Edited by Glen M. MacDonald, University of California, Los Angeles, CA, and accepted by the Editorial Board November 10, 2010 (received for review July 6, 2010)
Increasing human appropriation of freshwater resources presents a tangible limit to the sustainability of cities, agriculture, and ecosystems in the western United States. Marc Reisner tackles this theme in his 1986 classic Cadillac Desert: The American West and Its Disappearing Water. Reisner's analysis paints a portrait of region-wide hydrologic dysfunction in the western United States, suggesting that the storage capacity of reservoirs will be impaired by sediment infilling, croplands will be rendered infertile by salt, and water scarcity will pit growing desert cities against agribusiness in the face of dwindling water resources. Here we evaluate these claims using the best available data and scientific tools. Our analysis provides strong scientific support for many of Reisner's claims, except the notion that reservoir storage is imminently threatened by sediment. More broadly, we estimate that the equivalent of nearly 76% of streamflow in the Cadillac Desert region is currently appropriated by humans, and this figure could rise to nearly 86% under a doubling of the region's population. Thus, Reisner's incisive journalism led him to the same conclusions as those rendered by copious data, modern scientific tools, and the application of a more genuine scientific method. We close with a prospectus for reclaiming freshwater sustainability in the Cadillac Desert, including a suite of recommendations for reducing region-wide human appropriation of streamflow to a target level of 60%.
↵2Present address: Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, NC 27695-7908.
↵3Present address: Odum School of Ecology, University of Georgia, Athens, GA 30602.
Author contributions: J.L.S., L.C.B., and E.E.W. designed research; J.L.S., T.S., L.C.B., G.H.W.S., W.W.W., K.A.C., W.L.G., J.S.K., C.T., S.W.T., and E.E.W. performed research; J.L.S., T.S., L.C.B., G.H.W.S., W.W.W., and P.L.F. analyzed data; J.L.S., T.S., L.C.B., G.H.W.S., W.W.W., M.E.C., P.L.F., W.L.G., J.W.H., J.S.K., C.T., S.W.T., R.H.W., and E.E.W. wrote the paper; and T.S. coded, calibrated, and implemented hydrologic models.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission. G.M.M. is a guest editor invited by the Editorial Board.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1009734108/-/DCSupplemental.
