Beach Nourishment

UPDATE: EMERGENCY BERM SAND HAUL

Our contractor, CM Mitchell, has completed the sand haul work in areas 1, 2, and 8. They are currently working in areas 3, 5, and 7. Please see the attached map for details on where these areas are, along with other imminent critical areas. Areas 9, 10, and 11 were completed prior to the sea turtle moratorium date of April 30. Hauling of sand was initiated in areas 1, 2, 3, 7, and 8 before the turtle moratorium but we were unable to completely fill the design template before the sand haul work had to stop. The table below outlines the sand volume calculations that were needed as of November 15.

ALL VOLUMES EXPRESSED IN CUBIC YARDS (CY)

VOLUME SUMMARY

Dune Placement Area

BD Volume REQUIRED to Fill Template

Total Volume Placed

PAY VOLUME

Area 1

4,340

2,301

2,301

Area 2

3,306

1,935

1,935

Area 3

11,744

824

824

Area 4

15,796

0

0

Area 5

10,307

0

0

Area 6

8,883

0

0

Area 7

22,882

2,373

2,373

Area 8

6,255

1,191

1,191

Area 9

7,531

6,950

6,950

Area 10

13,442

11,175

11,175

Area 11

58,460

60,712

58,460

TOTAL PROJECT VOLUME:

162,946

87,463

85,211

The BD Volume Required to Fill Template column above represents the total fill needed to build the designed dune for each area, the Total Volume Placed column represents the total amount of sand that was hauled to each area and the PAY Volume represents the total volume of sand that the contractor is paid for. The contract for this project allows a +/- 0.5’ tolerance of fill to the template—in other words, the final graded dune has to be within a half foot (above or below) the design. The contractor is paid for all sand placed in an area with a cap at the total BD Volumes.

As you can see, areas 1 and 2, received approximately 1/2 to 2/3 of the total amount of sand they were supposed to get last spring. Combined, a total of 3,410 cubic yards of sand was still needed to complete this project. The offroad dump trucks on the beach hold approximately 40 CY each so about 85 additional truckloads of sand were needed to complete this portion of the job this fall.

TI Coastal's crew, including Jamie Pratt, are on the beach daily monitoring the hauling project. They perform pre-placement surveys of an entire area about 3 days prior to the contractor beginning work there so they can update our volume calculations, provide CM Mitchell with cross-sections, and make sure no template adjustments are needed. Because the contractor is paid via the volume of sand they place in template, they survey the placement daily before any wave or tide energy can erode the dune face. This also allows them to ensure they are grading the beach correctly and the project moves smoothly. In the event of a major coastal storm, such as the nor’easter a few weeks ago, they resurvey all pre-placement areas and update the volume calculations as the beach profile has changed dramatically.

We have received some questions/concerns about sand being placed just outside the template area. TI Coastal's best practice of intermittent dune construction requires them to build slightly past the terminal houses in each fill area and tie into the existing dune in an effort to reduce the likelihood of the new dune being breached directly adjacent to the critical houses. Admittedly, this tie in did extend a little bit further south than required (total overage of sand of approximately 191 cubic yards), but rest assured the volume of sand placed in this area has no bearing on the design template or volume of sand that is going on in that particular area. Each fill area is addressed independently and an extra 200 CY of sand placed in Area 1 has no impact on Area 3 or the rest of the project.


BEACH NOURISHMENT PROJECT:

As you know, the Town of Surf City has been working on a nourishment project to place sand on the beach from Banks Channel all along the Surf City oceanfront. This project will advance your shoreline to 150 feet wide with a 1 on 20 slope.

We plan to begin construction spring of 2020. However, prior to construction, the Town needs your approval to deposit sand and perform other work associated with beach nourishment on your property. The property on which the Town will need to work lies waterward of your frontal dune. This area is specifically described on the enclosed easement. Please be aware that this is not a perpetual easement; the Town only request the easement rights through 2048.

