2018 Annual Beach Monitoring Report

Transcription

1 May 1, 218 Town of Hilton Head Island, SC 218 Annual Beach Monitoring Report Submitted to: Town of Hilton Head Island, SC November 15, 217 Prepared by: Olsen Associates, Inc Herschel Street Jacksonville, FL 3224 (94) (Fax) olsen associates.com September 218

2 218 Annual Beach Monitoring Report September 218 EXECUTIVE SUMMARY This report summarizes beach conditions and changes along the sand shoreline of Hilton Head Island, South Carolina for the period from February 216 to June 218. The results discussed herein are principally related to the post-project beach conditions of the 216 Hilton Head Island Beach Renourishment Project and the 217 South Island Emergency Beach Fill Project as well as Hurricanes Matthew and Irma. This report serves as the first major discussion of the island s current shoreline conditions and the changes prescribed through the course of the aforementioned projects and storms, since the 216 Annual Beach Monitoring Report (Olsen Associates, Inc., 217). The conditions described herein represent June 218 conditions. The monitored sand shoreline is located between the Lands End Groin at Braddock Cove Creek on Calibogue Sound and the southern limit of the Hilton Head Plantation revetment on the Port Royal Shoreline, corresponding to approximately HHI-A and HHI-39, respectively. This report includes: (1) a summary of current beach conditions as of June 218, (2) a summary of shoreline and volumetric changes that occurred along the sand beaches of Hilton Head Island between February 216 and June 218, (3) a summary of beach conditions as of June 218 compared to post-216 project conditions in May 217, (4) a summary of shoreline position as of June 218 compared to a previously defined Recommended Minimum Beach Condition 1 (RMBC), (5) a summary of particular areas of interest, which include: Lands End, South Beach, The Heel, and Fish Haul Creek, and (6) a discussion of features unique to this report, including: Fish Haul Creek Marsh Grass, Joiner Bank, and Bay Point Shoals. Current Beach Conditions (June 218). Since the previous monitoring report (216), the island has seen the placement of two beach fill projects and the impacts of two major hurricanes (Matthew and Irma), analysis of the annual shoreline change rate and volumetric change rate have been omitted since the results would be biased by the placement activities and abnormally large erosion that resulted from the storms. Instead, overall changes in MHW and volume from 1 The minimum condition used herein is generally based upon the April 1997 island-wide beach position and condition. The beach survey conducted in April 1997 represents beach conditions that existed immediately prior to the construction of the 1997 Beach Renourishment Project (Olsen Associates, Inc., 24). i 218 Annual Beach Monitoring Report September 218

3 pre-216 project to post-217 project are presented to document the total beach change during this period. As of June 218, the island s beach was considerably wider than pre-216 project conditions. This is related to both the 216 and 217 beach nourishment projects. The only area of the island that is narrower than 216 conditions is a portion of the Calibogue Sound shoreline between the Lands End Groin and HHI-A. Here along, an area that has never been nourished is about 95 ft wide. This area also was the only reach along the island s shoreline where beach width was narrower than 2 ft. For monitoring purposes, the benchmark for a narrow beach width is a distance of 2 ft or less form the Beachline 2 to the 218 MHW (+3.72 ft NGVD29). The 2 ft distance is not a defined management distance, but rather a measurement used so that comparative assessments of relative shoreline conditions can be performed. The narrow beach width in this segment along Calibogue Sound is the same as that which has generally been reported over the last four monitoring periods. Despite being narrow, this area does not present itself as an erosional concern, currently, since it has historically been a generally stable to accretional beach. Relative to previous monitoring reports, the current condition has seen fewer narrow beach segments because of the effects of the two beach fill projects that are encompassed in the results. Overall, the average June 218 beach width is ft, with the maximum width of ft at HHI-29A3, and the minimum of 95.3 ft at HHI-A. February 216 and June 218. Between February 216 and June 218, the MHW shoreline experienced major changes along the entire beach due to the 216 and 217 beach projects and the effects of Hurricanes Matthew and Irma, most notably. On average, over the entire shoreline, the MHW advanced approximately ft (weighted 3 ) over the roughly twoyear period, with the greatest advance of ft at FH-6 and the greatest retreat of ft at FH-2. Shoreline advance occurred along all reaches except one. Two reaches, North Island (HHI-25 to HHI-28) and Inner Port Royal Sound (HHI-35 to HHI-39), experienced average shoreline recession during this period; however, these areas also did not receive any direct sand placement from either of the two projects. Three primary regions are shown to have experienced a retreat of the MHW and a loss of beach volume during this period: Calibogue Sound and South Beach (HHI-A to HHI-B and HHI-1A to HHI-1C), North Island (HHI-27 to HHI-HHI- 28), and The Heel (HHI-29D to HHI-29E); however, it should be noted that none of these reaches received direct sand placement during either of the projects. 2 The Town s Beachfront Line is a local regulatory line adopted by the Town in December 26 and is defined as having the same location as the 1999 OCRM Baseline. No development may be further seaward than this line. 3 The average MHW change was calculated by using the change computed at each monitoring station and is weighted by the distance between each monitoring station (e.g. a longer reach represents more of the average). ii 218 Annual Beach Monitoring Report September 218

4 Between February 216 and June 218, the sand volume all segments of Hilton Head Island beach increased by a net +3,326,6 cy (+37.7 cy/ft) 4. The largest increase in sand volume was by +272,6 cy (+87.1 cy/ft) between HHI-3 and HHI-4, while the greatest loss was - 18,1 cy (-31.2 cy/ft) between HHI-29E and HHI-29F. Foremost, it is noted that between February 216 and June 218 Hilton Head Island received direct sand placement during the 216 Island-wide Beach Renourishment Project and 217 South Island Emergency Beach Fill Project. Because of the projects, the majority of changes are attributed to the addition of sand to the system by the two projects. The projects masked the significant sand losses that occurred during Hurricanes Matthew and Irma as well as other natural sand losses. Increases in total beach volume were greatest along the Atlantic-fronting reaches of Central Island, South Island, and South Beach. The only area to have lost sand during this time was the Inner Port Royal Sound (HHI-35 to HHI-39) shoreline, which also did not receive beach fill over this period. May 217 to June 218. Along the entire length of the island, while excluding the effects of the 217 project between HHI-1C and HHI-8, the MHW shoreline retreated by an average of -6.7 ft between May 217 and June 218. Including the effects of the 217 beach project, the island advanced +4.6 ft. This change represents essentially all of the post-project changes associated with the 216 beach fill. The greatest MHW advance was by ft at FH-6 and the greatest retreat was by ft at FH-1. The highest variability of beach width changes occurred within the vicinities of the northern and southern termini of the island, likely due to the dynamic nature of the inlets and associated shoal features and further exacerbated by the impact of Hurricane Irma. Between May 217 and June 218, comparison of beach profile surveys suggest that the island shoreline gained a net of approximately +638,7 cy (+7.2 cy/ft) of sand. The greatest increase was by +229,2 cy (+71.2 cy/ft) between HHI-4 and HHI-5 and the greatest loss was by -45,5 cy (-68.4 cy/ft) between HHI-29 and HHI-29A1. This gain is principally related to the sand placed as part of the 217 Emergency Beach Fill project (completed November 217), which involved the placement of 79,5 along the South Beach and South Island shorelines. The 7,8-cy deficit between the net gain between surveys and the amount recorded as beach fill reflects the effects of: hurricane erosion (Irma); losses along the terminal ends of the island; and natural sand transport. Comparison of beach profiles to aerial imagery suggests that a portion of sand from the island may have been deposited into both Calibogue and Port Royal Sounds. If so, much of this sand will likely not return to the island in the near future as it is part of the active shoal system. During this time there also was notable movement of large sand waves along the South Beach, Heel, and Port Royal Sound shorelines of the island. Changes of the island-wide volume are expected to have been exacerbated by the impacts of Hurricane Irma during this time period. 4 Unless stated otherwise, the volume changes in this report were computed from the seaward edge of the most seaward dune feature evident in the beach profile data to the apparent location of beach profile closure. iii 218 Annual Beach Monitoring Report September 218

5 June 218 Shoreline Position Relative to RMBC. As of June 218, the average MHW (+3.7 ft NGVD) shoreline position was ft seaward of the RMBC. The June 218 MHW shoreline position was seaward of the RMBC (where there is a defined RMBC) for all but two transects over the entire island, HHI-A and HHI-B. This area, which has eroded beyond the RMBC, has never been nourished as part of the Town s beach nourishment program. The position of the June 218 shoreline relative to the RMBC is greatest at the terminal ends of the island, South Beach and The Heel, due to natural shoreline and inlet dynamics. Over this period, there was a maximum advance of ft at HHI-33, and maximum recession of ft at HHI-B. Additional Discussion Features. In addition to the discussion of overall beach conditions and change, other topics were explored. These are (1) the condition of marsh grass at Fish Haul Creek, (2) the apparent reformation of Joiner Bank, and (3) the conditions of Bay Point Shoals borrow area. Each of these were evaluated to document changes which have not typically been included in past monitoring reports, but may provide useful insight to future planning: Fish Haul Creek Marsh Grass Since completion of the 216 project, there has been a reduction of marsh grass coverage, likely due to the attachment of a sand spit to the breakwaters. This feature has landlocked the grass and reduced the water flow due to the position of the new mouth cut out by Fish Haul Creek. There were approximately 3.51 ac of marsh grass as of June 218, compared to the 4.84 ac prior to the 216 project. Joiner Bank The offshore feature has been progressively growing since at least 211 and currently shows approximately 3.7 ac as determined by aerial imagery. The bank has become thinner and longer than it has been in previous years. Bay Point Shoals Borrow Area Since completion of the 216 project, the Bay Point Shoals borrow area has gained +37,5 cy of sand within the area dredged in 216. The southeast portion of the shoals outside the dredge and permitted limits have deflated to some extent. This deflation may be related to the movement of sand from that portion of the overall shoal to the dredged area. 218 Annual Beach Monitoring Report September 218 iv

6 218 Annual Beach Monitoring Report September 218 TABLE OF CONTENTS EXECUTIVE SUMMARY... i 1. INTRODUCTION Background Brief Summary of Renourishment History Survey Control Physical Monitoring Program Hurricane Matthew Hurricane Irma BEACH CONDITION SUMMARY Organization of Monitoring Results Current Beach Condition (June 218) Monitoring Period Beach Changes (February 216 to June 218) Shoreline Change Beach Volume Change Project Performance: Beach Changes (May 217 to June 218) Shoreline Change Beach Volume Change June 218 Beach Condition relative to RMBC Detailed Discussion of Areas of Interest Lands End South Beach The Heel Fish Haul Creek ADDITIONAL DISCUSSION FEATURES Fish Haul Creek Marsh Grass Joiner Bank Bay Point Shoals Borrow Area SUMMARY REFERENCES APPENDIX A HISTORICAL BEACH PROFILE PLOTS... A-1 APPENDIX B SHORELINE AERIALS... B-1 APPENDIX C FIELD MONITORING PHOTOGRAPHS... C Annual Beach Monitoring Report September

