QUANTIFYING THE KEY FACTORS THAT CREATE ROAD FLOODING

Transcription

1 QUANTIFYING THE KEY FACTORS THAT CREATE ROAD FLOODING Joshua D. Kent Center for GeoInformatics Louisiana State University 2013 LA Transportation Conference February 20, 2013

2 Photo provided by the Greater Lafourche Port Commission Road Flooding 2/20/ LA Transportation Conference Baton Rouge, LA 2

3 Photo provided by the Greater Lafourche Port Commission Road Flooding Flooding Represents A Serious Operational Hazard for Evacuation Routes Located Across Southern Louisiana 2/20/ LA Transportation Conference Baton Rouge, LA 3

4 Photo provided by the Greater Lafourche Port Commission Road Flooding 2011 DOTD and LTRC Announced a Special Topics Research Grant: Quantify the Key Factors that Create Road Flooding 2/20/ LA Transportation Conference Baton Rouge, LA 4

5 Tropical Storm Lee September 3, 1:00am Landfall in Vermilion Parish 60mph winds 18 casualties $1.6 billion in damage 2/20/ LA Transportation Conference Baton Rouge, LA 5

6 Tropical Storm Lee Photo by Tim Osborne (NOAA) Louisiana Highway LA-1 South of Golden Meadow Towards Leeville 2/20/ LA Transportation Conference Baton Rouge, LA 6

7 Emergency Evacuation Routes Across Coastal Louisiana are Vulnerable to Inundation LA 56 South of Chauvin, Louisiana Terrebonne Parish 2/20/ LA Transportation Conference Baton Rouge, LA 7 Photo provided by Terrebonne Levee & Conservation District

8 Road Flood Hazards Louisiana Roads and Highways are at Risk of Inundation from a Variety of Weather and Environmental Conditions: Lunar Tide Cycles Northerly Winds Storm Surge Sea Level Rise Subsidence 2/20/ LA Transportation Conference Baton Rouge, LA 8 Tropical Storm Lee over Louisiana (NOAA, 2011)

9 PROJECT GOALS: Collected and synthesize data that can quantify flood risk. Operationalize actionable data to facilitate informed decision making. Assess flood risk to vehicles by type Todd Bigelow 2/20/ LA Transportation Conference Baton Rouge, LA 9

10 Project Objectives & Methodology Quantify Flood Hazard Define Flood Hazard Characteristics. Collect, Process, and Synthesize Data. Compute Flood Depths over Roads. Develop a Decision Support Tool that will Operationalize the Factors that Contribute to Road Flooding: Synthesized flood risk. Develop a Meaningful User Interface. Research and Assess the Flood Risk by Vehicle Type and Flood Conditions: At what Flood Depth is Road Travel Hazardous? Assess Risk to Different Vehicle Types. 2/20/ LA Transportation Conference Baton Rouge, LA 10

11 Steps to Quantify Flooding Define Road Flooding and Develop Formula Data Requirements Collect and Process the Data 2010 National Geographic 2/20/ LA Transportation Conference Baton Rouge, LA 11

12 Quantify Road Flooding Inundation = Road Elevation tides + waves + surge + other A road will flood when its elevation is exceeded by the sum of: Tidal Effects Wave heights Storm Surge Heights Other factors: wind direction, wind speed, local barriers, topography, and bathymetry. 2/20/ LA Transportation Conference Baton Rouge, LA 12

13 Data Requirements Model the Inundation from Hurricane Induced Storm Surge Over the Surfaces of 86 Unique LDOTD Routes Located Across the 5 Management Districts in South Louisiana. Current & Authoritative Data Selected routes due to historic vulnerability to flooding. Inundation derived from the maximum surge heights (ft.) estimated using the SLOSH surge models. Identify the nearest tidal or water gauge to the vulnerable routes. 2/20/ LA Transportation Conference Baton Rouge, LA 13

14 Data Sources Road Elevations: Derived from the LDOTD Pavement Management System (PMS) database. SLOSH: Sea, Lake, and Overland Surge from Hurricanes models published by the National Weather Service (NWS). Tide Gauges: Real-Time Stream and Tide Gauge Readings published online by NOAA, USGS, and other Agencies. Tide also included with surge models. Wave Action: Limited integrated within SLOSH models. Requires complex modeling of topography, bathymetry, and meteorological factors. 2/20/ LA Transportation Conference Baton Rouge, LA 14

