Cool things I’ve learned … like fluvial geomorphology
By Eric Fowler
Elkhorn River cutting across neck of meander near Stanton, June 16, 2010
I never really liked research class in high school (Sorry Mrs. Mann). So it’s ironic that research is now a major part of my work as a NEBRASKAland writer.
Dad used to tell me: “Pay attention and you’ll learn something.” Through 9 years of researching stories for NEBRASKAland, I’ve learned that I was never as smart as I thought I was. I’ve also learned about cool things like fluvial geomorphology. Before starting with the magazine, I didn’t even know how to spell that term. But now, thanks to Scott Luedtke, Gene Zuerlein and other Commission biologists, and to reams of reports and studies I’ve reviewed, mostly while working on a 2003 story about the Missouri River, “New Life for the Mighty Mo,” I not only know how to spell fluvial geomorphology, I know what it is: the science of science of how rivers work, especially meandering rivers. Or at least how they’re supposed to work.
Through their twists and turns, meandering rivers are always carving soil and sand away from one bank and depositing it on another. Through time, this process can create wide, sweeping bends that loop back on themselves. Like electricity, water likes to take the path of least resistance, and when given the chance, a river will readily take a shortcut across the neck of meander, leaving behind oxbow or backwater.
The Elkhorn River is lined with oxbows, a fact that is impossible to appreciate unless you’re flying above the river, be it in a Cessna or on Google Earth or the Interactive Map on the Commission’s web site. Study these maps and you can easily see where the Elkhorn used to flow.
I never imagined that I would see the river change course like I did while following the Elkhorn in a Cessna June 16, photographing the historic flooding that was taking place. Thankfully, I’d paid attention to Leudtke and company and recognized what I was seeing when I passed over the neck of a meander west of Stanton. The water ripping a new course through the land was hard to miss. I flew over three other cutoffs that day that I didn’t readily recognize but probably should have but didn’t, probably because everything was under water.
I visited the cutoff near Stanton a week later and was amazed at the amount of sand the river deposited in the upper end of the bend that was now blocked off from the river. Acres and acres of sand, much of it piled 6 to 8 feet above the water line. But photos from the ground didn’t do it justice, so I went back up in the air this week and revisited the spot. Using the tools in our online map, I can now estimate the sand bar in the upper end of the meander covers 40 acres. That’s more land than was lost from the south side of the riverbank, where a homeowner is now even more so in the path of where the river will likely someday flow. The landowner on the north, however, is happy with his new lake. There are winners and losers in this game rivers play.
If you live on a river, floods can be tragic. As has been found on the Missouri, which was re-engineered to reduce flooding, they are unstoppable when the rains really come.
Elkhorn River cutoff and new backwater near Stanton, Nov. 2, 2010
But flooding and the processes it drives are a critical part of a natural ecosystem. Overbank flooding pumps essential nutrients into the aquatic ecosystem to benefit fish and wildlife. And when meanders become oxbows, they create new habitat for fish and wildlife. Fly over the Elkhorn and you’ll see a diverse mosaic of these habitats, ranging from newer, lake-like backwaters and oxbows, including the lake at Dead Timber SRA near Scribner, to older ones that are now marshes, riparian woodlands stocked with mature cottonwoods and others with doghair stands of willows, and wide open sandbars or lowland prairie.
Unfortunately, at least for fish, wildlife and those who enjoy them, dams, levies and rip rap that protect farms, homes and businesses on rivers like the Platte and Missouri prevent these natural processes from happening, and as a result, these rivers are not healthy as they could be. That’s not the case with the Elkhorn, which for the most part is still free to do what meandering rivers do, which is a good thing unless it’s your house or corn field that got in the way of the river this summer, or in the case of the Commission, the Cowboy Trail.
In the months to come, you will see more photographs in NEBRASKAland that I captured this year while on and above the Elkhorn and the Missouri and from both land and air, as well as more on the benefits of flooding.
Yes, I did say benefits. That’s another thing I’ve learned. It’s all part of fluvial geomorphology.
See you out there.
Excellent post, Eric. And of course great pictures too!
Daryl B.
Great pictures. Rivers are amazing in what they can do. Years back we used to canoe down Ponca Creek to where it empties in to the Mighty Mo. On early fall we noticed that instead of going around a bend like normal, the land owner had cut a trench into the neck. it was about 6 feet wide, very deep, and the water was just rushing through. The next late spring, we could see where the old channel was (high and dry) but that channel that was cut, looked like a natural creek channel. Just as wide as the creek normally was, and about 3 feet deep. We were amazed with how it turned out.
Where to start. You took some great pictures of the new channel the Elkhorn River created. As I sit and look at them, however, it brings back memories of the hard work my grandfather did to farm that land. My grandfather George Voelker and grandmother Elsie spent may days working the land and enjoying a little free time fishing along the channel with my brother and I. When we were kids it seemed we had to walk for miles from the house to get to the river. If you look close you can still see the shell of what was once a home filled with laughter and smells of Thanksgiving dinner. When my uncle and mother sold the farm to Mr. Funk, who would have thought such a change would occur. Its amaizing how one can still be attached to the land or as others would say memories. Thanks for the flash of memories, as my children now have a picture of the land my grandfather work and the stories to go with the picture. Keep up the GREAT WORK!