Coastal Flooding Risks on the Rise
Abstract
Coastal communities are increasingly vulnerable to coastal flooding due to rising sea levels. The nonstationary sea level conditions pose planning and management challenges to stakeholders in coastal regions. Understanding the effects of sea level rise on frequency and consequences of coastal flooding and subsequent social and economic impacts are of utmost importance for policymakers to implement effective adaptation strategies. Effective strategies may consider impacts from cumulative losses from minor flooding as well as acute losses from major events. Extreme Value Analysis (EVA) is commonly used to examine infrequent extreme events. However, as sea levels rise, the annual exceedance probability of flood thresholds cannot be fully evaluated using only the upper tail extreme events. In the present study, a statistically coherent mixed Gaussian-GPD method was developed, which reconciles the probabilistic characteristics of the tail as well as the bulk of the sea level data. The frequency of extreme and non-extreme values of maximum daily sea level data were assessed using the Generalized Pareto Distribution (GPD) and Normal distribution respectively. The nonstationary sea level condition was incorporated using the Quantile Regression method to characterize variable GPD thresholds. The framework was employed to assess existing and future coastal minor and major flood frequency in 68 tidal stations across the coastal U.S. The results indicate that as sea levels rise, the frequency of minor and major flooding will subsequently increase along all U.S coastal regions. However, the changes in the frequency of minor and major floods are not geographically consistent. The west Pacific and southeast Atlantic coasts are anticipated to be exposed to higher amplification in major flooding. Conversely, amplification of minor flooding will pose a greater risk in the Gulf and northeast Atlantic coasts. The analysis for 10 major U.S. coastal cities indicates that even small increases in MSL will culminate in substantial increases in the exposure to minor flooding and subsequent damages to assets and communities.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS44B..02G
- Keywords:
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- 1225 Global change from geodesy;
- GEODESY AND GRAVITYDE: 1641 Sea level change;
- GLOBAL CHANGEDE: 4217 Coastal processes;
- OCEANOGRAPHY: GENERALDE: 4556 Sea level: variations and mean;
- OCEANOGRAPHY: PHYSICAL