8-14-23 Attachment CAtlantic Beach 2018 Stormwater Master Plan Update RecapAugust 14, 2023Attachment C to 8-14-23 Minutes
2Primary FocusUpdate Stormwater ModelConceptual Stormwater Improvements10‐year Capital Improvement PlanAttachment C to 8-14-23 Minutes
3Aquatic GardensAttachment C to 8-14-23 Minutes
4Impervious Impact AnalysisSelected Test AreaAdded “local‐scale” detail to the model in test AreaEvaluated 4 Scenarios Using Updated ModelCompared Max Flood Depth Increases for Design Storm EventsAttachment C to 8-14-23 Minutes
5Impervious Impact AnalysisScenario 1Scenario 2Scenario 3Scenario 4Attachment C to 8-14-23 Minutes
6Impervious Impact AnalysisKey Takeaways:• More impervious area = More Runoff = More Frequent/Intense Flooding• Impacts Ranged from 2‐6 inches• On‐site Storage Systems Need to Be MaintainedAttachment C to 8-14-23 Minutes
7On-Site Storage Review•Methodology was developed by CDM.•Reviewed the spreadsheet assumptions. •Developed a similar but independent approach.•Compared results. Attachment C to 8-14-23 Minutes
8On-Site Storage ReviewKey Takeaways:• Across sample parcels, the independent method required ~10% more storage volume on average. • The City’s method produced reasonable results.• City codes and storage calculations have changed slightly since 2018.Attachment C to 8-14-23 Minutes
Attachment C to 8-14-23 Minutes