Peter T. Leach | May 14, 2010 10:15AM EDT
The Port of Savannah is using a modified silt suspension system to maintain a depth of 48 feet at four of its Garden City Terminal berths and to increase oxygen levels in the river.
The Georgia Ports Authority, which faces environmental resistance to the Savannah Harbor Expansion Project to dredge the Savannah River to a depth of 48 feet from its present 42 feet, announced the new environmentally friendly suspension system Friday.
GPA Executive Director Curtis J. Foltz said the Garden City Terminal already offers 48 feet at four of its berths, which allows Savannah to accommodate post-Panamax ships today.
“While the Savannah Harbor Expansion Project is essential to the Port of Savannah’s future growth, maintaining 48 feet at berth enables the GPA to accommodate larger vessels, which are beginning to call on East Coast ports in anticipation of the Panama Canal Expansion,” Foltz said.
The GPA now has a silt suspension system consisting of 15 units online at Garden City Terminal, which substantially reduce the need for maintenance dredging at the berths.
The computer-controlled system produces a low-velocity flow that works in tandem with passing tidal currents to keep water moving near the berth, resulting in reduced siltation. The silt suspension units use hydraulic motors driven by vegetable oil.
The new air-injection system is a combination of two technologies,” said GPA’s Senior Director of Engineering and Facilities Maintenance Wilson Tillotson. “It uses silt suspension to disperse natural sediment into the river and assists with the absorption of oxygen into the water.”
The modified silt suspension unit in Berth 9 injects oxygen into the marine environment.
The GPA said that by gently introducing air into the river, dissolved oxygen is added into the water and protects aquatic life from potential diminished oxygen levels.
The new air-injecting unit operates from May through October, when the dissolved oxygen levels are naturally diminished in the Savannah River.
-- Contact Peter T. Leach at pleach@joc.com.