Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
Centre of Natural Hazards and Disaster Science, CNDS, Uppsala, Sweden.
Ambio. 2021 Oct;50(10):1798-1808. doi: 10.1007/s13280-021-01533-x. Epub 2021 Mar 8.
The sustainability of large dams has been questioned on several grounds. One aspect that has been less explored is that the development of dams and reservoirs often enables agricultural expansion and urban growth, which in turn increase water consumption. As such, dam development influences, while being influenced by, the spatial and temporal distribution of both supply and demand of water resources. In this paper, we explore the interplay between large dams, patterns of population growth and agricultural expansion in the United States over the past two centuries. Based on a large-scale analysis of spatial and temporal trends, we identify three distinct phases, in which different processes dominated the interplay. Then, we focus on agricultural water use in the Southwest region (Arizona, California and Nevada) and explore chicken-and-egg dynamics where water supply partly meets and partly fuels water demand. Lastly, we show that the legacy of dams in the United States consists of a lock-in condition characterized by high levels of water consumption, especially in the Southwest, which leads to severe water crises and groundwater overexploitation when droughts occur.
大型水坝的可持续性已经受到多方面的质疑。其中一个较少被探讨的方面是，大坝和水库的开发往往会促进农业扩张和城市增长，进而增加水资源的消耗。因此，水坝的发展影响着水资源的供需时空分布，同时也受到其影响。本文探讨了过去两个世纪以来，美国大型水坝、人口增长和农业扩张模式之间的相互作用。基于对时空趋势的大规模分析，我们确定了三个不同的阶段，其中不同的过程主导了相互作用。然后，我们重点研究了美国西南部地区（亚利桑那州、加利福尼亚州和内华达州）的农业用水，并探讨了水供应部分满足、部分推动水需求的“鸡生蛋、蛋生鸡”的动态关系。最后，我们表明，美国大坝的遗留问题造成了一种高耗水的锁定状态，尤其是在西南部地区，这导致了严重的水危机和地下水过度开采，一旦发生干旱更是如此。
