In her past life, Paulina Concha Larrauri, now a senior staff associate at the Columbia Water Center, made detergent for a living. She had earned an undergraduate degree in chemistry, and after five years of working as an engineer at an American multinational consumer goods company in Mexico, she asked herself if she wanted to hold on to her cushy job or pursue her passion for environmental engineering.
Even while she was with a huge corporation, she loved working on the environmental side of things. In all of her projects within that company, she pushed for less packaging and kept looking for ways through which they could manufacture detergent and reduce pollution. “But I started asking myself if making detergent for the rest of my life was something I wanted to do. There’s nothing wrong with that but even as a kid, I was specifically passionate about not wasting water,” says Concha-Larrauri, who grew up in Celaya, Guanajuato, which is located in central Mexico.
After leaving the company and graduating from Columbia University with a master’s degree in environmental engineering, she bagged an internship at a consulting firm that specializes in water projects. Unfortunately, due to visa issues, she lost that opportunity. But another door opened for her when she emailed one of her professors at the Columbia Water Center. She wrote to him about an agricultural water project she was interested in pursuing in Mexico and got a reply back immediately. That led Concha-Larrauri to get a job at the Columbia Water Center, where she has now been working for the last seven years.
At the Columbia Water Center, Concha-Larrauri has worked on a variety of projects to promote equal access to clean water, reduce risks to companies and disadvantaged populations, and protect the environment. She has assessed the risks of mine tailings dams to communities, the environment, and mining companies, and has investigated the potential for and impacts of dam failures in the U.S. She has also helped to enable rainwater harvesting — the collection and storage of rain in tanks or drums for use in irrigation, gardening, and even drinking and cooking.
In this interview with the State of the Planet, Concha-Larrauri talks about water issues in the U.S. and Mexico and her research projects in the field.
Can you tell us more about your work in Mexico and the rainwater harvesting projects that you took up?
We had first started the America’s Water Initiative, funded by the National Science Foundation. We analyzed what would be the role of decentralized water systems in the U.S. I got the opportunity to delve into which counties within the U.S. are ideal for rainwater harvesting, especially for use in peoples’ homes. That was how I first got introduced to this world of decentralized systems. And it’s now one of my passions.
After being approached by a Mexican company that builds water tanks and water systems, we pitched them the idea of analyzing the rainwater harvesting potential in Mexico City. The idea was to focus on the financial gains of doing rainwater harvesting and also benefits to the users. The research work was done in Mexico City at a very granular scale. We analyzed the differences between the 16 boroughs in the city that have very different socioeconomic and rainfall patterns. We then got a better understanding of in which areas it makes the most sense to have rainwater harvesting. We also further studied the issue of access to water for poor people and also, those who are willing to pay more for clean water. The analysis was a good introduction to what is possible in Mexico City that is known to face a lot of water problems. The rainwater harvesting project in Mexico became a possibility because of a grant from a private company.
What are some of the water problems that Mexico City faces?
It is a long list because there was a rapid increase in population and urban sprawl, and many bad decisions were made when it came to water management. Around 60 percent of the water in Mexico comes from an aquifer and the rest comes from very far away sources. That water has to be piped from thousands of kilometers away. So, the energy costs for doing that are crazy. There’s also a lot of stress for communities from where they are taking the water. Then there’s the issue of over-pumping from the aquifer that is making the city sink. As that happens, you also have the issue of drinking water pipes and wastewater pipes breaking. So, there is a lot of cross-contamination. During rainfall, there is frequent flooding because the city is a closed valley from where wastewater needs to be pumped out. Throughout Mexico, the water utilities don’t have the money or the capacity to manage the water in a better way. There are also issues with water scarcity.
How open are communities to installing rainwater harvesting systems?
In Mexico, it can cost anywhere between $500 to $1,000 to install a rainwater harvesting system in a home. In the U.S., it is more expensive, ranging from $1,000 to $5,000. But in some states in the U.S., there are problems with regulations. For instance, in Colorado, until 2016, it was forbidden to install any rainwater harvesting system because of the water rights laws that they have. So, the big question is, how do harvesting systems or decentralized systems fit into the current regulatory structure? That’s a whole other monster. Even today in Colorado, they are allowed to collect only 110 gallons of water — that’s just a few barrels. So, even though it is allowed, it is very restricted.
But in other places where there are no such restrictions, there have been some initiatives. A few corporate buildings in Mexico and the U.S. have installed rainwater harvesting systems. They also have water treatment plants where water can be reused repeatedly. In New York, several apartment buildings already have that. The World Trade Center building also has rainwater harvesting in their towers. New constructions in Mexico City are now required to have these systems in place. Other states like Arizona and New Mexico that have troubles with water have been very open to installing rainwater harvesting systems.
It is often not economically feasible to pipe water to all small communities. In remote places, rainwater harvesting, combined with water reuse, is essential if we are serious about providing drinking water for every single person in the U.S. It is not only about providing access to water to these communities. For instance, in Flint, Michigan, and even Alabama, the quality of water for many communities is poor. It is also important to provide them with a good quality of water. A decentralized system with real-time water quality sensors will allow people to have more control of their water.
What water projects are you currently working on?
In addition to the rainwater harvesting projects, I am working on a project that explores the links between climate and internally displaced people and refugees in Somalia and South Sudan. I am also analyzing the climate-related risk of dams in the U.S. My analysis covers how dams in the U.S. are aging. The average age of a dam is 50-60 years old and we have more than 90,000 dams in the U.S. But the budget for repairing these dams is meager and many of them are filling with sediment. So, the storage available for the dams is diminishing over time. And on top of that, you have like more intense rainfall and they are not designed to contain that frequency and intensity of rainfall. There is a real risk of dams failing.
What I do is not only look at that probability of failure and how it has changed but also, if the dams fail, what are the consequences? We are involved in mapping the floods caused by dam breaks and seeing how that impacts households and their access to electricity and clean water. There’s also the risk of high hazardous waste being released if there are chemical plants nearby, like in Michigan. There are cascading effects of a dam break that go beyond flooding. We are creating a map of such high risk areas that require more attention and resources.