Flood Risk in US coastal area

When there's severe weather in South Louisiana, New Orleans tends to flood a bit. Due to the thermal expansion caused by the warming of the ocean, the sea levels are rising. The Mississippi River Delta and coastal Louisiana are disappearing quite quickly. Louisiana has lost 2,000 square miles of land since the 1930's, and this is still ongoing. Therefore, by 2050, it's likely that New Orleans might sink underwater.

In 2021, floods and flash floods caused over three billion U.S. dollars worth of property and crop damage across the United States, up from around one billion U.S. dollars worth of damage in the previous year. Nonetheless, the economic damage due to floods and flash floods in the North American country was the highest in 2017, at around 60.7 billion U.S. dollars.

In 2021, there were a total of 146 fatalities reported due to flash floods and river floods in the United States. This was the second highest figure reported in the North American country during the period in consideration. The peak value was recorded in 2015, with a total of 176 lives lost due to floods.

The sea level rising is caused by the ocean thermal expansion and the land ice melting. While the surface height of the ocean rises globally as the planet warms, the impact is not the same for every coastal region. The US east coast face the risk higher than average.

Since there are nearly 4 in 10 U.S. residents live near a coastline, as well as a large part of the U.S. economy is there, the problem of rising sea levels causing increasing flooding on coastal areas cannot be ignored.

Please click on the play button to observe the change in the average number of days per year that coastal cities are affected by flooding。

From the annual flood days forecast for coastal cities in the map, all coastal cities will suffer from flooding more and more frequently, and if no action is taken, these cities will be swallowed by the sea in 50 years. Some research study said nearly 650,000 parcels of oceanfront property in the U.S. that currently sit on dry land will be at least partially submerged within 30 years due to rising sea levels from climate change.

Sliding from left to right, we can see the changes after the arrival of Hurricane Katrina. It can be clearly seen that the darker areas have increased, indicating that these areas were flooded.

Based on elevation, water rise records, and landcover information, it is possible to predict the areas in the New Orleans area that will be affected by flooding by 2050. The red part of the graph shows the areas that are likely to be flooded, and the blue part is the area that may be affected due to the lower elevation.

Based on previous experience, the authorities can conclude which areas will be severely affected. These areas are classified as high risk areas in the forecast and should be considered in planning to avoid the installation of critical infrastructures, also can consider raising the ground in these areas during construction.

In further planning, high-risk areas are delineated in detail in the plan. The AE means low-lying areas that are in close proximity to lakes, ponds and other large bodies of water, and VE means coastal regions that experience annual flash flooding, hurricanes and other weather-related hazards.

These designs allow for more flexible waterfront spaces use across time.