You will not lose land or access rights when you sign the easement. We are simply asking for your approval to deposit sand and work on a specific area of your property. All owners having an interest in the property must sign an easement.

Please return the easement with notarized signatures by January 7, 2019 to:

Town of Surf City – Easements

PO Box 2475, Surf City, NC 28445

Surf City Beach Nourishment Plan

Surf City Beach Presentation


On January 18, 2019 the Surf City Town Council hosted a beach nourishment work shop with TI Coastal LLC. The Council voted to proceed with the placement of sand berms in imminent critical areas. These areas will be identified specifically by TI Coastal in the coming days. If you are a private property owner who wishes to purchase sand for your berm please contact Town Hall at 910-328-4131 or clerk@townofsurfcity.com. This process will go up for bid acceptance at the March Council meeting. It is at that time the Town should know the exact cost per cubic yard of sand if you are wishing to purchase sand. Sand should being being placed back on the berms in late March to early April. The council voted to still proceed with the private nourishment project with TI Coastal slated to being in 2020.

February 5, 2019: TI Coastal has identified the imminent critical lots in Surf City, they are highlighted in green. Those lots that are not identified as imminent critical do have a choice to purchase sand for their lots. The design for is roughly 14 cubic yards per linear foots. For those property owners who plan to purchase sand the Town needs a commitment in writing (email) no later than Monday, February 11th at noon. The Town will be collecting payment prior to the sand placement and payment in full is due Thursday, February 28th. Dune replacement is expected to begin no later than mid-March.

November 16, 2019 the sand haul project for those lots identified as imminent critical, that did not receive sand in the spring of 2019 will begin to have sand placed. 

FEMA Imminent Critical Lot Analysis Explanation

Definitions:

“Imminently Threatened” – This is a NCDCM (CAMA) term that means that the dune escarpment (the “drop off”) is within 20 feet of the foundation of the house.

“Hyper-Critical”- This is a term I used to describe area where infrastructure or house foundations were at immediate risk of being undermined by another erosion event. In most cases these are areas where:

  1. The house or infrastructure meets the definition of imminently threatened.
  2. The infrastructure is installed below elevation 8’ NAVD88.
  3. Ground elevation for house is above elevation 14’ NAVD88.

Our process in determining the sand placement area is as follows:

First, using the Post-Florence beach surveys which went from the road to 3,000 feet offshore, we determined the +14’ and +8’ contours. These contours define the seaward face of the dune, the angle of the drop off, and where the dune had been completely over-washed. We then overlaid these contours onto post storm aerial photography to determine the distance of the escarpment from the houses. Next, we determined how much sand would be required to complete the berm at the north end to protect the water sewer and road infrastructure. This took approximately 60,000 of the 160,000 cubic yards of sand that we believe the Town can obtain for the $5M budget.

Next we looked at proximity of the escarpment to the houses based on the 14’ contour or lack thereof. We prioritized houses in blocks of 4 or more, as putting sand on less than a 200ft strip would result in too rapid of erosion. Some house that were substantially forward of their neighbors were eliminated based on this protocol.

Lastly we looked at ground elevation under the houses and prioritized houses with higher escarpments. This was important. House pilings are typically driven 8 feet into the ground. Thus if the ground elevation is 14’, then the bottom of the pilings is at elevation 6’ NAVD88. Dune erosion typically takes the elevation down to about elevation 6’. Thus a house built a house built at elevation 14’ or above would totally collapse with only 10 more feet of dune erosion, while a house built on ground elevation 8’ or less can survive a wash through.

All of these things were taken into account in order to protect the most sensitive areas first and the most areas possible with the 100,000 cubic yards available. All of these decisions were very tough as we feel the entire beach needs restoration. We have done our best to look out for the Town as a whole, strictly using scientific and mathematic principles. While some homeowners may disagree with the outcome of this process, it is the only ethical way to do complete this difficult task under the current constraints..

TI Coastal, PLLC