Sea level rise and tidal flooding in Miami

Critical severity. Severe, persistent harm to health, ecosystems or livelihoods. Severity is descriptive editorial metadata summarising documented effects. It is not a measured index or a score.

1. 01

   Global sea level rise

   Thermal expansion of seawater and melting land ice raise mean sea level, documented by tide gauges and satellite altimetry.

2. 02

   Porous limestone bedrock

   Water moves through the underlying limestone, so seawalls alone cannot prevent water emerging inland.

3. 03

   Very low ground elevation

   Much of the metropolitan area sits only a few metres above mean sea level.

4. 04

   Gravity-based stormwater drainage

   Drainage designed to discharge by gravity loses capacity as sea level rises.

1. 01

   Recurrent high-tide flooding

   Streets and low-lying property flood during seasonal high tides without any storm present.

2. 02

   Saltwater intrusion into drinking water

   Salt moving inland through the Biscayne aquifer threatens wellfields that supply the region.

3. 03

   Stormwater and septic system failure

   Higher groundwater reduces drainage capacity and can prevent septic systems from functioning.

4. 04

   Property and insurance pressure

   Repeated flooding affects insurance availability, cost and long-term property value.

1. Stormwater pumps and one-way valves

   Installing pumping and backflow prevention where gravity drainage no longer works.

   Expected effectReduces recurrent tidal street flooding in treated areas.

2. Road and seawall elevation standards

   Raising roads and requiring minimum seawall heights and freeboard for new construction.

   Expected effectProtects specific assets; requires coordination so water is not simply displaced.

3. Aquifer and wellfield protection

   Managing groundwater levels and relocating or protecting wellfields threatened by salt intrusion.

   Expected effectSafeguards drinking water supply for the region.

4. Regional planning with shared projections

   Using common sea level rise projections across counties for infrastructure planning.

   Expected effectAvoids inconsistent standards and poorly matched investment.

Global mean sea level trend

Rising

NOAA and IPCC document ongoing global mean sea level rise. Consult the NOAA Virginia Key tide gauge record for the local trend.

Local aquifer

Biscayne aquifer

The shallow, highly permeable Biscayne aquifer is the region's primary drinking water source and is vulnerable to saltwater intrusion.

1. [1]Sea Level Rise Technical Report (NOAA sea level rise portal)NOAA / US Interagency Sea Level Rise Task Force · Feb 2022oceanservice.noaa.gov(opens in a new tab)
2. [2]Unified Sea Level Rise ProjectionSoutheast Florida Regional Climate Change Compact · Jan 2019southeastfloridaclimatecompact.org(opens in a new tab)
3. [3]Saltwater intrusion in the Biscayne aquiferUnited States Geological Surveyusgs.gov(opens in a new tab)

Links open the publishing organisation's site. Some point to the publisher's main page, where the named report or dataset can be found.