Editing Lake Texcoco (section)

==History==
Between the [[Pleistocene]] epoch and the [[last glacial period]], the lake occupied the entire Mexico Valley. Lake Texcoco reached its maximum extent 11,000 years ago with a size of about {{convert|2189|mi2}} and over {{convert|500|ft}} deep. When the lake's water level fell it created several paleo-lakes that would connect with each other from time to time. At the north in the modern community of San Miguel Tocuilla there is a great [[Paleontological Museum in Tocuila|paleontological field]], with a great amount of pleistocenic [[fauna]]. The Lake was primarily fed by snowmelt from nearby mountain glaciers when the Mexico Valley had a temperate climate. Between 11,000 and 6,000 years ago, the climate naturally warmed and snowfall in central Mexico became less prevalent. This caused the water level of the lake to drop over the next several millennia. Remnants of the ancient shoreline that Lake Texcoco had from the last glacial period can be seen on some slopes of [[Mount Tlaloc]] as well as mountains west of Mexico City. The disarticulated remains of seven [[Columbian mammoth]]s dated between 10,220 ± 75 and 12,615 ± 95 years ([[Before Present|BP]]) were found, suggesting human presence.<ref>Siebe ''et al.'' (1999)</ref> It is believed that the lake disappeared and re-formed at least 10 times in the last 30,000 years.

Agriculture around the lake began about 7,000 years ago,<ref>Niederberger (1979)</ref> with humans following the patterns of periodic inundations of the lake.

Several villages appeared on the northeast side of the lake between 1700 and 1250 BC. By 1250 BC the identifying signs of the [[Tlatilco culture]], including more complex settlements and a stratified social structure, are seen around the lake. By roughly 800 BC [[Cuicuilco]] had eclipsed the Tlatilco cultural centers and was the major power in the Valley of Mexico during the next 200 years when its famous conical [[pyramid]] was built. The Xitle volcano destroyed Cuicuilco around AD 30, a destruction that may have given rise to [[Teotihuacan]].

After the fall of Teotihuacan, AD 600–800, several other city states appeared around the lake, including Xoloc, [[Azcapotzalco (altepetl)|Azcapotzalco]], [[Tlacopan]], Coyohuacan, Culhuacán, Chimalpa, and Chimalhuacán – mainly from [[Toltec]] and [[Chichimeca]] influence. None of these predominated and they coexisted more or less in peace for several centuries. This time was described as a Golden age in Aztec chronicles. By the year 1300, however, the Tepanec from Azcapotzalco were beginning to dominate the area.

=== Tenochtitlan ===
{{Main|Tenochtitlan}}
[[File:Painting of Tenochtitlan-Tlatelolco on Lake Texcoco (9755215791).jpg|thumb|right|250px|Tenochtitlan and Lake Texcoco in 1519.]]
According to a traditional story, the [[Mexica]] wandered in the deserts of modern Mexico for 100 years before they came to the thick forests of the place now called the Valley of Mexico.

[[Tenochtitlan]] was founded on an [[islet]] in the western part of the lake in the year 1325. Around it, the [[Aztec]]s created a large [[artificial island]] using a system similar to the creation of [[chinampa]]s. To overcome the problems of drinking water, the Aztecs built a system of [[dam]]s to separate the salty waters of the lake from the rain water of the [[effluent]]s.<ref name="Şentürk1994">{{cite book|author=Fuat Şentürk|title=Hydraulics of Dams and Reservoirs|url=https://books.google.com/books?id=NqzZdytUz3gC&pg=PA6|year=1994|publisher=Water Resources Publication|isbn=978-0-918334-80-0|page=6}}</ref> It also permitted them to control the level of the lake. The city also had an inner system of channels that helped to control the water.

The Aztec ruler [[Ahuitzotl]] attempted to build an aqueduct that would take fresh water from the mainland to the lakes surrounding the Tenochtitlan city. The aqueduct failed, and the city suffered a major flood in 1502.<ref name="Zurita1994">{{cite book|author=Alonso de Zurita|title=Life and Labor in Ancient Mexico: The Brief and Summary Relation of the Lords of New Spain|url=https://books.google.com/books?id=Z6vHgQg8osQC&pg=PA304|year=1994|publisher=University of Oklahoma Press|isbn=978-0-8061-2679-1|pages=304–}}</ref><ref>{{Cite news | url=https://www.telegraph.co.uk/culture/art/art-features/6213665/Moctezuma-the-leader-who-lost-an-empire.html | title=Moctezuma: The leader who lost an empire| date=2009-09-21}}</ref>

During [[Hernán Cortés]]'s siege of Tenochtitlan in 1521, the dams were destroyed, and never rebuilt, so [[flood]]ing became a big problem for the new [[Mexico City]] built over Tenochtitlan.

