by Gonzalo Merediz Alonso, Peter Bauer-Gottwein, Bibi N. Gondwe, Alejandra Fregoso and Robert Supper
“If there is magic on this planet, it is contained in water.”
American philosopher and nature writer
The only reliable source of fresh water for the Yucatán Peninsula is a large karstic groundwater reservoir. Karstic refers to areas of irregular limestone in which erosion has produced fissures, sinkholes, underground streams and caverns. Limestone allows groundwater to pass through it easily over time, which creates unique and irregular networks of caves. Karst areas often show no surface water.
Humans and ecosystems in the region depend on this resource for water, but massive population growth and economic development, particularly in the Mexican federal state of Quintana Roo, have led to critical pollution problems. Groundwater science can improve understanding of water flow and pollution in this area, while clear political commitments and specific institutional responsibilities are essential for effective groundwater management.
While Mexico has a strong institutional base for managing water policy, including the National Water Commission (CONAGUA) and regional water supply commissions, the Yucatán Peninsula’s unique and little-known karstic characteristics make current policy insufficient to avoid pollution and degradation from urban and tourism development. A major problem is the lack of a suitable groundwater monitoring network. CONAGUA maintains only about 35 groundwater-level monitoring stations for Quintana Roo, which, with an area of 51,000 square kilometers, is as large as Costa Rica.
Another issue is the need for an appropriate system to enforce groundwater resource protection in Quintana Roo. The results of groundwater research could help encourage two critical policy developments: the designation of protected areas and the design and implementation of an environmental service payment system.
Groundwater Management Problems
The Yucatán Peninsula includes the Mexican states of Quintana Roo, Yucatán and Campeche as well as portions of Guatemala and Belize. Its groundwater reservoir contains subterranean caves tens of kilometers long and tens of meters in diameter. In these caves, water and pollution travel fast. Moreover, saline seawater intrudes tens of kilometers inland into the aquifer. Groundwater use and wastewater disposal are rapidly increasing in response to the urban development and tourism of the Yucatán Peninsula.
In just 35 years, Cancun has grown from a small fishing village to the largest resort destination in Mexico. As tourism spreads south along Mexico’s Caribbean coast, communities like Playa del Carmen and Tulum boast annual growth rates of more than 15 percent. Quintana Roo, which has almost 80,000 hotel rooms, receives about 10 million visitors every year. This influx severely taxes the peninsula’s water resources. By federal policy, wastewater is re-injected into the ground-water often without any treatment; only 32 percent of the peninsula’s wastewater is treated.
Groundwater is important not only for consumption but for ecology. The region’s groundwater supports spectacular wetlands, including the Sian Ka’an Biosphere Reserve on the Caribbean coast, Mexico’s first biosphere reserve, which consists of 6,500 square kilometers of tropical forest, marshes, mangroves and coastal habitats. The reserve also protects 120 kilometers of the Mesoamerican Reef, the second largest coral reef in the world. Its geology generates sinkholes, hummocks, lagoons and freshwater springs. Reconciling human and ecosystem water demands is emerging as a key groundwater management problem in Quintana Roo.
Groundwater Science Tools
The important question for managing and protecting wells and ecosystems is “Where does the groundwater come from?” While science can provide powerful tools to understand groundwater flow and pollution in karstic areas dominated by submerged caves, a lack of field observations of Yucatán groundwater limits the use of some tools, such as computer modeling. In this case, satellite and aircraft survey data have been helpful. Helicopter-borne sensors that transmit and receive electromagnetic signals have mapped the underground cave systems in detail, and satellite imagery has shown faults and other regional-scale zones with potential for fast water flow. For example, satellite imagery reveals that about 17 percent of rainfall recharges the groundwater aquifer. And satellite-borne radar sensors, which investigated variations in Sian Ka’an’s wetlands, show that wetland flooding peaks three months later than the annual rainfall peak in October, and the wetlands connect to water from an area much larger than the biosphere reserve itself. These results demonstrate a need for land-use regulation to protect key source areas.
Political and Institutional Requirements
Based on groundwater flow maps, land-use planning at the municipal level can be used to define the human activities and developments that are compatible with the groundwater characteristics. Increasing the awareness of the fragility of local water resources encourages people to connect homes to local sewage systems and to demand higher quality and investment in wastewater treatment from state and federal agencies.
An environmental service payment plan could be set up to require that resorts benefiting from favorable land-use laws pay water fees into a fund that would compensate landowners in critical water source areas. This plan would provide sustainable financial tools to guarantee water availability for the resorts, as well as Quintana Roo’s ecosystems.
Current state and municipal laws and policies may not suffice to manage water resources in Yucatán. One solution is for local nongovernmental organizations to work with the National Water Commission to create a new legal framework that encompasses management, use and preservation of underground rivers, caves and cenotes (sinkholes).
Bibi N. Gondwe and Peter Bauer-Gottwein are from the department of environmental engineering at the Technical University of Denmark in Kongens Lyngby. Gonzalo Merediz Alonso and Alejandra Fregoso represent Amigos de Sian Ka’an in Cancun, and Robert Supper is from the Geological Survey of Austria in Vienna.