Irene Replenishment Project (2013)
Liberty Island Field Trip (3/15/13)
3/18/13 – Progress continues on the last two or three total project reaches, and the project will likely be completed by the end of this week. The progress maps above depict the remaining geographic areas that need to be completed in Reach 2 (Emerald Isle East) and Reach 3 (Emerald Isle West). Also, Great Lakes Dredge & Dock recently hosted a group of project sponsors from the County, Pine Knoll Shores, and Emerald Isle aboard the hopper dredges Dodge Island and the Liberty Island. Pictures obtained during the site visit to the Liberty Island are available above.
3/11/13 – This week’s construction summary will again be divided on a “reach-by-reach basis”, and the overall project is roughly 65% complete in terms of both volume and geographic distance.
Reach 3 (West Emerald Isle)
This 1.8 mile reach is actively being nourished utilizing the largest capacity hopper dredge of the three that are on site - the Liberty Island (6,540 cubic yard capacity). The sole submerged pipe landing for Reach 3 is located near the Emerald Isle Western Regional Access (a.k.a. – “The Islander”) and nourishment operations have proceeded east from this point since dredging/pumping started for Reach 3 on March 3rd. As today’s map indicates, the eastern segment of Reach 3 is almost complete, and we should see nourishment operations proceed west from the submerged pipe landing in a day or two – i.e., “flip the pipe west”.
Reach 2 (East Emerald Isle)
This 2.4-mile reach is over 1/2 completed and sand is currently being pumped to the beach via a 2nd submerged pipe landing near 22nd Street (see map); and is progressing east from this point. In the past week pumping operations were conducted off the 1stsubmerged pipeline landing for this reach located near 11th Street, and that pipeline assembly and the overall migration to the 2nd pipeline landing transpired over this past weekend.
Reach 1 (Pine Knoll Shores)
The hopper dredges Padre Island and Dodge Island completed the 2.4-mile Reach 1 on 2/24 (see map). The Padre Island and Dodge Island each have a 3,600 cubic yard capacity and have since been working in tandem in Reach 2.
3/4/13 – (NEW PHOTOS BELOW) - Inclement weather and sea conditions hampered progress in the early stages of last week, but now all three dredges are on-site and are currently working in the two out of three remaining reaches as summarized below;
Reach 1 (Pine Knoll Shores)
The hopper dredges Padre Island and Dodge Island completed the 2.4-mile Reach 1 on 2/24 (see map). The Padre Island and Dodge Island each have a 3,600 cubic yard capacity and are now working in tandem in Reach 2.
Reach 2 (East Emerald Isle)
This 2.4-mile reach is roughly ¼ completed and sand is currently being pumped to the beach via a submerged pipe landing near 11th Street (see map). Beach nourishment operations initially headed east from this point and are now heading westward from the 11th Street submerged pipe landing. Great Lakes Dredge & Dock will proceed for ~3,000 feet along the beach towards the west from 11th Street, and subsequently move to a separate submerged pipe landing that was installed last week located near 22nd street to complete Reach 2.
Reach 3 (West Emerald Isle)
This 1.8 mile reach will be nourished utilizing a third dredge that arrived to the area on Friday (3/1) and started dredging/pumping yesterday (3/3). The hopper dredge Liberty Island is the largest capacity dredge on-site and can hold 6,540 cubic yards under optimal conditions, and has started pumping sand through a submerged pipe landing located near the Emerald Isle Western Regional Access (a.k.a. – “The Islander”) and will work towards the east first, then west to complete the reach (see map).
2/25/13 – REACH 1 COMPLETED (see map). Working in tandem, the hopper dredges Padre Island and Dodge Island completed Reach 1 (Pine Knoll Shores) of the Post Irene Renourishment Project late yesterday, and subsequently started Reach 2 in East Emerald Isle working eastward off a submerged pipe landing near 11th Street (see map). Also, Great Lakes Dredge & Dock installed the submerged pipe landing for Reach 3 yesterday as well, near the Emerald Isle Western Regional Access (see map). The hopper dredge Liberty Island is expected to arrive later this work week and begin working westward from the Regional Access.