7 218 Annual Beach Monitoring Report September INTRODUCTION This report summarizes beach conditions and changes along the sand shoreline of Hilton Head Island, South Carolina for the period from February 216 to June 218. The results discussed herein are principally related to the post-project beach conditions of the 216 Hilton Head Island Beach Renourishment Project and the 217 South Island Emergency Beach Fill Project as well as Hurricanes Matthew and Irma. This report will serve as the first major discussion of the island s current shoreline conditions and the changes prescribed through the course of the aforementioned projects and storms, since the 216 Annual Beach Monitoring Report (Olsen Associates, Inc., 217). The conditions described herein represent June 218 conditions. The monitored area of the island is the 16.6-mile sandy shoreline between the Lands End Groin and Port Royal Plantation, corresponding to approximately HHI-A and HHI-39, respectively. The report includes (1) a summary of current beach conditions as of June 218, (2) a summary of shoreline and volumetric changes that occurred along the sand beaches of Hilton Head Island between February 216 and June 218, (3) a summary of beach conditions as of June 218 compared to post-216 project conditions in May 217, (4) a summary of shoreline position as of June 218 compared to the Recommended Minimum Beach Condition (RMBC) (Olsen Associates, Inc., 24), and (5) a summary of particular areas of interest, which include: Lands End, South Beach, The Heel, and Fish Haul Creek. The RMBC was established as a basis to evaluate the condition of the island s beaches relative to an assumed minimum width that the Town might want to consider. The minimum condition used herein is generally based upon the April 1997 island-wide beach position and condition. The beach survey conducted in April 1997 represents beach conditions that existed immediately prior to the construction of the 1997 Beach Renourishment Project. The defined RMBC was never formally adopted by the Town, but is used as an informal planning guideline. In this instance, it is simply used as a basis for discussion of conditions as they relate to a historical condition. In addition to these standard summary sections, other discussion features unique to this report include: Fish Haul Creek Marsh Grass, Joiner Bank, and Bay Point Shoals. These have been included to document beach and resource changes that may be of interest to the Town for future management purposes. 218 Annual Beach Monitoring Report September

8 1.1. Background The Town of Hilton Head Island has committed to a long-term beach management program that includes the preservation and enhancement of the island s sandy shorefront. The program was founded on shoreline restoration and maintenance with initial nourishment and subsequent, scheduled, periodic renourishment along portions of the island s Atlantic Ocean and adjacent sound shorelines. The program was initiated in 199 with the construction of the 199 Beach Restoration Project. Since 199, there have been seven other sand placement projects constructed by the Town of Hilton Head Island as part of their island-wide beach management program. The projects have included renourishment and expanded restoration of areas of the island s sand shoreline. Some of these projects have had multiple components that address problems along discrete areas. The seven projects include three large-renourishment projects, one in 1997, one in 26/7, and the other in 216; and four localized restoration projects, one in 1999, 211/12, 213, and 217. In sum, approximately 13.9 million cy of sand were placed (pay and non-pay) along more than 11 miles of the island s shoreline between 199 and 218. The details of each of these sand placement projects are presented below. The approximate location and extent of each of these projects is depicted in Figure Brief Summary of Renourishment History 199 Beach Nourishment Project. The Hilton Head Island 199 Beach Restoration Project was the initial comprehensive beach restoration project sponsored by the Town of Hilton Head Island. The project design called for the placement of approximately 2 million cy (pay volume) of sand from about the Westin Hotel (to the north) to just south of Coligny Circle (to the south). Including the tapers at both ends, the total project length was 35, ft (6.6 miles). Two offshore borrow sites were used for fill material. They were (1) the shoals seaward of Joiner Bank (at the island's north end) and (2) the landward-most section of Gaskin Banks (about 2.5 miles offshore of the island's central shoreline. The 199 project was constructed primarily during the summer months between May and August. The estimated total placed volume, pay and non-pay yardage, above the -1 ft NGVD contour was approximately 2,338, cy (Olsen Associates, Inc., 1992). 218 Annual Beach Monitoring Report September

9 HI-39 HI-38 HI-37 HI-36 HI-35 HI-34 HI-33 HI-32 HI-31 HI-29F HI-29C HI-29A2 HI-28D HI-28 HI-27 HI-26 HI-25 SINGLETON BEACH HI-24 HI-23 HI-22 HI-21 HI-2 HI-19A HI-19 HI-18 HI-17 HI-16 HI-15 HI-14 HI-13 HI-12 HI-11 HI-1 HI-9 HI-8 HI-7 HI-6 HI-5 HI-A HI-1 HI-1B HI-2 HI-4 HI Annual Beach Monitoring Report

10 1997 Beach Renourishment Project. In 1997, the shoreline reaches restored in 199 were renourished and new beach restoration work was performed along the Port Royal Sound shoreline (Figure 1.1). The latter was a new element of work and included the relocation of a tidal channel away from the shoreline and the placement of beach fill. In all, the 1997 Hilton Head Island Beach Renourishment Project consisted of three major elements (refer to Figure 1.1): (1) sand renourishment of approximately 38, ft of Atlantic Ocean shoreline (principally the same shoreline originally restored in 199), (2) relocation of a tidal channel within Port Royal Sound, and (3) sand placement along some 8,5 ft of Port Royal Sound shoreline. The tidal channel relocation and Port Royal Sound beach fill portions of the project were both necessary to provide comprehensive restoration of that shoreline. The entire project was constructed between May and November, The 1997 Hilton Head Island Beach Restoration Project included the placement of roughly 2,961,7 cy of sand (pay and non-pay) along approximately two-thirds of the island's Atlantic Ocean shorefront from about 1,7 ft north of the Westin Hotel, southward to Alder Lane at South Forest Beach, about 38, ft or 7.2 miles or shoreline. Similar to the 199 project, a no-fill section approximately 1,4 ft in length was located at The Folly. This no-fill area, which divided the project into two segments, was about 6 ft smaller than that for the 199 project due to the construction of a small sand-retention structure (i.e., rock groin) along the south side of The Folly. This new groin allowed beach fill material to be placed closer to The Folly at that location (Olsen Associates, Inc., 1999). The Port Royal shoreline channel relocation work required the excavation of about 315, cy of sand from the new channel area. Following completion of the channel relocation, the Port Royal Plantation shoreline received as beach fill approximately 421,3 cy (pay and non-pay) of beach fill along about 8,5 ft of soundfront shoreline. Two offshore borrow sites were used in the 1997 project. These were the same general areas used for the 199 project. These areas are located seaward of Joiner Bank (at the island's north end) and on the landward-most section of Gaskin Banks (about 2.5 miles offshore of the island's central shoreline) Emergency Beach Fill. A relatively small emergency beach fill project was constructed by the Town along a localized segment of shoreline at the south end of the island (i.e., South Beach) in The South Beach Beach Fill Project was constructed in January 1999 in response to chronic erosion on the southern terminus of Hilton Head Island adjacent to Calibogue Sound. This project placed about 29,2 cy along about 3,4-ft of shoreline in The Sea Pines Resort. The borrow area for the project was selected to be portions of the Barrett Shoals borrow site also identified for the Daufuskie Island beach nourishment project. The site lies just off the southern shoreline of Hilton Head Island in the Calibogue Sound ebb shoal 218 Annual Beach Monitoring Report September

11 complex. The South Beach project was constructed between January 1999 and February 1999 (Olsen Associates, Inc., 2). 26/27 Beach Renourishment Project. The 26/7 Hilton Head Island Beach Renourishment Project renourished portions of the previously constructed 199, 1997, and 1999 (i.e., South Beach) project segments that required sand fill at that time. The 26/7 project provided for the placement of beach-quality sand along about 8.4 miles of the island s sandy shoreline. The fill was placed along five distinct shoreline segments. Two of the project segments were along the Atlantic shorefront and covered roughly two-thirds of that portion of the island s sand shoreline from about 9 ft north of the Westin Hotel (HHI- 28) southward to Alder Lane at South Forest Beach (HHI-11). This is generally the same segment of shoreline restored in 199 and renourished in Including the tapers at both ends of the project, the final beach fill length along the Atlantic shorefront is about 38,7 ft (7.3 miles). The two segments are divided by The Folly, a small tidal creek on the north central area of the island s shorefront. Project permits required a no-fill area, approximately 1,3 ft in length, to reduce the potential for excessive shoaling of the creek mouth by beach fill migration (Olsen Associates, Inc., 28). The three other shoreline segments nourished as part of the 26/7 project included approximately 2, ft of shorefront along South Beach, 2,7 ft of shoreline along the Port Royal Sound shorefront in Port Royal Plantation, and a 2,2-foot stretch of Port Royal Sound shoreline north of Fish Haul Creek. As had been typical with the two past large nourishment projects on the island, no fill was placed along about 1,3 ft of shoreline between HHI-24 and HHI-25. This area includes the small tidal creek The Folly that is purposefully not filled to ensure that it remains open to tidal flows between the Atlantic Ocean and inland marsh. The 26/7 Hilton Head Island Beach Renourishment Project design called for the placement of approximately 2,725, cy of sand (pay and non-pay volume) along about 45,5 ft (8.4 miles) of shoreline at Hilton Head Island, SC. This included approximately 2,48, cy along the Atlantic Ocean shorefront, 158,1 cy along the Port Royal Sound shoreline, 57,3 cy along the South Beach shoreline, and 11,4 cy along the Fish Haul/Spa shoreline. In addition to beach fill construction at Fish Haul, the project included six small rubble mound (rock) breakwaters. The breakwaters were sited immediately seaward of the constructed beach, but detached from the shoreline and beach fill. 218 Annual Beach Monitoring Report September

