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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGEMENT TECHNOLOGIES FOR CONSERVATION OF WESTERN RANGELANDS

Location: Range Management Research

Title: Runoff responses to long-term rainfall variability in a shrub-dominated catchment

Authors
item Turnbull, L -
item Parsons, A -
item Wainwright, J -
item Anderson, J -

Submitted to: Journal of Arid Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 12, 2012
Publication Date: January 25, 2013
Repository URL: http://www.sciencedirect.com/science/article/pii/S0140196312003163
Citation: Turnbull, L., Parsons, A.J., Wainwright, J., Anderson, J.P. 2013. Runoff responses to long-term rainfall variability in a shrub-dominated catchment. Journal of Arid Environments. 91:88-94.

Interpretive Summary: This study investigates how rainfall changed between two nine year periods (1977-1985 and 2003-2011) and evaluates the effects of changes in rainfall on runoff from a shrub-dominated catchment in the southwestern USA. Rainfall characteristics show there is an overall increase in annual rainfall between these two periods, which corresponds with a long-term increase in rainfall in this region. Although there has been an increase in overall rainfall between the two periods, this has not resulted in an increase in runoff because of a change in the frequency-magnitude distribution of runoff-generating rainfall events. This reduction in runoff is anticipated to be due to a reduction in rainfall intensities between the two periods.

Technical Abstract: In this study we investigate how rainfall has changed between two nine year periods (1977e1985 and 2003e2011), and evaluate the effects of changes in rainfall on runoff from a shrub-dominated catchment in the southwestern USA. Analysis of rainfall characteristics shows that between these two periods there is an overall increase in annual rainfall, which corresponds with a long-term increase in rainfall in this region. Analysis of the frequency-magnitude distribution of rainfall events during these two periods indicates that there has not been a significant change in the return period of daily rainfall totals, whereas there has been a significant change in the return period of runoff-generating rainfall events. Between the two periods, there has been a large increase in the return period for a runoff event of a given magnitude. Although there has been an increase in rainfall between the two periods, results show that, contrary to what might be expected, an overall increase in rainfall has not resulted in an increase in runoff because of a change in the frequency-magnitude distribution of runoff-generating rainfall events. We anticipate that this reduction in runoff is due to a reduction in rainfall intensities between the two periods.

Last Modified: 10/20/2014