2/21/13 - The hopper dredges Padre Island and Dodge Island continue pumping sand off the second submerged line/beach landing at Station “790+50” in Pine Knoll Shores (Reach 1) and are heading west near the Clamdigger Inn (see map). Reach 1 is roughly 3/4 complete and nourishment operations should shift to Reach 2 this weekend located in East Emerald Isle.
2/18/13 - The hopper dredges Padre Island and Dodge Island have completed pumping sand off the first the submerged line/beach landing at Station “854+50” and are now working eastward from a submerged line/beach landing at Station 790+50 in Pine Knoll Shores (Reach 1) to tie in with the first filled section (see area of detail map above). Reach 1 could be completed this weekend and consequently, the Padre Island and Dodge Island will transition to “Reach 2” in Emerald Isle East and begin pumping eastward from Station 523+50 (see area of detail map above). As previously discussed below, a third dredge (Liberty Island) is scheduled to arrive and begin nourishment along Reach 3 (Emerald Isle-West) around February 28th. Overall, the sand quality has been excellent from a visual perspective and productivity/progress has been very robust over the past week (see photos below).
Photos (Feb. 18, 2013)
2/11/13 - The hopper dredge Padre Island arrived and started dredging/ pumping yesterday (2/10) and is now working in tandem with the Dodge Island off the submerged line/beach landing at Station “854+50” in Pine Knoll Shores (see area of detail map above). Great Lakes is working eastward from the beach landing and will subsequently work west from this point before moving to the western part of the PKS reach off a 2nd beach landing at Station 790+50. As previously discussed below, the third dredge (Liberty Island) is scheduled to arrive and begin nourishment along Reach 3 (EI-West) around February 22nd.
2/8/13 – PROJECT START (2/7/13). The Dodge Island arrived and started dredging/ pumping yesterday until the wind and waves suspended operations for roughly 12 hours. Dredging activities resumed this afternoon (see pictures below). The Padre Island is expected to arrive on Sunday (2/10) and will work in tandem off the submerged line/beach landing at Station “854+50” in Pine Knoll Shores. As previously discussed below, the third dredge (Liberty Island) is scheduled to arrive and begin nourishment along Reach 3 (EI-West) around February 22nd.
Photos (Feb. 8, 2013)
2/4/13 – Great Lakes installed the first submerged line (“subline”) this morning in Pine Knoll Shores at Station “854+50” (see area of detail map above). This will be the location where the dredges Dodge and Padre Islands will be used in tandem to pump sand to eastern half of Reach 1 – first extending to the east, then west. The subline will subsequently be moved to the western half of Reach 1 to complete this section. Pictures from this morning’s subline installation are below. In terms of scheduling, the Dodge and Padre Islands are expected to arrive later in the week with nourishment potentially starting over the weekend. As discussed below (1/25/13 update) - the Liberty Island is scheduled to arrive and begin nourishment along Reach 3 (EI-West) around February 22nd.
Photos (Feb. 4, 2013)
1/25/13 – Great Lakes intends to utilize three dredges for the project, and they will all stay on-site working once they arrive. The Dodge Island has a 3,600 cubic yard (cy) capacity and the Padre Island also has 3,600 cy capacity under optimal conditions – they will work in tandem and will mobilize to Bogue Banks once they complete a project in Sea Bright, N.J. The Liberty Island on the other hand has a maximum capacity of 6,540 cy and will follow the Dodge Island and Padre Island to the site after completing work in Destin, Fla. We could see pipe, trucks, and other ancillary equipment arriving later this week, signifying the beginning of the mobilization process. The dredges Dodge and Padre Islands are tentatively scheduled to arrive and begin nourishment in Reach 1 (PKS-East) around February 10th, while the Liberty Islandis scheduled to arrive and begin nourishment along Reach 3 (EI-West) around February 22nd. The maps above have been updated to reflect the first beach landing of pipe/nourishment and general direction that activities will first take place.