12 Sand for the project was dredged from two offshore borrow sites; Joiner and Barrett Shoals. Dredging and beach fill construction began 17 September 26 and concluded on 1 February /12 Port Royal Sound Shoreline Restoration and Stabilization Project. The purpose of the project was to restore a localized area of highly erosional beach with sand fill from an offshore borrow site and stabilize the area with a low-crested, leaky groin (terminal groin). The project included sufficient sand volume to minimize potential downdrift effects of the permeable groin and meet typical annual sand transport volume demands expected for the period between project completion and future sand placement activities. The project is located at the northeastern end of Hilton Head Island, SC at the intersection of the Atlantic Ocean and Port Royal Sound shorelines. The project included (1) the placement of approximately 1.1 million cy of beach compatible sand along approximately 5,7 ft of Atlantic Ocean shoreline between Barnacle Road (just north of The Westin Resort) and the southern area of the sand spit at the northeast tip of the island as configured at the time of construction and (2) the construction of a low-crested, leaky groin (terminal groin) at the northern terminus of the island s Atlantic Ocean shorefront and within the limits of the beach fill (Olsen Associates, Inc., 212). The project area is located between Atlantic Ocean and Port Royal Sound shorelines that have been nourished in the past. The project included fill placement throughout the Designated Critical Habitat area for Piping Plovers (Unit SC-15). The area for this project had not been previously nourished. Beach quality sand fill for this project was dredged from a portion of a large linear ebb tidal shoal feature located on the eastern side of the Port Royal Sound ebb tidal shoal platform. Dredging and beach fill construction began 21 December 211 and concluded on 23 January 212. Rock work began on 9 January 212 and concluded on 4 April Island-wide Beach Renourishment Project. The 216 Beach Renourishment Project was a scheduled renourishment of portions of the previously constructed 199, 1997, 1999, 26/7, and 211/12 project segments that required sand fill at the time of construction, as a part of the Town s beach management plan. The purpose of this project was to reestablish the intended design conditions of Hilton Head Island s engineered beaches, defined as those reaches that have received direct sand placement in the past. This project also called for sand placement between HHI-3 and HHI-4, which was beyond the historical sand placement limits. The 216 project provided for the placement of beach-quality sand along about 42,8 feet (8.1 miles) of the island s sandy shoreline. The fill was placed along five distinct shoreline segments. The first and largest of the project segments was along the central Atlantic shorefront between The Folly (HHI-24) and Alder Lane in South Forest Beach (HHI-11). This area, 218 Annual Beach Monitoring Report September

13 described as Central Island, is generally the same segment of Atlantic Ocean shoreline restored in 199 and renourished in 1997 and 26/7, less the portion of the shoreline to the north of The Folly. Including the tapers at both ends of the project, the final beach fill length along Central Island that received sand in 216 is about 28,3 feet (5.4 miles). Three project segments were located along the northern end of the island one at The Heel and two along the Port Royal Sound shoreline. The first of these, The Heel, located within the limits of the 211/12 renourishment, includes approximately 3,2 feet of shoreline fronting both the Atlantic Ocean and Port Royal Sound in the vicinity of the terminal groin, from HHI-28B to HHI-29C. The second north end segment was located along about 3,6 feet from HHI-29F to HHI-31B on the Port Royal Sound shorefront in Port Royal Plantation. The third north end segment covered about 2,1 feet of Port Royal Sound shoreline northwest of Fish Haul Creek, from FH-5 to FH-14 (HHI-35), in the vicinity of the breakwater field constructed in 26/7. The last project segment included approximately 5,6 feet of shorefront from HHI-1C to HHI- 4 along both the Atlantic Ocean and Calibogue Sound shorelines of South Beach in Sea Pines. Total sand placement volume for the 216 Hilton Head Island Beach Renourishment Project amounted to approximately 2,892,5 cy of sand, including additional sand placed along the Central Island reach for erosion experienced during Hurricane Matthew. Beach-quality sand for this project was dredged from portions of large linear ebb tidal shoal features located to the north (Bay Point Shoals in Port Royal Sound) and south (Barrett Shoals in Calibogue Sound) of the island. Dredging was performed by a hydraulic cutter-suction dredge and deposited and shaped on the beach. Dredging and beach fill construction began 17 June 216 and concluded on 3 December South Island Emergency Beach Fill Project and Extension. The 217 South Island Emergency Beach Fill Project was an emergency restoration of both the South Beach segment of the 216 Beach Renourishment Project and approximately 6,7 ft of previously unrestored shoreline immediately northward thereof. The project was required to address impacts along these shorelines associated with Hurricane Matthew. During construction of the project, Hurricane Irma impacted the island s shoreline. Following an assessment of Irma related impacts to the island, the project was expanded to include fill placement along an additional 5,2 feet of shoreline immediately north of the original project limit. This extension was designed and permitted, following Hurricane Irma, to replace sand lost during that event. The beach along the extension had not been restored previously. After the storm, certain areas of the project completed prior to Hurricane Irma were refilled to replace storm related losses. The overall, post-irma, project was located entirely along the Sea Pines Resort shoreline between HHI-1C (Brown Pelican Rd) and approximately 1, ft north of HHI-8 (Duckhawk Rd). 218 Annual Beach Monitoring Report September

14 Fill was placed within a single distinct segment along both the Atlantic Ocean and Calibogue Sound shorelines of South Beach and South Island in Sea Pines, from HHI-1C to approximately 1, ft north of HHI-8. Of this 12,1 ft segment, approximately 5,4 ft of shorefront, from HHI-1C to HHI-4, were within the footprint of the previously-restored South Beach segment. After the passage of Hurricane Irma, the portion of the template that was filled prior to the storm and impacted by the storm was refilled. After completion of the original project, construction progressed contiguously northward along the 5,2 ft of shoreline that was added to the project, following Irma. An elevated dune feature was also included in the post-irma restoration plan to restore more interior dune and upland areas that had been several impacted and eroded by both Hurricane Matthew and Hurricane Irma. This dune is located approximately 7 ft south of HHI-4 to the northern limit of the expansion. The total sand placement volume for the 217 South Island Emergency Beach Fill Project (original scope, post-irma replacements, and post-irma extension) amounted to approximately 655,1 cy. Beach-quality sand fill for this project was dredged from a portion of a large linear ebb tidal shoal feature called Barrett Shoals, located to the south of the island in Calibogue Sound. Dredging was performed by a hydraulic cutter-suction dredge and pumped from the borrow area to the fill site through a submerged pipeline and subsequently deposited and shaped on the beach. Dredging and beach fill construction began 23 August 217 and concluded on 14 November Annual Beach Monitoring Report September

15 1.3. Survey Control The Town of Hilton Head Island s beach monitoring program is founded on the use of established survey transects located at permanent reference monuments along the island s shoreline. This system of permanent monuments is the Town s beach monitoring baseline. The monuments are referenced to standard horizontal and vertical control systems and datums. The horizontal datum used is the South Carolina State Plane coordinate system which is relative to the North American Datum of 1983 (NAD83) in International Feet. The vertical datum used for the purposes of beach monitoring and beach fill construction control is the National Geodetic Vertical Datum of 1929 (NGVD29). Table 1.1 lists the elevations of various fixed vertical and tidal datums in the vicinity of Hilton Head Island as reported by the National Geodetic Survey (NGS). For the purposes of beach monitoring, 74 stations (or monuments) exist as permanent points of reference. Thirty-two of these monuments whole numbers 1 through 32 were established in 1985 and have been surveyed at least twice a year since Thirteen intermediate monuments (e.g. 1A) were established prior to the 1997 renourishment project in order to obtain greater detail of beach change and conditions in specific areas of the shoreline, particularly along South Beach and the Heel. Seven monuments whole numbers 33 through 39 were established prior to the 26/7 renourishment project and included an area along the Fish Haul/Spa shoreline. The last eleven monuments were established prior to the 211/12 renourishment project in order to obtain greater detail of beach change around the Heel. The addition of these monuments necessitated renaming the preexisting intermediate monuments between HHI-29 and HHI-3. The primary monument locations and transect azimuths, reflecting those that have been renamed as well as listing their previous name, are tabulated in Table 1.2. In addition to the seven primary stations developed prior to the 26/7 project, 14 intermediate stations were developed along the nourished Fish Haul shoreline. Three of these stations FH3, FH9, and FH14 are located concurrently with primary stations HI33, HI34, and HI35, respectively for 74 unique monuments established for surveying and control purposes. 218 Annual Beach Monitoring Report September

16 Table 1.1: Tidal datums for various tidal stations around Hilton Head Island (NGS). All elevations are in feet and relative to NGVD29. NGS Station ID NGS Station Name Fort Pulaski Broad Creek Daufuskie Landing Port Royal Pltn. Bloody Point Skull Creek South Mean Higher-High Water (MHHW) Mean High Water (MHW)* NAVD Mean Sea Level (MSL) Mean Tide Level (MTL) NGVD Mean Low Water (MLW) Mean Lower-Low Water (MLLW) * For analysis purposes, an elevation of 3.72ft NGVD29 was used for the MHWL. 218 Annual Beach Monitoring Report September

17 Table 1.2: Beach profile monument control tabulation for Hilton Head Island, SC. Origin Position Monument Grid Azimuth Profile Previous Name Easting (int'l ft-nad83) Northing (int'l ft-nad83) Elevation (ft-ngvd) (decimal degrees) A B A B C A A Annual Beach Monitoring Report September

18 Table 1.2 (cont): Beach profile monument control tabulation for Hilton Head Island, SC. Origin Position Monument Grid Azimuth Profile Previous Name Easting (int'l ft-nad83) Northing (int'l ft-nad83) Elevation (ft-ngvd) (decimal degrees) A B A B C D A1 29A A2 29A A3 29A B 29A C 29B D 29B E 29B F 29C A A B FH FH FH-3 (HI-33) FH FH FH FH FH FH-9 (HI-34) FH FH FH FH FH-14 (HI-35) Annual Beach Monitoring Report September

