Year 2004 Restoration Projects

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Year 2004
CRP Projects

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Project #3002

CRP #3002 Project Proposal

Habitat Restoration in the Saw Grass Point Salt Marsh:
the use of constructed reefs to minimize the
negative effects of boat wash and erosion

Applicant Information
Auburn University
150 Agassiz Street
Dauphin Island, AL 36528

Project Contact
LaDon Swann, Director
Mississippi-Alabama Sea Grant Consortium
150 Agassiz Street
Dauphin Island, AL 36528

Project Information

1. Project Title: Habitat Restoration in the Saw Grass Point Salt Marsh: the use of
constructed reefs to minimize the negative effects of boat wash and erosion

2. Acres to be restored: 2.25 acres

3. Project Location: Dauphin Island, Mobile County, Alabama Global Positioning System coordinates: N 30o 15.137’ W 88o 04.958’

4. Land Ownership: Town of Dauphin Island

5. Type(s) of habitat: Salt Marsh and Oyster Reef

6. Anticipated NOAA Trust Resource to benefit from restoration:
Atlantic croaker (Micropogon undulates) Speckled trout (Cynoscion nebulosus)
Black drum (Pogonias cromis) White trout (Cynoscion arenarius)
Red drum (Sciaenops ocellata) Sheephead (Archosargus probatocephalus)
Southern kingfish (Menticirrhus americanus) Pinfish (Lagodon rhomboids)
Naked goby (Gobiosoma bosci) Blue crab (Callinectes sapidus)
Striped blenny (Chasmodes bosquianus) Stone Crab (Menippe adina)
Oyster toadfish (Opsanus tau) Eastern oyster (Crassostrea virginica)
Skilletfish (Gobiesox strumosus) Cordgrass (Spartina sp.)
Shrimp (various species) Black rush (Juncus roemerianus)
Marsh elder (Iva frutescens) Groundsel tree (Baccharis halimifolia)
Wax myrtle (Myrica cerifera)

Project start date: December 19, 2020

Project end date: December 18, 2020

Partners involved: Town of Dauphin Island, Mobile County Commission, Auburn
University Shellfish Laboratory, the Mississippi-Alabama Sea Grant Consortium,
Bridgestone Firestone Cooperation, Dauphin Island Cub Scout and Boy Scout Troops, ExxonMobil, Mobile Bay National Estuary Program

Identification of required Federal, state, or local permits required:
a. U.S. Army Corps of Engineers and Alabama Department of Environmental
Management joint 404 Permit and Section 10 permits
b. Alabama Marine Police approval for breakwater installation.
c. Letter of Consent from Alabama Department of Conservation and Natural
Resources, State Lands Division
d. Project review by Alabama Department of Conservation and Natural Resources,
Marine Resources Division.

Project Introduction
Dauphin Island, Alabama is a barrier island located at the western side of the mouth of Mobile Bay. On the northeast end of Dauphin Island is Alonzo Landing, located in Fort Gaines Harbor. The landing serves as one of the Island’s two primary access points for recreational boats and provides quick access to the Gulf of Mexico. Pilot Boats for the Mobile Ship Channel, ExxonMobil Crew Boats, and the Mobile Bay Ferry navigating between Dauphin Island and Fort Morgan dock at Alonzo Landing.

The Dauphin Island Sea Lab and the U.S. Coast Guard also have docking/mooring facilities within Fort Gaines Harbor. Numerous private and commercial vessels navigate through Pass Drury Channel in route to the Dauphin Island Marina or private docks on the Bay side of Dauphin Island.

Although there is a no-wake zone in Fort Gaines Harbor and Pass Drury Channel, this area of high boat traffic creates coupled with frequent strong easterly winds, has led to erosion in nearby environmentally sensitive areas (Dr. Judy Stout, The University of South Alabama).

One of these, Saw Grass Point Salt Marsh, is immediately West of the ferry landing. This saline tidal marsh, one of only two on Dauphin Island, consists of 25.12 acres of wetlands bordered to the south by 2.68 acres of pine savannah. The Saw Grass Point Salt Marsh is separated from Little Dauphin Island on the north by the approximately 200 ft wide Pass Drury Channel. Little Dauphin Island has been identified
as important bird habitat and is part of the Bon Secour National Wildlife Refuge (BSNWF) which is a Gulf Ecological Managed Site (GEMS). Although not part of the BSNWF, the Saw Grass Point Salt Marsh has been identified by the Alabama Department of Conservation and Natural Resources-Division of Marine Resources, the Town of Dauphin Island, and the Dauphin Island Bird Sanctuaries, Inc., and as an area in need of protection (Dauphin Island Bird Sanctuaries 2003).

