Six Decades of River Flows in the U.S. Northern Rocky Mountains
Arrigoni, A.S., Greenwood, M.C. and Moore, J.N. 2010. Relative impact of anthropogenic modifications versus climate change on the natural flow regimes of rivers in the Northern Rocky Mountains, United States. Water Resources Research 46: 10.1029/2010WR009162.
In the present study, Arrigoni et al. (2010) examined discharge data they obtained from 34 stream gauges located in natural and anthropogenically-modified river basins of the Northern Rocky Mountains (USA) over the 59-year interval of 1950-2008, which period, in their words, "covers the majority of reported global climate change due to anthropogenic influences as defined by the Intergovernmental Panel on Climate Change's 2007 report, which concluded that climate change over the past half century has been greater than natural variability and is explained by anthropogenic forcing of the climate system."
Arrigoni et al. determined that over the past 59 years "direct anthropogenic modifications of river basins by direct development (i.e., damming and irrigation) have substantially altered river flow regimes in the Northern Rocky Mountains," but they found that reported climate change in the western United States has not "generated statistically detectable changes in the flow regimes in the Northern Rocky Mountains over the period of record." Specifically, in the words of the three researchers, "changes in climate to date have not been great enough to significantly detect changes in the timing of flows in most natural sub-basins in the Northern Rocky Mountains beyond the natural variability," corroborating the findings of Moore et al. (2007). And as a result, they conclude that "direct anthropogenic modifications of river basins over the past 59 years have been more detrimental to overall river processes and ecosystem health than reported climate change effects in the Northern Rocky Mountains."
Lins, H.F. and Slack, J.R. 1999. Streamflow trends in the United States. Geophysical Research Letters 26: 227-230.
Moore, J.N., Harper, J.T. and Greenwood, M.C. 2007. Significance of trends towards earlier snowmelt runoff, Columbia and Missouri Basin headwaters, western United States. Geophysical Research Letters 34: 10.1029/2007GL031022.