15 SLOSH Models Forecast model of Storm Induced Surge Over Land: Developed by the National Weather Service (NWS) Consists of an ensemble of deterministic, numerical models based on meteorological variables. 2/20/ LA Transportation Conference Baton Rouge, LA 15

16 SLOSH: Deterministic, Numerical Models Founded on Meteorological Variables: Saffir-Simpson Hurricane Wind Scale (e.g., Category 1-5) Tide Stage (e.g., low vs. high tide) Storm Direction & Speed (e.g., North-west at 10mph) Organized by Basins (e.g., New Orleans, Vermilion Bay, Sabine Lake, etc.) 2/20/ LA Transportation Conference Baton Rouge, LA 16

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18 Ensemble Surge Models Three basic types of Surge models published by the NWS: P-Surge Probabilistic Storm Surge MEWO Maximum Envelope Of Water MOM Maximum Of MEOWs 2/20/ LA Transportation Conference Baton Rouge, LA Readiness Landfall 48hrs Planning Mitigation Landfall > 120hrs Response Landfall < 48hrs 18

19 Tide Gauge Data: NOAA & USGS 2/20/ LA Transportation Conference Baton Rouge, LA 19

20 Tide Gauge Data: NOAA & USGS 2/20/ LA Transportation Conference Baton Rouge, LA 20

21 Tide Gauge Data: NOAA & USGS 2/20/ LA Transportation Conference Baton Rouge, LA 21

22 Wave Models Wave models are produced for large geographic areas, which make data synthesis too problematic for the defined objectives. 2/20/ LA Transportation Conference Baton Rouge, LA 22

23 Road Elevations Cat 15mph (Hi Tide) INUNDATION < < The Pavement Management System (PMS) Maintains a Road Database: Location Elevation Type LRS/Control Sec. District Etc. Tide & Water Gauges (2012) Agency!( NOAA ") USGS 2/20/ LA Transportation Conference Baton Rouge, LA 23

24 Implementing a Decision Support Tool Synthesize Road Elevations with SLOSH Surge Models and Tide Gauge Locations. Display as a Map in a GIS Relative to a Hurricane Scenarios: Represent data by LDOTD district. Illustrate flood depths in feet above the road surface. Organize by hurricane category, path, speed, and tide-range 2/20/ LA Transportation Conference Baton Rouge, LA 24

25 Tool Organization & Functionality The Operational Requirements for this Instrument were Designed & Implemented According to: map organization user interface & functionality 2/20/ LA Transportation Conference Baton Rouge, LA 25

26 Tool Development Coordinated Development with the Project Review Committee: Mr. Jonathan Brazzell, NWS Mr. Rhett Desselle, LDOTD Mr. Chris Fillastre, LDOTD Mr. Kurt Johnson, LDOTD Mr. Vincent Latino, LDOTD Mr. Lyle LeBlanc, LDOTD Dr. James E. Mitchel, LDOTD 2/20/ LA Transportation Conference Baton Rouge, LA 26

27 Customized Identify Tool Intuitive Map Tools Organized Table of Contents: Actionable Data Layers: Surge Vulnerable Road Features Real-time Gauge Data Basemap Layers: Major Highways LDOTD Districts Parishes Simplified Map Interface 2/20/ LA Transportation Conference Baton Rouge, LA 27

28 Map Bookmarks Tide Gauge Links 2/20/ LA Transportation Conference Baton Rouge, LA 28

29 Deliverables Project Delivered as a Proof of Concept for a Operational Tool Capable of Providing Effective Decision Support for Flood Hazards on Vulnerable, State-Maintained Routes. 2/20/ LA Transportation Conference Baton Rouge, LA 29

30 Tool Implementation & Utilization Five ArcGIS Desktop map documents were delivered for LDOTD districts: 02, 03, 07, 61, and 62 Inundation was computed for designated evacuation routes in each district. Inundated road segments (i.e., point features) were symbolized to depict the maximum (worse-case) flooding (ft.) for a given hurricane scenario. Name, description, and Web link to nearest realtime water and tide gauge facilities were added to each road point feature. 2/20/ LA Transportation Conference Baton Rouge, LA 30

