Subjectivity in delta area definition
The study relies on visual interpretation of Google Earth imagery to define delta areas, which introduces subjectivity and potential inconsistencies between researchers.
Simplified delta boundary delineation
The study uses a simplified five-point method to delineate delta boundaries, which may not accurately capture the complex shapes of all deltas. This could affect population estimates and flood risk assessments.
Coarse resolution elevation data
The elevation data used in the study has a coarse resolution (30 arc seconds), which may not adequately capture the micro-topographic variations within deltas. This could lead to inaccuracies in flood risk assessments, particularly in low-lying areas.
Neglecting flood defenses
The 100-year floodplain analysis does not consider the presence of existing flood defenses, which could underestimate the actual flood risk for certain deltas.
Lack of compound flooding analysis
The study does not account for compound flooding events (e.g., the combined effects of storm surge, river discharge, and tides), which can significantly increase flood risk in deltaic environments.
Potential overestimation of population in coastal areas
The population data used (LandScan) extrapolates population to some coastal areas, which may lead to slight overestimation of actual inhabitants.