COASTAL DATA APPLICATION

Transcription

1 2015 Coastal GeoTools Proactive By Design. Our Company Commitment COASTAL DATA APPLICATION Projecting Future Coastal Flood Risk for Massachusetts Bay Bin Wang, Tianyi Liu, Daniel Stapleton & Michael Mobile Page 1

2 Outline Objective: to present method and steps for site-specific coastal flood hazard analysis Small budget Relatively short project schedule Use of published data by USACE NACCS and other government agencies Overview of available data sources for coastal and water resource engineers Overview of numerical hydrodynamic modeling Page 2

3 Background Flood Damage Coastal Flooding Erosion Structural Damage Page 3

4 Background Coastal Resiliency To achieve coastal resiliency: critical infrastructure communities biohabitats natural resources Need to identify/quantify flood hazards: stillwater elevations wave action environmental loads shoreline and nearshore response Page 4

5 Background Massachusetts Bay & Cape Cod Bay Total Number of Cities/Towns = 53 Population = 1.90 M (2010 Census) Historical Coastal Towns Page 5

6 Background Massachusetts Bay Coastal Flood Hazard Nor-Easters Page 6

7 Background Massachusetts Bay Coastal Flood Hazard Hurricanes Page 7

8 Available Data GZA Coastal Engineering GeoTool South Shore Coastal Geomorphology: Beaches, Estuaries, Marsh, Structures Page 8

9 Available Data South Shore Coastal Geomorphology: Shoreline Change Page 9

10 Available Data North Shore Coastal Geomorphology: Beaches, Estuaries, Rocky Shore, Scarps, Structures Page 10

11 Available Data NOAA SLOSH Model Hydrodynamic Model Develops hurricane windfield NOAA developed DEMs Page 11

12 Available Data Page 12

13 Available Data NOAA/NOS/CO-OPS Tide Gages Observed water levels, e.g., time series for model validation/verification; extreme value analysis; empirical simulation technique (EST); Predicted tides and tidal constituents; Datum conversions (w/ Vdatum); Sea level trend Page 13

14 Stillwater Elevation (feet, NAVD88) Available Data NOAA/NOS/CO-OPS : Boston Harbor Observed Annual Maximum - Original Tide Data (ft, NAVD88) Calculated Stage-Frequency Curve w/ Original Tide Data Hingham Harbor (FEMA 2012) Observed Annual Maximum Adjusted w/ Sea Level Rise Calculated Stage-Frequency Curve w/ Sea Level Rise-Adjusted Tide Data Generalized Extreme Value (GEV) ,000 Return Period (Years) Page 14

15 Available Data FEMA Flood Insurance Study and Rate Maps Page 15

16 Available Data FEMA Flood Insurance Study and Rate Maps Page 16

17 Available Data Wave Information Studies (WIS) Frequency analysis Time series Page 17

18 Available Data Wave Information Studies (WIS) 100-year return period significant deep water wave height: +/- 35 ft Page 18

19 USACE NACCS USACE North Atlantic Coast Comprehensive Study (NACCS) Numerical Hydrodynamic Storm Surge and Wave Models Page 19

20 Numerical Hydrodynamic Modeling Site-Specific High Resolution Storm Surge, Wave and Flood Modeling Coupled ADCIRC + SWAN Models Page 20

21 Data Sources NOAA or State GIS topographic & hydrographic data layers (DEM) National or state land cover database NOAA COOPS tide gages water levels and other data; USACE Wave Information System (WIS) wave & wind gages National Climate Data Center - ground climate/weather stations NHC Hurricane Re-analysis project best track data Other (e.g., USGS stream gage data) Model construction Model inputs and calibration Page 21

22 Data Sources LiDAR Terrain Data ( m) U.S. Coastal Relief Model (30-m) Note: datum conversions & units Page 22

23 Data Sources Land Use building nodal attributes, Manning s friction values, surface roughness coefficients State: MassGIS LU2005 National: NLCD 2011 (v.2014) Page 23

24 Data Sources Tropical Cyclones: HURDAT / HURDAT 2 Historical Tracks IBtrACS - Int. Best Track Archive Others (e.g., RAMMB) Statistical analysis Time Series Verification Page 24

