The following story was written by a University of Missouri student as part of the 2012 Sonja Hillgren/Farm Journal Ag Journalism Field Reporting Institute. Learn more.
By Cade Cleavelin
Corning Conservation Area, a preserve hugging a bend on the Missouri River in the middle of some of Missouri’s most productive farmland, is extraordinarily untamed in contrast to the tidy cropland neighboring it.
Its tall grasses – gangly and disheveled – easily surpass eye level and obscure any reference to the horizon. It feels exotic. Trees are scattered and few, and only the very tops of the grasses fidget in the wind.
Photo: George Laur
Bushwhack, and the landscape eventually reopens, revealing a secret the vegetation hasn’t been able to conceal entirely – a broad, otherworldly sea of sand. Even the most industrious weeds can’t establish themselves here in the bald, monochromatic badlands of the conservation area.
Photo: Amy Bruer
Robert Jacobson, chief research hydrologist with the U.S. Geological Survey river studies branch in Columbia, Mo., calls it a "classic splay of sand." He also offers the somewhat romantic¬ alternative, "mega-dune."
"These sand splays are actually quite fascinating, because they effectively create a micro-ecosystem within the larger environment," Jacobson said.
Robert Jacobson, chief research hydrologist with the U.S. Geological Survey River Studies Branch in Columbia, Mo. Photo: J.B. Forbes
On a regional scale, sand splays are concentrated disasters, the products of isolated weaknesses in the levee system that heavy floods, like what occurred in 2011, can exploit.
"The flood water we see most of the time does not cause any damage," said Jud Kneuvean, chief of the Army Corps of Engineers emergency management branch in Kansas City.
"We knew several weeks in advance that we were going to have a flood emergency," Kneuvean said. "We did not know we were going to get 160,000 cubic feet per second."
Jud Kneuvean, chief of the Emergency Management Branch of the Army Corps of Engineers Kansas City District. Photo: George Laur
The speed and pressure were enough to scour channels underneath the levees, drag along millions of tons of heavier sediments, and spew sand and water out the other side like a broken fire hydrant. What’s left now are massive sand splays and the scour ponds they came from.
"You can see it’s very punctuated, all along the river," Jacobson said, later referring to a large satellite image taken of the region in November 2011. Roughly a dozen white splotches show where waters from the flood buried entire acreages under heavy sediment.