Lake Texcoco
Lake Texcoco (“Lago Texcoco”) was among the largest lakes in Mesoamerica, reaching its maximum size in the period following the last Ice Age (approximately 11,000 years ago when it covered almost the entire Valley of Mexico.
The Valley of Mexico spans approximately 7,000 sq kilometers. At its peak, Lake Texcoco covered 5,668 square kilometers with a depth exceeding 150 meters. Over time, climate fluctuations caused changes in the lake’s size.
Lake Texcoco primarily received water from melted snow and rain runoff. Between 11,000 and 6,000 years ago, natural climate warming reduced snowfall in central Mexico, leading to a significant decline in the lake’s water level.
Climatic changes and precipitation fluctuations likely influenced Lake Texcoco’s size. Increased rainfall could expand the lake, while drier periods caused it to shrink. As the water level decreased, several small paleolakes formed.
Texcoco varied in size from approx. 2,000 to 3,000 sq km during its existence.
Previously the lake extended over much of the southern half of the basin, where it was the largest of an interconnected chain of five large and several smaller lakes (Texcoco, Lakes Xaltocan, Zumpango, Chalco, and Xochimilco).
During periods of high water levels – usually after the rainy season from May to October – all lakes often combine into one body of water. During the drier winter months, the lake system tended to split into separate bodies of water.
Lake Texcoco was located at the lowest altitude of the lakes in the Valley of Mexico. The lake acted as a natural sink for the basin, drawing water from the surrounding area as the culmination of the valley’s drainage system.
Lake Texcoco was situated at the lowest point in the Valley of Mexico and naturally collected water from the surrounding area. This meant that water from the higher lakes in the mountains flowed downhill towards Lake Texcoco.
Lake Texcoco was home to a diverse marine life, including various fish species, sea turtles, and other aquatic animals. This rich biodiversity made the lake and its surroundings vital for the valley’s inhabitants as a source of food.
The lake was also an important source of fresh water for the valley’s inhabitants.
The lake’s marshy shores, covered with mangroves typical of humid tropical coastal zones, supported unique ecosystems and provided habitat for numerous plant and animal species adapted to aquatic environments.
Human activity around Lake Texcoco
The human activity around Lake Texcoco highlights the development of settlements and civilizations in the region over thousands of years:
Agriculture (circa 5000 BCE): Agriculture around Lake Texcoco began approximately 7,000 years ago. Early inhabitants likely utilized the fertile lands surrounding the lake for cultivation, marking an important transition towards settled lifestyles.
Tlatilco Culture (1700-1250 BCE): Settlements began to emerge on the northeastern shore of Lake Texcoco. This period coincides with the appearance of the Tlatilco culture, known for its distinctive ceramic artifacts and cultural practices.
Tlatilco Culture (1250 BCE): By 1250 BCE, signs of the Tlatilco culture became prominent around Lake Texcoco, indicating a flourishing society engaged in trade and artistic expression.
Cuicuilco (800 BCE): Around 800 BCE, Cuicuilco emerged as a major power in the Valley of Mexico, dominating the region for approximately 200 years. Cuicuilco is notable for its impressive circular pyramid and advanced agricultural practices.
Post-Teotihuacan Era (600-800 BCE): Following the decline of Teotihuacan, other city-states appeared around Lake Texcoco under the influence of Toltecs and Chichimecs. These city-states coexisted peacefully for several centuries.
Lake Texcoco was a hub of human activity and cultural exchange. The lake’s fertile surroundings, combined with its strategic location, attracted various civilizations that left a lasting impact on the history and heritage of the Valley of Mexico.
Lake Texcoco during the Aztec Empire
At the beginning of the 14th century, the Aztec tribes came to the valley.
On the islands of Lake Texcoco, the Aztecs founded their cities. Aztecs settled on a group of small natural islands in Lake Texcoco. These islands provided natural defensive advantages and were surrounded by shallow lake waters.
The main island on which the Aztecs founded their capital, was originally a small rocky island in the western part of Lake Texcoco. Tenochtitlan was founded on that islet and was connected to the shore by a network of dams and floating gardens.
