Mobile Bay shoreline erosion: bluffs, wakes and wave fetch

Natural waves on this bay are moderate. The plan modeled average annual-storm waves of 0.5 to 0.9 feet about 100 feet offshore. Gaillard Island shelters the shore from the Mobile River to the Theodore Ship Channel in south-wind storms. Mobile County Shoreline Management Plan

• Boat wakes add to the load. Tugboats make up 50 to 80 percent of recorded channel traffic. A passing tow at 14 knots can send waves of about 0.7 feet to the shore between Theodore and Cedar Point. Mobile County Shoreline Management Plan
• On Fowl River, wakes 0.2 to 2 feet high are likely the most damaging waves. They run two to four times the size of wind waves, and most of the channel has no speed control. Fowl River watershed plan
• Vertical bulkheads, about 20 percent of the Fowl River shore, reflect wake energy and scour their own toes. Fowl River watershed plan
• Sea level matters too. The plan reports a sea level trend of 4.43 millimeters a year at Dauphin Island since 1966. NOAA scenarios add 0.98 to 1.64 feet by 2050, measured from 2000. Mobile County Shoreline Management Plan

A lot, and the share keeps growing. Armored shoreline in Mobile County grew from 14 percent in 1974 to 38 percent in 2009. Alabama living shorelines manual On the west shore, bulkhead, revetment and seawall dominate every Mobile Bay segment from Dog River to Cedar Point. Mobile County Shoreline Management Plan

Sources: Alabama living shorelines manual; Alabama living shorelines manual.

The Eastern Shore is heavily walled. In the MBNEP plan's 2009 inventory, about 77,000 feet of roughly 143,800 mapped feet were bulkhead, near 54 percent. MBNEP Eastern Shore plan The Bailey Creek reach between Point Clear and Barnwell was 91 percent bulkhead. MBNEP Eastern Shore plan

Walls can pass the problem along. Hard structures slow erosion but tend to reflect waves onto unprotected neighbors. Alabama living shorelines manual

The Eastern Shore is a bluff coast, and rain and gullies hit the bluff face as well as the waves.

• The MBNEP plan records bank sloughing at Red Bluff in Montrose and shore loss at the Big Mouth Gully mouth. Ecor Rouge, also at Montrose, holds the remains of a wooden boat or pier in the shoreline. MBNEP Eastern Shore plan MBNEP Eastern Shore plan
• Gully sediment loads are large. Red Gully, at Bay Shore Drive, moved 15,590 tons for each square mile of watershed each year, and every site tested beat the natural rate. MBNEP Eastern Shore plan
• After Hurricane Danny in 1997, heavy rain caused landslides along the Eastern Shore and left homes teetering at the bay edge. NWS Mobile Danny page
• On Mon Louis Island, a 2002 bulkhead has failed and a steep bluff collapsed at the Utopia Club reach. Mobile County Shoreline Management Plan

Daphne sets the rule for new building. For new subdivisions and commercial sites, the city requires a 40-foot setback along coastal bluffs. A bluff is a natural landform with at least a 1:2 slope and 10 feet of rise. Daphne ordinance A steep slope there is any slope over 30 percent. Daphne ordinance

At Magnolia Beach in Fairhope, the city had paid for regular beach nourishment rather than build a bulkhead. Rock breakwaters were finished in 2026. Bay Business News FOX 10, September 2026 See the Fairhope guide and the Daphne guide.

The 2025 plan names specific reaches where land is moving fast.

• Hollinger's Island, near Hammock Road: about 3.4 feet a year over the past decade. Mobile County Shoreline Management Plan
• North Salt Aire: about 3.0 feet a year before the reach was armored with rock. Mobile County Shoreline Management Plan
• Mon Louis Island: about 2.8 feet a year in the long term, with a failed 2002 bulkhead at the Utopia Club. Mobile County Shoreline Management Plan
• Coden Belt and Shell Belt roads: about 5.7 feet a year since 1850, now close to zero because of the county's rock revetment. Mobile County Shoreline Management Plan
• Salt Aire marsh: about 415 feet of shoreline lost since the 1930s. Mobile County Commission

Where rock was added, retreat slowed or stopped. The plan still proposes marsh and sills in front of some of it. Armor can stop land loss on one lot and still push the problem along.

The Gulf side of the island is a moving beach, so the town bans hard armor there. Zoning Ordinance 105 allows no seawalls, retaining walls, riprap or similar devices on Gulf-fronting beaches. New development must follow Seawall Ordinance 106, which covers the shore from Fort Gaines to the western tip. Zoning Ordinance 105

The town is bound by ADEM's rules on the Construction Control Line (CCL). Nothing may be built on the Gulf side between mean high tide and the line. Zoning Ordinance 105

From the west end to Fort Gaines, the 200 feet south of mean high tide is closed to new structures. Older ones may stay only if unchanged, and one damaged or destroyed more than 50 percent must go. Zoning Ordinance 105

• West End beaches retreated 260 feet on average from 1957 to 2022. Town West End FAQ
• The fix is sand, not walls: 2,565,000 cubic yards over about 3.5 miles. Town permit application
• The Gulf Coast restoration council approved $38 million for it in 2026. Restoration council notice
• On the bay side, Aloe Bay's two shorelines each lost about 100 feet in 30 years. Town of Dauphin Island

See the west end guide and the bay side guide.

Match the tool to the shore. These are starting points for a conversation with an engineer, not designs.

Sources: Corps note to NWP 13; NWP 54; NWP 13; Mobile County Shoreline Management Plan.

• ADEM requires owners to rule out non-structural options before it approves a bulkhead or riprap. ADEM coastal rules
• State Lands prefers riprap and native plants over vertical seawalls where feasible. State Lands rule
• The Corps recognizes an owner's general right to guard land against erosion, and notes that strong forces can call for walls or riprap. 2026 Nationwide Permits
• A county survey found that erosion was the word owners used most for their shore, and that more than half had bulkheads. Mobile County Shoreline Management Plan

Shoreline protection below high tide needs a Corps permit, requested online, with copies to ADEM and State Lands. ADEM water quality review can take three to six months, and work near federal channels needs a separate Corps review. Mobile County Shoreline Management Plan

Start with the permit map, then read the living shoreline guide and the repair or replace guide. A local marine contractor can follow up when you send a request.