Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 12/5/2005
Publication Date: 7/1/2006
Citation: Abrahams, A.D., Neave, M., Schlesinger, W.H., Wainwright, J., Howes, D.A., Parsons, A.J. 2006. Biogeochemical fluxes across piedmont slopes of the Jornada Basin. In: Havstad, K.M., Huenneke, L.F., Schlesinger, W.H., editors. Structure and Function of a Chihuahuan Desert Ecosystem. The Jornada Basin Long-Term Ecological Research Site. Oxford, NY: Oxford University Press. p. 150-175. Interpretive Summary: No interpretive summary required.
Technical Abstract: This chapter is an overview of recent studies of the movement of water, sediment, and nutrients across a principle piedmont slope, or bajada, of the Jornada Basin. Bajadas are extensive, gently sloping surfaces formed by the coalescence of alluvial fans and are a major landscape component of the basin and range province. During the past four decades a considerable body of research has elucidated the form and function of alluvial fans (Bull 1977; Blair and McPherson 1994; Harvey 1997), but less attention has been paid to bajadas. In particular, the bajadas most neglected are those where channels converge and diverge at irregular intervals downslope. This type of bajada is found at the base of Summerford Mountain, the northernmost peak of the Dona Ana Mountains on the western edge of the Jornada Basin. For convenience, this bajada is hereafter referred to as the Summerford bajada. The research has involved rainfall simulation experiments on small plots, monitoring of two small watersheds on this bajada, and computer modeling of the processes operating in these watersheds and over the bajada as a whole. A detailed understanding of the hydrology and hydraulics of overland flow on this bajada requires a numerical model of the rainfall-runoff process. The objective of this chapter is to detail the model and draw conclusions from model simulations about hydrologic transports of sediment and nutrients across this bajada. Since these piedmonts are important surfaces in this desert an understanding of their hydrologic and biogeochemical dynamics is crucial to understanding landscape dynamics in the basin and throughout arid regions.