19 1.4. Physical Monitoring Program The Town of Hilton Head Island has been continually monitoring the physical condition of the island s sandy shorelines since Presently, the program includes semi-annual beach profile surveys at up to 74 individual beach profile transects and annual reports of findings. Data collected along the beach monitoring transects are used to track shoreline and beach volume changes as well as beach renourishment performance. In addition to the island-wide beach monitoring program, the 26 Fish Haul/Spa shoreline improvements permit required a project specific monitoring plan following completion of that segment that included a greater frequency of surveys in the first two years following construction. Although the permit related monitoring for the Fish Haul/Spa project is now complete, the Town of Hilton Head Island has incorporated the Fish Haul/Spa monitoring baseline into the semi-annual island-wide monitoring program. The intermediate survey lines along the Fish Haul/Spa project shoreline are only surveyed to wading depth Hurricane Matthew During this inter-survey period, Hilton Head Island was impacted by Hurricane Matthew between 7 and 8 October, 216. The center of the storm passed about 5 to 1 miles offshore of Hilton Head Island before making landfall as a Category 1 storm over the Cape Romain National Wildlife Refuge, approximately 8 miles northeast of Hilton Head Island. Through the course of the storm, the Island endured maximum winds of nearly 9 mph, more than 19 inches of rain, and peak water levels near +9.4 ft (NGVD 29) with wave-driven storm run-up that may have reached even higher elevations. The entire beach between the Lands End Groin and Fish Haul Creek lost a total of 836,2 cy (9.7 cy/ft) of sand from above the MHW shoreline due to Hurricane Matthew. Across the beach profile out to the depth of closure 5 (DOC) the beach lost a total of 384, cy (4.4 cy/ft) of sand. In addition to beach volume losses, there was an estimated loss of 33.6 acres of dune vegetation along approximately 44, ft of engineered shoreline as a result of the storm related erosion and dune loss. Hurricane Matthew impacted the Island during the final construction phase of the 216 Island-wide Beach Renourishment Project, which drove up the amount of sand lost above the MHW line; however, since the construction contractor was still on site, part of the beach fill was immediately refilled in the storm aftermath. For a complete analysis of the storm and its impacts to the Town of Hilton Head Island, see the Post-Hurricane Matthew Condition Assessment: October 216 Category G report submitted to FEMA in April 217 (Olsen Associates, Inc. Feb. 217). 5 The depth beyond which there is normally no change in profile with time. The offshore depth beyond which beach profiles taken over time at a given site coincide (Dean and Dalrymple, 24) Annual Beach Monitoring Report September 218

20 1.6. Hurricane Irma Hurricane Irma impacted Hilton Head Island between September 9 and 12, 217 with the most severe conditions occurring on September 11, 217. The impacts to the island were realized through the significant and sustained onshore flow associated with the powerful hurricane as it approached and moved up the Florida peninsula. During the storm, the island experienced sustained winds of up to 45 mph, and gusts reaching as high as 6 mph. Water levels in the vicinity of the Island were approximately +9. ft (NGVD29), with maximum storm surge of about 5.5 feet above the predicted levels. Through the course of Hurricane Irma, Hilton Head Island experienced island-wide sand losses, including previously completed areas of the 217 Emergency Beach Fill Project. Between the Lands End Groin and Fish Haul Creek, the beach lost a total of 526,6 cy (6.1 cy/ft) of sand from above the MHW shoreline due to Hurricane Irma. Across the beach profile out to the depth of closure (DOC) the beach lost a total of 255,7 cy (3. cy/ft) of sand. Unlike Hurricane Matthew, there was no observed vegetation loss through the impacts of Hurricane Irma. Hurricane Irma impacted the Island during construction of the 217 South Island Emergency Beach Fill Project, which drove up the amount of sand lost above the MHW line in the South Beach and South Island shoreline reaches. After the passage of the storm, a portion of the 217 beach fill that had been lost through the storm was refilled to the design template. For a comprehensive analysis of the storm and resulting impacts to all shorelines of Hilton Head Island, see the Post-Hurricane Irma Condition Assessment: September 217 FEMA Category G report (Olsen Associates, Inc. 218). 218 Annual Beach Monitoring Report September

21 2. BEACH CONDITION SUMMARY 2.1 Organization of Monitoring Results The following sections are organized to present shoreline and beach volume conditions for the entire monitored shoreline 6 of Hilton Head Island in their current state, for three intercomparisons of beach conditions, and for unique conditions along the shoreline. The first section explores the current, June 218, beach condition. The second explores three time periods: February 216 to June 218, May 217 to June 218, and June 218 relative to the RMBC. The February 216 to June 218 period represents overall change to the island s shoreline after both beach projects and Hurricanes Matthew and Irma. May 217 to June 218 was chosen to analyze the performance of the 216 Island-wide Renourishment Project over the appropriate reaches that did not receive additional beach fill in 217. The RMBC has been used as a baseline for comparison but has not been formally adopted by the Town. Nonetheless, it is useful for insight as to when the Town might consider taking action for a future renourishment project. The final section discusses unique conditions along the island s shoreline which have been identified for further analysis. The shoreline is sub-divided into segments which are defined using natural boundaries where appropriate (e.g. Braddock Cove Creek, The Folly, Fish Haul Creek) and other designations commonly-used to identify beach areas. Additionally, to simplify the presentation of results, the island is divided into two regions as delineated by The Folly. Herein, two regions, consisting of seven distinct shoreline segments, will be discussed: o South of The Folly Calibogue Sound Shoreline (Braddock Creek to HHI-1) South Beach Shoreline (HHI-1 to HHI-4) South Island (Atlantic) Shoreline (HHI-4 to HHI-11) Central Island (Atlantic) Shoreline (HHI-11 to The Folly) o North of The Folly North Island (Atlantic) Shoreline (The Folly to HHI-28) The Heel Shoreline (HHI-28 to HHI-29E) Port Royal Plantation Shoreline (HHI-29E to Fish Haul Creek) Fish Haul Creek Shoreline (Fish Haul Creek to HHI-35) Inner Port Royal Sound Shoreline (HHI-35 to HHI-39) 6 The monitored shoreline is located between the Lands End Groin at Braddock Cove Creek on Calibogue Sound and the southern limit of Hilton Head Plantation on the Port Royal Shoreline, corresponding to approximately HHI- A and HHI-39, respectively Annual Beach Monitoring Report September 218

22 2.2 Current Beach Condition (June 218) In this section, the current beach condition is described by the island s beach width, which is represented as the distance from the Town s Beachline 7 to the Mean High Water shoreline (MHW) of the June 218 survey. Figure 2.1 presents the beach width along the Hilton Head Island shoreline from Lands End Groin to Inner Port Royal Sound. Also included is the distance from the Beachline to the Parcel Boundary, where the Parcel Boundary is the seaward-most property line adjacent to the beach, which is, in most cases, the seaward-most extent of individual upland private property. The figure also highlights problem areas along the shoreline where the beach is narrower than typical conditions. Accompanying the figure is Table 2.1 which lists the beach width as of pre-project in 216 and current conditions in 218. Fill placement as part of the 216 project was planned to address areas where the combined effect of narrow beach width, both existing and projected twoyear conditions, and high shoreline change rates were expected to lead to problematic beach conditions prior to the end of the planned project life (i.e., 7-1 years following construction). Fill for the 217 project was designed to address the impacts of Hurricane Matthew, and subsequently Irma, along the South Beach and South Island shorelines. Overall, the average beach width for the entire monitored shoreline of the island was ft as of June 218. The greatest width was ft, found at HHI-29A3 (near the terminal groin), and the smallest width was 95.3 ft at HHI-A. The only area of the island identified as narrow 8 was a portion of the Calibogue Sound shoreline between the Lands End Groin and HHI- A, which has not required nourishments since inception of the Town s beach nourishment program in 199. For monitoring purposes, the benchmark for a narrow beach width is a distance of 2 ft or less from the Beachline to the 218 MHW (+3.72 ft NGVD29). The 2 ft distance is not a defined management distance, but rather a measurement used so that comparative assessments of relative shoreline conditions can be performed. The narrow beach width in this segment along Calibogue Sound is the same as that which has generally been reported over the last four monitoring periods. Despite being narrow, this area does not present itself as a concern, currently, since it has historically been a stable region. Relative to previous monitoring periods, the current condition has seen fewer narrow beach segments likely because of the effects of the two beach fill projects that are encapsulated in the results. 7 The Town s Beachfront Line is a local regulatory line adopted by the Town in December 26 and is defined as having the same location as the 1999 OCRM Baseline. No development may be further seaward than this line. 8 A benchmark for narrow is considered a distance of 2 ft or less between the Beachline and the 218 MHW Annual Beach Monitoring Report September 218

23 As of June 218, the Calibogue Sound shoreline (HHI-A to HHI-1) had an average beach width of ft. The thinnest and only narrow area of this shoreline reach was at HHI- A, which was 95.3 ft wide. The widest station along this reach was at HHI-1, which was ft wide. In South Beach (HHI-1 to HHI-4), the average beach width was ft, which tended to decrease in width from south to north. The widest portion of this reach was found at HHI-1A, which had a beach width of ft, and the thinnest area was around HHI-4, which was 25.3 ft wide. Along the South Island shoreline (HHI-4 to HHI-11), the beach was approximately ft wide, on average, and slightly increased from south to north. The widest measured beach width in this reach was 33.7 ft at HHI-11, while the thinnest was 25.3 ft at HHI-4. Generally, the South Island shoreline of the island has typically not had a very wide shoreline, but has not been a concern since the reach has historically been stable to moderately accretional. The Central Island shoreline (HHI-11 to HHI-24) had an average beach width of 331. ft, with the widest area of 41.4 ft found at HHI-18, and the thinnest area of ft at HHI-24. This shoreline reach was stable with no major fluctuations of beach width; however, the slightly decrease in width near from HHI-21 to HHI-24 was likely to be influenced by The Folly. Within the North Island shoreline reach (HHI-24 to HHI-28), the average beach width was 49.9 ft. The greatest beach width in this segment was ft at HHI-28, and the smallest beach width was ft at HHI-24. In the North Island shoreline, the beach width tended to increase from south to north towards The Heel. The Heel shoreline segment (HHI-28 to HHI-29E) was generally the widest reach of the island, with an average beach width of ft. The widest part of The Heel was ft at HHI29-A3, while the smallest width was 536. ft at HHI-29. The beach width in this segment increases from south to north and is principally sustained by the terminal groin structure in the vicinity of HHI-29A1 through HHI-29A3. Along the Port Royal Plantation shoreline (HHI-29E to HHI-32), the average beach width was 51.1 ft. The beach width in this segment tended to decrease from south to north as the shoreline progressed into Port Royal Sound. The greatest width was ft at HHI-29E, and the smallest width was ft at HHI-3A. 218 Annual Beach Monitoring Report September

