Attachment_23_Flagler_County_Physical_Monitoring_Plan_2025-01-13.pdf

Attachment #23

PHYSICAL MONITORING PLAN

Physical Monitoring Plan Flagler County Beach and Dune Restoration Project: Reach 2 FDEP JCP 0379716-001-JC 23-1 Foth | Olsen

Flagler County Beach and Dune Restoration Project: Reach 2

Flagler County, FL

MODIFICATION REQUEST

FDEP Joint Coastal Permit (0379716-001-JC) &

USACE DA Permit (SAJ-2019-02065 (SP-TMM)

SUPPORTING INFORMATION

Physical monitoring will continue from the pre-construction data and include data collection during the construction phase and post-construction. The long-term, post-construction monitoring will provide the data to evaluate project performance, impacts to adjacent shorelines, guidance for possible adjustments or modifications of future work, and to help identify the need for renourishment. Table 23.1 summarizes the planned monitoring schedule. This schedule will continue biennially until either the next nourishment or expiration of the design life. A renourishment event will restart the physical monitoring plan. Monitoring of this project will be coordinated closely with the monitoring of the adjacent USACE project (FDEP Permit 0378136-

001-JC) and be in accordance with the standards set-out in the FDEP Monitoring Standards for

Beach Erosion Control Projects dated October 2014.

Table 23.1: Flagler County beach/dune restoration project physical monitoring schedule.

Monitoring

Event

Profile

Surveys

Borrow Area

Surveys

Sand

Sampling

Aerial

Photography

Engineering

Report

Pre-Construction X X X1 X2

Post-Construction X X X X2 X

Year 1 X X2 X

Year 2 X X2 X

Year 3 X X2 X

Year 4

Year 5 X X2 X

1. Pre-Construction sand sampling collected as part of project development and presented in Attachments 16 & 17.

2. Aerial Photography to be acquired from commercially available sources.

Williams_MaK 0379716-003-jm

Physical Monitoring Plan Flagler County Beach and Dune Restoration Project: Reach 2 FDEP JCP 0379716-001-JC 23-2 Foth | Olsen

Beach Profile Survey: Topographic and bathymetric profile surveys of the beach and offshore shall be collected as listed in Table 23.1. A complete beach survey was completed in

February 2024 for the purpose of developing this permit modification request. A pre-construction survey will be completed within 90 days prior to the commencement of construction. The post-construction survey will be completed within 60 days following the completion of the project.

Beach profile surveys shall be conducted during a spring or early summer month, typically June.

Each survey should be conducted as close as practicable during the same month of the year. If there are less than six months between the post-construction survey and the first annual monitoring survey, the permittee can request to delay the first annual monitoring survey to the next year.

Beach profile surveys shall be collected at each of the published FEDP reference monuments within the beach fill area and extend approximately 3,000 ft along the adjacent shoreline north and south of the project area. Profile surveys will be conducted along published azimuths and extend a minimum of 3,000 ft offshore from the control monument or -30 ft

NAVD88, whichever is greater. Where practicable, survey data shall extend a minimum of 150 ft landward of the vegetation line or to the R-monument, whichever is more landward.

Borrow Area Surveys: Bathymetric surveys of the borrow area shall be collected concurrently with beach profile surveying, or as close as reasonably possible. A pre-construction survey will be completed within 90 days prior to the commencement of construction. The post-construction survey will be completed within 60 days following the completion of the project. A prior design survey of the offshore borrow area may be submitted for the preconstruction survey if consistent with the other requirements.

The bathymetric surveys shall encompass the entire dredged portion of the borrow area.

The surveys may be conducted on single-beam grid lines across the borrow area and shall be spaced to provide sufficient detail for accurate volumetric calculations but spaced not more than a maximum of 500 ft apart, and shall extend a minimum of 50 ft beyond the boundaries of the borrow site; or conducted alternatively by multibeam collection extending a similar 50 ft beyond the boundaries of the borrow site. The technical specifications provided in the FDEP Monitoring

Standards for Beach Erosion Control Projects dated October 2014 will be applied.

Sand Sampling: Beach sand sample collection and laboratory analysis shall be performed following the completion of the project as described in ITEM #16f: Sediment Quality

Assurance/Quality Control Plan and in accordance with FDEP Monitoring Standards for Beach

Erosion Control Projects dated October 2014.

Aerial Photography: Controlled digital color aerial orthophotography shall be acquired from public or commercially available sources, such as FDEP, USGS, USACE, Nearmap©, etc.

Aerial imagery will be acquired over a concurrent physical extent to the post-construction survey

Physical Monitoring Plan Flagler County Beach and Dune Restoration Project: Reach 2 FDEP JCP 0379716-001-JC 23-3 Foth | Olsen and each annual survey, and as close to the date of the beach profile surveys as possible. The photography shall be color vertical photos and centered on the local shoreline. The quality of acquired photos shall meet technical specifications provided in the FDEP Monitoring Standards for Beach Erosion Control Projects dated October 2014.

Engineering Report: Engineering monitoring reports shall be formulated and submitted to

FDEP along with the monitoring data within 90 days following completion of the post-construction survey and each annual and biennial monitoring survey for the first three-years and fifth year following project completion. The purpose of each report shall be to summarize the annual and biennial as well as cumulative database and to assess project performance including beach volume and shoreline position changes. The engineering report shall include plots of survey profiles and graphic representation of temporal and cumulative volumetric and shoreline position change for the entire monitoring area. Volumetric changes at each survey profile will also be presented in tabular form. Analyses shall discuss the data, shoreline change trends, and the performance of the beach fill project. The study will also seek to identify erosion and accretion patterns and any potential cause and effect relationship. In addition, the report will include a comparative review of project performance and identify any potential adverse shoreline impacts that may be attributable to the project. All baseline and survey data shall be submitted in a digital (ASCII) format consistent with the technical specifications provided in the FDEP Monitoring Standards for Beach Erosion

Control Projects dated October 2014.