River Meander Modeling - Wabash River

Science Center Objects

Significant flood events on the Wabash River between 3 mi downstream of Mt. Carmel, IL to 10 mi downstream from New Harmony, IN caused the collapse of the railroad pier, bridge, and trusses which crossed the river. Scientists are using two models to evaluate how future flooding may impact the current I-64 bridge and the river channel. One model will focus on river meander migration. The second model will be used for bridge scour analysis and the data derived from this model will be used for a new flood inundation map.

The Wabash River downstream from Mt. Carmel, IL to downstream from New Harmony, IN is crossed by two bridges: an abandoned railroad bridge and the I-64 bridge. Flooding on this part of the Wabash River is a common occurence. When these flood events occur, bridge piers can be damaged by bridge scour and the banks surrounding the start and end of the bridge can become unstable from erosion. 

Highest flood crests recorded at the USGS streamflow gaging station at the Wabash River at Mount Carmel, IL:

  • 34.02 ft on 05/03/2011
  • 33.95 ft on 01/13/2005
  • 33.24 ft on 06/14/2008
  • 33.00 ft on 03/30/1913
  • 32.35 ft on 05/17/2002

The flood event in January 2005, while not the highest crest, is significant because this flood caused the failure of the piers below a railroad bridge causing the bridge and trusses to fall into the river. One pier from the railroad bridge had previously failed during a flood event in 1992. In May 2005, fisherman reported to the Indiana Department of Transportation (INDOT) that the depth of the river under the I-64 bridge had increased signficantly. INDOT installed temporary bridge scour countermeasures in 2005 and permanent bridge scour countermeasures in 2006.

Sample output from the SRH-2D model
Sample output from the SRH-2D model.

Models

We will be using two models to evaluate future flood risks for bridge scour and river channel meandering:

SRH-2D model 

  • Provides a variety of data including velocities, water surface elevation, and shear stresses.
  • Base scenario: Current conditions.
  • Scenario 1: Increase peak flows.
  • Scenario 2: Levee removal.
  • Results can be used for scour analysis.
  • Resulting water surface elevations will be used to create flood inundation maps.
     

RVR Meander Model

River meander model user interface and results
  • Predicts meander migration at increments up to 100 yrs in to the future.
  • Base scenario: Replicate past events (50 yrs) and project into future (50 yrs).
  • Scenario 1: Project into future with increased peak flows.
  • Scenario 2: Armoring along right bank just upstream of I-64 bridge.
  • Data can be used to determine if the existing I-64 bridge is at a stable location on the river.