Florence Replenishment Project (2019)
Project Construction Map
Area of Detail - 3/29/2019, completed (Reach 2 & 3 – Indian Beach/Salter Path)
Area of Detail - 4/25/2019, completed (Reach 1 - East EI)
Fact Sheet (pre-project): Florence (2019)
Typical Cross Section (Plan) Typical Cross Section (constructed)
7/11/19 - DUNE PLANTING UPDATE. As mentioned in the previous update, Coastal Transplants took the July 4th week off but have resume hand planting of the dune slope and areas of the dune crest (flat part of the dune) that could not be accessed by the mechanical planter. Reaches 2 and 3 in Indian Beach/Salter Path are fully completed, as well 1st through 10th Street in Emerald isle (Reach 1). Hand planting will continue progressing westward from 10th Street to the “dog leg” 4WD Drive Access located just west of the Town’s Easter Regional Access. Again, please keep in mind sea oats when first installed are under a lot of the stress and may look gray/brown, but soon (2 weeks later) begin to shoot out new green growth. The picture below is a completed section in Indian Beach (Reach 2) – these sea oats were planted 2 months ago or less and look extremely healthy.
Dune Planting Photo (July 10, 2019)
|DUNE PLANTING CROSS SECTION|
6/26/19 - DUNE PLANTING UPDATE. Coastal Transplants is moving steadily down the beach hand planting the dune slope. Reaches 2 and 3 in Indian Beach/Salter Path are fully completed. 1st Street through 7th Street in Emerald Isle (Reach 1) are also completed and hand planning will continue progressing westward from 7th Street to the “dog leg” 4WD Drive Access located just west of the Town’s Easter Regional Access. Coastal Transplants will be taking the July 4th week off for logistical reasons associated with the influx of visitors and to take some time to address equipment maintenance. Please note sea oats when first installed are under a lot of the stress and may look gray/brown, but soon (2 weeks later) begin to shoot out new green growth.
Dune Planting Photos (June 26, 2019)
|Planting the Slope
6/12/19 - DUNE PLANTING UPDATE. Coastal Transplants completed the mechanical planting of the dune crest a few weeks ago in areas they could operate (wider crests and without obstructions). They have been hand planting the dune slopes and the discrete areas of the dune crests ever since. Roughly a day or two remain (~800 linear feet) before all of Reach 3 and 2 are complete (Indian Beach/Salter Path). Hand planting will then work from 4th Street in Emerald Isle back eastward to the Town Boundary with Indian Beach, and then 4th Street westward all the way down to the “Dog-Leg” 4WD Ramp. Roughly 175,000 of the 400,000 sea oats specifically grown for this project have been planted. Progress has been slowed down in part to the U.S. Fish & Wildlife and N.C. Wildlife Resource Commission's concerns that the pick-up trucks, water trailers, and tractor commonly employed with dune planting activities should be considered as “heavy equipment” and therefore conflicts with nesting sea turtles. Additional conservation measures have been implemented so the dune planting phase of the project can be completed this summer (estimated completion is August 1st.)
5/15/19 – DUNE PLANTING PROGRESSES. Coastal Transplants has made some nice progress utilizing the mechanical planter on the dune crest (top) – see photos below. Reach 3 and 2 is completed and Reach 1 (East Emerald Isle) could be completed by the end of the weekend. Manual planting of the dune slope will start immediately thereafter – the “second” pass if you will.
Dune Planting Photos using the Mechanical Planter (May 15, 2019)
|Planting & Watering 2
|Finished Dune Crest
||Planting & Watering 3|
5/8/19 - DUNE PLANTING UPDATE. Because of regulatory/environmental concerns with respect to nesting sea turtles, Coastal Transplants will be utilizing the mechanical planter first. The mechanical planter (see demo video) can only be utilized along flat surfaces for operational and safety reasons; and therefore we will be planting the entire dune crest initially in what can be considered as a first pass. Once the dune crest (top of the dune) is planted in all of the reaches, manual planting as depicted in the photos from 4/25/19 below will take place in a second pass. Thank you for your understanding.
