Soil loss and sinkholes behind Gulf Shores walls:
find the leak before you fill the hole

Why is there a sinkhole behind my seawall?

Water is carrying sand out through gaps, drain holes or the bottom of the wall, and the ground drops where it left.

• Open joints or holes in the wall face let fines escape.
• Rain and runoff flow to the edge and cut channels.
• Failed anchors let the wall move, which opens gaps.
• Scour at the toe undercuts the base so soil slides out.

Find the path out, close it, then restore the soil.

Safety first

Keep children, pets and vehicles away. Loose dirt dumped in the hole hides the void and washes out again.

What should you do in the first hours?

Make the area safe, record it, then call.

1. Mark the area. Use cones, tape or chairs to keep people back.
2. Photograph it. Take wide and close shots with something for scale. Note the tide stage and time.
3. Check utilities. Look for exposed pipes, wires or irrigation lines.
4. Call a marine contractor. Ask for a visit and a written cause.
5. Call the permit office. Gulf Shores is at (251) 968-1150; Baldwin County is at (251) 972-6837. Gulf Shores Building Department Baldwin County Building Department

If lives or property face real danger, the Corps may approve emergency repairs right after your first contact. Alabama general permit 15 ADEM may approve emergency actions without prior notice, for no more than 120 days. ADEM rule 335-8-1-.07

How to trace the leak

Follow the water. A leak path leaves a clue at the surface and another at the wall.

1. Walk the wall at low tide. Look for sand fans, wet streaks or gaps on the water side.
2. Watch a heavy rain. See where runoff meets the edge.
3. Trace the drains. Check downspouts, pool drains and irrigation.
4. Map the dips. Mark low spots with flags and photograph them.
5. Tell the contractor. Share your notes. They narrow the search.

Gulf Shores lets lots drain directly into Little Lagoon or the Intracoastal Waterway only when it causes no erosion, undermining or silting. Gulf Shores Code Sec. 7-108

What causes soil loss in salt and brackish water here?

• Rain on saturated ground. The rain from Ivan fell on ground already soaked by earlier storms. National Hurricane Center Ivan report
• Reverse flow after a storm. On the bay side, one gauge on Mobile Bay fell about 10.6 feet within roughly 20 hours after Sally. National Hurricane Center Sally report
• Boat wake. Constant slap loosens joints on the Intracoastal and canals.
• Corrosion. Salt eats steel panels, tie rods and fasteners.

Water trapped behind a wall can push it out when levels drop fast, so a lean can follow a washout.

Which fix matches the soil loss?

Read foam injection and tiebacks and anchors to compare.

What backfill rules apply in Gulf Shores?

Fill must be clean sand. Gulf Shores bans red, pink, yellow and brown clay and sand-clay fill. Gulf Shores Code Sec. 7-21

• Ask the contractor where the sand comes from.
• Keep delivery tickets.
• The city must approve changes to drainage and grading on any lot. Gulf Shores Code Sec. 7-33
• In zones A and AE, fill must not raise flood levels. Gulf Shores Code Sec. 7-88

Permits for soil and drainage work

Grading, filling and excavating usually need a city permit. Gulf Shores Code Sec. 7-106

• Where a building permit is also needed, the city approves a grading and drainage plan first and needs no separate land-disturbing permit.
• Work that touches the wall or the water also needs the Corps and State Lands.
• Baldwin County charges $25 per activity for filling, grading and excavating. Baldwin County Planning and Zoning fees

The bulkhead permit guide covers the Corps and State Lands steps. Gulf Shores Planning and Zoning is at (251) 968-1164. Gulf Shores Building Department FAQ

What does soil and drainage repair cost?

Cost depends on the cause. Drainage fixes cost little. Anchors and rebuilds cost a lot.

Sources: Baldwin County bid tabulation

The first three come from national or Texas contractor guides. The last is a public Baldwin County bid. See the bulkhead cost guide.

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Questions to ask a contractor

• What is the path the soil is taking out?
• How will you stop it before you fill?
• What backfill will you use and where does it come from?
• How will you compact it, and how will we check for settling?
• Do you plan weep holes, filter fabric or a drain?
• What permits apply, and who files them?

Where do owners ask about soil loss?

• Old-town canals, where shallow canal lots sit close to the water.
• Little Lagoon north shore, where the Mo's Landing bulkhead is failing. City RFQ for Mo's Landing
• Little Lagoon south shore, where Pine Beach road erosion has been repeated. Fish and Wildlife Service notice
• Waterway Village, where Intracoastal wake loosens joints.
• Fort Morgan bay side, where bay blowouts stress walls.

Soil loss questions answered

Why does my lawn keep sinking behind the wall?

Soil is leaving through the wall or from the bottom. Refilling without finding the path will repeat the problem.

Can I fill the hole with dirt?

Not safely. Loose dirt hides the void and washes out. Use clean sand, compact it and fix the leak first.

Is a sinkhole an emergency?

If it is large, growing or near a structure, treat it as one. Mark it, photograph it and call a contractor and the permit office.

Will insurance cover it?

The usual federal flood policy form leaves seawalls and bulkheads out. NFIP policy form Check your homeowner policy and see the insurance guide.

If a contractor proposes foam, read the foam injection guide first. It explains what foam can and cannot fix.