25 Data Sources Extratropical Cyclones Book: New England Weather, New England Climate (Zielinski & Keim, 2003) February 7, 1978 Page 25

26 Numerical Model USACE NACCS ADCIRC+SWAN Coupled Grid FEMA Model Grids Refined for New England Page 26

27 GZA High Resolution Local Model GZA High Resolution, Locally-Refined ADCIRC+SWAN Coupled Grid FEMA Region II Refined for Southern New England Page 27

28 Model Validation Hurricane Bob 1991 August Landfall: 41.4N, 71.4W Page 28

29 Water Surface Elevation (ft, NAVD88) Significant Wave Height (ft) Model Validation Validation Hurricane Bob 1991 NDBC Buoy Station Hurricane Bob Storm Surge Newport, RI Days in August, 1991 Observed Simulated Days in August, 1991 Observed Simulated Page 29

30 Synthetic Hurricane Modeling Extreme (Very Low Probability) Hurricane Bearing 10 R max V f V max DP 35 nm 20 kt 105 kt 68 mb Page 30

31 Synthetic Hurricane Typical track direction, similar to historical events Page 31

32 Sea Level Rise Note: The Commonwealth of Massachusetts has not officially adopted any SLC scenario. Page 32

33 Synthetic Hurricane Present Sea Level Page 33

34 Synthetic Hurricane 2100 USACE High SLR Page 34

35 Synthetic Hurricane Present Sea Level 2100 USACE High SLR Page 35

36 Synthetic Hurricane North Shore at greater risk for waves Page 36

37 ADCIRC+SWAN Calculated WL (ft, NAVD88) Synthetic Hurricane Station 1 - Salem Station 3 - Boston Station 5 - Scituate Simulation Time (days) Peak storm tide varies in space synchronized Boston at greater risk Page 37

38 Calculated Stillwater Level (ft, NAVD88) Impact of Sea Level Rise Peak Storm Tides for Selected Sea Level Scenarios North South Present SLR Int. SLR High Salem Revere Boston Quincy Scituate Page 38

39 Calculated Stillwater Level Increase (ft) Calculated Stillwater Level Increase (ft) Impact of Sea Level Rise 1.8 SLR Int. - Present Input SLR Int. 5.1 SLR High - Present Input SLR High Salem Revere Boston Quincy Scituate 4.8 Salem Revere Boston Quincy Scituate - Slightly nonlinear storm tide response to sea level rise; - For non-extreme cases, approximation by linear superposition; - For more extreme cases, numerical modeling needed Page 39

40 Comparison with USACE NACCS USACE NACCS Data Output Save Points Page 40

41 Stillwater Elevation (feet, NAVD88) Comparison with USACE NACCS NOAA/NOS/CO-OPS : Boston Harbor; NACCSpredicted flood-frequency curve Observed Annual Maximum Adjusted w/ Sea Level Rise Hingham Harbor (FEMA 2012) Calculated Stage-Frequency Curve w/ Sea Level Rise-Adjusted Tide Data NACCS Boston Harbor MT NACCS Boston Harbor HT MT ~ HT ,000 10,000 Return Period (Years) Page 41

42 Applying Model Output Overland Wave Inundation: CEDAS: ACES Module Page 42

43 Applying Model Output Flood Inundation Models Hydrodynamic Loads on Protective Barrier Maximum Flow Depth (ft) 1.9 Maximum Velocity (ft/s) 1.7 Impact Force (pounds) per linear feet 7.7 Page 43

44 Applying Model Output Shoreline Processes Beach Erosion Estuary Circulation; sediment transport Page 44

45 Applying Model Output Resiliency Design Page 45

46 Take-away Massachusetts Bay has significant flood risk: Tropical cyclones and nor easters Sea level rise Large population Critical infrastructure USACE NACCS: provides updated flood projections NACCS can be coupled with local, high resolution surge and wave models Page 46

47 Thank You! Bin Wang, P.E. Technical Specialist Norwood, MA Tianyi Liu, Ph.D. Coastal Engineer Specialist Norwood, MA Daniel C. Stapleton, P.E. Principal Norwood, MA Michael A. Mobile, Ph.D. Technical Specialist Bedford, NH Page 47

48 Synthetic Hurricane Page 48