Moving Water and Earth

By the time Lorenz Straub, a native of Kansas City, came to the University of Minnesota in 1930, the university had been pondering for decades a laboratory that would use the power of the falls to model natural processes. Civil engineering had begun to come into its own in America, and Straub was among the last generation who would need to travel to Europe to best learn the bedrock principles of this science. He returned from his studies in Germany excited to create engineering solutions to such tragedies as the Mississippi flood of 1927, which displaced 700,000 people in southern states, a disaster comparable in scope and impact to the aftermath of Hurricane Katrina.

Despite the Great Depression, Straub took on a host of bureaucracies and got the lab built, aided by two considerable benefactors. The city of Minneapolis contributed a riverfront site along with the rights to five mill powers of energy, or roughly one percent of the Mississippi’s average flow. (One mill power is the equivalent of 375 horsepower, or the energy generated by a flow of sixty-five cubic feet of water per second.) And the ditch-diggers’ brigade of the New Deal, the Works Progress Administration, provided the labor to excavate such a site; blasting was impossible, because the bedrock also held in place a nearby sensitive hydroelectric plant. The thirty thousand cubic yards of stone that occupied a future spacious laboratory had to be removed manually, a project that would have taken a single laborer 250 years. (University engineers seem to have a preference for difficult burrows: the Civil Engineering building on the Minneapolis campus extends nine stories beneath Pillsbury Drive.)

Straub himself designed the facility, boring and probing the limestone just ahead of the workers, and several essential design changes resulted in hefty cost increases. But his patient and detailed assessment stood in stark contrast to the cowboy engineering of the previous century, a spirit that nearly destroyed the falls.

During the 1860s, a prosperous Yankee named William Eastman acquired the southern end of Nicollet Island, several hundred yards upstream from the falls, and the real estate came with a share in the water power on the St. Anthony bank. In 1868, when the existing mills rebuffed his demand for direct access to the falls, he proposed a tunnel beneath the river that would run from the base of the falls and bore several blocks upstream to his Nicollet Island site.

But Eastman’s engineers had not assessed the bedrock beneath Nicollet Island; had they done so, they would have learned that the stout ledge of Platteville limestone on which the mills downstream sat quickly tapered to a brittle wafer above a porous sandstone substrate. That’s why the Falls of St. Anthony—absent the dams, millponds, headraces, tunnels, aprons and tailraces of nineteenth-century industry—were destined to disappear. And that is why, a year after the project started and the ambitious six-by-six-foot tunnel was nearly complete, the river suddenly plunged through the roof of the tunnel, spouted out of the downstream end of Hennepin Island, and sluiced away the foundations of several buildings. By nightfall the city was in full fret that the falls were doomed, and for months ad hoc gangs threw everything they could find into the whirlpool, including massive cribs of Rum River pine sunk with rock, which the river swallowed like so many birds’ nests. The temporary solution was to build coffer dams around the gape and divert the river from Eastman’s irresistible shortcut. A few days after the breach, the Minneapolis Tribune understated that Eastman was “dispraised if not denounced” by his fellow citizens.

It took almost a decade to secure the falls with the expertise of the Army Corps of Engineers, led by Civil War hero General G. Kemble Warren. The corps’ solution was a subterranean concrete dike moored forty feet deep into the sandstone and spanning 1,850 feet from bank to bank. This time the requisite boring did not bring catastrophe, and the sturdy dike can still be inspected via a four-foot underground tunnel. The Army Corps’ participation in the debacle was justified with a far-flung premise: that the Mississippi above St. Paul, a toothy and perilous course attempted only by the most desperate riverboat pilots, would one day be tamed by engineers and become part of the nation’s legally designated navigable waterways.

The early mission of the St. Anthony Falls Laboratory served that goal—to master rivers through impedance and control—and one of the first projects for which Straub secured funding was a scale model of a system of locks that would allow barges to travel above the falls that ran through his lab’s basement. Completed in 1963, the Upper St. Anthony Falls lock was the final link in that project, the highest of the thirty-two locks on the river, opening onto a nine-foot navigable channel that extends upstream just beyond the Lowry Avenue Bridge.

Overcoming the falls for navigation allowed for importation of many barrels of Washington, D.C. pork, but that was the end of meaningful commerce associated with the lock: One is most likely to see this magnificent device operate for passage of tour boats or various personal expressions of gas-burning masculinity. In a perfect inversion of the original justification for its construction—to foster commerce—the Corps now defends the lock’s existence based on its relief of congestion on local highways, because gravel transported by barge would otherwise be carried on trucks.

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