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This serves as notification from the Coastal Marshlands Protection Committee and the Georgia Department of Natural Resources of a request from Mapache, LLC for a Coastal Marshlands Protection Act (CMPA) permit under Official Code of Georgia (O.C.G.A.) 12-5-280 et seq., to construct a tidal wetland mitigation bank located between Umbrella Creek and the Satilla River, Camden County, Georgia.
The applicant proposes to construct the Isla de Mapache Mitigation Bank, in accordance to the proposed “Banking Instrument, Isla de Mapache Mitigation Bank, Camden County, Georgia” dated September 2022, on Racoon Key through restoration of hydrology, elevation, tidal regime, and native vegetation. The existing site consists of a network of dikes that were built in the 1950’s and 1960’s to create freshwater impoundments within what was historically coastal marshlands. The project area consists of a total of 101 acres that includes the following habitat types: 72.1 acres of freshwater impoundments, 1.2 acres of saltwater impoundments, 19.9 acres of upland and 7.8 acres of tidal wetlands.
The Banking Instrument (BI) calls for excavating portions of the dike system and filling portions of the interior canal/ditch system to restore a semi-diurnal tide cycle and allow natural regeneration of adjacent tidal marsh. The mitigation plan was developed after review of topographic survey data to determine elevations of dikes, canal elevations within the impoundments, and current elevations of existing marsh adjacent to the project site. The undisturbed areas of the impoundments currently contain elevations similar to the tidal marsh outside of the impoundments and no manipulation of these areas is proposed.
A target elevation of 2.0-2.5 feet NAVD88 was established for all dike excavation and canal fill areas. This elevation was based on existing adjacent marsh and was used to calculate cut and fill volumes associated with the project. The BI includes excavation of approximately 6.2 acres of dike for a total cut/fill balance of approximately 49,300 cubic yards. While initial construction of the impoundments included excavation of material from both inside and outside of the dikes, accretion and naturalization within canals outside of the impoundment limits proposed fill areas to canals within the impoundment. No fill of naturalized tributaries on the exterior of the dike and within functioning marsh will occur. Following completion of the project, the site will consist of restored and preserved tidal marsh.
The marshlands component for this project includes the areas where temporary disturbances will occur during the construction of the mitigation bank, including the removal of portions of the dikes and the filling of portions the ditches/canals within the impoundments. The CMPA jurisdictional area within the project site totals 11.1 acres, of which approximately 6.6 acres have been identified for temporary disturbance during construction. Most activities within tidal areas are associated with temporary disturbance required for the restoration of tidal marsh habitat; a 1.2 acre tidal impoundment that is currently open tidal waters will be filled with approximately 6,000cu.yds. of material to an elevation that supports tidal vegetation.
The upland component of the project includes 19.9 acres of upland within the project area. This will consist of 6.2 acres of excavated dike areas, 8.3 acres to be used for staging equipment and the upland areas where excess material from the restoration activities will be deposited and stabilized, and a 5.4 acres upland hammock to remain undisturbed. All activities within the upland component area are associated with the construction of the mitigation bank. Post construction, the areas that are excavated will be restored to marsh and the remainder of the upland component will be undeveloped upland area.
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: CoastalGaDNR.org under “Public Notices.” 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 March 10, 2023 to Paul Tobler, Department of Natural Resources, One Conservation Way, Georgia 31520 or via email at paul.tobler@dnr.ga.gov.
Click here for Project Description
Click here for Project Drawings
Click here for Site Photos_April 21, 2021
Click here for Site Photos_April 21, 2021
Click here for Banking Instrument-Isle de Mapache Mitigation Bank
