Issue four of the Water and Environment Journal is out now - the final issue this year

The final issue of 2023 of the Water and Environment Journal is out now, highlighting innovations and solutions that enhance water management best practice

The Water and Environment Journal (WEJ) has now published its last issue of volume 37, featuring papers on water tariffs and attitudes towards change, sustainable management of water resources and oxidation processes for the degradation of microplastics and the degradation of contaminants from water and wastewater.

WEJ associate editor Leopoldo Mendoza-Espinosa stresses that money, power, and ambition shouldn’t be the defining forces in water management, in his editorial for the last issue of 2023, which you can find below.

“When Spain conquered the Aztecs, the clash of cultures gave birth to Mexico. This brought positive and negative aspects into the new nation. Some of the negative aspects was the ambition of the Conquistadores for anything related to gold and precious stones. It has been documented that the Aztec population happily gave away gold and jewels to the Conquistadores in exchange for cheap shiny objects like mirrors and small pieces of coloured glass.

This is a pattern that can be found in many examples throughout human history, when two countries with uneven economic levels must share common resources. This is the case of Mexico and the United States of America (USA).

Both countries share 3152 kms of border and two rivers, the Colorado river, and the Río Bravo (or Río Grande, as it is known in the USA). Throughout a series of legal acts and minutes by the International Boundary and Water Commission (IBWC), water allocation is distributed between both countries.

However, a new and previously untapped source of water is currently being considered: seawater. The use of seawater for urban, industrial or agriculture necessarily requires treatment for the removal of salts, also known as desalination. This process usually requires the use of membranes that filter the water and remove the suspended solids (salts) from it. Because of the small size of the salts in seawater, the only type of membrane capable of removing all the salts in seawater is reverse osmosis (RO). The use of RO is energy intense and requires the disposal of brine. Although membranes have progressed significantly since their mainstream use, they are still high-energy demanding and there are few examples where alternative energies have successfully substituted carbon-based energy sources. In a world already largely impacted by climate change, this is hard to swallow.

Of particular concern are the projected plans of considering the Gulf of California (also known as Sea of Cortez) as a transboundary water basin. The USA state of Arizona, a region with very low natural sources of water, is considering “importing” seawater from the Sea of Cortez, located entirely in Mexico. Recently, the city officials from Phoenix (Arizona’s largest city with 1.5 million habitants) have determined that it does not have enough water for future housing developments. Thus, Arizona has considered Mexico’s seawater as a possible source of water for Phoenix. Such seawater (4.1 m³/s) will have to be desalinated in Mexico and transported more than 300 kms and climb over 650 m for its use in Phoenix Arizona. The desalination process would produce brine (4.1 m³/s too) that would have to be disposed of in the Gulf of California. Plus, although it has been proposed that the energy requirement for the desalination (52 MW) and transportation (28,000 kW, only in Mexico) of the water would be solar based, there is scepticism considering the surface area of solar panels needed to provide such an enormous amount of energy. On the other hand, if fossil fuels would be used for energy production, these would be burned, yes, in Mexico.

From a water management point of view, desalination should be considered only after water conservation measures are applied. Conservation efforts in Arizona should focus on the reuse of reclaimed water for green areas and landscaping, interchange of reclaimed water with farmers for the irrigation of crops, the use of native drought-tolerant plants for gardens and landscaping, the ban of high water-demanding constructions like swimming pools. Economic measures could also be applied, for example, increasing the water tariff to promote conservation.

Finally, better management of water for irrigation must be pursued. Currently 80 per cent of Arizona’s water is used for irrigation, 837,000 acres use flood irrigation and only 233,000 acres use drip or micro-irrigation.

It is puzzling that officials in Mexico are even considering the export of desalinated water as a viable option. Although the project has not been given the green light in Mexico, solid steps in that direction have been taken. In 2017, the Commissioners of the aforementioned IBWC, the binational USA-Mexico commission that has the mission to apply the boundary and water treaties of the United States and Mexico, signed Minute No. 323, “Extension of Cooperative Measures and Adoption of a Binational Water Scarcity Contingency Plan in the Colorado River Basin”, in which they expressed the need for continued and additional actions due to the impacts on Colorado River storage resulting from various factors, including meeting system demands, the effects of hydrologic conditions, and increased temperatures. Section IX.B of Minute 323, called “New Water Sources Projects,” noted the existence of opportunities for joint cooperative projects with the potential for increasing delivery or exchange of Colorado River water benefitting both nations, including the construction and operation of desalination plants along the border. By doing this, it opened the door to these types of projects.

So, what does Mexico get in return? Brine to be disposed of and the emission of gasses of greenhouse effect if fossil fuels are used to meet energy requirements. Money too, perhaps to compensate for the operation of the desalination scheme and for its transportation to the border. However, what about the compensation for the greenhouse effect gasses and for the impact of the brine on the natural marine population? How could Mexico be compensated for this? Is there a sensible and fair way to calculate it? Is it fair to Mexico?

Money, power, and ambition shouldn’t be the defining forces in water management. Or perhaps we haven't learned anything since the Aztecs and Conquistadores days.”

Leopoldo Mendoza-Espinosa is a Professer at University of Baja California, Mexico

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