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Little Bay Marsh Restoration and Protection Project

Created by Scott Douglass on Jul 14, 2017  
Role: Other; committee member

General
Construction Cost: 
$50-250K
Construction Dates: 
Actual
Nov, 2010
Bayou LaBatre , AL
United States
30° 22' 59.1384" N, 88° 16' 59.574" W
Alabama US
Pre-Project Conditions
Major Plant Species Present: 
Spartina patens (saltmeadow cordgrass)Other
Submerged Aquatic Vegetation (SAVs) present?: 
No
Bank elevation above MHW: 
1.0 foot
Pre-Construction Erosion Present?: 
Yes
Pre-Construction Erosion at Adjacent Parcels?: 
Yes
Average Nearshore Slope: 
1:0.0
Existing Structures or Debris?: 
No
Environmental Considerations
Name of Waterbody: 
Mississippi Sound - Portersville Bay
Site Classification: 
Straight
Maximum Exposed Fetch Distance: 
15.00 miles
Shoreline orientation relative to max. fetch distance: 
0 Degrees
Tidal Range: 
1.2 feet
Adjacent to Navigation Channel?: 
Yes
Boat wake exposure: 
Low
Project Site Within a Designated No-Wake Zone?: 
No
Salinity: 
Brackish: 0.5 – 30 ppt
Description of Nearby Structures: 
small navigation channel, the entrance channel to Bayou LaBatre, is updrift
100-year Flood Elevation Seaward of the Shoreline: 
19.0 feet
100-Year Flood Elevation Vertical Datum: 
Other
Design Considerations
Was fill brought in?: 
Yes
Type of Fill: 
Sand
Amount of Fill: 
130,000 cubic yards
Proposed nearshore slope: 
1:20.0
Area of shallow bottom conversion to marsh: 
900,000 sq ft
Area of upland conversion to marsh: 
0 square feet
Length of Project: 
5,000 feet
Average Project Width: 
300 feet
Width of Wetlands Above MHW: 
75 feet
Width of Wetlands Below MHW: 
225 feet
Design Criteria: 
Wave Height
Design Wave Height: 
2.5 feet
Structural Elements
Did the project involve a structure?: 
Yes
Type of Structure: 
breakwater
Describe construction materials: 
Individual concrete units, truncated four-sided pyramid-shape, 6-feet tall, 10-foot square base, with large holes in sides. These were called "WADs" for wave attentuation devices. Two rows of units were placed close together with an offset spacing between rows. 200-foot long segments with 40-foot open gaps. One 200-ft segment used shorter, different shaped WADs. Both ends of the breakwater were rock rip-rap.
Average distance of structure offshore (from existing MHW/NHW): 
300 feet
Average distance of structure offshore (from existing MLW/NLW): 
300 feet
Structure Base Width: 
20.0 feet
Length of Structure: 
5,000 feet
Structure Crest Width: 
16.0 feet
Width of Open Water Between Structure and Wetlands: 
100 feet
Structure Side Slope (V:H): 
1:2.0
Structure Monolithic or Layered: 
Layered
Height of Structure Above MHW: 
2.0 feet
Maximum depth at seaward edge of structure: 
4.0 feet
Maximum depth at landward edge of structure (including fill): 
100.0 feet
Drop downs, or openings or overlaps?: 
Yes
Width of drop downs or openings: 
40.0 feet
Spacing between gaps/ drop-downs: 
200 feet
Type of foundation: 
None
Was geotextile used in foundation?: 
No
Porosity of structure: 
High
Non-Structural Elements
Percentage of vegetative cover between structure and MHW line: 
50%
Was erosion fabric used for soil stabilization?: 
No
Primary Wetland species below MHW: 
Spartina alterniflora (smooth cordgrass)Juncus roemerianus (black needlerush)
Primary wetland species above MHW: 
Spartina patens (saltmeadow cordgrass)Other
Root mat developed by vegetation?: 
No
Cross-section width of planted area: 
200 feet
Additional expected ecological benefits from project?: 
oyster recruitement on breakwater units. Shore bird nesting habitat, terrapin nesting habitat,
Project Performance
Overall performance of Living Shoreline for erosion protection?: 
High
Overall performance of the habitat enhancement?: 
High
Describe overall structure and vegetation performance: 
Individual concrete units are differentially settling and vegetation growth has be outstanding
Overall performance of the structure and vegetation?: 
High
Describe overall erosion protection performance: 
excellent
Storm Exposure: 
Yes
Storm Date: 
Tuesday, June 8, 2010
Storm Intensity: 
High
Describe Project Storm Performance: 
Tropical Storm Lee. Design conditions. South winds with limited surge
Describe overall performance for the habitat enhancement: 
excellent. Formal monitoring being done by Dauphin Island Sea Lab
Unforeseen benefits from project?: 
While this was foreseen, the project resulted in no loss of natural marsh to the north in TS Lee.
Other Comments: 
WAD individual units are differentially settling

Performance Reports

Updated Performance
Oct 15, 2014 High
 

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