=== Artificial drainage ===
[[File:EnricoMartinez.JPG|thumb|Monument to Enrico Martinez in Mexico City]]

Mexico City suffered from periodic floods; in 1604 the lake flooded the city, with an even more severe flood following in 1607. Under the direction of [[Enrico Martínez]], a drain was built to control the level of the lake, but in 1629 another flood kept most of the city covered for five years. At that time, it was debated whether to relocate the city, but the Spanish authorities decided to keep the existing location.{{Cn|date=August 2023}}
[[File:Lake Texcoco (Lago de Texcoco) December 1855 map from Harper's New Monthly Magazine Volume 12 December 1855 to May 1856 (IA harpersnew12harper) (page 34 crop).jpg|thumb|Lake Texcoco map from [[Harper's New Monthly Magazine]], December 1855 ]]
Eventually the lake was drained by the channels and a [[Drainage tunnel|tunnel]] to the [[Pánuco River]], but even that could not stop floods, since by then most of the city was under the [[water table]]. The flooding could not be completely controlled until the twentieth century. In 1967, construction of the ''Drenaje Profundo'' ("Deep [[Drainage]] System"), a network of several hundred kilometers of tunnels, was done, at a depth between {{convert|30|and|250|m|ft|abbr=on}}. The central tunnel has a diameter of {{convert|6.5|m|ft|1|abbr=on}} and carries rain water out of the basin.  The [[Emisor Oriente Tunnel|eastern discharge tunnel]] was inaugurated in 2019.{{Cn|date=August 2023}}

The ecological consequences of the draining were enormous. Parts of the valleys were turned semi-arid, and even today Mexico City suffers from lack of water. Due to [[overdrafting]] that is depleting the aquifer beneath the city, Mexico City is estimated to have [[Groundwater-related subsidence|sunk]] 10 meters (33 feet) in the last century.<ref>{{cite news|last1=Sample|first1=Ian|title=Why is Mexico City sinking?|url=https://www.theguardian.com/science/2004/may/06/thisweekssciencequestions|access-date=3 October 2016|agency=The Guardian}}</ref> Furthermore, because soft lake sediments underlie most of Mexico City, the city has proven vulnerable to [[soil liquefaction]] during earthquakes, most notably [[1985 Mexico City earthquake|in the 1985 earthquake]] when hundreds of buildings collapsed and thousands of people died.<ref>{{cite journal|last=Moreno Murillo|first= Juan Manuel|year=1995|title= The 1985 Mexico Earthquake|periodical=Geofisica Colombiana|publisher=Universidad Nacional de Colombia|issue=3|pages=5–19|issn=0121-2974}}</ref>

The term "Texcoco Lake" now refers only to a big area surrounded by [[salt marsh]]es {{convert|4|km|mi|1|abbr=on}} east of Mexico City, which covers part of the ancient lake bed. Also there are small remnants of the lakes of [[Lake Xochimilco|Xochimilco]], [[Lake Chalco|Chalco]], and [[Lake Zumpango|Zumpango]].{{Cn|date=August 2023}}

Several species indigenous to the lake are now extinct or endangered (e.g. [[axolotl]]s).<ref name="auto"/>

The modern Texcoco Lake has a high concentration of salts and its waters are evaporated for their processing. A Mexican company, "Sosa Texcoco S.A." has an {{convert|800|ha|acre|adj=on}} solar evaporator known as [[El Caracol, Ecatepec|El Caracol]].{{Cn|date=August 2023}}

Land reclamation of the lakebed was part of Mexico's attempts at development in the twentieth century.<ref>Matthew Vitz, "'The Land with which we struggle': Land Reclamation, Revolution, and Development in Mexico's Lake Texcoco Basin, 1910-1950". ''Hispanic American Historical Review'' 92, no. 1 (2012): 41-71.</ref>