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Title:	Draft Environmental Assessment on the Expansion of the Port Everglades Harbor Ocean Dredged Material Disposal Site (ODMDS), Broward County, Florida
Authors:	United States. Army. Corps of Engineers. Jacksonville District.
Keywords:	Dredging Dredging spoil Environmental impact analysis Port Everglades (Fort Lauderdale, Fla.)
Publisher:	United States. Army. Corps of Engineers. Jacksonville District.
Abstract:	Port Everglades is a major cargo and cruise ship port in Florida contributing $14 billion of economic activity to Florida’s economy and nearly 10,000 jobs via the companies that provide direct services to the Port (http://www.porteverglades.net/about-us/). With the work well underway to enlarge the Panama Canal, larger ships are currently calling on Port Everglades, albeit light-loaded, and are not able to fully maximize their full capacity due to the channel depth limitations. In order to allow these vessels to fully maximize their capacity, the USACE is preparing a Congressionally authorized feasibility study and draft Environmental Impact Statement (DEIS) for dredging and expansion activities at Port Everglades. The proposed expansion would deepen the entrance channel from -45 feet to -57 feet mean lower low water (MLLW) (plus up to two feet of required and allowable overdepth) and to deepen all other channels to -50 feet MLLW (plus up to two feet of required and allowable overdepth) (USACE, in press). The project is expected to dredge material from six areas: the Outer Entrance Channel, Inner Entrance Channel, Main Turning Basin, Widener, Southport Access Channel, and Turning Notch. Depending on the selected plan, volumes of dredged material for ocean disposal will not exceed 6.63 million cubic yards (mcy). The composition of the dredged material varies. Due to previous dredging projects, some of the project area consists of exposed rock. Shoaling has covered some localized areas with a few feet of sand. Silts and clays overlay medium and fine sand, coupled with limestone and sandstone, in areas not previously dredged. Borings indicate likely dredged material compositions of 12% clay and silt, 33% limestone and sandstone gravel, 25% silty fine sand and 30% fine to medium to sand (Taylor 2010). Small deposits of peat associated with bulkhead construction near the turning notch are also possible. Beach placement of dredged material would require processing of the dredged material to screen out any materials greater than 1-inch and removing all silts, clays and peat deposits. The USACE has determined that processing is not viable due to space limitations at Port Everglades and additionally, there is limited capacity for beach material within the Shore Protection Project. Other beneficial uses of dredged material including construction fill, cap material in aquatic remediation projects, wetland creation, wetland restoration, landfill cover and recycling into commercial products will be evaluated as part the Port Everglades Harbor expansion project DEIS (USACE, 2011). The existing ODMDS was designated to accommodate dredged material from periodic maintenance events in the Port. It received final designation by USEPA in February 2005 (70 FR 2808) following the completion of a July 2004 EIS for the ODMDS designation. However, recent capacity modeling (Figure 2) indicates the existing, approved ODMDS is insufficient in size to contain the proposed 6.63 mcy of dredged material associated with the proposed Port Everglades expansion project discussed above (Taylor 2010). Therefore, there is a need to expand the existing ODMDS to accommodate the dredged material resulting from the planned Port Everglades Harbor expansion project. The need for ocean disposal is based primarily on the lack of economically, logistically, and environmentally feasible alternatives for the disposal of the projected quantities of dredged material deemed unsuitable for beach re-nourishment or beach placement (USACE, in press). Should the scope of the Port Everglades Harbor expansion decrease or should alternatives to ocean disposal be identified, EPA will re-evaluate the need for this action. A secondary need for expansion is for Operations and Maintenance (O&M) material and/or other non-federal projects. The USACE has estimated that over the next fifty years, there will be a need for ocean disposal of approximately 1.5 million cubic yards of maintenance material from the federal project (USACE, 2011; USACE 2005). The original site designation was based on individual maintenance projects of up to 500,000 cy material. In 2005, approximately 60,000 cy of dredged material was placed in the existing ODMDS via a release zone in the middle of the site. A 2006 post-disposal monitoring survey showed dredged material was observed to have exceeded the existing site’s northern boundary, forming an uneven ellipse elongated in a north-south direction (Germano & Associates, Inc. 2006). Figure 3 shows the extent and thickness of dredged material within and exceeding the Port Everglades ODMDS to the north of the site. Based on the results of this survey, the disposal release zone was moved to the southern end of the site to account for the strong northern Florida Current/Gulf Stream’s effect on the dispersion of the disposed material. USACE conducted an O&M dredging event in early 2013 of approximately five times more dredged material than in 2005. EPA is planning a post disposal monitoring event in 2014. The monitoring will determine if movement of the disposal release zone was sufficient to contain all material within the existing boundaries or if a site expansion is needed to accommodate O&M material. Broward County has also proposed using the ODMDS for disposal material from the Port Everglades Sand Bypass Project (SAJ-2008-2034). Project volumes could exceed 500,000 cubic yards (Creed, 2013) requiring capacity modeling and possible site expansion. If the revised disposal release zone is not sufficient to contain the dredged material within the ODMDS boundaries or if future projects are expected to exceed the capacity of the ODMDS, a need will exist to expand the site.
URI:	http://hdl.handle.net/11681/26145
Appears in Collections:	Environmental Documents