurposed materials to create art exploring various environmental themes, from river flow and water pollution to the impact of climate change on our lives. What can’t be reused will be diverted to landfills.

For decades, we’ve been putting tons and tons of durable, useful materials into our landfills with hardly a second thought to all the energy, talent, time, and design that went into creating them. We’ve been disregarding the fact that our old bottles and tires can be repurposed, and we’ve been pushing to the back of our minds the fact that all this waste is clogging our waterways, polluting our oceans, and harming wildlife.

Alter Terra’s work in Tijuana provides hope. Hope that we will see more cross-border cooperation not only between the US and Mexico, but also across the globe. Hope that we can create solutions to plastic pollution that also create jobs and contribute to our communities. And hope that we can find uses for the seemingly useless, and in the process, preserve our remaining natural places for generations to come.