This week a stretch of the the Mississippi below our home dropped by twelve feet.
The US Army Corps of Engineers had temporarily lowered the river between two dams so they could inspect infrastructure. They also opened one of the dams to the public.
This was a rare opportunity to explore the river bottom and to take a closer look at Upper St. Anthony Falls Lock and Dam.
Standing on Northern Pacific Bridge Number 9 (now a crossing point for pedestrians and cyclists) I looked upstream towards the stretch of river that had been lowered.
The Lower St. Anthony Falls Lock and Dam dominated the foreground. Upstream, through the arches of Stone Arch Bridge, I could see the white water of Upper St. Anthony Falls, the location of a second Lock and Dam. The water level had been lowered between these two dams.
I crossed the Northern Pacific Bridge, then headed upriver. A steep path took me down a cliff, past a hydroelectric plant, to the river bottom.
The surface was mainly limestone, which had dried out; occasionally, the ground was wet and spongy. At one point, people had placed stepping stones across a small stream.
The remains of a pier of the 10th Avenue Bridge, built 1874, stood high out of the water.
Normally, just the lighter-colored rock is visible above the surface of the river. The whole thing is listing, so it’s a matter of time before it collapses completely.
Many of the piers of the 1883 Stone Arch Bridge stood high and dry.
A 2D barcode was attached to each pier to guide an inspection drone.
The lowered river was an opportunity for engineers to inspect the footings before the old bridge undergoes major repairs.
Beyond the bridge, I looked up at the main St. Anthony Falls.
I retraced my steps up the steep path and made my way to Stone Arch Bridge. I couldn’t resist taking a photograph that has become a cliché.
I looked down at shadows of the bridge and tiny people on a strange, temporary landscape.
It seems that every day, there’s something different about these falls. Sometimes they are in full flood, other times the flow is modest. In the winter, ice forms at the edges and sometimes crashes over the edge. When the light is right, rainbows appear in the mist that often forms above the water. Today, the falls had gained twelve feet.
Finally, I visited the Upper St. Anthony Falls Lock and Dam.
To prevent the upstream migration of invasive species, it’s permanently closed to all river traffic. It continues to be used for flood mitigation, and is still maintained by the US Army Corps of Engineers. Usually visitors must be accompanied by a Park Service ranger, but this week the public could wander freely.
Right now, the water is already slowly rising. By next week, my footprints on the river bottom will be gone.