5/1/19 - DUNE PLANTING UPDATE & DEMOBILIZATION. Great Lakes Dredge & Dock hustled this past week to ensure all equipment was removed from the beach by May 1st as stipulated in permits/authorizations – dredge pipes, lights, work sheds, “the CRAB”, bulldozers, trash bins, everything. The beach is all ready for the turtle nesting season (and the summer tourism season as well!)
Dune planting progress is a little behind, but we still anticipate this phase to be completed sometime in over the course of the next several weeks – likely in the mid to late June timeframe. At the moment, planting activities are located around the Indian Beach 4WD Ramp; but will soon start at the east of the beachfill and proceed west (i.e., Reach 3 to Reach 2, to Reach 1).
Demobilization - The demobilization process has already started and is in full swing – the Liberty Island will depart this afternoon, and the submerged pipelines at 8th and 18th Street should be pulled this weekend. The land-based pipe are being staged on the beach at the “dog-leg” 4WD access in Emerald Isle and will be removed 5 to 6 at a time on large flatbed trailers. The beach is completely open for public use except in this very small confined area.
Endangered/Threatened Species - Another important component of this project was the endangered/threatened species protection measures, particularly trawling and relocation of sea turtles to limit possible encounters with the dredge. Our Biological Opinion and other authorizations for the project stipulated the implementation of trawling/relocation once the water temperature exceeded 57 degrees Fahrenheit. However in the abundance of caution, the project sponsors requested trawling begin as soon as the project started. Throughout the project 8 loggerheads, 5 greens, 4 kemps ridleys, and 1 leatherback sea turtle were safely trawled and relocated. 11 Atlantic Sturgeon were also trawled/relocated. Of course there is not a one to one correlation between trawling/relocation and interaction with a dredge(s), but the possibility of lethal or non-lethal take by the Liberty Island or Ellis Island was greatly diminished by doing so. And to this end, one kemps ridley turtle was taken by the Ellis Island but it survived in good shape and is being rehabilitated at the Karen Beasley Sea Turtle Center. It is very active and has begun to eat, and reportedly has been named “Hoppy” in the spirit of the Easter season and there is high optimism concerning its chances.
Dune Planting - Planting of sea oats (predominantly) and bitter panicum (sparsely) begun on Monday (4/22) and is in full swing (see pictures below). In general planting will progress east to west across the project and should take 8 to 10 weeks to complete.
Dune Planting Photos at the Indian Beach 4WD Access (April 24, 2019)
|Planting & Watering 2
|Planting & Watering 3
4/22/19 - 1,000 FEET TO THE FINISH LINE. Great Lakes Dredge & Dock got back to work with the Liberty Island hopper dredge yesterday morning (4/21/19) after this weekend’s storm and are approximately 1,000 linear feet away from completing the dredging/pumping phase of the project, or roughly 25,000 cubic yards (cy) of sand in terms of volume (SEE 4/22/19 PROGRESS MAP). A standard dump truck can hold roughly 12 cy of sand as a mental image, while the Liberty Island on the other hand is holding roughly 4,500 cy per load for our nourishment project. The total linear distance and cubic yardage (cy) for the project is 27,275 feet (5.2 miles) and 945,446 cy, respectively – meaning we’re 96% to 97% complete depending which metric one uses. We should be done by Wednesday, and Great Lakes Dredge & Dock has already begun the “demobilization” process – i.e., some of the land-based pipe, bulldozers, etc. have been taken off site. Our engineers at Moffatt & Nichol and the entire Great Lakes Dredge & Dock organization have done a great job during the entire project.
