Glynn County Public Works, Installation of Culvert Extensions and Headwalls, Sea Island Road, Tidal Drainage Ditch, Glynn County, Georgia


This serves as notification from the Coastal Marshlands Protection Committee and the Georgia Department of Natural Resources of a request from Glynn County Public Works for a Coastal Marshlands Protection Act (CMPA) permit under Official Code of Georgia (O.C.G.A.) 12-5-280 et seq., to install culvert extensions and headwalls in a tidally influenced county-maintained drainage ditch, Glynn County, Georgia. The proposed project is under 1/10 of an acre, and therefore may be considered a minor alteration of coastal marshlands under O.C.G.A. 12-5-280 et. seq.

The applicant is proposing to construct a new concrete sidewalk parallel to Sea Island Road from Demere Road to Hamilton Road. A portion of the sidewalk will be in an area that is currently a tidally influenced, county-maintained drainage ditch subject to jurisdiction of the CMPA. Activities on the southern end of the project area, near Demere Road, include extending an existing culvert, construction of a headwall, and placement of fill material to construct a sidewalk. Activities on the northern end of the project area, near Hamilton Road, includes the replacement of existing drainage pipes, installation of a new headwall on an existing culvert and the placement of rip rap for erosion control.

The marshlands component of the proposed project consists of a 0.01-acre portion of an existing tidal drainage ditch. The upland component includes all activities occurring within the 50ft. marshlands buffer along the ditch which totals 0.2-acres and consists of a maintained grassy road shoulder adjacent to Sea Island Road. 

The proposed culvert extension on the southern end of the project area includes installing two (2)16ft. culvert extensions (8cy.), a new headwall (2cy.), and rip rap installed over filter fabric at the opening of the culvert extension (10cy.). Once the extension project is complete, approximately 35cy. of general fill material will be used to bring the impacted area up to grade for the sidewalk construction. Total fill in coastal marshlands in the southern end of the project area will be 55cy.

The proposed headwall installation on the northern end of the ditch will consist of the replacement of three (3) existing drainage pipes (3cy.), constructing a new headwall (2.5cy.), and placement of associated rip rap (12cy.). Once the headwall is constructed, 5cy. of general fill material will be used to backfill around the structure. Total fill in coastal marshlands in the northern end of the project area will be 22.5cy.

Work will be performed by utilizing a backhoe to excavate wet soils existing headwalls, and for the placement of a stone base layer and new culvert extensions. The headwalls will be cast-in-place concrete and will be backfilled using regular fill dirt and rip rap around the sides of the pipes in order to stabilize the slopes.

The proposed activities within the upland component will consist of approximately 330 square yards of 4ft. paved shoulder widening of Sea Island Road, a sidewalk  measuring approximately 695ft. x 8ft., approximately 1,650 linear feet of silt fence, 22cy. of rip rap material for the installation of erosion and sedimentation control measures, and temporary impacts associated with construction. All temporary impacts within the 50ft. coastal marshlands buffer will be restored to the preconstruction state. Discharged stormwater from the upland component of the project will be managed according to the policy, criteria, and information including technical specifications and standards in the Coastal Stormwater Supplement to the Georgia Stormwater Management Manual.

It is the responsibility of the applicant to demonstrate that the project is not contrary to the public interest and that no feasible alternative sites exist. Impacts to coastal marshlands must be minimal in size. In passing upon the application for permit, the Coastal Marshlands Protection Committee shall consider the public interest: (1) Whether or not unreasonably harmful obstruction to or alteration of the natural flow of navigational water within the affected area will arise as a result of the proposal; (2) Whether or not unreasonably harmful or increased erosion, shoaling of channels, or stagnant areas of water will be created; and (3) Whether or not the granting of a permit and the completion of the applicants proposal will unreasonably interfere with the conservation of fish, shrimp, oysters, crabs, clams, or other marine life, wildlife, or other resources, including but not limited to water and oxygen supply.

A detailed public notice with drawings has been distributed and is available by visiting the Department of Natural Resources website: under “Marsh & Shore Permits.” Please provide this office with substantive, site-specific comments as to why the proposed work should or should not proceed.  Comments and questions concerning this proposed project should be submitted in writing and be submitted by the close of business on May 25, 2020 to Paul Tobler, Department of Natural Resources, 1 Conservation Way, Brunswick, Georgia 31520.

Click here for the Application.

Click here for the Project Description.

Click here for Project Drawings.

Click here for Site Photos.