Flood Risk Assessment for Single-Family Home in A Zone

Abstract

<p>In the United States, the Federal Emergency Management Agency (FEMA) delineates 100-year flood zones (special flood hazard area (SFHA) in the U.S.A.) to define flood risks and insurance rates. Quantifying flood risk in the SFHA which is the area of high risk of flooding is vital for individual, communities, and decision makers to minimize flood consequences. Flood risk is assessed as the product of the probability of flooding and the consequences associated with its occurrence. The unavailability of the modeled flood depth data for 100- year return period or for all return periods in most of SFHA’s areas make quantifying flood risk is challenging. This research develops a systematic approach that generates a synthetic flood parameter to quantify flood risk in A Zone- portion of the SFHA in which the potential base flood wave height is between 0.0 and 3.0 feet. The synthetic flood hazard parameters are generated in 100-year floodplain considering different flooding scenarios, and the flood risk is quantified in terms of average annual loss (AAL) at 100-year flood elevation (<em>E<sub>100</sub></em>), and with an additional elevation above <em>E<sub>100</sub></em> for single-family home with different attribute located in A Zone. The results reveal that the AAL for single-family home (i.e., one vs. two-plus stories, with vs. without basement), at <em>E<sub>100</sub></em>  and located in A Zone ranging of 0.27–0.98 percent of replacement cost value. The methodology and results generated in this research will benefit homeowners, engineers, surveyors, and community planners in enhancing resilience to the flood hazard in A Zone.</p>

Material quantities and estimated construction costs for new elevated IRC 2015-compliant single-family home foundations

“…Therefore, if CS-4 foundation type is not suitable due to site or design conditions, an open crawl space foundation with stemwalls may be a better choice than slab-on-fill. Raising the first floor elevation above the base flood elevation, also known as freeboard, is a recommended method of flood mitigation and has been shown to be a net benefit to homeowners (Gnan et al, 2022a;Al Assi et al, 2022;Gnan et al, 2022b;Gnan et al, 2022c;Al Assi et al, 2023a;Al Assi et al, 2023b;Friedland et al, 2023). Table 6 shows comparative cost premiums associated with freeboard for each foundation type, reiterating that raised wood floor on CMU piers (CS-4) is the least expensive while 0.3 m CMU stemwall foundation is the most expensive.…”

Freeboard life-cycle benefit-cost analysis of a rental single-family residence for landlord, tenant, and insurer

“…The building AAL (AAL b ) is estimated using the method presented in Gnan (2021) and Gnan et al (2022a). Flood depths derived from Monte Carlo simulations (e.g., Rahman et al, 2002;Brodie, 2013;Qi et al, 2013;Yu et al, 2013;Kind, 2014;Hennequin et al, 2018;Kind et al, 2020;Taghinezhad et al, 2020;Rahim et al, 2021Rahim et al, , 2023 with the fitted Gumbel extreme value distribution (e.g., Singh et al, 2018;Bhat et al, 2019;Kim and Lee, 2021;Manfreda et al, 2021;Mostafiz et al, 2021Mostafiz et al, , 2022bGnan et al, 2022b;Rahim et al, 2022;Al Assi et al, 2023) are translated to building loss percentages using the U.S. Army Corps of Engineers (USACE, 2000) depth-damage function (DDF) designed for the home's attributes (e.g., one-story or two-or-more stories, with or without basement). The loss percentages are then multiplied by the structure replacement cost [i.e., building value (BV)], and the average of the resulting losses of all Monte Carlosimulated flooding events is the AAL.…”

“…Notably, these losses differ depending on whether individuals are homeowners, landlords, or renters. However, existing research on residential flood risk assessment has predominantly focused on the losses faced by homeowners neglecting the losses borne by landlords and renters (Gnan, 2021;Al Assi et al, 2023).…”

Flood Damage and Shutdown Times for Industrial Process Facilities: A Vulnerability Assessment Process Framework

“…Recent studied tend to quantify the average annual loss to represent the flood risk (Al Assi et al, 2023b;2023c;Gnan et al, 2022b;Friedland et al, 2023;Mostafiz et al, 2022c;Quinn et al, 2019;Rahim et al, 2022;Wing et al, 2022). Messner and Meyer (2006) emphasized the importance of spatial scale for flooding characteristics, differentiating macro-, meso-, and micro-scale approaches.…”