31 The Decision Support Tool a brief demonstration 2/20/ LA Transportation Conference Baton Rouge, LA 31

32 TOOL DEMONSTRATION: Vulnerable District 02 Roads: Category 2 Hurricane Northerly Track 15mph Forward Speed Average Tidal Conditions Results: Inundation along select routs symbolized according to degree of flood depth above the road surface. 2/20/ LA Transportation Conference Baton Rouge, LA 32

33 Cat 15mph (Hi Tide) INUNDATION < < Tide & Water Gauges (2012) Agency!( NOAA ") USGS 2/20/ LA Transportation Conference Baton Rouge, LA 33

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38 The Decision Support Tool end of demonstration. 2/20/ LA Transportation Conference Baton Rouge, LA 38

39 Defining Vehicle Flood Risk Define Vehicle Categories Determine Flood Risk Parameters Assess Flood Risk Present Results 2006 (cc) ifish.net 2/20/ LA Transportation Conference Baton Rouge, LA 39

40 Lateral Force (lbs) Flood Risk by Vehicle Type At what flood depth is road travel hazardous? Mini Passenger Vehicle Weight: 1,750 lbs. Clearance: 5.5" mph 4 2.7mph 6 4.1mph 8 5.5mph mph Water Depth 6" 7" 8" 9" 10" 8" Threshold Ff = lbs. 9" Threshold Ff = lbs. 10" Threshold Ff = 56.5 lbs. Water Velocity (feet per second) 2/20/ LA Transportation Conference Baton Rouge, LA 40

41 Turn Around - Don t Drown 2/20/ LA Transportation Conference Baton Rouge, LA 41

42 Computing Flood Risk to Vehicles Develop a simplistic approach for computing vehicle risk follows a three-stage conditional function in which the buoyancy, lateral forces, and friction forces are combined. 2/20/ LA Transportation Conference Baton Rouge, LA 42

43 Computing Flood Risk to Vehicles 1) The net weight of a vehicle is reduced by the weight displaced by the rising water (i.e., buoyancy). 2) Lateral Forces of moving water against the vehicle (i.e., water pressure) are computed. 3) Friction Force is determined when the combined lateral forces of water pressure and buoyancy move the vehicle. 2/20/ LA Transportation Conference Baton Rouge, LA 43

44 Width: 6 feet Length: 18 feet Ground Clearance: 18 inches Weight: 5,040 lbs. 1-foot of water displaced by this vehicle weighs: (6ft x 18ft x 1ft x 62.4 lbs./ft 3 ) = 6,739 lbs. 6,739 lbs. > 5,040 lbs. 2/20/ LA Transportation Conference Baton Rouge, LA 44

45 Computing Vehicle Buoyancy Archimedes Principle: The buoyant force on an object is equal to the weight of the fluid displaced by that object. W B = W v (A v Z w ρ w ) W B = Buoyant Weight of Immersed Vehicle W v = Vehicle Weight A v = Vehicle Area Z w = Net Depth of Flood Waters (flood height ground clearance) ρ w = Water Density per Volume (~62.4 lbs./foot 3 ) 2/20/ LA Transportation Conference Baton Rouge, LA 45

46 Computing Lateral Force of Water Compute the force of the moving water against the vehicle, the weight of the vehicle, and the drag forces of the vehicle within the water F w = (A z P dw ) F w = Blasé Pascal s Second Law: the Force of Water A z = Submerged Surface Area of the Vehicle P dw = Dynamic Hydrostatic Pressure of Water 2/20/ LA Transportation Conference Baton Rouge, LA 46

47 Computing Lateral Force of Water Compute the force of the moving water against the vehicle, the weight of the vehicle, and the drag k = constant forces density of value the of water vehicle on a within the water F w = Blasé Pascal s Second Law: the Force of Water A z = Submerged Surface Area of the Vehicle P dw = Dynamic Hydrostatic Pressure of Water P dw = k V w 2 square object: ~1.4 lbs./ft 3 (AASHTO) V w = velocity of the water F w = (A z P dw ) 2/20/ LA Transportation Conference Baton Rouge, LA 47