4/19/19 – STORM PREPARATIONS (EVER SO CLOSE); NEW PHOTOS; & DUNE PLANTING UPDATE. As mentioned in our last update (4/17/19) the oncoming storm has resulted in a shutdown for the next day or two. The last load of sand was delivered by the Liberty Island this morning before going to safe harbor and beach nourishment has reached the Pier Point Condominium complex (SEE 4/19/19 PROGRESS MAP). This is Project Station “351+00” and the end of the project is just west at Station “335+00” – that’s only 1,600 linear feet remaining once the seas subside (351+00 – 335+00 = 1,600 feet). The total project is ~27,275 linear feet (~5.2 miles). So close – we are persevering however, and should be completed in the Tuesday to Wednesday timeframe depending on when Great Lakes Dredge & Dock can get back to work. The dredge Ellis Island departed the project yesterday morning to avoid the storm and head on to her next project. The Liberty Island is obviously staying to complete the project (dredging/pumping wise) – she has been here since day 1.
Dune Planting – This phase of the project will begin in earnest on Monday (4/22/19). The subcontractor (Coastal Transplants) was here yesterday to conduct a small test strip in Indian Beach (see photos below). Again, dune planting will essentially progress east to west – starting in Indian Beach and transitioning into Emerald Isle. The native plants, Sea Oats (predominantly) and Bitter Panicum will be planted in an approximate 21-inch spacing grid pattern.
Photos (April 17 & 18, 2019)
|Just Done Pumping||Ocean Reef (before - after - after)|
|Dune Plant Test Strip||Dune Plant Test Strip (Stay off the Dunes)|
4/15/19 - GREAT LAKES DREDGE & DOCK POWERS THROUGH THE WEEKEND – HOME STRETCH. Despite the onset of rough sea conditions on Friday (4/12/19), our dredging contractor (GLDD) kept both dredges (the Liberty Island and Ellis Island) in full operation throughout the weekend, until late last night as a second round of weather passed our area. Hopefully we will be back operating this evening. Regardless, the section between the two pipeline landings at 8th and 18th Street was completed yesterday and both dredges will now be working in tandem off the pipeline landing at 18th Street – pumping west of this point towards the end of the project (SEE 4/15/19 PROGRESS MAP). The discharge location is currently situated between 22nd and 23rd Streets. This equates to roughly 4,200 linear feet to go until the project’s western terminus is reached just past the “dog-leg” 4WD Access (total project linear feet is 27,275 = roughly 85% complete distance-wise). We are looking at next weekend’s sea conditions and that is playing in to when the project will be completed (dredging/pumping component).
4/12/19 - STRONG PRODUCTIVITY CONTINUES – WEATHER THIS WEEKEND. The Liberty Island and Ellis Island hopper dredges have been working methodically over the past couple of days dredging sand from the borrow source, sailing to Emerald Isle (Reach 1), pumping the sand to the beach via two different pipeline landings at 8th and 18th streets, and the sailing back to the borrow area. Both operations are progressing westward down the beach, and as of this morning were located at 14th and 22nd Streets (SEE 4/12/19 PROGRESS MAP). The Ellis Island is the largest hopper dredge (capacity wise) in the United States and she means some business when it’s time to pump sand to the beach. Meanwhile the Liberty Island’s rotation times have been fantastic. Unfortunately it appears we are going to encounter some rough seas over the course of the next few days which present several issues, including but not limited to; (a) safety concerns for the trawlers working ahead of both dredges in the borrow area that relocate endangered/threatened species when encountered (Reva Rose and Jessica Marie) , (b) difficulties hooking the dredge to the floating black pipe/cube one sees offshore at the pipeline landing areas, (c) operational concerns of the dredge itself while digging/excavating, and (d) other. Accordingly, we will likely encounter some down time over the weekend, but again; this is built into the overall schedule. And as a final note, dune planting in Reach 3 (“east Indian Beach/Salter Path) will likely start next week (see 4/5/19 and 4/3/19 updates below).
4/10/19 - BOTH HOPPER DREDGES IN OPERATION. As scheduled, the Ellis Island arrived on Monday (4/8/19) and delivered her first load of sand at about 6 pm that evening and has been working steadily ever since. She (Ellis Island) is pumping sand via a submerged pipeline landing at 18th Street and is progressing westward towards Emerald Isle’s Eastern Regional Access. The Liberty Island meanwhile continues to pump sand via a pipeline landing at 8th Street and is also progressing west from this point – currently at 12th Street (SEE 4/10/19 PROGRESS MAP). The "dredging - sail to beach - pump-out - sail back to the borrow area" cycle is different for each dredge – every now and then both will coincide with a beach pump-out (see figure below). We could run into rough seas this weekend, but weather and mechanical shutdowns are always built into the schedule.
