On the hottest day of the summer, I went to camp. Just for the day – “Curiosity Camp,” sponsored by the University of Minnesota. My destination was the national park in downtown Minneapolis. That’s right. Did you know that 72 miles of the Mississippi River through the Twin Cities constitutes the only urban national park in the country?
My curiosity led me to the hot and humid banks of the Mississippi River at St. Anthony Falls. Our subject: the birthplace of Minneapolis, St. Anthony Falls and preservation on the river. We toured the Mill City Museum, the Stone Arch Bridge and the surrounding neighborhoods.
The physical and cultural history of the river were presented very enthusiastically by National Park Service historian John Anfinson and professor Patrick Nunnally, a cultural historian in the architecture department at the U.
Perhaps because I never went to camp as a kid, I was thrilled at this urban camp experience. I discovered this program recently and quickly became a devotee. The course list was wide-ranging, which made it difficult to select a camp. I contemplated studying the geology under the Twin Cities, ending up at the archeological dig in Elliot Park. Or should I tour museums? Learn about making honey or cheese? Should I venture over to St. Paul to study the architecture there? Maybe Greece, Sherlock Holmes, or medieval times? Hmmm. But I picked the correct one. I love the river downtown, and discovered many new things about the beginning of our city. Do you know about the tunnel they built under the river, or the huge wall? Spirit Island?
I think most people know that modern Minneapolis began at St. Anthony Falls, and that the area became historically and internationally famous for the mills and the grains – for 50 years, Minneapolis was Flour King of the nation. Also significant was the lumber milling industry. The famous mills – Pillsbury A and Washburn A – are preserved as National Historic Landmarks. The Great Northern Railway Bridge is a National Engineering Landmark. The first electrical power ever generated through hydro generators in the Western hemisphere was produced here.
I could go into all the interesting historical tidbits I learned that day, but have not the space. So I will highlight what were some new and fun facts to me.
The falls migrated
The only natural falls on the river were once located near Fort Snelling, where the Mississippi meets the Minnesota River. They were 175 feet tall, before they migrated upstream to the present location. The river bottom is composed of layers of stone. The bottom is hard bedrock, which is covered with soft sandstone. A hard layer of limestone comes next, with a layer of soil on top. The riverbed eroded. The powerful water washed away the softer layers below the limestone; then when a piece of limestone was left projecting out over an eroded base, it would eventually break off, and the falls moved upriver. This process repeated itself until, around the 1850s, the falls arrived where they are today.
They would have kept going as far as Nicollet Island where the bottom rocks change, but human intervention and the building of the current falls structures stopped them there.
This small island no longer exists. It was spiritually important to the Dakota, thus the name. It was a small island just below the Stone Arch bridge area. It was covered with limestone, trees and bald eagles’ nests. The limestone was raided for building projects, and eventually the whole thing was subsumed by the riprap barrier leading to the lock and dam.
When the Mississippi delta on the other end of the river became unbearably hot in summer, Louisiana tourists traveled up the river in steamboats to visit the famous falls. The Winslow House hotel, built to accommodate them in 1857, still stands near St. Anthony Main.
The Eastman tunnel
Around 1865, mills were built on the east side of the river in what was then St. Anthony, and on the west side in Minneapolis. Another was proposed for Nicollet Island, but the two mills downstream feared their water flow would be altered by another mill. So the Nicollet Island mill decided to tunnel under the river from the south end of the island to Hennepin Island; this would divert the tailraces of the new mill to emerge downriver of the two existing mills.
The Eastman Tunnel was begun. A shaft was dug near Nicollet Island, and men dug straight down 2000 feet until they reached the sandstone level. Then they began a tunnel downriver. Unfortunately, the combination of the water forces and the soft stone caused the tunnel to cave in. A huge hole 90 feet wide and 16 feet deep opened in the river. Trying to plug it, residents sent rafts loaded with stones, trees and debris into the river and sank them in the hole. A second hole opened. For three years, they tried to fill the holes that kept opening, to save navigation on the upper river.
The underwater wall
The Army Corps of Engineers, worrying about the future of the river, proposed a solid wall underwater across the river just downstream of Nicollet Island, and just above the “horseshoe” of the current dam. In 1874, they excavated a 75-foot vertical shaft, then built a concrete wall 39 feet below the surface, from the east bank 1850 feet to the west bank. The wall was 11 to 25 feet thick. The falls were stabilized, the milling industry was saved, and the wall still stands today, fortifying the falls 153 years later.
As I watched tourists on Segways touring the mill area, I realized we have come full circle to enjoying the river today as those early tourists did. Then, a few days after I spent that interesting day on the river, our village shared the shock and pain of the devastating collapse of the bridge. We now must re-build a vital span over the river, just a short distance from the falls where the city began. The city and the river have changed and adapted to each other, and will again. Early citizens built a city with mills and a submerged wall –– we face a huge challenge of building another notable icon on the great river that gives us our sense of place. Engineers in 1874 tackled the problem wrought by man, to preserve the river for commerce and to secure the future use of the river. So we, too, look to engineers to return the bridge that will guide our city’s commerce and movement in the future. What will Curiosity Campers find here in 150 years?
To learn more
My curiosity was only piqued, not sated, by Curiosity Camp. I recommend it. If you would like to know more about the national park, visit the website: www.nps.gov/miss. Read historian John Anfinson’s book, The River We Have Wrought: A History of the Upper Mississippi. Visit Curiosity Camp at: www.cce.umn.edu/curiosity.
Mary Ann Knox lives in CARAG and is alway on the lookout for fun facts about familiar things.