Complete October 2021
A Floodway no-rise Certification for a Private Footbridge on the Rogue River
A homeowner’s property on the Rogue River is divided by a side channel that prevents use of a portion of the property. A footbridge was installed to access the previously unusable portion of the property. The footbridge is in a regulatory floodway and impacts the riparian corridor. RogueTech was hired to provide a floodway no-rise certification and a riparian mitigation plan to support the floodplain development and riparian corridor permit applications.
RogueTech obtained the FEMA model and data utilized in the effective Flood Insurance Study that list the published floodway elevations. We also performed a topographic survey of the bridge and surrounding terrain as well as an ordinary high-water determination. The topographic data were used to refine cross-sections and add the bridge geometry to the model to perform the no-rise hydraulic analysis. RogueTech utilized the ordinary high-water determination and coordinated with DSL, USACE, and ODFW to determine regulatory requirements for riparian improvements.
We were able to show the bridge did not result in a rise of floodway elevations and developed a plan to improve the riparian corridor to a higher quality than prior to the installation of the bridge.