Sea Level Rise and Flooding

For planning purposes, the county relies upon the Southeast Florida Regional Climate Change Compact's Unified Sea Level Rise Projection for Southeast Florida. Regionally, sea levels are expected to be 14 to 26 inches higher than 1992 levels by 2060.

Miami-Dade County's 3-D sea level rise viewer, which includes a 3-D layer of buildings in the county, allows planners and residents to view the impact of sea level rise, from one foot to six feet.

Miami-Dade County is located in a unique geographical area as it is surrounded by major bodies of water such as the Atlantic Ocean, Biscayne Bay and many rivers, lakes and canals. Rising sea levels lead to other issues including:

Coastal erosion. Sea level rise is increasing coastal erosion rates.

Storm surge. Sea level rise can increase the height of storm surge.

King tide flooding. Sea level rise is causing King Tides to happen more frequently, last longer and extend farther inland.

Urban flooding. Urban flooding can be caused by short-duration, very heavy rain events. Urbanization creates large areas of impervious surfaces (such as roads, pavement, parking lots and buildings) that heavy downpours can exceed the capacity of storm drains and cause floods.

Saltwater intrusion. Rising sea levels cause saltwater to "intrude" further landward into the freshwater Biscayne Aquifer, increasing the vulnerability of the region’s drinking water to saltwater intrusion. Additionally, rising sea levels push salt water further into the Everglades, potentially causing loss of wetland plants and habitat.

Infrastructure impacts. Due to higher water levels in Biscayne Bay, it takes longer to drain roadways when it rains, and some low-lying roads are directly inundated by high tides. Additionally, rising sea levels increase the flood risk for buildings near the coast.

• Septic Systems Vulnerable to Sea Level Rise - Nov. 2018 report

Socioeconomic impacts. Flooding can damage property, interrupt business and increase insurance costs.

As Miami-Dade County works to reduce its carbon footprint and stop fueling climate change, it must also prepare for the impacts that we know are unavoidable, including sea level rise. The County is working to strengthen infrastructure, plan for more resilient communities, enhance natural protections and promote economic resilience through policies and task forces.

• The Sea Level Rise Task Force provided direction for the County’s sea level rise adaptation efforts, resulting in a series of reports:
• Executive summary
• Flooding and saltwater intrusion
• Adaptation action
• Environmentally endangered lands
• Enhanced capital plan
• Climate Change Advisory Task Force
• Resilient transportation system
• Capital Project Overview and the Rapid Action Plan. Miami-Dade County requires that all capital projects consider the impacts of sea level rise, per Resolution No. R-451-14. In 2017, the County assessed the vulnerability of its assets to ensure the capital planning process incorporated changing flood risks due to sea level rise and heightened storm surge. Dubbed the Rapid Action Plan, the project analyzed the vulnerability of more than 700 County-owned assets and evaluated their criticality to departmental operations
• Adaptation Action Areas. The County's pilot Adaptation Action Area was the Arch Creek Basin. In 2016, the Urban Land Institute (ULI) hosted an advisory services panel that produced a final report which focused on the area’s flood challenges. In advance of that panel, the County published a briefing book. In 2015, ULI’s recommendations were taken further through a Resilient Redesign III charrette aimed at enhancing the resilience of three low-lying areas within the Arch Creek basin. The final presentation showcases the ideas of the design teams. In 2017, with support from the Knight Foundation, the County partnered with Citymart to launch a Flood Resilience Challenge
• Local Mitigation Strategy. Local mitigation strategy projects handled by Miami-Dade County Fire Rescue and Emergency Management are designed to reduce our vulnerability to short-term risks like hurricanes and long-term stresses like sea level rise
• Infrastructure improvements include raising roads, installing pump stations, protecting existing buildings with temporary flood panels and building new infrastructures higher. Saltwater intrusion is also being addressed. Salt water is pushing further landward into the fresh water Biscayne Aquifer, which is increasing the vulnerability of the region’s drinking water. Rising sea levels also push salt water further into the Everglades, potentially causing loss of wetland plants and habitat. Salinity control structures have been built at the entrances of major canals to separate fresh water and salt water and canals have been restored through plug barriers. Explore the Sea Level Rise story map to learn more
• Nature-based solutions such as beach renourishment, shoreline restoration for living shorelines like mangroves and dune restoration, protection of open buffer space through parks and the Environmentally Endangered Lands Program, and protection of mangrove forests and other wetlands of the Everglades to provide a protective buffer against storms and long-term sea level rise. The County has also built artificial reefs to keep ecosystems healthy and support fishing industries

Preparing for sea level rise and flooding

• Sea levels have been rising globally and similar changes have been seen in Miami-Dade County.
• Visit the National Oceanic and Atmospheric Administration (NOAA) Coastal Flood Exposure Map to determine if your neighborhood is prone to flooding, vulnerable to storm surge or likely to be affected by sea level rise
• Learn how to protect your home against flooding risks with insurance or protective measures.
• South Florida is a unique geographical area and particularly susceptible to flooding.
• The US Climate Resilience Toolkit from NOAA helps you understand and address your climate risks.

Preparing for storm surge and hurricanes

• Know your Storm Surge Planning Zone
• View projected storm surge depths by hurricane intensity on the storm surge simulator map
• Prepare for hurricanes before, during and after a storm

The Business Case for Resilience

The public and private sectors have a shared interest in investing in proactive flood protection and climate adaptation. In October 2020, the Urban Land Institute (ULI) released a study— “The Business Case for Resilience in Southeast Florida” – commissioned by the Southeast Florida Regional Climate Change Compact and the business community to systematically assess the economic impact of investments in resilience in Miami-Dade, Palm Beach, Broward, and Monroe Counties.

“The Business Case for Resilience in Southeast Florida” seeks to answer key questions about how to respond to flooding from sea level rise, including  the costs and benefits of different adaptation actions, and what actions can be taken today to promote economic resilience.

Key findings include:

• Lack of adaptation investment now will have major consequences for the economic wellbeing of the region. Adaptation implemented now will avoid $3.2 billion in structural losses regionally from tidal inundation in 2040. 
• Additionally, it can protect $7.7 million in tax revenue losses from 10-year storm events and $385 million in tax revenue from daily tidal inundation by 2070. Damage and losses can be reduced. Investing in adaptation provides direct benefits in the form of avoided losses to property, as well as indirect benefits such as reductions in insurance premiums, stable property values, and tax revenues.
• Community-wide adaptation measures have net benefits for the region. Investing in sea walls, dune restoration and beach nourishment, and berm construction provide significant benefits in the form of avoided tax losses and broad economic benefits to the community, demonstrating a 2:1 return on investment (ROI).
• Property and real estate values can be preserved and increase in value with building-level adaptation. The ROI for individual adaptation strategies is 4:1.  
• Jobs and economic activity can be preserved and generated. Adaptation investments will support new construction, operations, and maintenance jobs. 

Key findings for Miami-Dade County:

Building-level adaptations such as floodproofing, elevation, and the addition of permeable surfaces will generate $9 for every $1 invested and support 3,190 job years, which is one job per person each year, through 2040.

Community-wide adaptations, including green infrastructure, sea walls, and dune enhancement, will generate $5 for each $1 invested and support 15,200 job years through 2040.