The social impact of anthropogenic landscape modification in the Río Verde drainage basin, Oaxaca, Mexico

This article examines the effects of anthropogenic landscape modification in the upper drainage basin of the Rio Verde on environments and populations of the lower Rio Verde Valley, Oaxaca, Mexico. Archaeological and geomorphological research conducted by the Rio Verde Formative Project indicates that Late Formative (400–100 B.C.) population growth and agricultural intensification in the Oaxaca and Nochixtlan valleys increased erosion and runoff from the Verde's upper drainage. This geomorphic change in the highland valleys altered the drainage system and led to increased flooding and alluviation in the lower Rio Verde Valley. The environmental effect in the lower valley may have increased the agricultural potential of the region, leading to population growth, and at least indirectly to social change.