The chinampa was a system of narrow, rectangular raised fields built up from lake mud, decaying vegetation and staked willow margins in the shallow freshwater lakes of the Valley of Mexico. Worked intensively by Xochimilca, Chalca and later Mexica cultivators, the plots drew water and silt directly from surrounding canals, allowing several harvests a year without fallowing. The grid of fields and canals doubled as a navigable transport network and as the productive hinterland that fed Tenochtitlan. Around 750 hectares survive in cultivation at Xochimilco, inscribed by UNESCO in 1987.
It was among the most productive pre-industrial farming systems known and made possible the dense lacustrine metropolis of Tenochtitlan. The chinampa fused agriculture, water management and a canal-grid urban form into a single ecological infrastructure.