24 FISH HAUL CREEK Lands End Groin HILTON HEAD ISLAND Fish Haul Creek PORT ROYAL PLANTATION SOUTH BEACH Port Royal Sound WESTIN US 278 BUSINESS SOUTH FOREST BEACH SEA PINES BRADLEY BEACH SINGLETON BEACH PALMETTO DUNES NORTH FOREST BEACH COLIGNY CIRCLE MARRIOTT Groin Westin The Folly Atlantic Ocean HI32 HI31 HI3 HI29C HI29A HI29 HI28 HI27 HI26 HI25 HI24 HI23 HI22 HI21 HI2 HI19A Marriott Alder Ln HI19 HI18 HI17 HI16 HI15 HI14 HI13 HI12 HI11 HI1 HI9 HI8 HI7 HI6 HI5 HI4 HI3 HI2 HI1 HIB HIA Lands End Groin Beach Width < 2ft (Town Beachline) 216 Project 217 Project Beach Fill Projects 1 Parcel Boundary Fish Haul Creek 2 Westin 3 4 Beach Width from Beachline to MHW (ft) Groin Beach widths exceed 5 ft The Folly Marriott Alder Lane MHW Shoreline (May 218) Beach widths exceed 5 ft Lands End Groin MHW change exceeds 2 ft 1 MHW Change Feb-16 to May-18 (ft) 2 Volume change exceeds 12 cy/ft Volume change exceeds 12 cy/ft Beach Volume Change (cy/ft) Alongshore Distance from Lands End Groin (feet) Figure 2.1: Beach width, MHWL shoreline change, and beach volume change along the Hilton Head Island shoreline. Change is based on the period from February 216 to May Annual Beach Monitoring Report

25 Table 2.1: Hilton Head Island Beach Width and Shoreline Change Rates. Areas highlighted red indicate a narrow beach width (< 2 ft). Whole Island Calibogue Sound South Beach South Island Central Island Monument Range Alongshore Distance from Lands End (ft) Beach Width Distance to Town Beachline (ft) Feb-16 Jun-18 Change HIA 1, HIB 2, HI1 3, Average HI1 3, HI1A 4, HI1B 4, HI1C 4, HI2 5, HI2A 6, HI3 6, HI4 9, Average HI4 9, HI5 13, HI6 15, HI7 18, HI8 2, HI9 22, HI1 24, HI11 26, Average HI11 26, HI12 28, HI13 31, HI14 33, HI15 35, HI16 38, HI17 39, HI18 4, HI19 43, HI19A 45, HI2 46, HI21 48, HI22 51, HI23 53, HI24 54, Average Continued on next page 218 Annual Beach Monitoring Report September

26 Table 2.1 (cont.): Hilton Head Island Beach Width and Shoreline Change Rates. Areas highlighted red indicate a narrow beach width (< 2 ft). Whole Island North Island The Heel Port Royal Plantation Lands End Groin to Fish Haul Creek Monument Range Alongshore Distance from Lands End (ft) Beach Width Distance to Town Beachline (ft) Feb-16 Jun-18 Change HI24 54, HI25 56, HI26 6, HI27 64, HI27A 64, HI27B 65, HI28 66, Average HI28 66, HI28A 67, HI28B 67, HI28C 67, HI28D 68, HI29 68, HI29A1 69, HI29A2 69, HI29A3 69, HI29B 7, HI29C 7, HI29D 7, HI29E 71, Average HI29E 71, HI29F 71, HI3 72, HI3A 73, HI31 73, HI31A 74, HI31B 75, HI32 76, Average Average Minimum Maximum Annual Beach Monitoring Report September

27 Figure 2.2 displays the history of beach sand volume change along the entire Hilton Head Island shoreline relative to the February 199 pre-project condition. The figure presents total beach volume changes within the project limits measured to profile change closure 9. Volume changes are tracked from the February 199 pre-construction conditions until the current, June 218, survey and include the initial beach restoration in 199, the renourishment in 1997, the 1999 Emergency beach fill at South Beach, the renourishment in 26/7, the 211/12 Port Royal Sound Shoreline Restoration project, the 216 Island-wide renourishment, and the recent 217 South Island Emergency Beach Fill project. The figure shows that as of June 218, approximately Mcy of sand are located within project limits compared to the February 199 pre-project condition. Note that the inclusion of volumetric changes in this figure do not include the Calibogue Sound shoreline until April 1997 or the Inner Port Royal Sound shoreline until April 26. Figure 2.2: Hilton Head Island beach sand volume change over time. 9 The depth beyond which there is normally no change in profile with time. The offshore depth beyond which beach profiles taken over time at a given site coincide (Dean and Dalrymple, 24) Annual Beach Monitoring Report September 218

28 2.3 Monitoring Period Beach Changes (February 216 to June 218) This section presents a summary of shoreline and beach volume change that occurred along the island between February 216 and June 218. The February 216 survey is assumed to represent the beach conditions prior to the effects of the 216 beach renourishment project, Hurricanes Matthew and Irma, and the 217 post-matthew/irma emergency restoration beach fill. Results based upon comparison of these two surveys represent the total net change to the island s beach as a result of these four events Shoreline Change Figure 2.3 depicts the MHW shoreline (+3.7ft NGVD29 elevation) change of the beach between Braddock Cove Creek on Calibogue Sound and The Folly on the Atlantic Ocean for the period from February 216 to June 218. Figure 2.4 depicts the MHW shoreline change of the beach between The Folly and HHI-39, fronting Hilton Head Plantation on Port Royal Sound, for the same time period. Shoreline position changes at each beach monitoring station are listed below in Table 2.2. The table also presents the average shoreline position change for each beach segment as well as the entire sand shoreline between Braddock Cove Creek and HHI-39. Between February 216 and June 218, the MHW shoreline experienced major changes along the entire beach due to the 216 and 217 beach projects and the effects of Hurricanes Matthew and Irma, most notably. On average, over the entire shoreline, the MHW advanced approximately ft (weighted 1 ) over the roughly two-year period, with the greatest advance of ft at FH-6 and the greatest retreat of ft at FH-2. Shoreline advance occurred along all reaches except one. Two reaches, North Island (HHI-25 to HHI-28) and Inner Port Royal Sound (HHI-35 to HHI-39), experienced average shoreline recession during this period; however, these areas also did not receive any direct sand placement from either of the two projects. Three primary regions are shown to have experienced a retreat of the MHW and a loss of beach volume during this period: Calibogue Sound and South Beach (HHI-A to HHI-B and HHI-1A to HHI-1C), North Island (HHI-27 to HHI-HHI-28), and The Heel (HHI-29D to HHI-29E); however, it should be noted that none of these reaches received direct sand placement during either of the projects. The Calibogue Sound (HHI-A to HHI-1) shoreline experienced an average MHW advance of ft over this period, with a maximum advance of ft at HHI-1 and a maximum recession of ft at HHI-B. The South Beach (HHI-1 to HHI-4) shoreline experienced advance of ft over the same period, with the majority of stations moving 1 The average MHW change was calculated by using the change computed at each monitoring station and is weighted by the distance between each monitoring station (e.g. a longer reach represents more of the average) Annual Beach Monitoring Report September 218

29 seaward. The greatest advance in this segment was at HHI-2A, which grew ft, and the greatest retreat was at HHI-1A, which retreated ft. Over this period, the South Island shoreline advanced, on average, ft (HHI-4 to HHI-11). The greatest advance in this segment was at HHI-4, which advanced ft, and the only retreat was seen at HHI-1, where the shoreline effectively stayed in the same position, only moving -2.6 ft. This was the first period that included sand placement along the South Island shoreline. 218 Annual Beach Monitoring Report September

30 Figure 2.3: Mean high water shoreline (MHW, +3.7 ft NGVD29) changes along Hilton Head Island between February 216 and June 218, south end. Project areas shaded grey. 218 Annual Beach Monitoring Report September

31 Figure 2.4: Mean high water shoreline (MHW, +3.7 ft NGVD29) changes along Hilton Head Island between February 216 and June 218, north end. Project areas shaded grey. 218 Annual Beach Monitoring Report September

32 Table 2.2: Hilton Head Island MHW Change Summary (February 216 to June 218). 216 Fill 217 Fill 216 Fill Alongshore Shoreline Position (ft) Alongshore Shoreline Position (ft) Distance (ft) at MHW (+3.7 ft, NGVD) Distance (ft) at MHW (+3.7 ft, NGVD) Seg Mon from Lands End Feb-16 Jun-18 Change Seg Mon from Lands End Feb-16 Jun-18 Change Braddock Cove Creek HI-28 67, HI-A 1, HI-28A 67, HI-B 2, HI-28B 68, HI-1 3, HI-28C 68, , HI-28D 68, HI-1 3, HI-29 69, HI-1A 4, HI-29A1 7, HI-1B 4, HI-29A2 7, HI-1C 5, HI-29A3 7, HI-2 5, HI-29B 71, HI-2A 6, HI-29C 71, HI-3 7, HI-29D 71,685 1, HI-4 1, HI-29E 71,975 1, , , HI-4 1, HI-29E 71,975 1, HI-5 13, HI-29F 72, HI-6 16, HI-3 73, HI-7 19, HI-3A 74, HI-8 21, HI-31 75, HI-9 23, HI-31A 75, HI-1 25, HI-31B 76, HI-11 27,75 1,1.1 1, HI-32 77, , , HI-11 27,75 1,1.1 1, Fish Haul Creek HI-12 29, , FH-1 79, HI-13 31, FH-2 79,52 1, HI-14 34, HI-33 79,77 1, HI-15 36, FH-4 8, HI-16 39, FH-5 8, HI-17 4, FH-6 8, HI-18 41, FH-7 8, HI-19 43, FH-8 81, HI-19A 46, HI-34 81, HI-2 47, FH-1 81, HI-21 49, FH-11 81, HI-22 52, FH-12 82, HI-23 54, FH-13 82, HI-24 55, HI-35 82, , , The Folly HI-35 82, HI-25 57, HI-36 83, HI-26 61, HI-37 85, HI-27 64, HI-38 86, Calibogue Sound North Island Central Island South Island South Beach HI-27A 65, HI-39 87, HI-27B 66, ,3-4.2 HI-28 67, ,63 1, The Heel Port Royal Plantation Fish Haul Creek Inner Port Royal Sound Fill 216 Fill 216 Fill 218 Annual Beach Monitoring Report September

