Returning to my roots: Exploring groundwater resource vulnerability and water scarcity in Quintana Roo, Mexico

Maria Jose Iglesias-Thome, M.S. Student, Water Resources Science

My passion for water started at a very young age. When I look back at my childhood, the things that interested me growing up, and where I stand today, I can’t help but think that this trajectory makes sense. When my thesis advisors gave me the chance to propose a research project, I jumped at the opportunity to study groundwater in my hometown. 

I grew up in Puerto Morelos, Mexico, a small coastal town situated a few yards from the Caribbean ocean, nestled between vine-covered sand dunes and dense marshy mangrove forests and sitting on top of an ancient underground network of “rivers”. For locals, the idea that underneath lies a hyper-connected and inherently sensitive groundwater system, is part of the traditional knowledge passed on through generations. As the region continues to grow and develop, the abstract ideas of how the local aquifer flows, are replaced with an erroneous notion that clean water will always be accessible and will never cease to exist.

The place: Complexity hidden beneath our feet

Figure 1. Map of Quintana Roo. Tony Burton (2010)

The whole Yucatan peninsula sits on a flat limestone platform, built on top of millenia of fossilized calcified skeletons from creatures past. The carbonate rock that was left behind is highly soluble and vulnerable to rainwater dissolution. Throughout the years, heavy rainfall, common in this tropical environment, has carved a series of conduits, revealing a contiguous coastal aquifer and a landscape virtually devoid of rivers and non-groundwater dependent surface water systems. This process is known as karstification and the topography it leaves behind is known as karst. Scattered across the Yucatan peninsula are larger dissolution conduits: caves and sinkholes that have collapsed to form what are locally referred to as cenotes, derived from the Mayan ts’onot, that give us a direct look into the aquifer. Other important hydrogeologic features include major faults systems and regional-scale flow patterns from the center towards the marginal ends of the Peninsula, the coast. Inside these coastal karst aquifers, a thin freshwater lens (5-7 meters deep) lays atop an intruding saltwater layer, known as the “cuña salada”, penetrating 10-15 meters into the subsurface. This shallow layer provides most of the water for an increasingly growing population across the entire peninsula.

The problem: Chaotic population sprawl 

The complexity of this groundwater system results in an inherently vulnerable resource, especially to anthropogenic sources of disturbance. Likewise, it is unclear how patterns of water use may be depleting groundwater quantity and/or degrading groundwater quality and how these changes are affecting water availability to local communities and ecosystems in the region. Extreme urbanization and population growth may be a large driver of water insecurity and scarcity.  In 2017, the state of Quintana Roo hosted over 17 million tourists and sustained an average hotel occupancy of around 83%. The number of tourists visiting Quintana Roo has more than doubled in the last 10 years, with a 120% increase in yearly tourists between 2009 and 2019. Similarly, the population in the area has grown around 40% over the past 10 years. Spatially, development in the region follows an overall gradient from north to south, while the population is currently concentrated in northern communities, southern communities are experiencing higher rates of population growth. In other words, development is quickly spreading south.

As urbanization continues to sprawl across the coastline, concerns about saltwater intrusion, deep-aquifer contamination through wastewater injection, and shallow-aquifer contamination through septic tank leaks and fertilizer application continue to grow.

Understanding the relationships between social and ecological systems through their shared reliance on groundwater resources is important for evaluating water security and subsequent water scarcity issues. It may also prove critical in examining how coastal communities that rely on water for their livelihoods may be disproportionately affected by ongoing changes in water resources in the region.

Figure 2. Situation map for a hypothetical aquifer in Quintana Roo, showcasing transformations (yellow diamonds), flows (arrows) and storages (white boxes).

