Intuition & Logic was retained by the City of Chesterfield to determine if the Eagle Crest Estates development, as constructed, meets the conditions of the Conditional Letter of Map Revision (CLOMR) previously approved by the Federal Emergency Management Agency (FEMA). 



We began with the effective paper copy of the FEMA model for Caulks Creek and developed the duplicate effective and then corrected effective models.  The corrected effective model included corrections to the existing bridges and cross sections using historical aerial contours and topographic survey from before the development was constructed. The current conditions were developed from LiDAR and supplemental topographic survey of the bridges obtained for the study.



The analysis found that the constructed development did not meet the No-Rise condition the developer used in the CLOMR. Intuition & Logic developed and evaluated potential modifications to address the inadequate flood benches and bridge opening configurations.  Our study included a sensitivity analysis of the subdivision bridge and constructed flood benches.  The study found that the constructed flood benches were the primary contributor to the CLOMR variance and modification to 1,300 feet of the constructed flood benches would be necessary to achieve the approved CLOMR conditions.