How were Aztec chinampas constructed?

Aztec Chinampas are small artificial islands supported by stakes and reeds beneath fresh water lakes. Each Chinampa measured about 100 feet by 8 feet and was bordered by a fence of interwined branches. This tended to solidify with mud, then the area was filled with soil. This agricultural system greatly maximized production.

Chinampas were an Aztec form of Agriculture which consisted of small rectangular plantations.