The Geoarchaeology of Gullies and Arroyos in Southern Arizona

Many of the major rivers and streams in the arid and semiarid American Southwest can be classified as gullies and arroyos. The history of deposition, stability, and erosion of gully and arroyo environments has had a profound influence on the archaeological record contained within valley and bajada (piedmont) alluvium. The temporal and spatial sample of archaeological sites in southern Arizona is as much a reflection of geological processes as it is of cultural processes. Where both geological and archaeological data sets are well preserved, detailed landscape reconstructions are possible and prehistoric activity can be placed in the context of the prehistoric landscape. In southern Arizona, the location of Hohokam agricultural settlements at any particular time, changes in position of these settlements through time, and agricultural technology were affected by the configuration of the landscape, by the hydrologic regime of the bajada gullies and valley arroyos, and by landscape changes that have occurred through time. In fact, prehistoric Hohokam agriculturalists may have initiated some of the environmental degradation observed in the geological record.