Photos (April 9 & 10, 2019)
|Both Dredges Pumping Out||Ellis Island Pump-Out @ 20th Street|
4/8/19 – PIPE FLIPPED TO THE WEST, ELLIS ISLAND ON THE WAY. Great Lakes Dredge & Dock finished working eastward from the submerged pipeline landing at 8th Street on Saturday (4/6/19), and is now working westward from 8th Street (at 10th Street this morning – SEE 4/8/19 PROGRESS MAP). The beachfill connecting Reach 1 in Emerald Isle to Reach 2 in Indian Beach have now been merged, the pipes have been removed from the beach, etc.
The dredge, Ellis Island is on her way from Charleston as this update is being prepared (she’s on the north side of Cape Fear @ ~9 am) and should begin dredging/pumping later today. The Ellis Island will be pumping sand to the beach near 18th street in Emerald Isle and will proceed west towards the Towns Eastern Regional Access. The Liberty Island will continue pumping from the submerged pipeline at 8th Street and work west.
The dredges Liberty Island has a maximum capacity of 6,540 cubic yards and the Ellis Island 14,800 cubic yards under optimal conditions. The Ellis Island has been in operation since December 2017 and is the largest hopper dredge in the U.S. This will be one of her first beach nourishment template jobs (i.e., not just disposal, but meeting a prescribed nourishment template – see cross section). We’re glad to see her here!
Also earlier today, the project sponsors, engineers, and contractor had a meeting with the dune plant subcontractor (Coastal Transplants). We discussed our planting grid, watering methods, fertilizers to be used during installation, etc. Coastal Transplants will likely start planting the dune crest and dune slope towards the latter stages of next week - starting in Reach 3, then Reach 2, and Reach 1 (basically "east to west" - in the same order as the nourishment project has been completed). The dune grasses (mostly sea oats and some bitter panicum) are sensitive to their new environment when first planted – they are going from a controlled greenhouse environment to the salt air and wind that dominate the beach. There will be tens of thousands of plants installed as part of this project and they need to be disrupted as little as possible so they can successfully grow and survive. Thus, please stay off the vegetated part of the dunes – stay in the bare sand pathways that will be created at each walkway. Please pass along this friendly reminder to your friends or visitors you may see as well. Thank you.
Photos (April 5, 2019)
|Photo 1||Photo 2||Photo 3||Photo 4|
4/1/19 - We’re on to Reach 1 (East Emerald Isle) and beach nourishment activities are currently moving east from the submerged pipeline landing near 8th Street back towards the completed Indian Beach section (SEE 4/1/19 PROGRESS MAP). That submerged line ("subline") was not fully ready on Friday afternoon and roughly two hopper loads were placed off the subline already in place near 18th Street (see 4th and 3rd Pipeline Landing in progress map). Photos from today’s activities and dune plants from the greenhouse are below.
Photos (April 1, 2019)
|Photo 2||Photo 3|| Photo 4
3/29/19 – REACH 2 COMPLETED, VEGETATION NOTE, ELLIS ISLAND ARRIVING ON THE 8th – Today is somewhat of a transition day. For one Great Lakes Dredge & Dock have completed pumping to Reach 2 (SEE 3/29/19 PROGRESS MAP), which therefore concurrently signifies the start of Reach 1 - East Emerald Isle (roughly 65% of the project volume wise). To this end, the submerged pipeline (subline) that serviced the dredge Liberty Island in Reach 2 is being moved today to East Emerald Isle near 7th Street. The Liberty Island is using this time to refuel and will likely start using the “new” subline at 7th Street later this afternoon/early evening or the subline already installed near 16th Street (see 4th and 3rd pipeline landing, respectively in the REACH 1 MAP).