33 The Central Island beach, from Alder Lane to The Folly, experienced an average advance in MHW shoreline position of ft, with the beach advancing seaward at all transects during this period. The greatest MHW advance was at HHI-16 ( ft), while the smallest was at HHI-12 (+55.5 ft). The entirety of this reach was nourished during the 216 project and after Hurricane Matthew. This contributed to the large and consistent shoreline advance along the whole segment during this period. The North Island shoreline, from The Folly to HHI-28, retreated by -6.8 ft, on average. Four of the six transects experienced moderate erosion, while the beach at HHI-25 and 26, adjacent to The Folly, experienced accretion. The greatest accretion along North Island was at HHI-25, which grew by ft, and the greatest recession was at HHI-27B, which retreated ft. The beach narrowing along the northern portion of this reach and widening towards the south end may be indicative of the continual southerly directed movement of sand from The Heel. Over this period, the North Island shoreline was not nourished; however, this segment of shoreline may be benefitting from sand placement along The Heel. The Heel MHW shoreline, between approximately HHI-28 and HHI-29E, MHW shoreline advanced by ft, on average during this period. 66% of the Heel reach, by length, was filled as part of the 216 island-wide renourishment project, with the largest advance of ft occurring at HHI-29A2. The segment between HHI-29C and HHI-29F saw the greatest retreat of ft at HHI-29E this segment is north of the groin and was not filled, which is why that section saw the greatest retreat within this shoreline reach. The Heel continues to be a very dynamic area of the island, characterized by large sand movements associated with south to north sand movement along the shoreline and adjacent nearshore shoals (see Figure 2.17). A large shoal feature near HHI-29F appears to be influencing the shoreline change most along a segment of The Heel reach immediately north of the groin. The Port Royal Plantation shoreline, from HHI-29E to Fish Haul Creek (just past HHI- 32), advanced by an average of ft during this period. Except for HHI-29E and 29F, which retreated -97. ft and -44. ft, respectively, this entire reach advanced, with the largest advance of ft at HHI-3. As evidenced by the aerials presented in Appendix B, the section between HHI-29F and HHI-31B appeared to be highly eroded in February 216, so the nourishment of 216 provided a significant amount of width to the very narrow beach. In addition to the beach project, the continued south to north movement of the aforementioned large sand wave may have also provided this area with additional width. It is difficult to determine, however, the extent of onshore migration contributions from the remnants of Joiner Bank due to the effect of the 216 beach fill. During this period, the Fish Haul Creek (FH-1 to HHI-35) shoreline advanced by ft, on average. Through the course of the 216 project, between FH-5 and FH-14 was 218 Annual Beach Monitoring Report September

34 the only area to receive fill and was the only area to record an advance between February 216 and June 218. It is evident that the northern portion of this segment was impacted by the movement of a large sand mass within the Fish Haul Creek reach, as seen by the attachment of the sand spit at FH-4 in the 216 to 218 aerial images in Figure As discussed in Section 2.6.4, the attachment of the sand spit to the northernmost breakwater has stopped Fish Haul Creek from draining to the north. Since the creek is not able to drain to the north, and now only drains directly to the east, the area to the north has begun to fill in with sand. Other sand movement can also be seen by the retreat of the shoreline between FH-1 and FH-4 and the progressive advance of the shoreline beginning at FH-5. The greatest advance was found at HHI-6 for ft, and the greatest retreat was at FH-2 for ft. Along the Inner Port Royal Sound segment of the island, from HHI-35 to HHI-39, the MHW shoreline retreated by -4.2 ft on average. The greatest advance in this reach was at HHI-35 for ft, and the greatest retreat was at HHI-36 for ft. The only advance in this segment was at HHI-35; whereas, the shoreline between HHI-36 and HHI-39 retreated. This segment did not receive any sand placement during the 216 or 217 projects Beach Volume Change Figure 2.5 displays the computed beach volume changes along the shoreline between Lands End Groin on Calibogue Sound and The Folly on the Atlantic Ocean for the period between February 216 and June 218. Additionally, Figure 2.6 depicts the volume change for the shoreline located between The Folly and HHI-39, fronting Hilton Head Plantation on Port Royal Sound. The top graph on each figure displays the local beach volume density change in cubic yards per foot of shoreline (cy/ft), and the bottom portion of the figure shows the cumulative beach volume change in cy summed along the shoreline from Braddock Cove Creek (HI-A) to The Folly and The Folly HHI-39, respectively. The corresponding beach volume changes are listed below in Table 2.3 for each beach segment along the monitored shoreline. The red line around HHI-B and HHI-1 denotes that a special method of volume calculation was used to accommodate shoreline curvature, discussed in the following paragraph. Figure 2.7 illustrates the approach applied to more accurately approximate the volume change than the traditional average end-area method, due to the curvature of the Island between HHI-B and HHI-1. In the traditional method, the average change of two cross-shore profiles is multiplied by the distance between them to estimate the total volume change. For curved shorelines, however, the distance between the profiles varies depending on which portion of the cross-shore profile is being inspected. In the applied approach, the HHI-B and HHI-1 profiles are split into three zones: nearshore, mid-shore, and offshore. The beach profile volume density was computed along each profile and averaged between the corresponding zones of each profile (e.g. average of 1-1 and 2-1), then multiplied by the arc length (d1, approximate centroid 218 Annual Beach Monitoring Report September

35 of zones 1-1 and 2-1) between them. The purpose of using three zones is to more accurately portray the total alongshore distance between corresponding portions of the profiles; that is, the deep-water part of the profile describes a larger area than the nearshore portion. The results are added together for the three zones to represent the volume change between the two profiles. Clearly, more zones could be used to increase the accuracy, but it was assumed that three zones were sufficient for beach change monitoring purposes. Between February 216 and June 218, the total monitored area of the island s beach Braddock Cove Creek on Calibogue Sound to the southern end of the Hilton Head Plantation revetment on Port Royal Sound gained a net +3,326,6 11 cy (+37.7 cy/ft) 12. This volume represents the net change that occurred during this period. This included the changes associated with the 216 and 217 beach fill projects as well as Hurricanes Matthew and Irma. Because of the beach fill projects, the net increase in volume is attributed to the addition of sand to the system. Increases in total beach volume were greatest along the Atlantic-fronting reaches of Central Island, South Island, and South Beach. The only area to have lost sand during this time was the semi-isolated Inner Port Royal Sound (HHI-35 to HHI-39) shoreline, which also did not receive any sand placement over this period. Along the Calibogue Sound (HHI-A to HHI-1) shoreline, the beach was highly accretional, gaining +199,5 cy (+54.1 cy/ft) of sand, primarily due to unusually large accretion ( cy/ft) at HHI-1. It is noted that this reach was not filled during the 216 or 217 project. Gain of sand across this profile is attributed to the general northeast to southwest migration of sand at the toe of the island and the potential for deposition where the shoreline transitions from the Atlantic to Calibogue Sound shoreline. Along South Beach (HHI-1 to HHI-4) the shoreline gained +56, cy (69.7 cy/ft) of sand from February 216 to June 218. Within the same fill limits of the 216 and 217 projects, from HHI-1C to HHI-4, the greatest gain of sand was between HHI-3 and HHI-4 for +272,6 cy (87.1 cy/ft) over 3,13 ft. Outside of the project limits, between HHI-1 and HHI- 1A, there was a gain of +11,5 cy of sand, again due to a large sand lobe. Changes in sand volume in this reach were concentrated between MHW and the DOC, as can be seen in the profiles found in Appendix A. Sediment accumulation can be found in the gorge of Calibogue Sound, where the sand does not appear likely to move back onshore. Along the South Island segment, from HHI-4 to Alder Lane (at approximately HHI-11), the total beach volume increased by +599,3 cy (+35.2 cy/ft). Gains across this segment are 11 This number is only from profiles surveys and does not include the estimated 29, cy of sand Fish Haul Creek. Including the estimation at Fish Haul Creek, the total would be +3,355,6 cy. 12 Unless stated otherwise, the volume changes in this report were computed from the seaward edge of the most seaward dune feature evident in the beach profile data to the apparent location of beach profile closure Annual Beach Monitoring Report September 218

36 principally due to the 217 project, which extended from HHI-4 to HHI-8+1 in the South Island segment. Gains range from a maximum of +23,4 cy (+87.1 cy/ft) between HHI-4 and HHI-5 to a minimum of +1,9 cy (+1. cy/ft) between HHI-9 and HHI-1. Much of the sand in this segment is found between MHW and the DOC because of continuous equilibration of the beach after the 217 project. The beach along the Central Island segment, from Alder Lane (HHI-11) to The Folly, gained about +1,4,3 cy (+48.4 cy/ft). This entire segment received fill during the 216 project and all segments currently have a positive sand volume, relative to the pre-project conditions of February 216. The greatest increase of volume occurred between HHI-15 and HHI-16 for +218,2 cy (+75.8 cy/ft), which had previously been a narrow (< 2 ft wide) stretch of shoreline prior to the 216 project. The smallest increase in volume was between HHI- 24 and The Folly for +35,3 cy (+53.5 cy/ft). The North Island shoreline was another reach which did not receive any sand placement from neither the 216 nor 217 projects. From The Folly to HHI-28, the beach gained +11, cy (+1. cy/ft) of sand from February 216 to June 218, with gains and losses varying throughout the segment. Four of the transects experienced erosion, while two of the transects accreted. Between The Folly and HHI-25 the shoreline eroded, which may be due, in part, to water drainage from The Folly, particularly during Hurricanes Matthew and Irma. Above MHW, the shoreline experienced mild overall erosion; yet, there was more accretion in the lower portion of the profile, possibly due to southerly directed transport from The Heel. The greatest volume increase was by +22,8 cy (+6.6 cy/ft) between HHI-26 and HHI-27, and the greatest loss was by -8,1 cy (-11.4 cy/ft) between HHI-27B and HHI-28. The Heel shoreline, from HHI-28 to HHI-29E, gained a total of +163,2 cy (+32.2 cy/ft) of sand across the entire profile. During the 216 project, a segment of this reach was filled between HHI-28B and HHI-29C and currently has a positive sand volume, relative to the preproject conditions. The greatest volume increase was by +54,1 cy (+81.3 cy/ft) between HHI- 29 and HHI-29A1, while the greatest loss was -14,4 cy (-49.6 cy/ft) between HHI-29D and HHI-29E. The Heel is generally a very dynamic reach of Hilton Head Island, due to the interactions between the northern terminus of the island, Port Royal Sound, and Joiner Bank. Over this period, sand from Joiner Bank has been observed to be attaching to the north end of the island which may have an influence on the sediment transport in this region (see Figure 2.17). The Port Royal Plantation shoreline, from HHI-29E to Fish Haul Creek, gained +346,3 cy (+51.8 cy/ft) during this period. A portion of this reach, between HHI-29F and HHI-31B, was filled during the 216 project. The greatest increase of beach volume in this reach was +118,4 cy ( cy/ft) between HHI-3 and HHI-3A. The greatest, and only, loss was -18,1 cy ( cy/ft) between HHI-29E and HHI-29F. 218 Annual Beach Monitoring Report September

