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How did irrigation support cities on the desert coast of Peru?

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distribution of aboriginal South American and circum-Caribbean cultural groups — South American Indian Distribution of aboriginal South American and circum-Caribbean cultural groups.

On the desert coast of Peru, irrigation was essential for supporting urban centers and large populations in an otherwise arid environment. By channeling streams that flowed down from the Andes into extensive systems of irrigation canals, coastal societies were able to practice intensive agriculture.12

These irrigation networks allowed for the cultivation of crops such as corn (maize) and beans, which provided the necessary food staples to sustain concentrated urban populations. In many northern valleys, these systems reached a significant scale, sometimes connecting multiple rivers to pool scarce water resources for agricultural use. For example, the Chimú state utilized these elaborate systems to maintain their cities, including their capital, Chan Chan.321

While these irrigation works were vital for urban development, they also created a dependency that made these societies vulnerable; the need to maintain and control these systems was a key factor in the political organization of coastal polities and influenced their susceptibility to military conquest by groups like the Inca.32