Seawall replacement in Miami

When replacement makes sense

Replacement is the answer when panels are cracked through, the wall leans, repairs would cost more than half of a new wall, or the wall is too low for your city's new standard.

• Panels cracked through or leaning
• Repeated sinkholes despite repairs
• A city notice to raise or rebuild
• Planned dock or lift work that needs a sound wall

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 replacement wall is built to the current height from the start, so the panels, piles and cap are sized for it.[1]

What DERM charges in Miami

A DERM short-form permit costs $470 plus $25 for each $1,000 of construction above $10,000, and every fee carries a 7.5% surcharge. A seawall cap or tie rod job on DERM's expedited track has a $75 review fee, and after-the-fact applications for work already done pay double.

A full replacement needs the complete permit set, so we start on drawings and surveys early.[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.

The tide also sets how much of the wall can be worked on dry at low water, which changes crew time.[3]

What would count as a substantial repair

The 2020 Miami proposal defined a substantial seawall repair three ways: work on 50% or more of the barrier length, work costing 50% or more of a new wall, or a change in elevation along 50% or more of the length. It also asked for new walls that can be raised to at least 8 ft NAVD 88 later, with a variance route for undue hardship.

Knowing where that line sits lets you choose between a repair now and a full raise later with your eyes open.[1]

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.[2][4][5]

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.

What a seawall replacement involves

A Florida engineer designs the wall to the site's soil, water depth and the local top elevation. Most replacements go in front of the old wall, which stays in place as backing, because removing it can undermine the yard.

1. Survey and engineered drawings
2. DERM, city and state approvals
3. Turbidity barrier and manatee watch in the water
4. New panels or sheet piles, tiebacks and cap
5. Backfill, drainage and yard restoration

How far out can the new wall go?

Florida Statute 403.813 exempts restoring a seawall at its previous location, upland of it, or within 18 inches waterward of it. Miami-Dade's short form and the federal SPGP VI use the same 18 inch line, measured wet face to wet face, and need no seagrass survey within it.[7][2][5]

Federal permits

Under SPGP VI, the Florida DEP could verify the federal Army Corps authorisation for qualifying seawall work along with the state decision. That permit's stated expiration date was 27 July 2026, and we have not been able to confirm a replacement, so for each job we confirm the federal route with the agencies before we file.[5][11]

Working around manatees

Permits attach the state's Standard Manatee Conditions: all in-water work stops if a manatee comes within 50 ft, and resumes only once it has moved beyond 50 ft or 30 minutes pass without it reappearing. Turbidity barriers must not entangle or block manatees.[12]

Frequently asked questions