A general type of supercritical flow flume has been developed over many years of experience and testing in discharge measurements at the Walnut Gulch experimental watershed, Tombstone, Ariz. The design and experience with .the original type flume, called the Walnut Gulch .flume, is discussed and its features and .application difficulties are described. Methods have been developed to analyze flows that exhibited lateral asymmetry in cross sectional profile, and porous dikes have been developed to considerably reduce asymmetry in the alluvial approach section to these flumes. Rating relations have been developed by both experimental and theoretical means. The experience with the Walnut Gulch flumes has led to an improved design of supercritical flume, called the Santa Rita flume. The Santa Rita .flume design is presented in several sizes, along with a discussion of design requirements for stilling well intakes to minimize sediment inundation, record lag interpretation, and construction methods.