Missouri River 2011 rise brings flood of information

Major disturbance events – such as the rise of the Missouri River last year – are out of the scope of most researchers and research projects, according to one expert.

Gerald Mestl, Missouri River program manager with the Nebraska Game and Parks Commission, discusses last year’s river rise during a presentation at the Missouri River Institute Research Symposium Thursday. (Photo by David Lias)

"We'll still be understanding this flood decades from now, so it's going to be very interesting how that information is compiled and brought forward as new people work on it," said Gerald Mestl, Missouri River program manager with the Nebraska Game and Parks Commission.

Mestl discussed some of the effects of last year's river conditions and the history of flooding along the river as part of the annual Missouri River Institute Research Symposium, which was held Thursday at the University of South Dakota.

Despite the chaos it can cause, a rise along the Missouri River does have some positive outcomes, Mestl said.

"It expands the aquatic habitat," he said. "It makes the river bigger and provides more habitat choices for organisms."

The restructuring of the physical environment along the river makes it possible for young fish to get into the floodplain and avoid predation, Mestl said.

It also can connect habitat patches and increase nutrients in the overall system, he said.

"By having that annual flood, we basically feed the system each year," Mestl said. "We provide the energy that the system needs to run."

A rise in water also can result in an increased sand deposition on the floodplain.

Last year, 67,000 acres of land along the Missouri River were covered in sand, Mestl said.

He did add that it "probably only represents land covered by more than 60 centimeters" of sand, and land that is not under vegetation.

"But that's a massive amount of structural alteration to the floodplain," Mestl said.

This alteration could lead to an increase among various bird species that have known to be decreasing, he added.

Mestl said there were "about five flood events" along the Missouri over the past 48 years, from 1964 through this year.

"There were a few more floods the last half of this time period than before," he said.

From 1934 to 1963 the number of floods was actually quite high by comparison, he said.

"I think this was a function of us building the navigation channel, and at the same time not having the dams available to make a complete system," Mestl said.

Without the dams in place, the water had nowhere to go, he said.

Mestl said that it has long been thought that the Historic Missouri River flooded often in the late 19th and early 20th centuries. However, he said he found this was not quite true.

In actuality, although the river saw dramatic rises throughout that period, there was an average of only one flood about every 20 years, he said.

"Although we were seeing these annual fluctuations, most of these were within the confines of the banks," Mestl said.

But due to the fact that it is no longer an annual occurrence, a significant rise along the banks has a different meaning today.

"We've lost that ability to manage the river within the banks," Mestl said. "The channel capacity has been changed through channelization and things like that."

Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>