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1. Recognizing flood exposure inequities across flood frequencies

   https://doi.org/10.1016/j.ancene.2023.100371  

   Selsor, Haley; Bledsoe, Brian P.; Lammers, Roderick (June 2023, Anthropocene)

   Urban flooding is a growing threat due to land use and climate change. Vulnerable populations tend to have greater exposure to flooding as a result of historical societal and institutional processes. Most flood vulnerability studies focus on a single large flood, neglecting the impact of small, frequent floods. Therefore, there is a need to investigate inequitable flood exposure across a range of event magnitudes and frequencies. To explore this question, we develop a novel score of inequitable flood risk by defining risk as a function of frequency, exposure, and vulnerability. This analysis combines high-resolution, parcel-scale compounded fluvial and pluvial flood data with census data at the census block group scale. We focus on six census tracts within Athens-Clarke County, Georgia that are highly developed with diverse populations. We define vulnerable populations as non-Hispanic Black, Hispanic, and households under the poverty level and use dasymetric mapping techniques to calculate the over-representation of these populations in flood zones. Inequitable risks at each census tract (approximately neighborhood scale) were estimated for multiple (e.g., 5-, 10-, 20-, 50-, and 100-year) flood return periods. Results show that the relatively greatest flood risk inequities occur for the 10-year flood and not at the largest event. We also found that the size of inequity is dynamic, depending on the flood magnitude. Therefore, addressing a range of events including smaller, more frequent floods can increase equity and reveal opportunities that may be missed if only one event is considered. 

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2. Flood Monitoring and Mitigation Strategies for Flood-Prone Urban Areas

   https://doi.org/10.1109/SIEDS49339.2020.9106583  

   Finley, Pat; Gatti, Grayson; Goodall, Jonathan; Nelson, Mac; Nicholson, Kiri; Shah, Kruti (April 2020, 2020 Systems and Information Engineering Design Symposium (SIEDS))
3. The complexities of urban flood response: Flood frequency analyses for the Charlotte metropolitan region: THE COMPLEXITIES OF URBAN FLOOD RESPONSE

   https://doi.org/10.1002/2016WR019997  

   Zhou, Zhengzheng; Smith, James A.; Yang, Long; Baeck, Mary Lynn; Chaney, Molly; Ten Veldhuis, Marie-Claire; Deng, Huiping; Liu, Shuguang (August 2017, Water Resources Research)
4. Heading for the Hills? Effects of Community Flood Management on Local Adaptation to Flood Risks: Management and Adaptation to Flood Risks

   https://doi.org/10.1002/soej.12340  

   Noonan, Douglas S.; Liu, Xian (January 2019, Southern Economic Journal)

   The Community Rating System (CRS) program was implemented by the U.S. Federal Emergency Management Agency (FEMA) in 1990 as an optional program to encourage communities to voluntarily engage in flood mitigation initiatives. This article uses national census tract-level data from 1980 to 2010 to estimate whether CRS participation and flood risk affect a community's local patterns of population change. We employ an instrumental-variables strategy to address the potential endogeneity of CRS participation, based on community-scale demographic factors that predict when a tract’s host community joins the CRS. The results find significant effects of the CRS program and flood risk on population change. Taken together, the findings point to greater propensity for community-scale flood management in areas with more newcomers and programs such as CRS stabilizing population, though not especially in flood- prone areas. We observe the CRS neither displacing population toward lower-risk areas nor attracting more people to flood-prone areas. 

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5. Process-based flood frequency analysis in an agricultural watershed exhibiting nonstationary flood seasonality

   https://doi.org/10.5194/hess-23-2225-2019  

   Yu, Guo; Wright, Daniel B.; Zhu, Zhihua; Smith, Cassia; Holman, Kathleen D. (January 2019, Hydrology and Earth System Sciences)

   Abstract. Floods are the product of complex interactions among processes includingprecipitation, soil moisture, and watershed morphology. Conventional floodfrequency analysis (FFA) methods such as design storms and discharge-basedstatistical methods offer few insights into these process interactions andhow they “shape” the probability distributions of floods. Understanding andprojecting flood frequency in conditions of nonstationary hydroclimate andland use require deeper understanding of these processes, some or all ofwhich may be changing in ways that will be undersampled in observationalrecords. This study presents an alternative “process-based” FFA approachthat uses stochastic storm transposition to generate large numbers ofrealistic rainstorm “scenarios” based on relatively short rainfall remotesensing records. Long-term continuous hydrologic model simulations are usedto derive seasonally varying distributions of watershed antecedentconditions. We couple rainstorm scenarios with seasonally appropriateantecedent conditions to simulate flood frequency. The methodology is appliedto the 4002 km2 Turkey River watershed in the Midwestern United States,which is undergoing significant climatic and hydrologic change. We show that,using only 15 years of rainfall records, our methodology can produce accurateestimates of “present-day” flood frequency. We found that shifts in theseasonality of soil moisture, snow, and extreme rainfall in the Turkey Riverexert important controls on flood frequency. We also demonstrate thatprocess-based techniques may be prone to errors due to inadequaterepresentation of specific seasonal processes within hydrologic models. Ifsuch mistakes are avoided, however, process-based approaches can provide auseful pathway toward understanding current and future flood frequency innonstationary conditions and thus be valuable for supplementing existing FFApractices. 

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