River Training Structure Design Study For Stabilization At Bonanza Bar

The Huntington District (LRH) currently dredges on a nearly annual basis at Ohio River Mile (RM) 353, a location known as Bonanza Bar. An in-channel bar has developed from the placement of the dredged material along the left-descending bank side of the navigation channel. And in recent years, the need for navigation channel dredging in this segment has decreased. The in-channel bar is not connected to the left bank; instead, a side channel has developed that supports a mussel bed. No endangered mussels are known to inhabit the bed. Dredging of the navigation channel is done by both clamshell and hydraulic dredge, based on the availability and cost of the dredging asset. The clamshell dredge is used more frequently than the hydraulic dredge and allows for more control in material placement location. Dredging is reported to be necessary due to the size of bedforms moving through the reach; bedforms 5 ft. high were observed, and bedforms as high as 10 ft. have been reported. LRH has a need to analyze the potential effects of river training structure usage just upstream of the bar. A 2-dimensional HEC-RAS numerical model study was conducted to assist in the analysis of alternatives of different river training structure shapes, orientations, and lengths with the goal of a preferred alternative that reduces velocities and shear stresses around Bonanza Bar and its adjacent side channel for bar stabilization and increased mussel habitat. Specific requirements for limiting velocity and shear stress impacts to the mussel beds along the left descending bank adjacent to the bar are compared to model results in coordination with LRH biologists monitoring the mussel beds. The project is an excellent example of beneficial use of dredged sediment within a river system and coordination with other entities to achieve bot navigation and habitat goals. The river training structures modeling results can be applied to other applicable river systems where bar formation from dredged sediment and habitat creation is a goal.