The Town of Dauphin Island has conceptual plans for developing part of Fort Gaines Harbor. The initial plan includes a marina, store, walkways and other amenities to provide services and promote tourism in the area of Alonzo Landing (Figure 2). The benefit of this proposed restoration effort is not only compatible with any capital improvements to Alonzo Landing, it provides additional justification for the project.

Scope of Work
Coastal wetlands currently make up about 30% of the wetlands in the lower 48 states and since the 1700s more than half of all wetlands in the lower 48 states have been lost ( Similar, more than 12,000 acres (-29% change) of non-freshwater wetlands in Mobile Bay were lost between 1955 and 1979 (Roach, Wazin, Scurry, and Johnston, 1987). Implementation of this project would result in restoring 2.25 acres of saline wetlands on Dauphin Island.

There are four interconnected project objectives. The objectives include the following:

  1. Removal of four derelict vessels along the southeastern edge of Saw Grass Point Salt Marsh.
  2. Create and monitor constructed breakwaters along the eastern edge of the Saw Grass Point Salt Marsh.
  3. Replant and monitor marsh grasses and native woody plants behind the newly established breakwaters.
  4. Provide educational opportunities and foster community participation in the restoration project.

Objective 1: Removal of four derelict vessels along the southeastern edge of Saw Grass Point Salt Marsh.

Currently, there are three semi-submerged derelict boats next to the southeastern edge of Saw Grass Point Salt Marsh and one metal derelict vessel in the marsh. These derelict boats are impeding the natural tidal fluctuations essential to the eastern end of the salt marsh.
We will utilize volunteers and in-kind match support from the Town of Dauphin Island and the Mobile County Commission to remove these vessels. The Alabama Department of Conservation and Natural Resources, Division of Marine Resources has estimated the average cost to remove numerous vessels in Mobile Bay and Mississippi Sound at $8,000 per vessel. For the purpose of budgeting we will use $5,000 per vessel.

Objective 2: Create and monitor constructed breakwaters to serve as oyster reefs along the eastern edge of the Saw Grass Point Salt Marsh.
Once the vessels are removed, emergent breakwaters 20 ft in diameter and on 10 ft centers will be constructed approximately 60 ft from shore (Figure 4). Breakwaters will be constructed of non-toxic materials consisting of limestone or concrete rubble. Preference will be given to rock; however, material costs may require the use of cheaper concrete rubble. Each 20 ft in diameter breakwater will be approximately 4 ft tall and be placed in water approximately 3 ft deep.
Individual components for each breakwater will range in size from 200-400 pounds. The average volume of each conical shaped breakwater will be 15 yd3 (total: 450 yd3). Assuming a 6 linear distance of 900 ft and a diameter of 20 ft per breakwater on 10 ft centers, then 30 staggered breakwaters will be required.
Installation of breakwaters is a major cost of the project and will be contracted to the lowest bidder. Once the breakwaters are in place, 2000 spat-on-shell oysters obtained from the University of South Alabama Oyster Restoration project or the Mobile Bay Oyster Gardening program (both obtain spat from the Auburn University Shellfish Laboratory) will be placed over each breakwater (60,000 spat). The breakwaters will provide excellent hard substrate for juvenile oysters and they will help to reinforce the breakwater. At some point after the breakwaters are established, we expect sediment accretion to occur behind the breakwaters.
Marsh grass plantings outlined under Objective 3 are expected to expand into the areas of newly deposited sediment.

Objective 3: Replant and monitor marsh grasses and native woody plants behind the newly established breakwaters.
Behind the created breakwaters, native marsh grasses will be planted. Along the shore, where a buildup of sediment has occurred, native woody vegetation will be planted to stabilize the shoreline and to provide wildlife habitat. Juncus sp. and Spartina sp. plugs will be transplanted from existing marsh grass areas within the Saw Grass Point Salt Marsh (Figure 4). Marsh elder (Iva frutescens) and groundsel tree (Baccharis halimifolia), and wax myrtle (Myrica cerifera) will be obtained from nurseries and planted along the “high ground” built-up as a result of sediment deposition (Figure 4). The woody plantings will provide wildlife habitat and help to stabilize the perimeter of the eastern edge of the Marsh.

Objective 4: Provide educational opportunities and foster community participation in the restoration project.

