PHOTOGRAPHS

2009 #3- (1/11/2010)

2009 #2- (12/15/2009)

2009 #1- (12/11/2009)

2006 #4 - (7/19,20/2006)

2006 #3 - (7/13/2006)

2006 #2 - (7/5,6/2006)

2006 #1- (6/28,29/2006)

Project Background

Dredging maintenance activities at and near Bogue Inlet and the Atlantic Intracoastal Waterway (AIWW) are divided into two separate scopes of work. The actual navigation project associated with Bogue Inlet extends from the Atlantic Ocean northward through the ocean bar and traverses to the AIWW via the connecting channel depicted on Figure 1. This is considered as the Bogue Inlet Navigation Project.

View Graphic: Figure 1 - Site Location Map

The authorized channel dimensions fluctuate from -6 to -8 foot mean low water to widths ranging from 90 to 150 foot wide, with a total length estimated at 20,000 feet. The U.S. Army Corps of Engineers (Corps) has traditionally maintained (dredged) the project utilizing the government fleet of sidecast dredges (Merritt and Fry) and to a lesser extent, their special use split-hull dredge (Currituck) in the 1980s. The Corps is authorized to follow the deep water channel at the time maintenance activities are conducted. The area referred to as the ocean bar, which encompasses the most seaward 7,000 foot of the project, underwent significant modifications in 2005 as the Town of Emerald Isle and State of N.C. financed the repositioning of the inlet thalweg (deep water channel) to a central position within the Bogue Inlet floodway, equidistant between Bogue Banks to the east and Bear Island (Hammock’s Beach State Park) to the west.

The sidecast dredge does not have the capability to place dredged material on the beach or in upland disposal sites, but rather “sprays” the shoal material approximately 100 – 150 foot to the port or starboard side of the vessel and away from the channel. Consequently, maintenance work provides short-term navigation benefits with an expectation that repeated dredging will be necessary to keep the channel at safe navigable depths. The Corps has historically dredged the connecting channel several times per year as needed, depending on shoaling conditions and the availability of government-owned sidecast dredges.

Figure 1 also depicts the area where the Bogue Inlet Project and AIWW confluence, known as the inlet crossing. Although the Corps has environmental clearances to utilize the government fleet to maintain this reach of the AIWW, they prefer to utilize industry pipeline dredges on a 2-3 year basis. The dredged shoal material is pumped to the westernmost oceanfront shoreline of Emerald Isle indicated as the disposal area in Figure 1. The average dredged volume placed along the beach per event is approximately 42,000 cubic yards (~3,500 dump truck loads of material) and this scope of work is designated under the N.C. AIWW line item within the Corps operation & maintenance account (Table 1). The AIWW has an authorized depth of -12 foot mean low water with varying widths along the N.C. corridor.

View Graphic: Table 1 - Historical Dredged Volumes

There are several important differences in the dredging methodologies and accounting framework for the scopes of work at Bogue Inlet and its confluence with the AIWW. The ocean bar/connecting channel work (i.e., Bogue Inlet proper) is; (a) executed by the government side-cast fleet with no beach or upland disposal, (b) is performed 2 - 4 times a year, and (c) is under its own line item (Bogue Inlet) within the Corps accounting structure. Conversely, the inlet crossing work is; (a) executed by means of contract pipeline dredge with beach disposal, (b) is maintained infrequently every 1 – 3 years, and (c) is under a separate line item designated for the N.C. AIWW. Also, there are a total of eight inlet crossings across the State and this cluster of projects, along with other shallow draft projects, are usually maintained under a single or series of dredging contracts. The eight crossings along the AIWW in N.C. include from north to south; Bogue, Bear to Brown, New River, Topsail Creek, Shinn Creek, Carolina Beach, Lockwoods Folly, and Shallotte inlet crossings. Because a pipeline dredge is used, the disposal area for each crossing involves an upland or beach target site. A comprehensive navigation project map for N.C. is available here.

Project Funding

The next cycle of maintenance work at the Bogue Inlet AIWW crossing that includes concurrent beach nourishment is scheduled for winter 2009-10 and is part of a larger contract including the following projects; Lockwoods Folly Inlet Crossing, Shallotte Inlet Crossing, Snows Cut/Carolina Beach Boat Basin (DA 10), Southport Boat Basin, and the Bogue Inlet Crossing with entrance channel work to the USCG facility at Emerald Isle. The contract is expected to take two environmental windows to complete – Lockwoods Folly and Shallotte Inlet crossings were completed in winter 2008-09, and the remaining projects listed in the contract are scheduled to be completed this winter (2009-10). Three bids were received for the work in November 2008 - Southwind Construction was awarded the contract at a cost of approximately $5.2 million total.

The Corps did not receive adequate federal appropriations for the entire cluster of work listed in the contract, and for the Bogue Inlet AIWW crossing work (in addition to others); additional funding was leveraged by the State and Local governments to complete the work (see Table 2 below).

View Graphic: Table 2 - Local Cost Funding Schedule

Project Scope of Work

Similar to the 2006 inlet crossing work, The Town of Emerald Isle (EI) received regulatory clearances to place the dredged shoal material from the AIWW inlet crossing near the inlet shoreline at the Point rather than the oceanfront disposal area traditionally utilized for inlet crossing work (see Fig. 2 below). The estimated volume associated with the Bogue Inlet AIWW crossing and U.S. Coast Guard channel work for 2009-10 is approximately 74,000 cubic yards. The proposed fill template for the nourishment reach will be determined “on the fly” as a balance is struck between; (a) the actual volume of sand that is pumped to the Point shoreline, (b) the volume of sand that is lost as part of the hydraulic delivery process (i.e., fine-grained sediments lost to the template), (c) existing bathymetry and shoreline configuration at the time of nourishment, and (d) the area that is desired to be filled.

View Graphic: Fig. 2 - Inlet Crossing Map (aerial photo)

Sediment samples were also obtained by the Corps within the Bogue Inlet AIWW crossing for analysis in accordance with the State’s sediment criteria rules for beach nourishment. Visual observations of the sediment placed along the oceanfront beach in the past from the inlet crossing have been very favorable. Results from this year’s analysis indicate the shoal material contains less than 10% mud, which is within parameters stipulated in the State’s sediment criteria rules. Work at the Bogue Inlet AIWW crossing is scheduled to begin during the week of December 6, 2009 and should take a few weeks to complete.