Over time, the Aztecs expanded the territory by creating artificial islands (chinampas). This expansion allowed them to significantly increase residential and agricultural areas around the capital.
Tenochtitlan became a powerful city-state and the center of the Aztec Empire. Tenochtitlan’s strategic location on the lake contributed to its fame and success in the region.
The Aztecs built a system of dams to separate the lake’s salt water from sewage and rainwater.
This dam system also allowed the Aztecs to control lake levels.
During Aztec times, Lake Texcoco had 200 to 300 chinampas. These artificial islands were critical to agriculture and helped the Aztecs support their population in the region by providing fertile land for farming among the lake’s waters.
The artificial islands were connected one to another and to the shores by dams and artificial paths.
Due to its size and strategic location, the lake played a central role in the development of the Aztec Empire, providing water for agriculture and transportation, as well as serving as a natural protective barrier for Tenochtitlan.
Dams (or embankments) were used to create floating gardens and maintain the viability of cities on the islands. They also served to provide a route of communication between various parts of the lake and the shore.
These were structures made of earth, stones, and trees that were built to hold water and create paths for movement.
The Aztec ruler Ahuizotl attempted to build an aqueduct that would carry water from the mainland into the lakes surrounding the city of Tenochtitlan. The aqueduct failed and the city suffered severe flooding in 1502.
The Valley of Mexico had already begun to become shallow before the arrival of the Spaniards due to natural processes and human activity. Drainage and irrigation systems also affected the water level in Lake Texcoco and contributed to its gradual drying up.
The construction of canals, dams, and irrigation systems to support agriculture and urban livelihoods in the Valley of Mexico led to a decrease in the area of Lake Texcoco and its surrounding lakes.
Thus, changes in the size of Lake Texcoco are the result of a complex combination of natural processes and human influence on the environment over a long period of history.
The destruction of the water management system
During the Spanish siege of Tenochtitlan in 1521, the dams were destroyed. After the fall of the Aztec Empire, the Spanish destroyed Tenochtitlan’s water management system, which eventually led to floods.
Flooding became a serious problem in Mexico City, built on the ruins of the former Aztec capital. Flood control efforts resulted in most of the lake being drained, but Mexico City continued to suffer from periodic floods.
After the flood of 1604, there was another flood in 1607.
The drainage did not help, and the major flood in 1629 submerged much of Mexico City. The issue of moving the Mexico City was even discussed, but the Spanish authorities decided to preserve the existing location of the capital.
The Spanish began draining Lake Texcoco to control flooding and control the water. As a result of the construction of a drainage system to reduce the water level in the valley, Lake Texcoco gradually dried up.
This change had profound environmental consequences for the region and led to the gradual disappearance of the lake. The remnants of the lake were divided into smaller bodies of water – Xochimilco, Chalco, and Zumpango.
These lakes remained partially submerged and became the basis for the modern neighborhoods of Xochimilco and Chalco in Mexico City. Today, most of the lake’s former basin is almost entirely occupied by urban development.
The Valley of Mexico is a basin with an average elevation of 2236 m above mean sea level. This high altitude contributes to the region’s unique climatic and environmental characteristics. The valley is surrounded by mountains.
Previously, rainwater flowed into the lakes, which contributed to their size and interconnectedness. After the disappearance of Lake Texcoco and the drying up of other lakes, the hydrology of the valley changed dramatically.
Without these natural reservoirs, rainwater has difficulty finding its way out, leading to problems in managing water flow and increasing evaporation rates. As a result, much of the rainwater that flows into the valley evaporates.
About 72-79% of the rainwater that falls into the valley evaporates.
Today, the term “Lake Texcoco” refers only to a big area surrounded by salt marshes 4 km east of Mexico City, which covers the ancient lake bed. Also, there are small remnants of the lakes of Xochimilco, Chalco, and Zumpango.
Lake Texcoco Ecological Park
The Lake Texcoco Ecological Park is an initiative by the Mexican government to create a vast urban park within the State of Mexico, an integral part of the vast urban area in the valley. Mexico, adjacent to Mexico City.
The park is scheduled to open in 2024. Its creation followed the cancellation of plans to build an airport on the same site, marking a significant shift towards green restoration and sustainable urban development.
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