The drought that severely affects the northern states of Mexico is mainly caused by "La Niña", a climatological phenomenon that has been unusually extended for three consecutive years since 2020 and will last until the end of 2022. In addition, there are social aspects that have an impact on the deepening of the water crisis, according to UNAM specialists.
"Climatologically it is something very rare; we had more than 20 years without such a prolonged phenomenon. This impacts the availability of water in the north and changes wind and rainfall patterns worldwide," said Christian Domínguez Sarmiento, a researcher at the Institute of Atmospheric Sciences and Climate Change.
The cold anomalies of the surface temperatures of the tropical Pacific Ocean cause that during the summer it rains a lot in the center-south of the country, mainly in the states of the Gulf of Mexico, and in the winter there is no precipitation, especially in the north, described the researcher as the characteristics of "La Niña".
He cited reports from the National Water Commission (Conagua), which indicate that there has been 20.8 percent less rainfall in the country from October 1, 2021, to May 29, 2022, concerning the historical average for that same period.
The most recent report of the Technical Committee for the Operation of Hydraulic Works (issued on May 31, 2022) indicates that none of Mexico's 210 main dams were at 100 percent full: 117 at less than 50 percent; 61, between 50 and 75 percent of their capacity; and 32 were above 75 percent without reaching their full capacity.
Drought in Mexico
Those of the Cutzamala System (El Bosque, Valle de Bravo, and Villa Victoria) used to supply part of the Metropolitan Zone of the Valley of Mexico were at 42.7 percent of their filling level, 17.4 percent less than the historical level for that date. With less rainfall, radiation enters directly into Mexican territory and causes water to evaporate, which reduces the level of the dams.
The National Meteorological Service reports that 77.68 percent of the nation has some drought condition, and 32.42 percent is in severe drought, although the latter percentage is lower than that recorded in 2021 when 54.8 percent of the national territory was in that condition.
Although the percentage of the territory under these severe drought conditions is lower, the problem is very focused in the northern states. There has been greater direct radiation input, compared to the average from 1981 to 2010 in Coahuila, Nuevo Leon, Tamaulipas, part of Chihuahua, Sinaloa, a little of Sonora, San Luis Potosi, Durango and Zacatecas.
According to future climate change scenarios, Domínguez Sarmiento estimated that northern regions will suffer more frequent and extreme droughts. Therefore, decision-makers need to use climate forecasts, which allow -three months in advance- to know how the rainy season will come, as well as to know when there will be less rainfall than the historical average and to determine preventive measures.
Regarding the water crisis in the city of Monterrey, Nuevo León, Mexico's third-largest city, the university expert considered that it is appropriate to build a third dam -additional to El Cuchillo and Cerro Prieto- to provide the liquid, although the average will not solve the drought problem in the long term, nor will emergency measures, such as transferring water from one state to another.
The university coordinator for Sustainability, Leticia Merino Pérez, said that the country is facing a disastrous scenario on this issue. "I believe that the water policy has generated a time bomb, which is exploding". The Ph.D. in Anthropology, dedicated to research on the integral and sustainable use of natural resources, said that since the concession system began, with the National Water Law in 1992, resource hoarding has increased; "there is more water under concession than is available in many basins".
There is great concentration. It is estimated that eight large users own 80 percent of the water under concession. This hoarding prevents water from being available to a significant number of municipalities and ecosystems. If the crises caused by aridity and climate change are added to people's lack of access to the resource, the problem is "tremendous," said Merino.
There are other additional difficulties: there is a lack of rainwater catchment, pollution, and overexploitation of the resource, and areas where, once again, regulation and public policies are inadequate.
It is estimated that 40 percent of Mexico's watersheds are contaminated at a medium to very serious level; together with China, we are the only country that uses sewage for irrigation in agriculture, contaminated "with everything we can think of", such as coliform bacteria that cause gastrointestinal diseases, drug residues, heavy metals, and microplastics, among others.
In a study by Adalberto Noyola Robles, researcher and former director of the Engineering Institute, carried out a few years ago, it was estimated that 60 percent of the country's treatment plants, which are run by municipalities, are not working. "We drink contaminated water and, to a large extent, this has led to the widespread consumption of bottled water that generates excess plastic waste."
Towards a Sustainable Water System
A few months ago, after years of struggle, the Mexican Official Standard NOM-001-SEMARNAT-2021 was issued to establish the permissible limits of pollutants in waste discharges into receiving bodies owned by the nation. All the companies had long resisted the control of their waste. The industrialists requested five years for its application and the Ministry of the Environment and Natural Resources does not have enough inspectors to verify the application of the NOM.
Another concern is the privatization of municipal water services, including treatment plants. Access to water is a human right and the State, the federation, the states, and the municipalities, with the participation of citizens, need to put together an institutional structure to ensure its provision and quality in the localities. We need to provide it from a focus on equity, and environmental justice, as a way to alleviate vulnerabilities.
I am convinced, she affirmed, that consumption practices are important, as is generating environmental citizenship and demanding better laws and public policies so that those who have control of the liquid under concession carry out better practices, are monitored, and do not overexploit the resources, and do not pollute them. There is much to be done in terms of citizen mobilization.
UNAM: an example to follow
If we imagine the national territory as a uniform space, approximately 1.5 billion cubic meters are precipitated annually by rainfall; however, the reality is that there is an unequal distribution of the liquid in the national territory, considered the technical coordinator of the UNAM Water Network, Fernando González Villarreal.
The also director of the Regional Center for Water Security UNESCO, said that a few years ago a study of the Program for Management, Use and Reuse of Water at UNAM (PUMAGUA) on droughts over time, revealed that this phenomenon occurs in Mexico, in general, once every 10 years, and has durations ranging from two to three years.
More efficient use
Added to this, added the winner of the 2015 National Engineering Award, are circumstances that aggravate the situation, such as deforestation and urbanization. The change in land use modifies the hydrology of the basins and causes runoff to be faster, reducing infiltration into aquifers and shortening river floods, caused by precipitation, especially in the Valley of Mexico.
The reality is that we have little storage and although Mexico has five thousand aqueducts and dams -some built since colonial times-, 180 of these are large and store approximately 150 thousand cubic hectometers of water. Faced with extreme problems such as the floods caused by hurricane Agatha in Oaxaca and the drought in northern Mexico, the most important solution is to be more efficient in the use of natural resources.
Water security in Latin America and the Caribbean
This implies promoting water-smart cities, where good quality and sufficient supply is guaranteed in urban areas and the countryside; supply for economic activities; providing what is necessary to the environment in ecological flows, to maintain ecosystems and biodiversity; and, above all, to achieve this under extreme conditions due to the influence of climate change.
The next thing to improve is the infrastructure for storage and treatment of wastewater, which allows for a circular economy, where the waste is not garbage and goes to the sewer, but can be used in another process, and this also requires resources.
Although Mexico has more than 3,000 treatment plants, one of the problems is that a significant percentage of them work poorly and this is due, in part, to the fact that the operating agencies of the sanitation system "are bankrupt".
Due to the work of monitoring, adequate consumption, revision of leaks, and generation of a culture of care for the resource, UNAM hosts UNESCO's Regional Center for Water Security for Latin America and the Caribbean, whose purpose is to exchange ideas and experiences. Thanks to this, alliances are made with international actors such as the University of Florida on cybersecurity, or the UNESCO Center of Japan on integrated risk management.