Scribner Covered Bridge Flooding Remediation

Johnson, Vermont

The historic Scribner Covered Bridge and an adjacent roadway intersection and residence are subjected to frequent flooding by the Gihon River. The bridge is undersized, significantly constricting the channel width, and rests on ledge. DuBois & King identified alternatives to reduce flooding and advanced a preferred alternative to preliminary design. Services included hydraulic modeling of the river and the floodplain for the 10-, 25-, 50-, and 100-year flood events. The project team identified 8 distinct alternatives to reduce the frequency or severity of flood damages in the area and prepared accompanying cost estimates. Alternatives included the addition of culverts, drainage ditches, roadway realignment, riprap or articulated concrete blocks, and specific combinations of these options. The preferred alternative included grading changes to concentrate the over-topping flows and armoring of the surface to reduce damages. Floodplain access was maintained to promote river stability. Professional services included:

Topographic survey
Geomorphologic review
Hydrology to develop peak river flow estimates
Hydraulic modeling
Identification and evaluation of alternatives
Cost estimates
Preliminary plans for the preferred alternative