A term of Spanish origin used in the American West for an ephemeral stream channel with a rectangular cross section entrenched in alluvium. They may be up to 20 m deep, over 50 m wide and up to hundreds of kilometres in length. Arroyos are produced by climatic change and/or landuse change. valley-fill deposits in some arroyos provide evidence of repeated phases of incision and aggradation since the early Holocene whereas, in other areas, incision appears to have commenced when white settlers arrived in the late nineteenth century. They differ from gullies, which tend to be V-shaped in cross section and may be excavated also in soil and colluvium. The relative roles of rainfall and landuse change in accounting for arroyo cutting in the American Southwest was a recurring theme of formative quantitative American geomorphology.
[See also wadi]
- Date of channel trenching (arroyo cutting) in the arid Southwest. Science 42: 338-344. (1925)
- Arroyos and environmental change in the American South-West. Oxford: Clarendon Press. ; (1976)
- Evolution of arroyos: Incised channels of the southwestern United States. In Darby, SE; Simon, A (eds) Incised river channels. Chichester: Wiley, 153-185. ; ; (1999)
- Recent formation of arroyos in the Little Missouri Badlands of southwestern Dakota. Geomorphology 38: 63-84. (2001)
- The arroyo problem: Paleohydrology and paleohydraulics in the short term. In Gregory, KJ (ed.) Background to palaeohydrology: A perspective. Chichester: Wiley, 279-302. (1983)
- Late Quaternary arroyo formation and climate change in the American southwest. Geology 29: 399-402. ; (2001)