Educational Opportunities
The education potential is tremendous and the beneficiaries numerous from a successful implementation of this project. Each year more than 75,000 people visit the Dauphin Island Sea Lab Estuarium with many of them accessing Dauphin Island by way of the Mobile Bay Ferry (Robert Dixon, personal communication). In 2000 the ferry had 162,732 passengers and 64,679 vehicles. Of this total 10,014 were walk-ons. Just across Bienville Boulevard is the camp grounds operated by the Dauphin Island Park and Beach Board. Just west of Alonzo Landing is the Audubon Bird Sanctuary where approximately 10,000 people used the area in 1996 (Kerlinger 1997). Restoration of the eastern edge of the Saw Grass Point Salt Marsh will provide Island visitors with an opportunity to view a large functional salt marsh and learn how important salt marshes and oyster reefs are to the flora and fauna in Mobile Bay and offshore habitats.

The learning opportunities will be provided through a boardwalk and viewing platform through the marsh which originates from the southeast edge of the marsh (Figure 1). The boardwalk will have finished dimensions of 150 ft long by 8 ft wide. The uncovered boardwalk will also have railings on both sides and will be handicapped accessible (Figure 5). The boardwalk will follow state environmental guidelines on height above the marsh and spacing between individual boards to ensure no damage to marsh vegetation underneath boardwalk. At the end of the boardwalk will be a viewing platform with interpretative signs. Other signage will provide information on the value of oyster reefs and will include the life cycle of the Eastern oyster. In addition to the learning opportunities resulting from the boardwalk, the Dauphin Island Elementary School, the local Boy Scout Troop, the Dauphin Island Sea Lab Discovery Hall Program, and various ecology classes and the University of South Alabama will use the marsh to learn more about local ecological habitats (personal communications with local teachers, troop leaders, and faculty).

The project coordinator will coordinate the development of a wetlands fact sheet specific for Mobile Bay using relevant data from this project. The educational product will be developed in collaboration with Dauphin Island Sea Lab faculty (Drs. Ken Heck and Just Cebrian), the designated NOAA Community Based Restoration Program Outreach Coordinator, the designated Gulf of Mexico Foundation Outreach Coordinator, the Mon Louis Island GEMS Coordinator, the Mississippi-Alabama Sea Grant Consortium (MASGC) Communications Coordinator the Sea Gant Extension Program Leaders and the MASGC funded wetlands specialist (Dr. Mark LaSalle). Finally, news releases and other news information will be produced during each major phase of the project (vessel removal, breakwater creation, and plantings).

Community Participation
Community involvement will focus on two primary aspects of the project. First, the Dauphin Island Sea Lab graduate student association and the local Boy Scout Troop will assist in the initial phase of removing the four derelict vessels (Figure 3). In this phase, the Mobile County Commission will provide in-kind match by providing a dumpster and loader to dispose of the derelict vessels. Overall, coordination of the vessel removal will be provided by the project coordinator. It is estimated that approximately 300 hours of volunteer time will be necessary to remove all four vessels.

The second area of volunteer involvement will be to assist with the plantings of native wetland plants once the restoration site is prepared. The local Cub Scout Dens and Boy Scout Troop will assist with this phase of the project. A local Eagle Scout candidate is required to complete a community service project for his Eagle Scout Badge. The Scout and his family have expressed interest in this project. If acceptable approved by his Scout Master and Council, the Eagle Scout candidate will coordinate the plantings. The local elementary school science classes will also assist with the plantings. Dauphin Island residents will also volunteer with the plantings. The volunteer time required to complete the plantings is estimated to be 100 hours.

Project Evaluation and Monitoring
Project evaluation will be based on monitoring the viability of the created breakwaters and growth of the plantings along the shoreline. Auburn University Shellfish Laboratory personnel will collaborate in the monitoring phase of the project with the University of South Alabama faculty responsible for administering a Federal shellfish grant. Evaluation of the project will occur during project implementation with follow-up evaluations at six-month intervals for two years following the completion of the project.

The project evaluation/monitoring will be conducted using the following procedure:

  1. Diving the constructed breakwaters to quantify the extent of oyster colonization on the breakwaters.
  2. Comparing baseline water depth data with sediment accretion behind the breakwaters.
  3. Monitoring plant growth of new plantings and their spread onto any newly deposited sediments behind breakwaters. Plant growth into restored areas will be monitored using appropriate scientific methods such as photo points before and after restoration to determine percent cover.
  4. Information from this monitoring program will be shared with the Gulf of Mexico Foundation and data will be used in the development of the wetlands fact sheet described under the education section of this proposal.

Long-term Management
Long-term management of the restored site will be the responsibility of the Town of Dauphin Island. The State Lands Division of the Alabama Department of Conservation and Natural Resources owns the land and has a provided a long-term lease of the property to the Town of Dauphin Island. The funds used to purchase the property came from the Federal Coastal Impact Assistance Program that used funds derived from offshore from oil and gas tax revenues. There is expected to be very little management required for the completed project. Most management of the project will involve maintenance of the boardwalk and interpretative information.

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