Jumbo: A Runaway Artesian Well
by Robert D. Libra
Since the settlement of Iowa began in earnest over 150 years ago, tens of thousands of water wells have been drilled, bored, or dug. Drilling and construction of wells is at times a difficult and frustrating endeavor, as unseen conditions below the land surface must be anticipated and dealt with. While the drilling of some water wells might be described as a "routine" operation, the drilling of others is decidedly not.
In the 1880s, a number of wells drilled north of Belle Plaine in Benton County encountered a sand and gravel aquifer at a depth of about 300 feet. The aquifer has since been shown to fill extensive parts of an ancient river valley, and to be overlain by relatively impervious glacial tills. These tills act hydrologically to seal the aquifer and create strong artesian pressures. The water levels in the wells north of Belle Plaine, which were located in the uplands above the Iowa River valley, rose to within 25 to 50 feet of the surface, depending on the surface elevation. These wells yielded large volumes of water that although somewhat salty, were acceptable to livestock.
In 1886, a well for a creamery was drilled at Belle Plaine in the Iowa River valley; this well also tapped the sand and gravel aquifer. The elevation of this well was about 100 feet lower than the previously drilled livestock wells, resulting in a strong flow of water from the well. At the well head, the artesian pressure of the aquifer was sufficient to lift the water 67 feet above the surface. Several other wells were drilled into the aquifer at Belle Plaine, and while the strong flows complicated construction of the wells, they were completed without incident.
In August 1886, the City of Belle Plaine contracted to have a well drilled for fire protection. This well soon became widely known by the name "Jumbo." In the words of geologist W.H. Norton (1896): "The notoriety of Jumbo was strictly that of a member of the criminal class, and began with his resistance to control, and lasted only until his final imprisonment. The beginning of the trouble lay in the fact that the driller attempted to use the force of the flow in reaming out the two-inch bore, which he had put down for want of a larger drill, to three inches, the dimension specified in the contract. This task the water speedily accomplished in the unindurated clays and sands, but not stopping there went on and soon enlarged the bore to over three feet in diameter." H.R. Mosnat (1898) notes, "When the driller saw the result of his inexcusable carelessness, which result he ought to have foreseen, he hastily decamped and was not heard of until the popular excitement had subsided."
The flow from Jumbo roiled out of the three-foot bore in a fountain that stood five feet high. Estimates of the initial, maximum flows varied from 30,000 to 50,000 gallons per minute. The flow diminished rapidly, and two weeks later was calculated to be about 2,000 gallons per minute, by Professor T.C. Chamberlain from the University of Chicago. Along with the water came sand -- an estimated 500 to 1,000 carloads of sand. "The quantity was certainly so great that only with the greatest effort could the ditches be kept open to carry off the water" (Mosnat, 1898). Chunks of fossil wood and stones weighing over two pounds were also hurled from the well.
Norton (1896) describes the effort to stem the flow, which ultimately took over 13 months: "During this time the well, 193 feet deep, devoured, as the local historian recounts, 163 feet of 18-inch pipe, 77 feet of 16-inch pipe, 60 feet of 5-inch pipe, an iron cone 3 feet in diameter and 24 feet long, 40 carloads of stone, 130 barrels of cement, and an inestimable amount of sand and clay."
While Jumbo was obviously an unusual occurrence, Mosnat (1898) notes, "The accounts of the well given in newspapers were in many instances most sensational, their extravagance increasing according to the square of the distance from Belle Plaine. European papers published accounts of the water spouting hundreds of feet into the air, with a roar that could be heard for miles and even pictured people being rescued by boats from the third and fourth stories of houses!" Other reports connected Jumbo's unleashing with the great Charleston earthquake, which occurred four days later, and to renewed geyser activity in Yellowstone Park. This prompted Professor Chamberlain to comment "The only similitude of seismic disturbance, as the cause of this well, was in the moral faculties of said reporter."
Many other wells were drilled into the buried sand and gravel within the Iowa River valley between Belle Plaine and Marengo, and were often allowed to flow relatively unchecked. The great artesian pressures have therefore been decreased over parts -- but not all -- of the area. As the Belle Plaine weekly newspaper noted in 1986, "Beneath this city lurks a monster discovered 100 years ago." The Geological Survey's research driller, Darwin Evans, found the aquifer was still a force to be reckoned with when he drilled a test hole into it in 1984. While his efforts to control and plug the hole took a few hours, as opposed to 13 months, the situation prompted him to comment: "We were about five minutes away from making Good Morning America." Meanwhile, in Belle Plaine, a bronze plaque attached to a granite boulder still marks the spot where the runaway artesian Jumbo entered the history books.
Photos of "Jumbo" courtesy The University of Iowa Calvin Collection.
Reprinted from Iowa Geology 1995, Iowa Department of Natural Resources