Dauphin Island East End Beach and Barrier Island Restoration Project. Beau Buhring South Coast Engineers

Dauphin Island East End Beach and Barrier Island Restoration Project Beau Buhring South Coast Engineers

Funding Funded with qualified outer continental shelf oil and gas revenues by the Coastal Impact Assistance Program (AL-28: Dauphin Island Shoreline Stabilization Project), Fish and Wildlife Service, U.S. Department of the Interior

Overview Physical Background Project Description Sand Search Investigation Regulatory Hurdles Design Considerations Construction Phase Beach Monitoring

Background Project Location MOBILE COUNTY BALDWIN COUNTY MOBILE BAY PROJECT LOCATION GULF OF MEXICO PERDIDO BEACH RESORT

Background Coastal Processes Erosion Areas Accretion Areas

Background Site Conditions

Project Description Goals Reduce saltwater intrusion risk to valuable freshwater lake and maritime forest habitat Restore erosional foraging and nesting habitat for birds and sea turtles Introduce beach sands into the littoral drift of the Gulf barrier island Increase longevity of new sand by concurrent use of rock breakwaters

Project Description Benefits Wide beaches provide protection from waves and storm surge to upland properties during tropical events Wide beaches contribute economically, thanks to visitor spending and taxes

Project Description Beach Dredging and placement of ~320,000 cubic yards of beach sand Beach template widths to vary from ~100 feet to ~350 feet Beach nourishment: The placement of large quantities of good quality sand directly on the beach to widen the beach.

Project Description Structures Eight existing, shore-perpendicular, rock groins to be disassembled Three new, shore-parallel breakwaters to be built from old rocks and new stone Structures intended to better retain sand at the eastern end of the project

Sand Search Overview Extensive sand search investigation undertaken in 2010 to identify potential sources of borrow sand Borrow Area Concerns and Priorities Grain size compatibility Proximal to site Free of contaminants Sufficient sand quantity Avoid cultural resources and infrastructure

Sand Search Sampling

Sand Search Compatibility

Sand Search Compatibility Material Source Borrow Area I Borrow Area II East End Native Mean Grain Size Sorting Silt Dry Color (mm) (phi) (phi) (%) Munsell Value 0.26 1.95 0.63 1.3 7 0.23 2.13 0.54 1.4 7 0.28 1.86 0.69 3.6 7

Sand Search Borrow Area

Final Borrow Sub-area

Regulatory Cultural Resources Investigation areas filled with historic shipwrecks Magnetometer and side scan sonar surveying Sub-area identified to minimize cultural impacts Damn the torpedoes! Full speed ahead! - Admiral David Farragut, 1864 (paraphrased)

Regulatory Tribal Concern j ay resté a l isle, que je nomme du Massacre - Pierre Le Moyne d Iberville, 1699 Island has ancient Native American burial mounds Project reviewed by tribal consultant with the U.S. Corps of Engineers

Regulatory Wildlife Concerns Alabama beaches are nesting areas for endangered shore birds and sea turtles Construction activities avoided nesting seasons Lighting surveys after construction Photo: alabamaseaturtles.com

Regulatory Monitoring During construction: dredge position, onsite bird and turtle activity, and turbidity changes due to fill Post-construction: beach profile surveys, aerial photography, compaction testing, and escarpment surveys During Construction Post- Construction Year 1 Year 2 Year 3

Regulatory Mean High Tide Alabama state law requires the municipality to establish a mean high tide line before construction Filled waterbottoms seaward of the mean high tide line are held in trust by the state Identified by survey in a public hearing

Regulatory Property Concerns Alabama state law requires the municipality to obtain by conveyance certain rights necessary to fill areas upland of the new MHT line Property owners included quasi-public entities (Dauphin Island Park & Beach Board and Dauphin Island Sea Lab) and the federal government (U.S. Coast Guard)

Design Beach Fill Estimated and permitted ~320,000 cubic yards of new sand to restore the beaches

Design Beach Fill Profile

Design Breakwater Layout

Design Breakwater Profile

Construction Groin Reclamation

Construction Breakwater Core

Construction Breakwater Armor

Construction Dredge & Pipe

Construction Beach Fill

Monitoring Imagery

Before & After

Monitoring Beach Profiles

Monitoring Beach Surveys

Monitoring Shoreline

Monitoring Compaction Biological opinion required cone penetrometer testing to ensure that the new beach is appropriate for nesting turtles Test results showed that the beach was not too compacted for turtles

Monitoring Escarpments Biological Opinion required postconstruction escarpment surveys to ensure that sea turtles can access the beach First post-construction survey conducted, no major escarpments found

Award Best Restored Beaches

Questions