Knoxville, Tennessee
2018 Engineering Excellence Grand Award, Studies, Research and Consulting Category, ACEC Tennessee
According to 2013 FEMA mapping, World's Fair Park would face the theoretical inundation of 11 feet of flood waters during a 500-year flood event. However, initial review of this mapping raised concerns about its accuracy. After extensive analysis of both the terrain characteristics and comparison with the 2013 model results, significant discrepancies became apparent in the flood modeling.
The existing model indicated a downstream obstruction to overland flow that did not exist in the field. Throughout this project, Commercial & Investment Properties and the City of Knoxville collaborated to revisit the model and challenge its initial conclusions. All parties took the necessary steps at the local, state, and federal levels to ensure that the remodeling efforts were justified, conducted in accordance with FEMA requirements, and that a map revision was warranted.
Ardurra (CCI) was commissioned to evaluate the existing FEMA Flood Insurance Rate Map (FIRM) and HEC-RAS model for Second Creek in the vicinity of The Tennessean building and the Holiday Inn within World's Fair Park. Our team developed an independent HEC-RAS model to provide more accurate mapping of overland flow patterns, including bypass conditions at the existing box culvert, and to delineate 500-year floodplain boundaries within World's Fair Park properly.
Based on our comprehensive analysis, FEMA issued a Letter of Map Revision (LOMR) that corrected the inaccuracies in the previous flood mapping. This project demonstrates the importance of a thorough technical review and the value of challenging assumptions when field conditions don't align with regulatory mapping.