Alternative Metric Units for Acre‐Foot and Acre‐Inch

Abstract

Acre‐foot is an important water measurement term in the United States, particularly in the American west. Although less common, its derivative, acre‐inch, is widely used within the irrigation community. No meaningful equivalents for these terms exist in the current International System of Units (SI). The two metric equivalents proposed here, hectare‐meter for acre‐foot and hectare‐centimeter for acre‐inch, are presented as alternatives to those generally found in SI conversion tables. Each is conceptually similar to its counterpart in the U.S. Customary System, thus creating comparable mental images that, in turn, greatly aid comprehension. Official recognition within SI of these two proposed metric equivalents, deserves serious consideration. During the course of almost a century, acre‐foot and acre‐inch have evolved with the needs of irrigation and hydrology in the United States. As a result, they have acquired not only practical but cultural and historical significance, becoming part of a heritage that should not be lost. Measurement bilingualism is recommended as a new policy for the federal government, to replace that of voluntary metrication adopted in 1975. Such a policy would expand our communication skills while maintaining linguistic diversity.