The development of irrigation agriculture on valley floors in the southwestern United States has substantially altered natural drainage systems. This study discusses five anthropogenic factors that have altered the hydrologic function of a dryland basin floor in south-central Arizona. These factors are: (1) upstream urbanization and channel entrenchment, (2) dam construction, (3) artificial diversion of drainage, (4) obstruction of flow by transportation routes, and (5) stream channelization. The first two factors have altered hydrologic inputs to the basin floor, the third and fourth factors have changed regional and local patterns of flooding, and the fifth factor has resulted in channel instability and reduced flood attenuation. These five factors, along with a recent increase in the frequency of incursions of tropical moisture into southern Arizona, have enhanced flow variability and the potential for devastating flooding on the basin floor. This research demonstrates the need for basin-wide approaches to stream management in drylands and illustrates the importance of basing management decisions on geomorphic information concerning fluvial forms and processes.
ASJC Scopus subject areas
- Environmental Chemistry
- Water Science and Technology
- Environmental Science(all)
- Earth and Planetary Sciences (miscellaneous)
- Earth and Planetary Sciences(all)