Reclaiming freshwater sustainability in the Cadillac Desert

Abstract

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%.

A Tale of Two Rivers: Implications of Water Management Practices for Mussel Biodiversity Outcomes During Droughts

“…In the United States, sustainable water use is not only a concern in the arid southwest (Sabo et al 2010) but even in humid areas such as the southeast (Pederson et al 2012). Freshwater is vital for human life, but biologically complex and intact freshwater ecosystems provide key ecosystem services that also benefit society (Baron et al 2002).…”

Predicting the river’s blue line for fish conservation

“…Exceptional droughts and climate change are one cause of drying-surface water is scarcer and that trend is not changing (1)(2)(3)(4). Increasing human appropriation of groundwaterespecially during drought-is another cause (5,6). River drying has clear implications for freshwater biodiversity, including mass mortality of commercially important fish if large reaches of a river dry completely (7).…”

Upstream Landscape Dynamics of US National Parks with Implications for Water Quality and Watershed Management

“…A future refinement to our analyses is to include additional information on the characteristics of dams and their effects on aquatic resources. For example, watersheds in the eastern US tend to have a higher density of dams than western watersheds, but because the size of dams varies, the storage capacity as a portion of annual flow is nearly the same in the east and west (Sabo et al, 2010). Thus western rivers generally have fewer but larger dams, so fragmentation is greater in the east but dams in the west alter hydrological dynamics more.…”

“…These impoundments have dramatically altered hydrological flow regimes, sedimentation processes, inhibited or prevented biological migrations and other movements, and influenced virtually every ecological process in some catchments (Ward & Stanford, 1979). Following Sabo et al, (2010) and Lawrence et al, (2011) we used the density of impoundments (count/km 2 ) in the contributing watershed as an indicator of river fragmentation. A future refinement to our analyses is to include additional information on the characteristics of dams and their effects on aquatic resources.…”