Also there has been a change in schedule for the second dredge, the Ellis Island to arrive, which is now planned for April 8th – not the 2nd as reported earlier this week. This does not hamper the overall completion schedule for the project – April 8th was the approximate date the Ellis Island was originally slated to arrive when the schedule was first presented by Great Lakes Dredge & Dock months ago.
And lastly, some initial discussions with respect to the dune planting phase of the project have taken place and planting of the dune crest and slope (see cross-section) in Reach 3 could begin in a couple/few weeks. We are using Sea Oats and Bitter Panicum, which are native plants to this area.
3/27/19 - FLIPPED THE PIPE IN REACH 2 - The eastern reach off the 2nd pipe landing was completed yesterday and we are working westward now to complete Indian Beach and therefore Reach 2 (SEE 3/27/19 PROGRESS MAP). Next week will likely mark a shift in the project in a couple of ways. (1) We will be starting or will have started Reach 1 (eastern Emerald Isle). (2) The dredge Ellis Island is scheduled to begin dredging/pumping on April 2nd and will service the “3rd pipeline landing” located near 16th Street in Emerald Isle and will progress west towards the Eastern Regional Access first, then flipped towards the east. And (3) in all likelihood, the pipeline currently being used in Reach 2 will be moved near 7th Street in Emerald Isle, representing the “4th pipeline landing”. The Liberty Island will be utilizing this pipeline landing and will first work back east towards the Town line shared with Indian Beach, then flip to the east to meet up with the Ellis Island pipeline/nourishment (See PROGRESS MAP).
Photos (March 27, 2019)
|Photo 1||Photo 2||Photo 3||Perspective|
3/25/19 - Beach nourishment activities were paused during the latter part of last week because of weather/sea conditions. However, nourishment resumed early Saturday morning (3/23/19) and has progressed nicely since. The dredge Liberty Island is using the pump-out station/submerged line in Reach 2 and nourishment activities are advancing eastward from this point – past the Ocean Club, and now past SummerWinds (SEE 3/25/19 PROGRESS MAP).
Photos (March 25, 2019)
|Photo 1||Photo 2||Photo 3|
3/20/19 - Beach nourishment continues to progress eastward towards SummerWinds from the active submerged pipe landing (see March 20, 2019 PROGRESS MAP). The dredge Liberty Island is now going to be accompanied by the second dredge (Ellis Island) a little earlier than first scheduled and should arrive the 1st week of April. Both dredges will work in tandem to complete Reach 1 (East Emerald Isle – SEE MAP).
3/18/19 – REACH 3 COMPLETE - Reach 3 (“east” Indian Beach and Salter Path) was completed yesterday (3/17/19), and subsequently the first load of sand was delivered to Reach 2 - SEE 3/18/19 PROGRESS MAP. Beach nourishment activities are now progressing eastward from the 2nd submerged pipeline landing, and will be “flipped” westward once the eastward run is completed. Also, the submerged line for Reach 1 in Emerald Isle has been installed near 16th Street (see MAP).
Photos (March 18, 2019)
|Photo in Reach 2||Photo 2|
3/15/19 - Strong productivity continues and Reach 3 (Indian Beach/Salter Path) could be completed this weekend (see 3/15/19 Progress Map). If so, dredging/pump-out operations will move to Reach 2 in Indian Beach where nourishment will progress eastward off the 2nd pipeline landing.
3/13/19 – Productivity/progress remains strong. Great Lakes Dredge & Dock (GLDD) has completed ~3,000 linear feet of the project in less than 5 days and the eastward leg from the first subline landing in Reach 3 (Indian Beach/Salter Path) is complete - see photos below. GLDD begun progressing west from the subline landing this morning (SEE 3/13/19 PROGRESS MAP).
