Coastal Construction Manual - National Ready Mixed Concrete ...

Volume I
CONTENTS
3.3.4.10 Atmospheric Ice............................................................................................. 3-27
3.4 Coastal Flood Effects.................................................................................................................3-28
3.4.1 Hydrostatic Forces ....................................................................................................... 3-28
3.4.2 Hydrodynamic Forces................................................................................................... 3-28
3.4.3 Waves............................................................................................................................ 3-31
3.4.4 Flood-Borne Debris....................................................................................................... 3-33
3.5 Erosion......................................................................................................................................3-35
3.5.1 Describing and Measuring Erosion...............................................................................3-40
3.5.2 Causes of Erosion..........................................................................................................3-42
3.5.2.1 Erosion During Storms..................................................................................3-42
3.5.2.2 Erosion Near Tidal Inlets, Harbor, Bay, and River Entrances........................3-44
3.5.2.3 Erosion Due to Manmade Structures and Human Activities......................... 3-47
3.5.2.4 Long-Term Erosion........................................................................................ 3-49
3.5.2.5 Localized Scour..............................................................................................3-51
3.5.3 Overwash and Sediment Burial..................................................................................... 3-52
3.5.4 Landslides and Ground Failures.................................................................................... 3-52
3.6 NFIP Flood Hazard Zones........................................................................................................ 3-53
3.6.1 Base Flood Elevations.................................................................................................... 3-54
3.6.2 Flood Insurance Zones.................................................................................................. 3-55
3.6.3 FIRMs, DFIRMs, and FISs.......................................................................................... 3-56
3.6.4 Wave Heights and Wave Crest Elevations...................................................................... 3-59
3.6.5 Wave Runup................................................................................................................. 3-61
3.6.6 Primary Frontal Dune................................................................................................... 3-61
3.6.7 Erosion Considerations and Flood Hazard Mapping.....................................................3-62
3.6.8 Dune Erosion Procedures..............................................................................................3-62
3.6.9 Levees and Levee Protection..........................................................................................3-64
3.7 Flood Hazard Assessments for Design Purposes........................................................................3-64
3.7.1 Determine If Updated or More Detailed Flood Hazard Assessment is Needed.............. 3-65
3.7.1.1 Does the FIRM Accurately Depict Present Flood Hazards?........................... 3-65
3.7.1.2 Will Long-Term Erosion Render a FIRM Obsolete?......................................3-66
3.7.1.3 Will Sea Level Rise Render a FIRM Obsolete?..............................................3-66
3.7.2 Updating or Revising Flood Hazard Assessments.......................................................... 3-67
3.8 Milestones of FEMA Coastal Flood Hazard Mapping Procedures and FIRMs..........................3-67
3.9 References..................................................................................................................................3-69
COASTAL CONSTRUCTION MANUAL
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