Article Figures & Data
Figures
- Figure 1
Study Area Flood Hazard, Exposure, and Risk
- Figure 2
Effect of Removing Observations inside the Inundation Boundary on Estimates for Inundated Properties inside the Special Flood Hazard Area (SFHA)
- Figure 3
Residual Plots: Inundated Inside the Special Flood Hazard Area (SFHA), Near Misses, Inundated Outside the SFHA, with 95% Confidence Intervals (CI)
Tables
- Table 1
Flood Insurance Premiums for Single Family Pre- and Post-FIRM SFHA Properties (Dollars)
Building Coverage Contents Coverage Pre-FIRM Annual Premium Pre-FIRM Premium NPV Post-FIRM Annual Premium Post-FIRM Premium NPV 20,000 8,000 297 9,900 481 16,033 30,000 12,000 446 14,867 721 24,033 50,000 20,000 743 24,766 1,202 40,067 75,000 30,000 1,121 37,367 1,488 49,600 100,000 40,000 1,509 50,300 1,550 51,667 125,000 50,000 1,897 63,233 1,612 53,733 150,000 60,000 2,285 76,167 1,674 55,800 200,000 80,000 3,061 102,033 1,798 59,933 250,000 l00,000 3,837 127,900 1,922 64,066 Note: Rates calculated for properties without basements. Pre-FIRM rates are for valid properties built prior to the first floodplain regulations in 1969. Premium net present value (NPV) calculated into perpetuity assuming constant premium rates, yearly payments, and a discount rate of 3%. Post-FIRM payments calculated assuming property has one flood and that the flood is at the same elevation as the base flood elevation. FIRM, Flood Insurance Rate Map; SFHA, Special Flood Hazard Area.
Variable Description Mean Std. Dev. Min. Max. Price Property sale price in unadjusted U.S. dollars 424,036 284,924 50,000 4,724,509 Flood SFHA 1 if building is in the Special Flood Hazard Area, 0 otherwise 0.04 0.19 0 1 Postflood 1 if sale occurred after the 2013 flood, 0 otherwise 0.47 0.50 0 1 Inundated 1 if building is located inside the inundation boundary, 0 otherwise 0.03 0.17 0 1 500yrFP 1 if building is in the 500-year floodplain, 0 otherwise 0.07 0.25 0 1 Location Stream0to600ft 1 if building is within 600 feet of a stream, 0 otherwise 0.09 0.28 0 1 Stream601to1800ft 1 if building is between 601 and 1,800 feet of a stream, 0 otherwise 0.24 0.43 0 1 Stream1801to5000ft 1 if building is between 1,801 and 5,000 feet of a stream, 0 otherwise 0.20 0.40 0 1 Stream5001to8000ft 1 if building is between 5,001 and 8,000 feet of a stream, 0 otherwise 0.14 0.35 0 1 Dist2Lake Parcel distance to lakes and reservoirs in feet 738 477 0 2,474 Dist2OpenSpace Parcel distance to open space areas in feet 998 855 1 3,840 Dist2Trailhead Building distance to closest trailhead in feet 10,135 5,551 378 29,948 Dist2Road Building distance to main road in feet 756 553 41 3,307 Elevation Elevation of parcel centroid in feet 4,944 753 4,500 10,260 Structure Age Age of building in years 37 24 1 151 Sqft Finished square footage of the building 1,884 891 324 11,657 Lotsize Lot size in acres 0.17 1.82 0.01 69 CarStorage 1 if property has car storage, 0 otherwise 0.93 0.25 0 1 FinishedBasement 1 if building has a finished basement, 0 otherwise 0.60 0.49 0 1 NumberBedrooms The number of bedrooms a building has 4 1 0 12 NumberFullBaths The number of full baths a building has 2 0.84 0 7 Number3qtrBaths The number of 3/4 baths a building has 1 0.72 0 9 VeryGoodQuality 1 if building is listed as very good quality or above, 0 otherwise 0.11 0.31 0 1 Note: For the analysis, Price, Dist2Stream, Dist2OpenSpace, Dist2Road, Sqft, and Lotsize were transformed with natural logs. Age was transformed by squaring the variable.
No Inundation
(1)Inundation as a Control Variable
(2)Inundation as a Moderating Variable
(3)SFHA –0.063*** (0.019) –0.057*** (0.020) –0.042* (0.023) Inundated –0.024 (0.023) 0.020 (0.027) SFHA × Inundated –0.083* (0.046) SFHA × Postflood –0.001 (0.034) 0.023 (0.031) 0.053* (0.031) Inundated × Postflood –0.061* (0.036) –0.017 (0.032) SFHA × Inundated × Postflood –0.121 (0.083) Structure and location characteristics Yes Yes Yes Municipality fixed effects Yes Yes Yes Census block group fixed effects Yes Yes Yes Year-quarter fixed effects Yes Yes Yes R-squared 0.775 0.776 0.776 Observations 15,056 15,056 15,056 Total Marginal Effects Preflood Average inside the SFHA –0.063*** (0.019) –0.057*** (0.020) Average inside the inundation boundary –0.024 (0.023) Inundated inside the SFHA –0.105*** (0.031) Near miss –0.042* (0.023) Inundated outside the SFHA 0.020 (0.027) Postflood Average inside the SFHA –0.063** (0.032) –0.034 (0.028) Average inside the inundation boundary –0.085*** (0.033) Inundated inside the SFHA –0.190*** (0.066) Near miss 0.011 (0.026) Inundated outside the SFHA 0.003 (0.025) Treatment Definition Mean Preflood Quantity Index Mean Postflood Quantity Index Welch t-Test p-Value 
5.522 (5.439, 5.606) 5.570 (5.469, 5.671) 0.476 5.311 (5.262, 5.361) 5.322 (5.265, 5.380) 0.781 5.296 (5.233, 5.359) 5.303 (5.230, 5.378) 0.876 5.353 (5.344, 5.362) 5.343 (5.333, 5.353) 0.143 Note: The first two columns report the mean quantity index for each risk group, before and after the flood; 95% confidence intervals surrounding the means are given in parentheses. The last column reports the p-values from a Welch two-sample t-test comparing the pre- and postflood means. The null hypothesis of the Welch two-sample t-test is that the true difference in means is equal to zero.
