Most of us have heard of the Pyramids, the Roman aqueducts, and Stonehenge – construction projects that required feats of engineering seemingly out of grasp for the ancient builders. We are still investigating the why and how of these well-known sites. New discoveries are uncovering many of these marvels of engineering in the Americas – a land previously thought to be remote and largely undeveloped.
The Bajada Canals
The American southwest is an area with a high need for water control and distribution. A discovery, published in January of 2019, shows that ancient native populations faced this same problem and they had the capacity to solve it. Near Safford, Arizona, twelve systems of canals of at least 41 small canals in total appear to have been constructed by migrants from Northeastern Arizona. Most of the canals were constructed between a.d. 1250 and 1450 – a few were constructed as early as a.d. 1100.
The study used high-precision general purpose computer mapping and satellite image applications to identify and map the canal system. To validate their findings, researchers also surveyed the canals on foot. The builders used a cut and fill process. Soil removed in the excavation of the canal channel was immediately used as fill in downstream sections of the canal. Hanging segments of the canal were designed along sheer sides of mesas to allow for the most direct route regardless of terrain. As the study concludes, “the bajada canal systems are the most outstanding of the many prehistoric human landscape modifications that characterize the central Safford Basin”.
Running Water in Tenochtitlán
Tenochtitlán was the most important city in Mexico and was larger than Paris at the time. The actual city construction itself was impressive. Tenochtitlán was built in the middle of Lake Texcoco by bringing in off-site soil to create an island. Much like Venice, Tenochtitlán was supported by a system of canals and raised causeways.
The Aztec emperor, Chimalpopoca, recognized the need for an efficient and clean water supply. He ordered the construction of an aqueduct to support the city. The aqueduct, 12 km long and 7 m wide, delivered water from nearby spring fed lakes and was distributed through an underground water distribution system – much like our own. Rich citizens had abundant running water in their homes that fed drinking fountains, baths, and pools. When the Spaniards came to Tenochtitlán, they were shocked by the level of cleanliness the Aztecs maintained – far outpacing the standards for cleanliness in Europe at the time.
Engineered Rainforest
The Amazon is probably the most well-known forest in the world. Studies are now revealing that this forest, rich in edible plants, was shaped by native populations over the millennia to suit their needs. The study found that 20 percent of the trees in the Amazon are domesticated species such as the Brazil nut, the Amazon tree grape and the ice cream bean tree. If the Amazon were a pristine, unaltered forest, researchers would expect the percent of domesticated trees to be about 15%.
When researchers looked closer, they noticed that the domesticated species of trees were mainly clustered around ancient human communities. They also noted the species were often very far from where it had originated – too far for animals or the wind to have spread the seeds. This implies that humans were the ones to spread and share the plants. Around five centuries have passed between pre-Colombian time and this study. With such a long time-span, many other things could have influenced the composition of the Amazon, so further studies are needed to corroborate these findings.
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