Des Moines River Stabilization

Location: Palo Alto County, IA

Project Type: Shorelines & Waterways

Application: River Bank Stabilization

Product Used: SCOURLOK & ARMORMAX

The West Fork of the Des Moines River in Palo Alto County, had experienced years of erosion and flooding. From 2006 to 2019, the riverbank had receded up to 215 feet in the middle of the bend. Approximately three acres of soil had been lost during that timespan, and the receding shoreline was approaching an existing roadway. The historic Kirby-Flynn Bridge was also in jeopardy of approaching waters. This bridge is the only remaining pin-connected Pratt high-truss bridge in the U.S., and dates back to 1881.

The Sioux City Natural Resource Conservation Service (NRCS) wanted to stabilize approximately 865 lineal feet of the bank, and reinstate channel alignment to what it was in 2006. Initially the project engineer considered using rock riprap, but wanted to find a more cost effective solution.

A combination of SCOURLOK® and ARMORMAX® was selected because it provided long-term protection from erosion, promoted reinforced vegetation, and helped improve water quality at a lower cost than rock. Both systems are designed to resist extreme hydraulic stresses and are able to withstand wave action.

The design included two rows of SCOURLOK along the 2006 channel alignment with a benched area protected by ARMORMAX to the current bank condition. Additionally, an upper wall section with one row of SCOURLOK was installed to protect the current bank location.