Photos (March 13, 2019)
|Photo 2||Photo 6|
|Photo 3||Looking up from Berm|
|Photo 4||Sand Quality|
3/10/19 - Great Lakes Dredge & Dock has made some nice progress in less than 48 hours of starting the project (pictures below), and have completed ~1,000 linear feet of beach thus far (see 3/10/19 UPDATE). The sand quality is excellent visually speaking. We have received a lot of questions regarding how the dune feature will be constructed and tied into the existing, scarped dune that characterized Bogue Banks after hurricane Florence. Hopefully this schematic next to an actual constructed portion will provide a good mental image = dune construction image.
Photos (March 10, 2019)
|Photo 2||Photo 8|
|Photo 3||Photo 9|
|Photo 4||Photo 10|
|Photo 5||Photo 11|
|Photo 6||DUNE CONSTRUCTION EXAMPLE|
3/8/19 (PROJECT START) – Right on schedule. The dredge Liberty Island arrived earlier this morning from Charleston, S.C., underwent a series of mandatory inspections, and subsequently excavated, sailed, and delivered the first hopper load of sand to Reach 3 at roughly 4:15 pm (pictures below). Note that beach nourishment will first be progressing eastward off the 1st subline landing (depicted here). Also, the second subline has been installed today at Reach 2 (see “Station 514+00” here).
Photos (March 8, 2019)
|Dozers Sculpting Dune ahead of Subline||Pumping Sand/Water|
|Pumping Zoom||Crab and Dredge Pipe|
|Pumping looking east||Pumping looking east (2)|
Other dredging work in the area - It is also noteworthy to mention the hopper dredges Dodge Island and Padre Island started dredging maintenance work for the Morehead City Harbor Federal Navigation Project on February 26th and will likely conclude at the end of March. Shoal material will be dredged predominantly from Range A and placed in the new nearshore berm east offshore disposal site (see image). This scope of work is part of a regional hopper approach for the Brunswick, Savannah, Wilmington, and Morehead City Harbors (~700,000 cubic yards for Morehead City - bid abstract).
Also a second federal contract for Morehead City Harbor maintenance, which represents a carryover project from the previous fiscal year was also awarded to Great Lakes Dredge & Dock utilizing a pipeline dredge (bid abstract). The dredging ranges include both the Cutoff and Range A utilizing either the nearshore berm east or west disposal sites (see image), and will likely start sometime in April (~1,600,000 cubic yards).
And lastly the Corps of Engineers’ small hopper dredge, the Murden should be arriving to the area in the middle of March and will service both Morgan Creek (~6 days of dredging and ~7,500 cubic yards) in Range 1 (map) and Bulkhead Channel (~4 days of dredging and ~ 3,596 cubic yards) in Range 1 (map). Offshore disposal at the nearshore berm west.
Photos (Feb. 26, 2019)
2/25/19 - Land-based piping has begun arriving at the Indian Beach 4WD Ramp is actively being staged along the beachfront (pictures below).
Photos (Feb. 25, 2019)
2/20/19 - Both the Indian Beach 4WD Ramp and Dog Leg 4WD Drive Access will be used to transfer land-based dredge pipe arriving via flatbed trucks to the beach. Front-end loaders and other ancillary equipment should arrive at the Indian Beach 4WD Ramp early next week. Some sub-line (water-based piping), derricks, barges, etc. have arrived and are holding tight in Bogue Sound, situated just north of Ft. Macon. Otherwise, there are no schedule changes to report as the dredge Liberty Island is planned to initiate dredging/nourishment the first week of March in Indian Beach (Reach 3) and will be accompanied by the Ellis Island several weeks later - the temporary sub-line pipe landing locations from offshore as depicted for Indian Beach/Salter Path and East Emerald Isle remain the same.
2/14/19 - No schedule changes to report. The dredge Liberty Island is planned to initiate dredging/nourishment the first week of March in Indian Beach (Reach 3) and will be accompanied by the Ellis Island several weeks later - the temporary pipe landings from offshore as depicted for Indian Beach/Salter Path and East Emerald Isle remain the same. Mobilization of dredge pipe, ancillary vessels, and equipment to the area should be more pronounced in the weeks ahead.