37 Along the Fish Haul Creek shoreline, from the creek to HHI-35, there was a net gain of +16,5 cy (+27.6 cy/ft). The greatest increase of volume was +23,6 cy (+94.2 cy/ft) between FH-5 and FH-6, while the greatest loss was -13, cy (-51.8 cy/ft) between FH-1 and FH-2. This segment was filled between FH-5 and HHI-35 during the 216 project. As seen in Figure 2.18, much of the change experienced, as with the MHW, was due to the attachment of the sand spit to HHI-34. The spit has attached to the northernmost breakwater along Fish Haul Creek and appears to be filling in with sand landward thereof. At this point it is unclear how much farther the spit may attach to Fish Haul Creek. To account for the volume change across the creek not captured by surveys, where sand is seen to be accumulating in the aerials (Appendix B), the volume change was estimated by multiplying the surface area of the uncaptured region by the average profile height change from February 216 to June 218 at FH-1. It is estimated that approximately +29, cy 13 exists across the creek and nearby shorelines. Lastly, the Inner Port Royal Sound segment of the island, from HHI-35 to HHI-39, experienced a loss of -5,5 cy (-1. cy/ft) over the monitoring period. Three of the four reaches in this segment experienced losses, with accretion of +6,1 cy (+4.6 cy/ft) between HHI-35 and HHI-36, and the greatest loss of -6,1 cy (-4.6 cy/ft) between HHI-36 and HHI This +29, cy is not included in the total shown in Table 2.3. The total change would be +3,355,6 cy from February 216 to June 218 if it were included Annual Beach Monitoring Report September 218

38 Figure 2.5: Beach volume changes on Hilton Head Island, SC between February 216 and June 218. Areas filled in 216 and 217 are shown in grey. 218 Annual Beach Monitoring Report September

39 Figure 2.6: Beach volume changes on Hilton Head Island, SC between February 216 and June 218. Areas filled in 216 are shown in grey. 218 Annual Beach Monitoring Report September

40 Table 2.3: Hilton Head Island Beach Volume Change Summary (February 216 to June 218). February 216 to June 218 Calibogue Sound South Beach Monument Range Reach Length (ft) Average Volume Change (cy/ft) Above +3.7' Above.' DOC LEG to HIA 1, ,4-4,4-12,3 HIA to HIB 1, ,5-5,8 13,9 HIB to HI , 13,4 197,9 Subtotal 3, Above Volume Change (cy) Above +3.7' Above.' Above DOC ,2 199,5 HI1 to HI1A , 3,2 11,5 HI1A to HI1B ,5-7,8 23,6 HI1B to HI1C ,3-7,3-11,8 HI1C to HI ,3 4,6-12,4 HI2 to HI2A ,4 35,9 33,3 HI2A to HI3 1, ,7 69,5 99,2 HI3 to HI4 3, ,4 142,1 272,6 Whole Island South Island Central Island North Island Subtotal 7, , 24,2 56, HI4 to HI5 3, ,6 114,7 23,4 HI5 to HI6 2, ,2 8,3 135,2 HI6 to HI7 3, ,1 9,5 141,4 HI7 to HI8 2, ,9 37,3 57, HI8 to HI9 2, ,3 12,9 22,4 HI9 to HI1 1, ,7 1,9 HI1 to HI11 2, ,9 5,4 11, Subtotal 17, ,3 341,1 599,3 HI11 to HI12 1, , 22,2 4, HI12 to HI13 2, ,7 62,4 1,3 HI13 to HI14 2, ,2 86, 133,8 HI14 to HI15 1, ,5 77,4 127, HI15 to HI16 2, ,7 124,6 218,2 HI16 to HI ,9 37,5 66,9 HI17 to HI18 1, , 44,3 77,7 HI18 to HI19 2, ,4 6,4 98, HI19 to HI19A 2, ,8 68,9 14,5 HI19A to HI2 1, ,6 27,3 38,9 HI2 to HI21 1, ,9 57,6 81,6 HI21 to HI22 2, ,5 81,7 111,5 HI22 to HI23 1, ,8 52,8 74,1 HI23 to HI24 1, ,9 6,5 92,5 HI24 to Folly ,4 23,4 35,3 Subtotal 28, ,3 887, Folly to HI25 1, ,5-1 -6,2 HI25 to HI26 3, ,3 8,4 9,6 HI26 to HI27 3, ,5 4,2 22,8 HI27 to HI27A , -2,2-5 HI27A to HI27B ,9-5,4-6,6 HI27B to HI ,1-6,9-8,1 Subtotal 1, ,4,3-18,3-2, 11, Continued on next page 218 Annual Beach Monitoring Report September

41 Table 2.3 (con t): Hilton Head Island Beach Volume Change Summary (February 216 to June 218). February 216 to June 218 The Heel Monument Range Reach Length (ft) Average Volume Change (cy/ft) Above +3.7' Above.' Above Volume Change (cy) Above +3.7' Above.' Above DOC DOC HI28 to HI28A ,8-4,1-2,9 HI28A to HI28B ,1 HI28B to HI28C ,3 4,7 1,6 HI28C to HI28D , 9,2 17,8 HI28D to HI ,5 2,3 35,4 HI29 to HI29A ,6 32,8 54,1 HI29A1 to HI29A ,4 21,6 33,2 HI29A2 to HI29A , 15,4 19,5 HI29A3 to HI29B ,8 9,9 9,1 HI29B to HI29C ,4 6,2 2,5 HI29C to HI29D ,8 HI29D to HI29E , -14,4 Whole Island Port Royal Plantation Fish Haul Creek Inner Port Royal Sound Subtotal 5, HI29E to HI29F ,5 2,5-18,1 HI29F to HI ,2 55, 46,2 HI3 to HI3A ,5 1,6 118,4 HI3A to HI , 66,6 85,2 HI31 to HI31A ,5 4,7 48,5 HI31A to HI31B ,7 26,9 26,5 HI31B to HI , 6,4 9,7 HI32 to FHC 1, ,3 14,2 29,9 Subtotal 6, ,7 312,9 FHC to FH , -42,6-12,4 FH1 to FH ,2-13,1-13, FH2 to HI ,6-5,7-5,7 HI33 to FH ,9 2,3 FH4 to FH ,1 11,4 12,9 FH5 to FH ,1 19,3 23,6 FH6 to FH ,2 16,4 2,7 FH7 to FH ,1 9,5 12,4 FH8 to HI ,7 7,3 8,9 HI34 to FH ,2 9,9 9,8 FH1 to FH ,6 14,3 14,4 FH11 to FH ,5 14, 14,2 FH12 to FH , 11,2 11,2 FH13 to HI ,4 7,2 7,2 Subtotal 3, HI35 to HI36 1, ,8 7,9 6,1 HI36 to HI37 1, ,8-8,9-6,1 HI37 to HI38 1, ,7-5,7-1,5 HI38 to HI39 1, , -3,1-4, 27.6 Subtotal 5, ,3 29,7 11,3 163,2 346,3 61, 16,5-3,7-9,8-5,5 TOTAL 88, ,79,4 1,943,9 3,326,6 218 Annual Beach Monitoring Report September

42 Figure 2.7: Volume change between HHI-B and HHI-1 (February 216 to June 218). 218 Annual Beach Monitoring Report September

43 Project Performance: Beach Changes (May 217 to June 218) This section presents a summary of shoreline and beach volume change that occurred along the island between May 217 and June 218 as they relate to the performance of the 216 project. The May 217 survey is assumed to represent the beach conditions prior to the effects of Hurricane Irma and the post-matthew/irma emergency restoration beach fill. Results based upon comparison of these two surveys represent the total net change to the island s beach as a result of these two events Shoreline Change Figure 2.8 depicts the MHW shoreline change of the beach (+3.7 ft NGVD29) along the Calibogue Sound, South Beach, South Island, and Central Island shorelines from the post-216 renourishment conditions in May 217 to June 218. Figure 2.9 depicts the change of the MHW shoreline along the North Island, Port Royal Plantation, and Inner Port Royal Sound shorelines for the same time period. Shoreline position changes at each beach monitoring station are listed in Table 2.4. Average shoreline position change for each beach segment as well as the entire sand shoreline between Braddock Cove Creek and HHI-39. During the period from May 217 to June 218, Hurricane Irma impacted the Island in September of 217 and therefore the effects of the storm may be partially realized through this analysis. Additionally, during this period the 217 South Island Emergency Beach Fill Project and Extension was constructed between HHI-1C and approximately HHI-8+1. Because of this additional beach fill, the project zone will not be considered in the analysis but is included in the tables and figures for reporting purposes. Along the monitored shoreline of the island, excluding the effects of the 217 project between HHI-1C and HHI-8, the MHW shoreline retreated by an average of -6.7 ft. Including the effects of the beach project, the island advanced +4.6 ft between May 217 and June 218. The greatest changes of beach width occurred within the vicinities of the northern and southern termini of the island, likely due to the dynamic nature of the inlets and associated shoal features and further exacerbated by the impact of Hurricane Irma. Figures 2.8 and 2.9 show the position of the MHW as of October 217 (post-irma) and June 218, both relative to May 217. During this period, the Calibogue Sound (HHI-A to HHI-1) MHW shoreline advanced by an average of ft, with the greatest advance occurring at HHI-1 (+11.4 ft). As noted, Calibogue Sound and South Beach are characterized by a large sand mass that has been shifting into Calibogue Sound, as seen by the increase of beach width along this reach (see Figure 2.16) and the aerials presented in Appendix B. Calibogue Sound has never received beach fill placement since the inception of the Town s beach renourishment program. 218 Annual Beach Monitoring Report September

44 The South Beach and South Island shorelines received sand fill during the 217 project in a single, continuous, fill segment between HHI-1C and HHI-8+1. Within South Beach, from HHI-1 to HHI-1C (outside project limits), the MHW shoreline advanced an average of +6.1 ft. This average is primarily carried by HHI-1, where the greatest gain was recorded as ft. The greatest loss was realized at HHI-1C where there was a retreat of ft. Within South Island, from HHI-8 to HHI-11 (outside project limits), the MHW shoreline advanced approximately ft, which likely benefitted by diffusion from the project area. The greatest increase in this segment was at HHI-9, which advanced ft, while the greatest loss was by ft at HHI-1. The shoreline along the Central Island segment (HHI-11 to HHI-24), from Alder Lane to The Folly, which includes South Forest Beach, North Forest Beach, and Palmetto Dunes, experienced an average shoreline retreat of ft, with all transects but HHI-11 (+8.2 ft) experiencing shoreline retreat. Retreat was most significant from HHI-12 to HHI-17, averaging ft, with a maximum retreat of ft at HHI-14. Very little change occurred to the shoreline between HHI-18 and HHI-19 (average of -2.8 ft), indicating only small losses of the 216 fill in this segment. From HHI-19A to The Folly, the average shoreline retreat was -18. ft, which is partially due to the combined effects of The Folly blocking some sediment transport coming from the north and the net southerly directed transport along this shoreline. The entirety of this shoreline was nourished during the 216 renourishment project. The North Island segment (The Folly to HHI-28) did not receive any direct sand placement during the 216 renourishment project. Along this shoreline, the MHW advanced by approximately +1.6 ft, on average, with the only retreat occurring at station HHI-27B (-8.3 ft). This segment likely benefited by the net southerly sand transport from the beach fill placement in the vicinity of The Heel in 216. The greatest advance in this segment was ft at HHI-25, immediately adjacent to The Folly. The Heel (HHI-28 to HHI-29E) is typically a dynamic region of the island. During the period from May 217 to June 218 this reach saw an average retreat of ft the greatest retreat of the island s shoreline. One segment within this reach, HHI-28B to HHI-29C, was filled as part of the 216 renourishment. This fill segment generally includes the shoreline directly south and north of the terminal groin, located between HHI-29A1 and HHI-A3. The greatest retreat in this segment, and the whole island, was at HHI-29A1 (-11.5 ft), on the southern side of the terminal groin. The greatest advance in this segment was by ft at HHI-28A. This is primarily due to the southerly directed net sediment transport from the north. From HHI-29B to HHI-29E, there was an average shoreline retreat of ft. Several factors may have influenced the retreat of the shoreline in this segment, such as the impact of Hurricane Irma and natural inlet dynamics. 218 Annual Beach Monitoring Report September

