22 October 2011

Post-flood Assessment Underway Along Missouri River

Federal officials are currently evaluating conditions following the extensive flooding at properties they manage along the Missouri River from Ponca State Park to Rulo, Nebraska.

At over 20 sites owned by the Army Corps of Engineers, efforts are now underway to evaluate what has happened after the more than one hundred days of water flows above flood stage in the river valley. This process will continue for the next few months.

Additional sites managed by partners in river habitat management are also being evaluated. Assessment work is being done by the Iowa Department of Natural Resources, Nebraska Game and Parks and at two federal refuges in this section of the river which are maintained by the U.S. Fish and Wildlife Service.

"We are doing visual assessments and using aerial photographs," at Corps' properties, said Jolene Hulsing, a natural resources specialist in the Omaha District of the Army Corps of Engineers. Not all of the sites have been visited at this time.

"There are many differences that need to be considered," she said. Particular changes that occurred and have been noted include:

  • sand deposition at "several places" including especially at Winnebago Bend, where there were additional changes in the channel configuration
  • presence of shallow water habitat not normally present
  • changes in vegetation, including the loss of large stands of tall, mature cottonwood trees and the scouring of ground vegetation leaving behind a barren expanse of bare ground
  • deeper areas of river channel water due to scouring
  • changes in channel configuration including modifications in the shape of riverine chutes

Other impacts that need to be considered include the status of pumping stations which were flooded and impacts to rock structures installed for habitat management purposes.

"We need to complete an assessment process to evaluate if their might be any ecological benefits," due to flood processes on the land which the Corps owns, Hulsing said.

An evaluation of the site assessments will be a cooperative effort with local agencies to "determine where to go," when determining management options, Hulsing said. Any final decisions on would probably occur in several months.

During visits to some Corps sites along the river, only a limited amount of information has been kept on bird use of the ephemeral habitats.

There were a "lot of pelicans" at Pelican Point near Decatur, Hulsing said, and many Great Blue Herons at other locales where remnant flooded area continued to occur along the river after the water flows decreased below flooding levels.

Aerial view of the floodplain south from Nathans Lake. Image from video taken October 15, 2011 by the Army Corps of Engineers, during a flight from Omaha to Decatur.