1/3/13 – Great Lakes Dredge & Dock should begin mobilizing land- and water-based pipe, heavy equipment, personnel, etc. towards the latter parts of January and although the schedule is tentative, dredging/pumping could begin the first week of February.
HOW TO INTERPRET THE PROGRESS MAPS
for The Post Irene Renourishment Project
The Post Irene Renourishment Project will utilize a maximum of 913,165 cubic yards (cy) of sand obtained from the Offshore Dredged Material Disposal Site (ODMDS) associated with Morehead City Federal Navigation Project. Pine Knoll Shores (PKS) and Emerald Isle (EI) will receive 283,868 cy and 629,297 cy, respectively along 6.6 miles of shorelines in three discrete reaches depicted in the Project Construction map above. As a mental picture, a conventional dump truck holds roughly 15 cubic yards of dry sand. The project is scheduled to be constructed between the January 1 to March 31, 2013 construction window established to limit impacts to biological resources and the dredging contract has been awarded to Great Lakes Dredge & Dock. The ocean-certified, self-contained hopper dredges Liberty Island, Dodge Island, and Padre Island will be employed for the project. Great Lakes will utilize the Iron Steamer Beach Regional Access (PKS) and the Eastern Regional Access in EI as their main equipment staging facilities and points of beach access for heavy equipment.
Hopper dredges utilize dragheads affixed to trailing-arm suction pipes mounted on both sides of the vessel (port and starboard). The dragheads loosen the sand on the bottom off the seafloor and deliver the material to the vessel’s “belly” via the suction arms. Subsequent to completing a “cut” and filling the hopper, the dredge will travel and discharge (pump) sand to a buoyed pipeline located offshore that extends to the pre-construction dry beach. A secondary “T-valve” discharge pipe is used to transport material in one direction (east or west), then the other along the beach to complete ~1-2 mile sections. The buoyed pipeline and T-valve assembly is subsequently transited down the beach until the nourishment reaches have been filled. Dredged sand will be bulldozed into general construction specifications for subsequent grading into final contours, tilled, and opened for recreational use. The dredges Liberty Island has a maximum capacity of 6,540 cy, Dodge Island 3,600 cy, and Padre Island 3,600 cy under optimal conditions.
Project engineers use “stations” positioned along the beach to monitor construction progress and to verify in-place volumes of sand placed on the beach by dredging contractors. The progress maps above provide detailed views of the Post Irene Renourishment Project reaches to be completed in winter of 2013 with the location/identification of the station numbers and the location of the buoyed pipeline. The shaded areas in red represent the completed portions of the project and will be updated on a weekly basis throughout the construction.
The station numbers included in the progress map conveniently correspond to thousands of linear feet along the beach. For instance, the distance between station “797+77” and “807+77” on the Pine Knoll Shores Area of Detail graphic above is approximately 1,000 feet. If you visit the beaches of Bogue Banks this winter, you may see wood or metal stakes at the base of the dunes that will identify these station numbers as such.
PROJECT DEVELOPMENT & SUMMARY
The Federal Emergency Management Agency’s (FEMA’s) Public Assistance Program and the N.C. Division of Emergency Management will reimburse communities for the replacement of sand lost during a federally-declared disaster event provided an original beach nourishment project was predominantly non-federally funded, and project sponsors have developed and adhered to a beach maintenance and monitoring program. This general formula was applied to hurricane Irene that impacted Carteret County in August 2011, particular the 27th of that month, and as explained in more detail below, FEMA has approved a reimbursement package to replace the 269,628 cubic yards (cy) of sand lost during the Irene storm event across the shorelines of Pine Knoll Shores (PKS) and Emerald Isle (EI) – 112,555 cy and 157,073 cy, respectively. As a mental picture, a conventional dump truck holds roughly 15 cubic yards of dry sand. The Post Irene Renourishment Project is scheduled to be constructed between the January 1 to March 31, 2013 construction window established to limit impacts to biological resources.