48 Computing Friction Force Critical force applied to a vehicle sufficient to overcome its static inertia is dependent on both the friction forces keeping the vehicle still and the lateral forces of the water incident to the vehicle s surface area. F f = Friction Force of a Vehicle F f = C f W B C f = Coefficient of Friction for a Wet Surface (~0.4) W B = Apparent Weight of Immersed Vehicle 2/20/ LA Transportation Conference Baton Rouge, LA 48

49 Assessing Vehicle Risk Lateral Force of Water (F w ) Friction Force (F f ) Risk assessed for a static vehicle in moving flood waters can be assessed by combining each of the previous equations Associated Press 2/20/ LA Transportation Conference Baton Rouge, LA 49

50 17.5 4,050 lbs. Example: Vehicle Risk Assessment A vehicle is stalled in flood waters moving at 6 feet per second: Lateral Force: lbs. Friction force: lbs. 3,310.5 lbs Width: 6.5 ft. Length: 14 ft. Clearance: 10.5 in. Weight: 4,050 lbs. Flood Depth: 17.5 in. Submerged Depth: ft. Water Velocity: 6 ft. sec. -1 Net Weight: 4,050 l = lbs. Friction Force: 0.4 x lbs. = lbs. 2/20/2013 Risk: lbs. < LA lbs. Transportation Conference Baton Rouge, LA 50

51 Compute Risk by Vehicle Type Actionable Data for Realistic Search & Rescue Strategies When is a flooded road impassable? What are the rescue hazards? Search & Rescue Vehicle Fording Options 2/20/ LA Transportation Conference Baton Rouge, LA 51

52 Civilian Vehicle Specifications CLASS BODY MEAN CURB WEIGHT (lbs.) MEAN LENGTH (feet) MEAN WIDTH (feet) MEAN GROUND CLEARANCE (inches) PASSENGER MINI (PC/Mi) SUBCOMPACT (PC/L) COMPACT (PC/C) MIDSIZE (PC/Me) FULL-SIZE (PC/H) 1, , , , , MULTI-PURPOSE VEHICLE (MPV) SPORT UTILITY VEHICLE MINIVAN 2, FULL 2, MID-SIZED 3, FULL 5, PICKUP/TRUCK MID-SIZED 3, FULL-SIZE 5, /20/ LA Transportation Conference Baton Rouge, LA 52

53 Military Vehicle Specifications CLASS BODY AVG. CURB WEIGHT (lbs.) AVG. LENGTH (feet) AVG. WIDTH (feet) AVG. GROUND CLEARANCE (inches) High Mobility Multipurpose Wheeled Vehicle (HMMWV) humvee M-998 5, M-1114/6 7, ½ Ton Cargo deuce and a-half M-35/G , (30 w/fording kit) Family of Medium Tactical Vehicles (FMTV) M LMTV (2.5 ton) M FMTV (5-ton) 17, , /20/ LA Transportation Conference Baton Rouge, LA 53

54 Lateral Force (lbs) Lateral Force (lbs) Lateral Force (lbs) Flood Risk to Civilian Vehicles The stability threshold is represented as a dashed line, which illustrates the point at which the friction force, F f, is overwhelmed by the lateral forces, F w, exerted by moving flood waters. A Compact Passenger Car is at Risk when: Estimates based on idealized assumptions of an debris-free water over smooth surfaces against and evenly submerged vehicle. 9 deep flood flowing at 13 ft sec deep flood flowing at 9.7 ft sec deep flood flowing at 6.9 ft sec Subcompact Passenger Vehicle -1 Weight: 2,250 lbs. Clearance: 6" mph 4.7mph 6.1mph 7.5mph 8.9mph Water Velocity (feet per second) Water Depth 6.5" 7.5" 8.5" 9.5" 10.5" 8.5" Threshold Ff = lbs. 9.5" Threshold Ff = lbs. 10.5" Threshold Ff = lbs. 2/20/ LA Transportation Conference Baton Rouge, Water LA Velocity (feet per second) Mini Passenger Vehicle Weight: 1,750 lbs. Clearance: 5.5" mph 2.7mph 4.1mph 5.5mph 6.8mph Water Velocity (feet per second) Compact Passenger Vehicle Weight: 2,750 lbs Clearance: 6.75" mph 4.7mph 6.1mph 7.5mph 8.9mph Water Depth 6" 7" 8" 9" 10" 8" Threshold Ff = lbs. 9" Threshold Ff = lbs. 10" Threshold Ff = 56.5 lbs. Water Depth 7" 8" 9" 10" 11" 9" Threshold Ff = lbs. 11" Threshold Ff = lbs. 10" Threshold Ff = lbs.