1/30/19 – There will be three temporary pipeline landings that will serve the dredges Liberty Island and Ellis Island. In general the sand will be pumped ashore from the hopper dredge and progress east or west, then reversed as generally depicted in the new updated maps for Reach 2 and 3 (see - Indian Beach/Salter Path) and Reach 1 (see - East Emerald Isle). The Liberty Island will arrive on site likely the first week of March followed by the Ellis Island.
1/22/19 – Great Lakes Dredge & Dock should begin mobilizing land- and water-based pipe, heavy equipment, personnel, etc. towards the latter parts of February and although the schedule is tentative, dredging/pumping could begin the first week of March.
HOW TO INTERPRET THE PROGRESS MAPS
for The Post Florence Renourishment Project
The Post Florence Renourishment Project will utilize 945,446 cubic yards (cy) of sand obtained from the Offshore Dredged Material Disposal Site (ODMDS) associated with Morehead City Federal Navigation Project. Emerald Isle (EI), Indian Beach (IB), and the unincorporated area of Salter Path (SP) will receive 617,131 cy, 271,905 cy, and 56,410 cy, respectively along 5.2 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 conducted between the March 1 to April 30, 2019 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 and Ellis Island will be employed for the project. Great Lakes will utilize an area near the "Dog Leg" 4WD Ramp in EI and the IB 4WD Ramp Parking Area as their main equipment staging facility 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 via 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 approximately 1 - 2 mile sections as lengths of pipe are added and subsequently broken down. 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, possibly tilled, and opened for recreational use. The dredges Liberty Island has a maximum capacity of 6,540 cy and the Ellis Island 14,800 cy under optimal conditions.
Project engineers use “stations” positioned along the beach to monitor construction progress and to verify in-place volumes of sand pumped on the beach by dredging contractors. The progress maps above provide detailed views of the Post Florence Renourishment Project reaches to be completed in 2019 with the location/identification of the station numbers and the location of buoyed pipelines. 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 “418+00” (15th Street) and “473+00” (5th Street) on the Reach 1 - East Emerald Isle Area of Detail graphic above is 5,500 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 PLANNING & IMPLEMENTATION
The geographical extents and basic geometries of the Post Florence Renourishment Project are included in the accompanying maps below and the project is essentially a re-formulation of a nourishment project that was planned for this winter (2018-19) along the shorelines of EI, IB, and SP. Hurricane Florence passed by Bogue Banks in September 2018 and just before the project was bid. This same reach of beach lost ~945,000 cubic yards of sand in the wake of Florence and accordingly we re-focused our efforts, made a few slight changes, and re-termed our project to the Post-Florence Renourishment Project (Phase I). This best describes what we are trying to accomplish, and is more consistent for FEMA reimbursement purposes. Decisions from FEMA concerning reimbursement for beach nourishment or their “428” program, which provides a fixed-cost number in lump-sum will be made later this year (2019). Great Lakes Dredge & Dock furnished the lone bid for the project bid totaling $20,109,385. We have internally added some safety-net, contingency funding that increases the total to $20,910,385. Maps and a Fact Sheet summarizing the cost schedule and geographic ranges of the project are below. Phase II of the Post-Florence Renourishment Project is tentatively scheduled for winter 2019-2020 and will encompass Central and Western EI, Pine Knoll Shores, and East Atlantic Beach.
In cross-section going from the top of the dune seaward, the beachfill will be contoured by; (1) tying into the existing, eroded frontal dune at +12 feet NAVD 88 and maintaining that top dune elevation at vary lengths as one progresses seaward, (2) the slope of the newly constructed frontal dune will be graded on a 5:1 slope to the elevation of +6 feet NAVD 88, (3) the beach berm (flat part of the beach) will be extended from that point seaward at +6 feet NAVD 88 at varying lengths, and (4) the slope of the fill from the berm crest out to sea will be on a 20:1 slope. The newly created dune crest and dune slope will be planted (vegetated) with Sea Oats and Bitter Panicum as part of the contract (see typical cross-section below).
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 2004, 2007, and 2013 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-Florence Renourishment Project, has performed additional sediment sampling and analyses in the ODMDS to hone the areas of beach quality sand.