Texcoco (salt flats)

Texcoco (salt flats)
Name	Texcoco (salt flats)
Other names	Lake Texcoco salt flats
Location	State of Mexico and Mexico City, Mexico
Type	Endorheic basin, salt flat
Basin countries	Mexico
Area	Variable (historic lake extent reduced)
Elevation	~2,240 m

Texcoco (salt flats) is the remnant of a palaeolakebed formerly occupied by Lake Texcoco on the Basin of Mexico plateau near Mexico City, Tenochtitlan, and Texcoco (municipality). The site lies within the administrative boundaries of Nezahualcóyotl, Ecatepec de Morelos, Chalco, and Texcoco (municipality) and is linked historically and hydrologically to the Valley of Mexico, Lagoons of the Valley of Mexico, and the Lerma River–Río de la Piedad drainage. The salt flats form a distinct geomorphological and ecological unit within the high-altitude Trans-Mexican Volcanic Belt and the Balsas Basin margins.

Geography and geology

The salt flats occupy part of the former Lake Texcoco basin adjacent to volcanic constructs such as Nevado de Toluca, Popocatépetl, and Iztaccíhuatl and are underlain by lacustrine sediments deposited during the late Pleistocene and Holocene. Regional tectonics involving the North American Plate, Cocos Plate, and regional faulting such as the San Andrés Fault and the Chalco Fault influenced basin subsidence and sedimentation, while pyroclastic deposits from Xitle and stratovolcanic eruptions contributed tephra layers. The salt crusts, halite beds, and evaporite minerals overlay clays and silts related to lacustrine transgressions and regressions recorded alongside archaeological sediments from Aztec Triple Alliance era constructions. Nearby infrastructural landmarks include the Mexico City International Airport, the Circuito Exterior Mexiquense, and the New International Airport for Mexico City (NAICM) proposals that have intersected geological assessments.

History

Human settlement of the Basin of Mexico involved groups such as the Chichimeca, Acolhua, Tepanec, and later the Mexica whose imperial capital at Tenochtitlan engineered hydraulic works tied to Lake Texcoco. Colonial projects by Enriquez de Almansa, Viceroyalty of New Spain, and later republican engineers including Alexander Von Humboldt observers and Porfirio Díaz-era modernization accelerated drainage, leading to the desiccation that produced the modern salt flats. Twentieth-century urban expansion driven by administrations of Miguel Alemán Valdés, Luis Echeverría, and Gustavo Díaz Ordaz further transformed the basin, while eco-engineering initiatives in the late 20th and early 21st centuries involved institutions like the Instituto Nacional de Antropología e Historia, Universidad Nacional Autónoma de México, and state agencies.

Hydrology and salinity

The flats are part of an endorheic sub-basin where water balance is controlled by precipitation from the North American Monsoon, evaporation under high-altitude solar radiation, and limited inflow from ephemeral channels draining the Sierra de Guadalupe, Sierra de Chichinautzin, and the Aculco River catchments. Historical hydraulic structures—causeways, canals, and dikes built by Nezahualcóyotl, the Aztec Empire, and later colonial engineers—altered lake connectivity, while twentieth-century drainage works by agencies associated with the Comisión Nacional del Agua and the Sistema de Aguas de la Ciudad de México intensified salinization. Salinity gradients produce sodium chloride, gypsum, and sodium carbonate precipitates that mirror patterns seen in other endorheic systems such as the Great Salt Lake and Salar de Uyuni.

Ecology and biodiversity

Despite high salinity and anthropogenic disturbance, the flats and adjacent wetlands support halophytic vegetation similar to communities described in studies from the Baja California Peninsula and the Altiplano, including salt-tolerant assemblages and migratory bird stopovers used by species cataloged in regional censuses by CONABIO and the World Wildlife Fund. Faunal records indicate occurrences of waterfowl linked to the Western Hemisphere Shorebird Reserve Network flyways, amphibian and reptile taxa studied by researchers at the Instituto de Biología (UNAM), and invertebrate halophiles comparable to taxa found in Mono Lake and Salton Sea research. Urban pollution from sources tied to Lago de Texcoco reclamation, landfill leachate, and industrial effluents has reduced native richness, while invasive species documented by conservation NGOs have modified trophic interactions.

Human use and impacts

The flats have been used for salt extraction since pre-Hispanic and colonial times, with commercial saltworks operating into the 19th and 20th centuries alongside contemporary mineral exploitation proposals. Urbanization expanded across the former lakebed with settlements such as Nezahualcóyotl, State of Mexico and industrial hubs like Ciudad Nezahualcóyotl, increasing groundwater extraction tied to metropolitan demand managed by SAPASA and municipal utilities. Airborne dust storms, subsidence observed near La Venta and metropolitan districts, and contamination incidents have prompted environmental assessments by agencies including the Secretaría de Medio Ambiente y Recursos Naturales and cross-jurisdictional legal actions involving the Supreme Court of Justice of the Nation.

Restoration and management efforts

Restoration proposals range from wetland reconstruction championed by academics at IPN and UNAM to large-scale engineering plans proposed during the NAICM debates and pilot projects by the Comisión Nacional de Áreas Naturales Protegidas. Initiatives emphasize managed aquifer recharge, constructed wetlands modeled on systems in the Netherlands and California, and integrated watershed management involving the Lerma–Chapala Basin Authority analogs. International collaborations have included experts from institutions such as the World Bank, the Inter-American Development Bank, and environmental NGOs including The Nature Conservancy to design salinity mitigation, dust suppression, and biodiversity corridors linking urban green infrastructure like Chapultepec Park.

Cultural significance and archaeology

Archaeological sites around the flats include artifacts and urban remains tied to Tula (Toltec) influences, Teotihuacan trade networks, and the late Postclassic city-states of the Acolhua. Ethnohistorical texts such as the Codex Mendoza and accounts by chroniclers like Bernal Díaz del Castillo document economic and ritual practices associated with the lake, while contemporary cultural memory is preserved by museums including the National Museum of Anthropology (Mexico) and local cultural centers. The salt flats feature in artistic representations, literature referencing Sor Juana Inés de la Cruz-era landscapes, and debates over heritage protection involving agencies such as the Instituto Nacional de Antropología e Historia.

Category:Landforms of Mexico Category:Salt flats Category:Valley of Mexico