Unparalleled Efficiency

The next task included updating the hydraulic model simulating the contributing flows within the Bedman Creek/Dog Canal waterway. The software HEC-RAS and GeoHECRAS was utilized to prepare the updates to the hydraulic model and properly geo-reference the study area. The updates included adding forty (40) new cross-sections to the system and updating the existing cross-sections with more detailed topographic information and verified land cover conditions. Once the hydraulic model parameters were verified, the contributing flows were incorporated, and many iterations were conducted to validate the model results and determine updated water surface elevations for the various storm events/durations. Upon completion of the hydraulic modeling, updated flood zone delineations for the 1% annual-chance-event storm and 2%-annual-chance storm events were completed. In addition, a new delineation for the regulatory floodway area was also prepared.

In summary, the results of the new detailed analyses indicated a reduction in the contributing flows, decrease in the regulatory base flood elevations and a reduction in the width of the regulatory floodway boundary. The final step in the project is facilitating a Letter of Map Revision (LOMR) through FEMA for acceptance of the new detailed studies and revised mapping for the watershed. Once the LOMR is approved, many residents will experience the benefit of a reduction in the base flood elevations and reduction in the floodway area.