A black-and-white drawing of the SAFL lab.

The flume that started it all

How one man's vision weathered the years

Two years after he arrived at the University of Minnesota, associate professor of hydraulics Lorenz Straub published an article about the importance of using physical models and experiments to analyze water flow when designing structures to manage it.

In that four-pager for the Minnesota Techno-Log, Straub told readers how to tackle scaling issues between models and prototypes, arguing in favor of engineers learning the “laws of similitude” as part of their professional training.

In 1936, four years following this article, Straub began directing the construction of the St. Anthony Falls Hydraulic Laboratory—now the St. Anthony Falls Laboratory—on Hennepin Island in downtown Minneapolis. He established a long-lasting and adaptable floor space for hydraulic modeling.

But why stop at designing an innovative building?

Straub had a hand in all the equipment that went into it as well. The main channel, a 275-foot-long flume spanning the length of the lab’s first floor, is his creation (original blueprint above). Another Mississippi River supply channel is located one floor up. It routes water to various small- and large-scale experimental flumes and basins within the building.

A black-and-white image of a flume.
Lorenz Straub built this portable flume in the 1930s, and it’s still being used today (see image above).

“There are, of course, numerous other applications of the principle of similarity,” Straub wrote in his article. “The success of the isolated experiments performed under the direction of capable investigators points definitely to the remarkable possibilities of this method of design.”

With that, Straub heralded the future.

The lab, celebrating its 80th anniversary this year, has diversified beyond river hydraulics. Visitors on the free public tours will find all manner of studies showing an interdisciplinary approach to fluid mechanics, including delta restoration, wind energy, and even the flying patterns of fruit flies.

For lab tours, visit events.umn.edu; search “SAFL.”