Enmark Properties, LLC., Installation of a Silt Suspension System, Savannah River, Chatham County, Georgia

Chatham

This serves as notification from the Coastal Marshlands Protection Committee and the Georgia Department of Natural Resources of a request from Enmark Properties, LLC. for a Coastal Marshlands Protection Act (CMPA) permit under Official Code of Georgia (O.C.G.A.) 12-5-280 et seq., to install and operate a silt suspension system at The Savannah Yacht Center, located on the Savannah River, Chatham 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 property includes two (2) wet slips, a graving dock, and approximately 15.6 acres of upland. Most recently, CMPA Permit #736 was issued for the demolition of then-existing enclosures and the addition of a variety of structures including a vessel lift system and silt suspension units at the northernmost wet slip. Both wet slips are maintained at a depth of -30ft. MLW. Currently, the depths at the southern wet slip are maintained by agitation dredging. A silt suspension system is being proposed at this location as an alternative to maintenance dredging and to provide the ability to maintain proper depths. 

The proposed silt suspension system will consist of a series of submerged, near-bottom units, called SEDCON units, mounted below grated walkways between floats. Each unit has a hydraulic motor-driven impeller that draws water downward into a bell mouthed intake and discharges it outward across the bottom of the berth. A computer operates each unit in sequence starting on the upstream end of the system. This creates a flow of water across the bottom of the berth. The units will be lowered and operated only during ebb tide so that sediments suspended in the water will be swept out of the berthing area and into the federal channel. 

The applicant proposes to install a total of five (5) SEDCON units evenly distributed around the southern wet slip area. The area to be impacted consists of an approximately 48,187sq.ft. wet slip that contains approximately 5,882sq.ft. of floating docks, 554sq.ft. of gangways, and 455sq.ft. of platforms.

Each individual unit with mounting equipment will impact approximately 26.12sq.ft. of tidal water bottoms. Total impacts for all five (5) SEDCON units will be 130.6sq.ft. The SEDCON units will be attached to a 1ft. diameter pipe with a 1ft. x 0.3ft. T/Guide. The raising and lowering equipment will consist of an 1ft. x 5.3ft. H-beam that will be welded to the top of an existing guide pile. A small winch will be mounted to the H-beam to raise and lower the unit.

As proposed the project will impact approximately 130.6 square feet (0.003-acres) of coastal marshlands. 

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 “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 March 26, 2020 to Paul Tobler, Department of Natural Resources, 1 Conservation Way, Brunswick, Georgia 31520.

Project Application

Project Description

Project Drawings

Project Photos

Project Photos