Presented by: Joseph L. DiLorenzo, Ph.D. NAJARIAN ASSOCIATES

1. COASTAL STORM CHARACTERISTICS ANDCHANGES IN FLOOD INSURANCE RATE MAPS FOR COASTAL MONMOUTH COUNTY Presented by: Joseph L. DiLorenzo, Ph.D.NAJARIAN ASSOCIATES

2. OVERVIEW OF PRESENTATION • Characteristics of coastal storms in New Jersey • Changes in new FEMA Flood Insurance Rate Maps (FIRMs) for Monmouth County • Map accuracy NajarianAssociates

3. TWO TYPES OF COASTAL STORMS • Tropical cyclones • (hurricanes) • Extra-tropical storms (Nor’easters) No central eye NajarianAssociates

4. TROPICAL CYCLONES (HURRICANES) • warm-core systems that derive energy from oceanic evaporation • cause intense, short-duration surges and wind • potential catastrophic damages, but somewhat localized NajarianAssociates

5. HURRICANE TRACKS (SINCE 1850) Most hurricanes skirt NJ and weaken NajarianAssociates

6. HURRICANE DONNASeptember 12, 1960 at Sandy Hook MSL NajarianAssociates

7. MONMOUTH COUNTY INUNDATION ZONES Category 1 & 2 hurricanes since 1850 On Sept. 3, 1821, a Category 4 hurricane passed over LBI

8. EXTRATROPICAL STORMS (NOR’EASTERS) • cold-core cyclonic systems • formed in areas where strong surface temperature gradients coincide with a strong jet stream aloft NajarianAssociates

9. EXTRATROPICAL STORMS – NOR’EASTERS • Cause prolonged flooding when blocked by presence of high pressure systems in northeast Canada • large scale systems – can flood and erode east coast regions NajarianAssociates

10. HISTORIC NOR’EASTERDecember 11, 1992 at Sandy Hook MSL

11. TIDAL DATUMS AT SANDY HOOK Mean High Water North American Vertical Datum of 1988 Mean Sea Level 1.09 ft 0.86 ft Sea level Datum of 1929 Mean Lower Low Water (Source: NOAA) NajarianAssociates

12. 1992 NOR’EASTER – NOAA SITES Maximum Stillwater Elevations Highest observed water level over ~100 year record (January 1910 - present) NajarianAssociates

13. JOLINE AVENUE, LONG BRANCHDEC. 11, 1992 NajarianAssociates

14. 1992 NOR’EASTER – USGS SITES Amplification at head of funnel-shaped Raritan Bay Like Atlantic City maximum elevation (7.35 ft) NajarianAssociates

15. COASTAL FLOOD RANKINGS Top Eight Coastal Storms at Sandy Hook (1910-present; Source: NOAA) NajarianAssociates

16. FEMA’s BASE FLOOD • The flood event having a probability of 0.01 (1%) of being equaled or exceeded in any given year • Commonly called the “100-year flood” (on average) NajarianAssociates

17. BASE FLOOD ELEVATION (BFE) • The corresponding water surface elevation of the 1% annual chance flood (100-year flood) • Often determined by numerical modeling of coastal hydrodynamic processes NajarianAssociates

18. BASE FLOOD ELEVATION (BFE)IN NO WAVE ZONES NajarianAssociates

19. BASE FLOOD ELEVATION (BFE)IN AREAS AFFECTED BY WAVES • Combines 100-year stillwater elevation, 100-year wave crest elevation and inland extent of wave runup • BFEs used to delineate Flood Hazard Areas inundated by 100-year storms on Flood Insurance Rate Maps (FIRMs) NajarianAssociates

20. NEW FLOOD INSURANCE RATE MAPS (FIRMS) • New FIRMS delineate Flood Hazard Areas inundated by 100-year flood with blue dot shading • BFEs labeled (in feet, NAVD-1988) in Zone AE (e.g., EL11) • Areas inundated by 500-year flood (0.2% chance flood) are shaded with black dots NajarianAssociates

21. KEY QUESTIONS • Are delineated flood hazard areas significantly different from previous maps for coastal Monmouth County? • What are the reasons for the changes? NajarianAssociates

22. CHANGES IN THE NEW FIRMSFOR MONMOUTH COUNTY • Some changes are due to re-delineations of flood hazard areas based on updated topographic data • Major changes along Bayshore are due to new FEMA standards for dunes and flood control structures NajarianAssociates

