Agricultural manipulation of floodplains in the southern Basin and Range Province

Floodplains in arid lands can be agriculturally productive, but they can also be geomorphically unstable environments. Many of the floodplains of higher order basins in southern portion of the Basin and Range Province of the American Southwest have been farmed intermittently for hundreds of years, and continuously for the past century. In order to be productive, however, these floodplains were modified considerably by human agency. This paper reviews the different types of human manipulations to floodplains that may result in land degradation and geomorphic change, including vegetation, topography, soils, hydrology, and channel banks. Emphasis is on the direct and indirect consequences of geomorphic modification, and the long-term viability of such changes in the contexts of landscape sensitivity and sustainability. Evidence documents transformation of natural floodplains to agricultural surfaces, with examples from southern Arizona, USA, and Sonora, México.