Ranking Restoration Alternatives for the Lower Mississippi River:  Application of Multi-Criteria Decision Analysis

There are a variety of engineering techniques available for restoring aquatic habitat in rivers. These include, but are not limited to: reconnecting backwaters and other off-channel features (Hoover et al. 2000; Fischenich and Morrow 2000); enhancement of borrow pits near levees (Hoover and Killgore 2002); creation and preservation of gravel bars (Miller 2006); removal and management of sediment (Killgore et al. 2008). Most could be used at numerous sites along the Lower Mississippi River, but choosing one is the challenge, since an objective method of selecting the best overall technique does not exist. This study describes the creation of a decision support model that ranks river restoration categories for projects identified by the Lower Mississippi River Conservation Committee (LMRCC). Resulting decision scores for different categories represent a consensus of experts participating in model development. Highranking categories provide greatest benefit for the Mississippi River Conservation Initiative. (Read ERDC Tech Note)

Ranking Secondary Channels for Restoration Using an Index Approach

There are over 100 secondary channels in the Lower Mississippi River depending on river stage. Most have closure dikes in the upper reaches or throughout the channel to redirect flow towards the main channel to increase navigable depths. Recent environmental engineering practices in Corps Districts have recognized that many secondary channels can be reconnected without compromising navigation benefits. To accomplish this process, three indices were developed to rank the relative importance of secondary channels: Habitat Quality, Economy of Restoration, and Priority. Using aerial, geo-referenced video and aerial photography, five attributes or metrics of secondary channels were measured to establish an Index of Habitat Quality:  

  • Presence of gravel.
  • Number of macrohabitats.
  • Percent forested riparian on the island-side.
  • Percent forested riparian on the land-side.
  • Distance to Mississippi River mainline levee or natural bluff.

(Read ERDC Tech Note)