23. RE-DELINEATION OF FLOOD HAZARD AREAS • New maps re-delineate 100-year floodplain boundary using the SAME BFEs but with updated Monmouth County topography (2 foot contours) NajarianAssociates

24. MINOR CHANGES IN MOST COASTAL AREAS • Example of minor re-delineation of 100-year (1%) flood lines due to use of updated topography • Old: Yellow Line • New: Blue Line NajarianAssociates

25. MAJOR CHANGES ALONG BAYSHORE • Massively expanded flood hazard area due to more stringent FEMA standards for protective dunes/levees NajarianAssociates

26. PROJECT HISTORY • 1968-73: Keansburg area project constructed 1968-1973. Dune and levees built 15 ft high based on highest storm to date • Early 1980s: FEMA provisionally approves 14,700 foot long “levee,” with minimum flood insurance burden to residents • Over time, dune thickness decreased significantly - area vulnerable NajarianAssociates

27. PROJECT HISTORY • 2000-2007: Army Corps plans repairs • Beach renourishment proposed • Use same 15 ft dune crest elevation (not 18 ft BFE) • Benefit/Cost >1 Keansburg, Port Monmouth & Union Beach NajarianAssociates

28. PROJECT HISTORY • 2007: FEMA revises standards (44 CFR 65.10-11) • No longer considers the “levee” a levee or a protective dune NajarianAssociates

29. LEVEE STANDARD • 44 CFR §65.10 • Must be non-eroding structure during the 100-year storm • Must be 1 ft above 100-year storm wave height (i.e., no wave over-topping) • In this case: • “Structure” erodes • About 40% of “structure” below required height • 17.7 ft NAVD-1988 (10.5 ft + 6.2 ft+ 1 ft) NajarianAssociates

30. DUNE STANDARD • 44 CFR §65.11 (Dune standards) • Cross-sectional area must exceed 540 sq. ft and have vegetative cover • (seaward of dune crest and above 100-year SWE of 10.5 ft NAVD-1988) • In this case: • Bayshore dune cross-section too small (<70 sq. ft.) • FEMA still giving credit by eliminating V-zone behind dune • BFE 11 ft behind dune, essentially same as 100-year SWE NajarianAssociates

31. PRESENT DILEMMA • U.S. Army Corps shelved previous (non-compliant) dune repair plans which would not eliminate flood insurance burden • Compliant new plans will not satisfy benefit-to-cost criteria NajarianAssociates

32. ISSUE: AGENCY DISCONNECTIN INITIAL DESIGN LEVEL • ARMY CORPS: whichever design level provides maximum net benefits to the government (may be as low as a 5-yr level with 50% assurance) • FEMA: 100-yr design with 95% assurance NajarianAssociates

33. BIGGER DISCONNECT INLONGEVITY REQUIREMENTS • USACE: 50-year design life is typical; however all maintenance is the local responsibility, and is subject to budgetary constraints • FEMA: Full design level required throughout actuarial policy life, NOT dependent on budgetary constraints or human intervention NajarianAssociates

34. POSSIBLE SOLUTIONS(Chris Rasmussen, USACE) • USACE changes their optimum benefit requirement and only designs for a 100-yr event with 95% assurance for the full 50-year project life (e.g., the very few projects with benefits exceeding costs). • FEMA changes their actuarial rate calculations to allow varying levels of protection (e.g., homeowner would pay vastly higher rates reflecting a 20-yr level in year 1, a 15-yr level in year 3, etc.).

35. RECOMMENDATION • Beneficially use dredged sand from offshore navigation channels to enlarge protective dune • (using geotextile tubes) NajarianAssociates

36. MAP ACCURACY LIMITATIONS • FIRM delineations based on County’s topographic data • Aerial survey with 2-foot elevation contour intervals • Typical accuracy: about half a contour interval (~ 1 ft) NajarianAssociates

37. ACCURACY ISSUE EXAMPLE • Our field survey crews checked the topography along 5 Hazlet streets as they crossed into the mapped A zone • Along Tavern and Central Avenue there are 4 homes that may be moved out of the FHA • Along Holly, Laurel and Pinewood there are 4 homes that should be in the FHA NajarianAssociates

38. WHAT CAN BE DONE TO CORRECT MISTAKES? • LOMA • land survey of site • File application (Next Presentation) NajarianAssociates