When does riprap make sense in the Keys?
Riprap fits when the toe of a wall is scouring, when an open-water shoreline is eroding, or when a failing open-water wall cannot be rebuilt as a new vertical wall. Keys codes ask for it first.
Riprap is loose rock, boulders or clean concrete rubble, placed on a slope or at the foot of a wall. It breaks up waves instead of reflecting them.
When should I call about riprap or shoreline erosion?
- The bottom is washing away at the base of your seawall.
- An unwalled shoreline is losing ground after storms.
- Your open-water seawall is failing and you need a plan the code allows.
- Mangroves on your shoreline are undercut or growing into the wall.
How is riprap used on a Keys waterfront lot?
- Toe protection: rock at the foot of a solid seawall. Monroe County places riprap at the toe of solid seawalls to absorb waves and give habitat, and Marathon encourages it. Monroe County code 118-12(k) Marathon code 106.36
- Revetment: a sloped rock shoreline instead of a vertical wall, usually over filter cloth.
- Transition: rock at the base where your wall line does not match a neighbor’s. Marathon uses angled bulkhead lines or riprap for this. Marathon code 106.36
Why do Keys codes favor riprap over new seawalls?
| Where | Rule | Source |
|---|---|---|
Unincorporated Monroe County | Native plants or riprap with filter cloth come before any new canal wall; walls and riprap go landward of mangroves where feasible. | |
Key West | Riprap is the first alternative to hardening; pervious interlocking systems and filter mats preferred; nothing waterward of mean high water except in the public interest; a revegetation program is required. | |
Marathon | Natural boulders or clean rubble 6 inches to 3 feet, no rebar, landward of mangroves, no steeper than 2 to 1, reaching no more than 8 feet from the landward edge or mean low water, with no fill or dredging. | |
Layton | Plan policy requires riprap, plants or cantilevered platforms instead of vertical bulkheads. | |
Key Colony Beach | The opposite approach: seawalls required where allowed, and no sloping seawalls. |
Local guides: Marathon, Key West New Town (the Salt Ponds and Riviera Canal fall under Key West’s shoreline plan rule) and Long Key and Layton. Key West Code 110-181
What are the state riprap limits in the Keys?
| Rule | Limit |
|---|---|
DEP general permit, Rule 62-330.431 Rule 62-330.431 | At the toe of an existing seawall: no steeper than 2 to 1 and no more than 10 feet out. Or up to 100 feet of single-family shoreline, toe within 10 feet of mean high water. Boulders or clean rubble 1 to 3 feet across. No fill on seagrass or coral, no backfill to gain land. |
DEP exemption, Rule 62-330.051(12) Rule 62-330.051(12) | Riprap in artificial waterways and residential canals; restoration up to 18 inches waterward after damage within the last year |
State-owned bottom, Rule 18-21.005 Rule 18-21.005 | Letter of consent for riprap up to 10 feet waterward |
Army Corps benchmark, SAJ-82 (expired) Army Corps permit SAJ-82 | New riprap to 10 feet waterward of mean high water; repairs within 1.5 feet of the old location |
Marine sanctuary Sanctuary nearshore permits | Placing a riprap revetment is on NOAA’s list of work needing sanctuary review |
When two rules differ, the stricter one governs the project. In Marathon, that means the 8-foot city limit, not the state’s 10 feet. Marathon code 106.36
What about mangroves on my shoreline?
Mangrove questions in the Lower and Middle Keys go to DEP, not the county or city, because none of them runs the state mangrove program. DEP delegation list Call DEP Marathon at (305) 289-7070. DEP Marathon office
- Owners may trim mangroves to 10 feet without a permit, never below 6 feet, on shorelines of 150 feet or less. F.S. 403.9326
- DEP treats trimming mangroves growing into a seawall as exempt wall maintenance. Send photos to DEP before you start. DEP mangrove FAQ
- In V and Coastal A zones, altering mangroves in unincorporated Monroe County also needs DEP approval and an engineer’s analysis. Monroe County code 122-27
- Marathon asks owners on developed canals to keep mangroves within 10 feet of mean high water or 20% of the canal width. Marathon Code 36-88
- Key West requires replanting at three to ten times any mangrove habitat affected. Key West Code 110-182
Can I put riprap on a beach in the Keys?
Usually not. Monroe County bars seawalls, riprap and other hardening on or waterward of any beach berm that is a known or potential turtle nesting area. Monroe County code 118-12(k)(7) Marathon has the same bar for nesting beaches and their setback. Marathon code 106.36
Monroe County has no Coastal Construction Control Line. Only its critically eroded sandy beaches fall under the state’s 50-foot setback rule. DEP CCCL page F.S. 161.052
Is a living shoreline an option in the Keys?
On a sheltered shore, maybe. NOAA describes living shorelines as options for sheltered coasts, bays and estuaries, not open-ocean beaches. NOAA Fisheries Wave energy, slope, elevation and the neighbors’ shorelines all shape the design. NOAA Fisheries
The Keys codes already lean this way: the county lists native vegetation before riprap, and Key West requires a revegetation program with any hardening. Monroe County code 118-12(k)(3) Key West Code 110-182(c) Permits still apply. NOAA living shorelines Read the living shorelines guide.
