Potatoes, Irrigation, and the Making of the Snake River Plain

Stand in the middle of the Snake River Plain in late summer and what you see is green, improbably green, on a landscape that receives perhaps ten inches of rain a year. This is irrigation country, and it is one of the most thoroughgoing acts of agricultural engineering in American history.

The first significant irrigation canals in southern Idaho were dug in the eighteen seventies and eighties, many of them by Mormon settlers who had already transformed Utah's desert with water works. By the nineteen hundreds, the federal Reclamation Act of nineteen oh two funded the Minidoka Project, which eventually brought water from the Snake River to more than a million acres of volcanic soil that turned out to be remarkably fertile once it had water.

The potato arrived in Idaho as an incidental crop. Henry Spalding, a Presbyterian missionary, planted potatoes at his mission near present-day Lapwai in the late eighteen thirties, partly to teach Nimiipuu converts to farm in the European manner. Potatoes grew well in the loose, volcanic, well-drained soil. They grew even better once irrigation arrived at scale. By the middle of the twentieth century, southeastern Idaho's Snake River Plain had become the most productive potato-growing region in the United States. The Russet Burbank variety, with its thick skin and high starch content, became synonymous with Idaho's brand.

Idaho produces roughly one-third of all potatoes grown in the United States. The "Grown in Idaho" seal marks potatoes from the state. And the underlying reality is simple: this is not a place that should be this green. The green is human work, canal by canal, pump by pump, across a volcanic plain that had been sagebrush and lava rock for ten thousand years before the ditches came.