55 Lateral Force (lbs) Lateral Force (lbs) Lateral Force (lbs) Lateral Force (lbs) 1, Midsized Passenger Vehicle Weight: 3,250 lbs Clearance: 7" mph 4.7mph 6.1mph 7.5mph 8.9mph Water Velocity (feet per second) Water Depth 8" 9" 10" 11" 12" 11" Threshold Ff = lbs. 12" Threshold Ff = lbs. 10" Threshold Ff = lbs. 1,200 1, Full-Sized Passenger Vehicle Weight: 3,750 lbs. Clearance: 7.5" mph 6.8mph 10.23mph 13.6mph Water Velocity (feet per second) Water Depth 8.5" 9.5" 10.5" 11.5" 9.5" Theshold Ff = 1,084 lbs. 10.5" Theshold Ff = 876 lbs. 11.5" Threshold Ff = 668 lbs Minivan Multi-Purpose Vehicle Weight: 2,400 lbs. Clearance: 10" mph 4.1mph 6.8mph 9.5mph 2/20/ LA Transportation Conference Baton Rouge, LA 55 Water Velocity (feet per second) Water Depth 10.5" 11.5" 12.5" 13.5" 14.5" 12.5" Threshold Ff = lbs. 13.5" Threshold Ff = lbs. 14.5" Threshold Ff = lbs Minivan Multi-Purpose Vehicle Weight: 2,250 lbs. Clearance: 7" mph 5.5mph 8.9mph Water Velocity (feet per second) Water Depth 8" 9" 10" 11" 9" Threshold Ff = lbs. 10" Threshold Ff = lbs. 11" Threshold Ff = 88.8 lbs.

56 Lateral Force (lbs) Lateral Force (lbs) Lateral Force (lbs) Lateral Force (lbs) 1,200 1, Midsized Sport Utility Vehicle Weight: 3,250 lbs Clearance: 11" mph 6.8mph 10.23mph 13.6mph Water Velocity (feet per second) Water Depth 11.5" 12.5" 13.5" 14.5" 15.5" 13.5" Theshold Ff = lbs. 14.5" Threshold Ff = lbs. 15.5" Threshold Ff = lbs. Full-Sized Sport Utility Vehicle Weight: 5,250 lbs. Clearance: 15.5" 1,800 1,600 1,400 1,200 1, mph 6.8mph 10.23mph 13.6mph Water Velocity (feet per second) Water Depth 16" 17" 18" 19" 20" 18" Threshold Ff = 1,516.9 lbs. 19" Threshold Ff = 1,283.7 lbs. 20" Threshold Ff = 1,050.5 lbs. 1,400 1,200 1, Midsized Pickup Weight: 3,750 lbs. Clearance: 11.75" mph 6.8mph 10.23mph 13.6mph Water Velocity (feet per second) Water Depth 12" 13" 14" 15" 16" 14" Threshold Ff = 1,046.6 lbs. 15" Threshold Ff = lbs. 16" Threshold Ff = lbs. 2/20/ LA Transportation Conference Baton Rouge, LA 56 1,800 1,600 1,400 1,200 1, Full-Sized Pickup Weight: 5,250 lbs. Clearance: 15.5" mph 6.8mph 10.23mph 13.6mph Water Velocity (feet per second) Water Depth 16" 17" 18" 19" 20" 18" Threshold Ff = 1,516.9 lbs. 19" Threshold Ff = 1,283.7 lbs. 20" Threshold Ff = 1,050.5 lbs.