Do I need a permit for riprap in the Keys?
| Where your lot is | Local permit office | What matters for this job |
|---|---|---|
Unincorporated Monroe County | Stock Island (305) 295-3990, Marathon (305) 289-2501, Big Pine Key (305) 289-2877 Monroe County Building, Stock Island Monroe County Building, Marathon Monroe County Building, Big Pine Key | Riprap is permitted under county code 118-12(k), with state or federal approval before the Notice to Proceed. A $10 environmental education fee applies. Monroe County code 118-12(k)(9) Res. 277-2025 |
City of Key West | (305) 809-3956 Key West Building Department | Riprap counts as hardening, allowed only for a critical peril, with approval from other agencies first. Key West Code 110-182(c) |
City of Marathon | (305) 289-5052 Marathon Building Department | The seawall fee rate covers riprap along canals or shoreline. Marathon Res. 2025-73 |
Key Colony Beach | (305) 289-1212, ext. 3 Key Colony Beach Building Department | Seawalls are the city’s required erosion control; ask the building official before planning rock. KCB Code 5-25 |
City of Layton | City Hall (305) 664-4667 Layton City Hall | Start with City Hall. Layton city staff |
What does riprap or toe protection cost?
Riprap is priced by tons of rock, length of shoreline and access. Barge delivery and sanctuary surveys can outweigh the rock itself.
One public Keys number covers a concrete alternative at the toe. Key West’s 2019 seaport bid priced 174 feet of concrete toe-wall footers, anchored to the existing wall, at about $550 to $850 a foot across four bidders. ITB 19-017 bid sheet Key West ITB 19-017
Key West’s funding request for the Southernmost Point seawall paired a new wall with riprap armoring and wave attenuation. Florida Senate LFIR 1134 Build your own budget with the cost guide.
What to ask before you sign for riprap work
- Which rule limits this slope and reach: the city, the county or the state?
- What rock size and type, and will it sit on filter cloth?
- Is there seagrass, coral or hardbottom in the footprint? Who does the survey?
- Are mangroves in the way, and has DEP seen photos?
- Will rock come by barge, and who handles the sanctuary review?
- Is the contractor licensed for revetments? Florida’s marine specialty license covers them. Rule 61G4-15.100
Riprap and shoreline questions
How far out can riprap go in Marathon?
No more than 8 feet from the landward edge or mean low water, at a slope no steeper than 2 to 1. Marathon code 106.36 The state’s toe-riprap permit allows 10 feet, but the stricter rule governs.
Can I use broken concrete as riprap?
Yes, if it is clean and free of rebar. Marathon allows rubble 6 inches to 3 feet, and the state permit 1 to 3 feet across. Marathon code 106.36 Rule 62-330.431
Does riprap need a permit on a canal?
Yes, locally. The state exempts riprap in residential canals, but the county or city permit still applies. Rule 62-330.051(12)
Show sourcesHide sources
- Monroe County Land Development Code, Chapter 118 - Environmental ProtectionSource reviewed 2026-10-28
- LDR Sec. 106.36 Criteria For Approval (Hardened Shorelines)Source reviewed 2026-10-28
- Code of Ordinances, Subpart B Land Development Regulations, Ch. 110 Resource Protection, Art. IV Coastal ResourcesSource reviewed 2026-10-28
- Comprehensive Plan Amendment Package (Ord. No. 2022-11-01), adopted June 1, 2023Source reviewed 2026-10-28
- Code of Ordinances Ch. 5, Art. III Marine Construction and Improvements, Docking of BoatsSource reviewed 2026-10-28
- Rule 62-330.431, F.A.C. (General Permit for Installation of Riprap)Source reviewed 2026-10-28
- Rule 62-330.051, F.A.C. (Exempt Activities)Source reviewed 2026-10-28
- Rule 18-21.005, F.A.C. (Forms of Authorization)Source reviewed 2026-10-28
- Regional General Permit SAJ-82Source reviewed 2026-10-28
- Nearshore Construction PermitsSource reviewed 2026-10-28
- Mangrove Trimming Delegated Local GovernmentsSource reviewed 2026-10-28
- SED Marathon OfficeSource reviewed 2026-10-28
- Section 403.9326, Florida Statutes (2026)Source reviewed 2026-10-28
- Mangrove Frequently Asked QuestionsSource reviewed 2026-10-28
- Monroe County Land Development Code, Chapter 122 - Floodplain ManagementSource reviewed 2026-10-28
- Code Sec. 36-88 Mangrove MaintenanceSource reviewed 2026-10-28
- LOCATE the Coastal Construction Control Line (CCCL)Source reviewed 2026-10-28
- Section 161.052, Florida Statutes (2026)Source reviewed 2026-10-28
- NOAA Fisheries: Understanding Living ShorelinesSource reviewed 2026-10-27
- Building and PermittingSource reviewed 2026-10-28
- Resolution No. 277-2025 (Building Department permitting fee schedule)Source reviewed 2026-10-28
- Building Department - About UsSource reviewed 2026-10-28
- BuildingSource reviewed 2026-10-28
- Resolution 2025-73, Exhibit A Permit Fee ScheduleSource reviewed 2026-10-28
- Building Department and Code EnforcementSource reviewed 2026-10-28
- Contact UsSource reviewed 2026-10-28
- City StaffSource reviewed 2026-10-28
- ITB 19-017 Bids Spreadsheet (attachment to Resolution 19-217)Source reviewed 2026-10-28
- Executive Summary: Awarding of Contract for ITB #19-017 - Seawall Repairs (Resolution 19-217)Source reviewed 2026-10-28
- Local Funding Initiative Request, Fiscal Year 2024-2025, LFIR #1134: Key West Southernmost Point Seawall RepairSource reviewed 2026-10-28
- Rule 61G4-15.100, Certified Specialty Contractors (final rule text, effective 8/28/2024)Source reviewed 2026-10-28