Farming on the Water
1In about 1325 the Mexica, the people often called the Aztecs, founded the city of Tenochtitlan on a swampy island in Lake Texcoco. The lake lay in the Valley of Mexico, a high basin more than 2,000 meters above sea level and ringed by mountains. Rivers from the mountains drained into the lakes, but no river carried water out to the sea. The water in the eastern part of the lake was salty, while springs fed fresher water into the lakes to the south.
2The island had little dry land, so the Mexica, like other peoples of the valley, farmed on the water. To make a chinampa, farmers staked out a long, narrow plot in shallow fresh water, wove a fence of reeds and branches around it, and piled up layers of mud and rotting plants inside. They planted willow trees along the edges, and the trees' roots grew down through the plot into the lake bed. Canals between the plots let farmers travel by canoe, and each year they scooped rich mud from the canal bottoms onto their beds. Chinampas grew maize, beans, squash, chiles and flowers, and they could produce more than one crop a year.
3As the city grew to perhaps 200,000 people (estimates vary), the Mexica reshaped the lake around it. Long causeways of earth and stone linked the island to the shore. An aqueduct carried fresh drinking water from the springs at Chapultepec on the western shore. Still, the lake could be dangerous. In years of very heavy rain, the water rose quickly, and salty water from the east could spread into the fresher water near the city.
4According to later accounts, a great flood struck in 1449 and covered streets and fields. The ruler Moctezuma I asked for advice from Nezahualcoyotl, ruler of the allied city of Texcoco, who was famous for his building projects. The council scene below is imagined, but the problem the speakers argue about was real.