To fully leverage/maximize the high dollar mobilization/demobilization costs associated with beach nourishment projects; the communities of PKS and EI in cooperation with the County’s Beach Commission/Shore Protection Office elected to pursue a “delta” component of the project whereby additional funding would be provided by the local governments to place an additional 643,537 cy of sand in the reaches of PKS-east/PKS-west, EI-east, and EI-west. The ceiling of the delta component was predicated upon the funds PKS and EI had residing in their nourishment accounts only (i.e., they did not want to finance any new debt), and an overall 25% Town – 75% County cost share ratio was utilized for the delta component. Hence the nourishment effort inclusive of FEMA reimbursement yields a project totaling 913,165 cy (269,628 cy FEMA + 643,537 cy delta) for a cost of $14,612,321 ($6,922,054 FEMA + $7,960,267 delta). This equates to an overall cost-share ratio of 47% federal, 39% County, and 13% Towns. Please see the fact sheet above for a more detailed summary of the project.
Each of the communities that participated in the Bogue Banks Beach Restoration Project, including EI, Indian Beach (IB), and PK, has a FEMA monitoring and maintenance plan in place and the County Beach Commission’s beach monitoring program provides repetitive surveys intended to track coastal changes, trace the fate of beachfills, and create a “pre-storm” benchmark that can be utilized to document the losses attributed to individual or a collection of storms. As a quick reminder, the Bogue Banks Beach Restoration Project was a predominantly locally-funded beach nourishment effort completed in three distinct phases; Phase I in 2001-02 along the shorelines of PKS and IB, Phase II in 2003 along eastern EI, and Phase III in 2005 along western EI that also entailed the realignment of Bogue Inlet.
In 2011, a post-Irene beach survey was conducted days after the Hurricane departed Bogue Banks and quantified the beach losses attributed to Irene, satisfying FEMA’s requirements to apply for reimbursement and yielding the cumulative 269,628 cy figure mentioned above.
PROJECT PLANNING & IMPLEMENTATION
The geographical extents and basic geometries of the Post Irene Renourishment Project are included in the accompanying maps and is a function of several constraints. (a) For the FEMA reimbursement element, we can only place sand in the regions where the reimbursement is granted. (b) The maximum volume of sand for the “delta’ portion of the project was based on what the municipalities can afford at this time. (c) We need to utilize a general rule that the minimum placement rate is 20 cy per linear foot to prevent field operations associated with dredging/pumping from becoming too costly/prohibitive. This obviously limits the length of the project reaches. (d) The shape of the beach and offshore region also plays into the fill density (i.e., certain areas of the beach may require more or less sand to establish the same beach width, slope, etc. across the project). (e) We can’t “leapfrog” and include an excessive amount of reaches because that will limit the effectiveness of the nourishment and would escalate the placement cost.
The borrow source for this nourishment effort is the Offshore Dredged Material Disposal Site (ODMDS) associated with Morehead City Federal Navigation Project. This dump site is essentially a repository for dredged material historically extracted from the Outer Harbor reach of the navigation channel and based upon experiences with a 2004 and 2007 Section 933 Project that utilized channel material for beach nourishment and a 2004 and 2007 post hurricane projects that actually utilized the ODMDS, we expect the sand quality to be excellent. This also makes intuitive sense, because for the most part, the shoal material that enters the navigation channel at Beaufort Inlet is sand that has traveled from adjacent beaches. Construction, or deepening material that resides in the ODMDS should be avoided. To this effect the firm of Moffatt & Nichol, who has been retained by the Bogue Banks communities as the engineering consultant for the Post Irene Renourishment Project, has performed additional sediment sampling and analyses in the ODMDS to hone the areas of beach quality sand, which basically corresponds to the northeast corner of the ODMDS. Great Lakes Dredge & Dock has been awarded the dredging contract and PKS is scheduled to be nourished first, followed by EI East and EI West last as the project will generally proceed “east to west”.