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Full H&H Investigation with Permitting

Bridge & Stream is proud to offer full-service hydrology and hydraulic (H&H) investigations complete with environmental permitting to prepare your project for construction. For this example project, the existing 107-foot timber bridge was planned for replacement and Bridge & Stream executed the following tasks:

  • Site survey, including structural members and hydraulic aspects

  • Drawing preparation showing detailed dimensions and elevations

  • Hydrology analysis using multiple methods including 2D rain-on-grid to estimate design flows

  • 2D hydraulic analysis to size a replacement structure that meets hydraulic design criteria

  • Scour analysis and riprap design to provide erosion protection of the new structure

  • FEMA floodplain permitting

  • USACE environmental permitting


For this project, the advanced 2D hydrology and hydraulic analyses showed that the bridge could be down-sized by over 20 feet resulting in a significant cost savings. The 2D hydraulic analysis also showed that FEMA floodplain requirements could still be met with the smaller structure which expedited the permitting process.


The 2D hydraulics are shown in the video below.

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