Why did some Colorado River Indigenous groups practice agriculture?

Indigenous groups along the Colorado River practiced agriculture primarily because the river provided a reliable source of water in an otherwise arid desert environment.1

For groups such as the River Yuman (including the Mojave, Quechan, Cocopa, and Maricopa), the Colorado River was essential for subsistence. Each spring, the river overflowed its banks, depositing fresh silt and moisture onto the surrounding bottomlands. This natural flooding allowed these groups to cultivate small, irregular fields of corn, beans, pumpkins, melons, and grasses. Because the Colorado River was too large and its flow too variable for the type of canal irrigation used by other groups like the Hohokam, these tribes utilized extensive floodplain farming techniques.12

While these agricultural harvests were significant, they were not the sole source of food; these groups supplemented their crops with wild fruits, seeds, fish, and small game. The extent to which any group relied on farming versus foraging was largely determined by their proximity to permanent water sources.13