Tue June 07, 2005
Brian Kern
Pensacola’s Project Greenshores is the byproduct of an opportunity that exploited industrial rubbish for the purpose of environmental improvement.
Through the effort, environmentalists hope to restore marine habitat to the sensitive coastal area of Pensacola Bay.
The Florida Department of Environmental Protection (DEP) capitalized on the situation at site I of the two-phase project — and plans are in place to continue in the same vein with site II.
A Florida Department of Environmental Protection project summary reported that 6,000 tons (5,400 t) of recycled concrete rubble from Naval Air Station (NAS) Pensacola, 14,000 tons (12,700 t) of Kentucky limestone and discarded oyster shells from restaurants and 40 wave attenuators were used to create a 7-acre (2.8 ha) protective reef.
Eric Schneider, DEP project manager, said the oyster reef breakwater component of Project Greenshores will once again enlist the aid of contractors, businesses, government agencies and volunteers for site II, set to begin this summer, pending permit issuance.
“We are investigating the possibility of linking up with local dredging operations being conducted by the Port of Pensacola and Naval Air Station Pensacola to have sand pumped to the site II,” Schneider said.
The sediments being dredged by the port and NAS can be used only if they meet certain specifications required by the permitting agencies. Schneider said the sediment must contain at least 99 percent sand and be free of contaminants.
“We don’t want to use any clays or silts,” Schneider said.
According to the Florida DEP report, introduction of clean sand will allow two areas of Pensacola Bay between the Pensacola Bay Bridge and the Port of Pensacola to be graded to inter-tidal elevations (submerged at high tide, but exposed at low tide).
The rock, broken concrete and wave attenuators placed at site I created a breakwater necessary to calm the wave action that is characteristic of this section of shoreline located along the northwest side of the Pensacola Bay Bridge in downtown Pensacola. In order for newly planted marsh vegetation to get a foothold, a less intense setting is required. The breakwater also provides 7 acres of oyster reef habitat.
The 8-acre (3.2 ha) salt marsh at site I incorporated 35,000 cu. yds. (26,800 cu m) of sand, 40,000 smooth cord grass plants and 3,900 propagated seedlings of widgeon grass.
A John Deere 544 front end loader moved the concrete rubble onto dump trucks at Pensacola NAS. The trucks dumped the material onto a barge, which in turn carried the rubble to the site where it was offloaded by a crane.
A Komatsu DEM 543 bulldozer was employed to push displaced sand to desired elevations at site I after the sand was pumped into the designated area.
Schneider said site II will include 2,500 ft. (762 m) of shoreline and more than 30 acres (12 ha) at an estimated cost of $1.7 million. CEG
This story also appears on Construction Equipment Guide.