Antonio de Espejo
In February 1583, Espejo arrived at the territory of the Piros, the most southerly of the Pueblo villagers. From there the Spanish continued up the Rio Grande. Espejo described the Pueblo villages as "clean and tidy". The houses were multi-storied and made of adode bricks. "They make very fine tortillas," Espejo commented, and the Pueblos also served the Spanish turkeys, beans, corns, and pumpkins. The people "did not seem to be bellicose". The southernmost Pueblos had only clubs for weapons plus a few "poor Turkish bows and poorer arrows". Further north, the Indians were better armed and more aggressive. Some of the Pueblo towns were large, Espejo described Zia as having 1,000 houses and 4,000 men and boys. In their farming, the Pueblos used irrigation "with canals and dams, built as if by Spaniards". The only Spanish influence that Espejo noted among the Pueblos was their desire for iron. They would steal any iron article they could find.
Colorado River
These sedentary peoples heavily exploited their surroundings, practicing logging and harvesting of other resources on a large scale. The construction of irrigation canals may have led to a significant change in the morphology of many waterways in the Colorado River basin. Prior to human contact, rivers such as the Gila, Salt and Chaco were shallow perennial streams with low, vegetated banks and large floodplains. In time, flash floods caused significant downcutting on irrigation canals, which in turn led to the entrenchment of the original streams into arroyos, making agriculture difficult. A variety of methods were employed to combat these problems, including the construction of large dams, but when a megadrought hit the region in the 14th century A.D. the ancient civilizations of the Colorado River basin abruptly collapsed. Some Puebloans migrated to the Rio Grande Valley of central New Mexico and south-central Colorado, becoming the predecessors of the Hopi, Zuni, Laguna and Acoma people in western New Mexico. Many of the tribes that inhabited the Colorado River basin at the time of European contact were descended from Puebloan and Hohokam survivors, while others already had a long history of living in the region or migrated in from bordering lands.