The methods: Mixed methodology and an evolving plan

Mixed research methods are useful tools in studying complex social-ecological system problems, like those in Quintana Roo. Qualitative interviews are a central component of my research methodology. This summer I had the privilege of conducting semi-structured interviews with large and small water users, water managers and water protectors. Interviewees included hotel representatives, domestic users, NGO and civil society leaders, and local government officials. My interviews covered a variety of topics and were rooted in concepts related to water scarcity, resilience theory and social-ecological systems frameworks. The data collected with these interviews will allow me to understand important exposure to water scarcity and other hazards, social vulnerabilities and sensitivities that affect how individuals and groups respond to water stress and aid in evaluating adaptive capacity from varying degrees of scale. Synthesizing important hydrogeological knowledge as well as the data collected through interviews, will allow for a holistic approach to understanding and measuring  water scarcity through an integrated assessment model-framework (IAMF). The model aims to integrate biophysical aspects of water scarcity, such as seasonality, water source, quantity and quality, with socioeconomic aspects of water scarcity, such as accessibility, reliability and social vulnerability.  It also hopes to include nuances that are often overlooked in water security models and water scarcity assessments. 

It is fascinating to research a place and a problem that are so dynamic and often evolving. One of the reasons why I am so deeply interested in natural resource management and specifically water resource science is because I grew up seeing the landscape around me change. I feel infinitely privileged to be working in a place I love and know, and hope to continue to contribute to what is known about it.

Playing in Nature: Graduate Student Edition

Aleah Hahn, Marine Resource Management Student

Flashback to my childhood: I am maybe 8 years old, wearing some worn out hand-me-down clothes from my brothers. I put on my trusty light blue crocs and callout to my mom, “I’m going to go play in the woods!” Stumbling through the leaf litter and sticks and fallen trees, the cold, wet, yuckiness of a Michigan fall does not phase me. I climb up the hill to my favorite spot. The sun decides to come out and light up my small patch. The birds are excited about the sun, too, so I sit and watch them play. I get distracted by a worm wriggling into the ground and giggle in awe of all the life around me. I am in my own slice of paradise.

I have always found myself connected to the outdoors. Whether swimming in the nearest body of water, going for a hike in the woods, or catching a bluegill in the creek, nature is where I am happiest.

Now, I am 22 years old, and for the past year I have been playing in a river –I mean, working on data collection for my master’s thesis.

My research site is east of Eugene, OR and sits below Cougar Dam. I am looking at a new approach to river restoration and trying to understand how different habitat qualities might impact the spawning and rearing of Chinook salmon. Before treatment, the river was not connected to its floodplain, the nursery habitat for juvenile Chinook. Treatment reconnected the river once again to its floodplain. The model I am using requires me to understand how fast the water moves and how deep it is before and after treatment. A team of five undergraduates and I collected that data, monitoring an untreated section of river upstream of the treatment area and regions in the treated area.

I have traded in my crocs and hand-me-downs for wading boots and thick neoprene waders. The waders were helpful when bushwhacking through stinging nettle, blackberries, salmonberries and virtually everything pokey in the world. If it is pokey, I found it, I probably grabbed it, and I most definitely learned my lesson.

My fieldwork involved walking on large wood placed throughout the river. When I began the work, I was slow and cautious, but by the end of the summer, I had to remind myself to slow down so my undergraduate helpers could keep up.

The weather and field conditions were not always the most pleasant to work in. I don’t recommend trying to get through stinging nettle taller than yourself –their radiating sting is unpleasant. Sticking my arms and face in the chilly water to retrieve sensors and replace them, doing my best, unsuccessfully, to keep the water from pouring into my waders, is, again, not recommended.

But during all the unpleasantness, I was truly living my best life. Some of the most uncomfortable parts of life can be the most enjoyable; it is all about perspective. I would rather have a bad day in the field and breathe in the fresh (well, sometimes smoky) air, see the life booming around me, and connect with nature, than have a mediocre day in the office. My favorite memories are of the times when we simply stopped and let the view in. The treated area was always busy with birds, butterflies, and fish. I would pull a rock out of the river and show my students the different macroinvertebrates crawling around. The ability to find life in all corners and crevices of the site excited my inner child.

Being at my study site reminded me of those days in the woods as a kid. It was MY place, my little slice of paradise. It also showed me that I didn’t have to do research to go out to the woods and frolic. So even though my field season has ended for my master’s project, you will always be able to find me revitalizing my soul out in the woods somewhere.