The legacy of large dams in the United States

Abstract

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.

Global expansion of sustainable irrigation limited by water storage

“…Total reservoir storage for irrigation could increase further if some of the identified 3,700 hydropower dam sites ( 44 ) would be designed and operated to provide not only hydropower but also water storage for irrigation, as was often the case in the past ( 35 , 37 ). However, only a fraction of total reservoir storage will be available to meet irrigation water demands on the field.…”

“…Water storage for irrigation can be provided through water harvesting with small dams ( 32 ), managed aquifer recharge ( 33 ), and better management of soil moisture ( 34 ). Yet, existing irrigation systems often rely on gray infrastructure in the form of dammed reservoirs ( 30 , 31 ) to provide water storage ( 30 , 35 – 37 ).…”

Cuantificación del déficit hidrológico reciente en la región de Cuyo a partir de indicadores de caudales bajos

“…Desde principios del siglo XXI se han construido tres nuevos embalses en la región, los cuales incrementan la capacidad para hacer frente a las condiciones de sequía hidrológica imperantes, sobre todo en la cuenca del río San Juan (Tabla 2). No obstante, los embalses generan alteraciones en los regímenes hidrológicos, afectando a la biodiversidad y los procesos ecológicos (Di Baldassarre et al, 2021), así como también el desarrollo de actividades humanas como la ganadería en zonas áridas (Montaña et al, 2016). Con lo cual, a pesar de tener claros beneficios, todavía existe cierta controversia a nivel mundial respecto a estas infraestructuras (Boyé y de Vivo, 2016;Di Baldassarre et al, 2018).…”

Drought Diagnosis: What the Medical Sciences Can Teach Us

“…Since the early 1900s, the economy and population of California grew through extensive infrastructure developments. With 95% of its residents living in urban areas, the highest percentage in the country, cities have expanded in environmentally, economically, and socially unsustainable ways and generated conflicting demands with agriculture for adequate drinking water supply (Di Baldassarre et al., 2021; US Census Bureau, 2012). The legacy of dam construction and high groundwater abstraction that drove this growth has led to a lock‐in condition with unsustainable levels of water consumption that are very difficult to reverse (Di Baldassarre et al., 2021).…”