57 Lateral Force (lbs) Flood Risk to Military Vehicles The stability threshold is represented as a dashed line, which illustrates the point at which the friction force, F f, and the vehicle s buoyant weight, W b, is overwhelmed by the forces exerted by the moving flood waters. Military Vehicles chosen represent those accessible to and used by the Louisiana National Guard. 7,000 6,000 5,000 4,000 3,000 2,000 1,000 2½ Ton (M35/G742) Military Vehicle Weight: 18,000 lbs. Clearance: 20" mph 11.6 mph 15.0 mph 18.4 mph Water Velocity (feet per second) Water Depth 21.5'' 22.5'' 23.5'' 24.5'' 25.5'' 20.5" Threshold Ff = 5,095.1lbs. 19.5" Threshold Ff = 5,477.8 lbs. 18.5" Threshold Ff = 5,860.5 lbs. Estimates based on idealized assumptions of an debris-free water over evenly submerged vehicles. 2/20/ LA Transportation Conference Baton Rouge, LA 57

58 Lateral Force (lbs) Lateral Force (lbs) 2,500 2,000 1,500 1,000 HMMWV (M998) Military Vehicle Weight: 5,500 lbs. Clearance: 16" Water Depth 16.5'' 17.5'' 18.5'' 19.5'' 20.5'' mph 9.5 mph 13.6mph Water Velocity (feet per second) 20.5" Threshold Ff = 1,203.2 lbs. 19.5" Threshold Ff = 1,424.7lbs. 18.5" Threshold Ff = 1,646.2 lbs. 3,500 3,000 2,500 HMMWV (M1114/6) Military Vehicle Weight: 7,800 lbs. Clearance: 16" Water Depth 16.5'' 17.5'' 2,000 1, '' 19.5'' 20.5'' 1, " Threshold 500 Ff = 2,123.2lbs. 19.5" Threshold 0 Ff = 2,344.7lbs " Threshold 6.8 mph 10.9 mph 15mph 19.1mph Ff = 2,676.9 lbs. 2/20/ LA Transportation Conference Baton Rouge, Water LA Velocity (feet per second) 58

59 Lateral Force (lbs) Lateral Force (lbs) 7,000 6,000 5,000 4,000 3,000 2,000 1,000 LMTV (2½ Ton) Military Vehicle Weight: 17,000 lbs. Clearance: 22" mph 17.1 mph 23.9 mph 30.7 mph Water Velocity (feet per second) Water Depth 22.5'' 23.5'' 24.5'' 25.5'' 20.5" Threshold Ff = 5,577lbs. 19.5" Threshold Ff = 5,926.4 lbs. 18.5" Threshold Ff = 6,275.8 lbs. 10,000 9,000 8,000 7,000 6,000 5,000 4,000 3,000 2,000 1,000 FMTV (5 Ton) Military Vehicle Weight: 20,000 lbs. Clearance: 22" mph 17.1 mph 23.9 mph 30.7 mph 2/20/ LA Transportation Conference Baton Rouge, LA 59 Water Velocity (feet per second) Water Depth 22.5'' 23.5'' 24.5'' 25.5'' 20.5" Threshold Ff = 6,660.5lbs. 19.5" Threshold Ff = 7,043.2 lbs. 18.5" Threshold Ff = 7,425.9 lbs.

60 Results Summary of Passenger Vehicle Flood Risk CLASS BODY MEAN CURB WEIGHT (lbs.) MEAN LENGTH (feet) MEAN WIDTH (feet) MEAN GROUND CLEARANCE (inches) WATER DEPTH NEEDED FOR NEUTRAL BUOYANCY (inches) VELOCITY OF WATER NEEDED TO DESTABALIZE VEHICLE (ft./sec.) PASSENGER MINI 1, PASSENGER SUBCOMP ACT 2, PASSENGER COMPACT 2, PASSENGER MIDSIZED 3, PASSENGER FULL-SIZED 3, MPV MINI-VAN MPV FULL-SIZED 2, SUV MIDSIZED 3, SUV FULL-SIZED 5, PICKUP MIDSIZED 3, PICKUP FULL-SIZED 5, /20/ LA Transportation Conference Baton Rouge, LA 60

61 Results Summary of Military Vehicle Flood Risk CLASS BODY MEAN WEIGHT (lbs.) MEAN LENGTH (feet) MEAN WIDTH (feet) MEAN GROUND CLEARANCE (inches) WATER DEPTH NEEDED FOR NEUTRAL BUOYANCY (INCHES) VELOCITY OF WATER NEEDED TO DESTABALIZE VEHICLE (FT/SEC) HMMWV M-998 5, M-1114/6 7, Ton M-35/G , FMTV M LMTV M FMTV 17, , /20/ LA Transportation Conference Baton Rouge, LA 61

