Seawall raising in Miami

Who needs a seawall raised

Owners whose walls overtop at king tides, owners who have been cited, and owners planning a repair big enough to trigger the city's height rule.

• Water over the cap at high tide
• A city citation for overtopping
• A repair of $300 or more per linear foot in Miami Beach
• Plans to sell, rebuild or add a dock

Two seawall heights split by the Rickenbacker Causeway

The City code text that File 7338 set out to replace puts seawall tops at +5.00 ft NGVD north of the Rickenbacker Causeway and +6.00 ft NGVD south of it, so the same job can have a different minimum depending on which side of the causeway the lot sits. The 2020 proposal would have moved every wall east of US-1 to 6 ft NAVD 88, with the Miami River left to its own section of the code.

A raise is designed to that number, measured in the right datum, and checked by survey before the cap pour.[1]

Miami's flood insurance class

FEMA moved the City of Miami to Class 6 in the Community Rating System in May 2022, worth a 20% discount on most flood insurance policies issued or renewed from 1 October 2022. Flood barriers and vents do not change the city's class, but they protect the building that the policy covers.

Raising the wall stops tidal overtopping, but the home behind it still relies on its own flood protection.[2]

The tide at the Miamarina gauge

NOAA's Miami Miamarina station on Biscayne Bay records a mean tidal range of 2.17 ft and a great diurnal range of 2.37 ft, with mean higher high water about 0.26 ft above NAVD 88 (1983 to 2001 tidal epoch). Those numbers set how far a lift has to travel, how far a floating dock rises and falls, and how much freeboard a seawall cap really has.

Those numbers show how much margin a raised wall really gives above an ordinary high tide.[3]

What makes Miami waterfront work different

Most of Biscayne Bay and its natural tributaries, including the Miami River and Little River, are state-owned submerged lands, so docks over them need the state's consent alongside the DERM permit. The Biscayne Bay Aquatic Preserve is listed by DERM as a permitting contact, and FDEP's free online dock self-certification is not available in aquatic preserves. The federal seagrass range used in dock design reaches central Biscayne Bay.[4][5][6]

City of Miami seawall height

In 2020 the City considered an ordinance (File 7338) to set a 6 ft NAVD 88 minimum for new and rebuilt seawalls east of US-1, outside the Miami River. We have not confirmed that it was adopted, so for every Miami seawall job we confirm the current height rule with the City before design.[1]

Permits in Miami

• Miami-Dade DERM, Coastal Resources Section: Class I permit for any work in, on or over tidal water, the Miami River included, with exempt, expedited and short-form routes for small jobs. Phone (305) 372-6575.
• City of Miami Building Department: Structural and zoning approval for seawalls, docks and lifts inside city limits.
• Florida DEP or South Florida Water Management District: State permit or exemption, and consent to use the state-owned bottom of Biscayne Bay, the Miami River and Little River, which DERM grants for most of the bay on the state's behalf.
• US Army Corps of Engineers, Jacksonville District: Federal sign-off for work in the bay and the river. SPGP VI, the small-project route, passed its stated 27 July 2026 expiry, so we confirm the current route for each job.

Seawall height rules by city

Each city sets its own standard, and they do not all use the same vertical datum (NAVD 88 or the older NGVD 1929), so the engineer's survey must state the wall height in the same datum as your city's rule.

Miami Beach: 5.7 ft NAVD for new walls and substantial repairs, or 4 ft NAVD designed to reach 5.7 ft. Coral Gables: a minimum of 6 ft NGVD 1929, structurally able to support 7.5 ft. Fort Lauderdale: a minimum of 5 ft NAVD88, and walls permitted before 1 January 2035 may be built at 4 ft if designed to reach 5 ft by 1 January 2050. Boca Raton: new or replaced walls between 4.0 and 6.0 ft NAVD88, designed to take another 12 to 18 inches.

City of Miami: a 2020 proposal set 6 ft NAVD 88 east of US-1. We have not confirmed it was adopted, so we check with the City for each job.[9][12][14][15][1]

Help with the cost

Miami Beach's Private Property Adaptation program accepts seawall applications on a rolling basis and reimburses 50% of costs up to $20,000, including the $2,500 assessment value; qualifying low to moderate income households need no match up to $17,500. Homes built at least 1 ft above base flood elevation are not eligible. Coral Gables waives a fee for existing homes raising seawalls for sea level rise.[10][13]

Frequently asked questions