Drivers of Interbasin Transfers in the United States: Insights from Sampling

Abstract

Interbasin transfers (IBTs) are manmade transfers of water that cross basin boundaries. In an analysis of 2016 data, this work identified 2,161 reaches crossing United States (U.S.) Geological Survey hydrologic unit code 6 boundaries in the U.S. The objectives of this study were to characterize and classify IBTs, and examine the development drivers for a subset of 109 (~5%) of the IBT reaches through examination of samples from different climate regions of the U.S. The IBTs were classified as being near irrigated agricultural lands, near cities, or rural IBTs not near cities or irrigated land. IBTs near both cities and irrigated agricultural land were designated as city + irrigated agriculture. The 109 samples were selected, based on approximate proportional distribution to the total number of IBTs within each climate region, with representation of areas having a high density of IBTs. Analysis of the samples revealed that in the U.S., there have been four major drivers for basin transfers: irrigation for agriculture, municipal and industrial water supply, commercial shipping or navigation, and drainage or flood management. The most common has been drainage or flood management, though IBTs at least partially driven by agricultural needs are also prevalent. The majority of the sampled IBTs were constructed between 1880 and 1980, with peaks in development between 1900–1910 and 1960–1970. The samples also showed the drivers of IBT development evolved over time, reflecting changes in regional economies, populations, and needs.

Inter-basin surface water transfers database for public water supplies in conterminous United States, 1986–2015

“…The volume of IBT research overall increased steadily from the early 1990s to 2014, and most especially so in China, the US, Australia, and to a lesser extent Canada, toward the end of that period 30 . Many early works focused on ecological changes resulting from IBTs 22 , 31 – 35 , but researchers have also examined social effects of IBTs through lenses such as political ecology 36 , political economy 37 , and cultural politics 38 , as well as the political and economic drivers of IBTs 39 . As issues of climate change and the sustainability, or otherwise, of human water engineering become ever more pressing, IBT research at every scale is increasing in importance and increasingly focused on the nexus of human population growth, environmental needs for water, and the changing availability of water under accelerating climate change 25 , 26 , 40 – 46 .…”