62 Conclusions Quantified the Flood Hazards Defined Flood Hazard Characteristics Collected Authoritative Data & Models Computed Flood Risk over Roads Developed a Proof of Concept Decision Support Tool that Presents Worst-Case Flooding over Evacuation Routes. Synthesized Flood Risk via District Map Developed a Functional User Interface Provided Recommendations for Future Developments Researched Flood Risk by Vehicle Type: Defined Vehicle Types Assessed Buoyancy, Lateral Forces of Water, and Friction Forces Determined Risk for Civilian and Military Vehicle Types Provided Recommendations for Evacuation Strategies 2/20/ LA Transportation Conference Baton Rouge, LA 62

63 Discussion Numerous Caveats when Estimating Inundation over a Vulnerable Routes were Computed by Subtracting the Road Elevations from Modeled Surge. Road Elevations Worse-Case Scenario Surge Estimates Vehicle Flood Risk 2/20/ LA Transportation Conference Baton Rouge, LA 63

64 Data Uncertainty & Limitations SLOSH Model Accuracy: 20% accurate when forecast simulations matched actual storm conditions. Caution when interpreting of the estimates as anything beyond guidance for potential flood intensity. SLOSH Surge Uncertainty: Grid cells are often too large. Estimates are effectively skewed relative to outlier elevations. Limitations of the hydrological data that mask the occurrence of actual shallow flooding events. Topographic issues are directly related to the spatial resolution of the SLOSH basin. Does not parameterize the specific values for tide, wave, or rainfall. 2/20/ LA Transportation Conference Baton Rouge, LA 64

65 SLOSH Cell Sizes Can Be Too Large Varying Grid Cell Size 2/20/ LA Transportation Conference Baton Rouge, LA 65

66 Uses the Mean Water Height and Elevation for Each Cell 2/20/ LA Transportation Conference Baton Rouge, LA 66

67 Resolution of the Barriers and Features Average Elevation Mask Shallow Flooding Topographic Barriers Topographic and Impedances are Barriers and the model s weakest Impedances link. 2/20/ LA Transportation Conference Baton Rouge, LA 67

68 Summary of SLOSH Accuracy Accuracy within ± 20% of Peak Storm Surge Accounts for Astronomical Tides Does not include rainfall, river flow, or wind-driven waves 2/20/ LA Transportation Conference Baton Rouge, LA 68

69 Summary of SLOSH Accuracy Intense storms cause higher surges. The highest surges usually occur to the right of the storm track. Fast moving storms = high surges along open coast. Slow moving storms = greater flooding inside bays and estuaries. Large storms impact more coastline. Direction impacts flood extent Shallow shorelines = greater surge Steep shorelines = lesser surge 2/20/ LA Transportation Conference Baton Rouge, LA 69

70 Decision Support Tool Recommendations Decision Support Tool Demonstrated to the Project Review Committee in May, 2012 Effectiveness as an operational instrument questionable. Need to be implemented as Web-based tool. Simplify the User Interface (UI). Questions about Data accuracy and age of non real-time data. Incorporate more Real-Time data Districts to begin collecting data for flood events. 2/20/ LA Transportation Conference Baton Rouge, LA 70

71 Vehicle Risk Recommendations Vehicle Flood Risk Presented to the Project Review Committee in May, 2012 Need for a consistent vehicle classification scheme. Resolve differences between curb weight and gross vehicle weight. Need to revise estimates for computing Hydrostatic Pressure applied to submerged vehicle dependent on vehicle design (e.g., ground clearance and aerodynamics). Differentiation of debris vs. clear water and flow. Address PSA challenges and risks when driving through any flooded road, regardless of water depth! 2/20/ LA Transportation Conference Baton Rouge, LA 71

72 Thank You Questions? Joshua D. Kent, Ph.D. Center for GeoInformatics Louisiana State University Baton Rouge, LA /20/ LA Transportation Conference Baton Rouge, LA 72