45 Figure 2.8: Mean high water shoreline (MHW, +3.7 ft NGVD29) changes along Hilton Head Island relative to May 217. Areas filled during 216 and 217 are shaded grey. 218 Annual Beach Monitoring Report September

46 Figure 2.9: Mean high water shoreline (MHW, +3.7 ft NGVD29) changes along Hilton Head Island relative to May 217. Areas filled during 216 and 217 are shaded grey. 218 Annual Beach Monitoring Report September

47 Table 2.4: Hilton Head Island MHW Change Summary (May 217 to June 218). 216 Fill 217 Fill 216 Fill Alongshore Shoreline Position (ft) Alongshore Shoreline Position (ft) Distance (ft) at MHW (+3.7 ft, NGVD) Distance (ft) at MHW (+3.7 ft, NGVD) Seg Mon from Lands End May-17 Jun-18 Change Seg Mon from Lands End May-17 Jun-18 Change Braddock Cove Creek HI-28 67, HI-A 1, HI-28A 67, HI-B 2, HI-28B 68, HI-1 3, HI-28C 68, , HI-28D 68, HI-1 3, HI-29 69, HI-1A 4, HI-29A1 7, HI-1B 4, HI-29A2 7, HI-1C 5, HI-29A3 7, HI-2 5, HI-29B 71, HI-2A 6, HI-29C 71,465 1, HI-3 7, HI-29D 71,685 1, HI-4 1, HI-29E 71, , , HI-4 1, HI-29E 71, HI-5 13, HI-29F 72, HI-6 16, HI-3 73, HI-7 19, HI-3A 74, HI-8 21, HI-31 75, HI-9 23, HI-31A 75, HI-1 25, HI-31B 76, HI-11 27,75 1,58.4 1, HI-32 77, , , HI-11 27,75 1,58.4 1, Fish Haul Creek HI-12 29,645 1,71.4 1, FH-1 79,27 1, HI-13 31, FH-2 79,52 1, HI-14 34, HI-33 79,77 1, HI-15 36, FH-4 8,2 1, HI-16 39, FH-5 8,27 1, HI-17 4, FH-6 8, HI-18 41, FH-7 8, HI-19 43, FH-8 81, HI-19A 46, HI-34 81, HI-2 47, FH-1 81, HI-21 49, FH-11 81, HI-22 52, FH-12 82, HI-23 54, FH-13 82, HI-24 55, HI-35 82, , , The Folly HI-35 82, HI-25 57, HI-36 83, HI-26 61, HI-37 85, HI-27 64, HI-38 86, Calibogue Sound South Beach South Island Central Island North Island The Heel Port Royal Plantation Fish Haul Creek Inner Port Royal Sound HI-27A 65, HI-39 87, HI-27B 66, ,3-2. HI-28 67, Excluding 217 Project 1, (HHI-1C to HHI-8) 71, Including 217 Project 87, Fill 216 Fill 216 Fill 218 Annual Beach Monitoring Report September

48 The Port Royal Plantation shoreline, from HHI-29E to Fish Haul Creek (HHI-32), retreated by an average of ft, with the greatest retreat occurring at HHI-29F ( ft) and the greatest advance at HHI-3A (+95.3 ft). Changes along this shoreline during this period from May 217 to June 218 are attributed to the attachment of a sand mass that has migrated onshore from Joiner Bank (see Figure 2.17). A single segment of shoreline, between HHI-29F and HHI- 31B, received sand placement during the 216 renourishment project. This project segment had been completed prior to the passage of Hurricane Matthew; thus, it has endured the impacts of two hurricanes (i.e. also Irma) since completion. With the movement of the sand mass along the Port Royal Sound shoreline, Fish Haul Creek (FH-1 to HHI-35) has been subject to major changes of MHW shoreline position from May 217 to June 218. Although the average shoreline advance in this segment was +2.4 ft, the reach saw advances as great as ft, at FH-6, and retreats up to ft, at FH-1. Fish Haul Creek was nourished between FH-5 and HHI-35, during the 216 project, though much of these changes have likely been caused by the alongshore movement of sand. These changes can be visualized by the accompanying aerials of Fish Haul Creek shown in Figure 2.18 and Appendix B. At the time of this report, it is unclear if the movement of sand within and along the Fish Haul Creek shoreline will continue to propagate further into the sound. Along the Inner Port Royal Sound segment of the island (HHI-35 to HHI-39), the MHW shoreline retreated by -2. ft on average. During the period from May 217 to June 218, the greatest advance was by ft at HHI-35, while the greatest retreat was by ft at HHI-36. This reach of shoreline did not receive sand placement in during the 216 project. 218 Annual Beach Monitoring Report September

49 2.4.2 Beach Volume Change Figure 2.1 shows the computed beach volume changes along Calibogue Sound, South Beach, South Island, and Central Island shorelines between May 217 and June 218. This time period represents changes to the island s beaches since completion of the 216 project. Figure 2.11 depicts the computed beach volume changes along the North Island, Port Royal Plantation, and Inner Port Royal Sound shorelines for the same period. Like the previous section (on MHW), the intent of this section is to analyze areas of the shoreline that were filled during the 216 project. The top graph of each figure displays the measured local beach volume density change (in cy/ft) at each monitoring profile and the bottom portion shows the cumulative beach volume change (in cy) summed along the shoreline from (1) the Lands End Groin at Braddock Cove Creek (about HHI-A) to The Folly (HI-24) and (2) The Folly (HHI-25) to HHI-39. Beach volume changes are listed in Table 2.5 for each beach segment along the monitored shoreline of the island. Between May 217 and June 218, comparison of beach profile surveys suggest that the entire island shoreline gained a net of approximately +638,7 cy (+7.2 cy/ft) of sand. The greatest increase was by +229,2 cy (+71.2 cy/ft) between HHI-4 and HHI-5 and the greatest loss was by -45,5 cy (-68.4 cy/ft) between HHI-29 and HHI-29A1. It is important to note that this gain is principally related to the sand placed as part of the 217 Emergency Beach Fill project (completed November 217), which involved the placement of 79,5 along the South Beach and South Island shorelines. The 7,8-cy deficit between the net gain between surveys and the amount recorded as beach fill reflects the effects of: hurricane erosion (Irma); isolated losses along the terminal ends of the island; and natural sand transport. Comparison of beach profiles (Appendix A) to aerial imagery (Appendix B) suggests that a portion of sand from the island may have been deposited into both Calibogue and Port Royal Sounds. If so, much of this sand will likely not return to the island in the near future as it is part of the active shoal system. Changes of the island-wide volume are expected to have been exacerbated by the impacts of Hurricane Irma during this time period. The remainder of this section will discuss the areas filled during the 216 project (outlined in green on Table 2.5) except for South Beach and South Island, which were filled as part of the 217 project. Changes of the island-wide volume are expected to have been exacerbated by the impacts of Hurricane Irma during this time period and other seasonal nor easter weather patterns. The Central Island segment, from Alder Lane (approx. HHI-11) to The Folly (HHI-25), lost about -193,9 cy (-6.7 cy/ft), of the total 1,728,3 cy placed in 216 this change equates to an approximate 11.2% loss of beach volume between May 217 and June 218. During this period, 12 of 15 transects experienced losses, 9 of which lost sand across the entire profile, while 218 Annual Beach Monitoring Report September

50 the other 3 had losses above. (NGVD29) but a gain of sand between. and the DOC. The greatest loss in this segment was -34, cy (-11.8 cy/ft) between HHI-15 and HHI-16. As of June 218, the cross-shore beach profile shape generally shows a sand ridge in the intertidal zone 14 as seen in Appendix A which explains most of the accretion below.. It is expected that sand in this ridge will be naturally transported landward. The portion of The Heel shoreline filled in 216, from HHI-28B to HHI-29C, lost a total of -126,1 cy (-36.7 cy/ft) of sand from May 217 to June 218, with the greatest losses adjacent to the terminal groin structure. The greatest loss in this segment was -45,5 cy (-68.4 cy/ft) between HHI-29 and HHI-29A1. Since the 216 project, this segment has lost approximately 39.1% (126,1 cy) of the 322,3 cy of placed sand; however, based on the 216 to 218 volume changes (discussed in Section 2.3.2), this section is still net positive in sand volume, relative to pre-project. Along the filled portion of the Port Royal Plantation shoreline (HHI-29F to HHI-31B), there was a net loss of -8,3 cy (-2. cy/ft) between May 217 and June 218, of the total 334,5 cy placed in 216. This change represents an approximate 2.5% loss of beach volume since completion of the 216 project. Additionally, this shoreline reach has endured the impacts of both Hurricane Matthew and Irma (Port Royal Plantation was not refilled after Hurricane Matthew). The final reach to have received beach placement during the 216 project was Fish Haul Creek (FH-5 and HHI-35). The total amount placed during the project was 92,7 cy, and it has since accreted by +25,6 cy (+11.4 cy/ft) between May 217 and June 218. This accretion represents a 27.6% increase in volume of that amount placed during the 216 project. The accretional zone was between FH-5 and HHI-34, which saw an average gain of cy/ft, primarily due to the attachment of the sand spit near Fish Haul Creek (see Figure 2.18). From HHI-34 to HHI-35, there was an average erosion of -8.4 cy/ft. 14 Area of the cross-shore beach profile that is defined as between MLW (-3.16 ft, NGVD29) and MHW (+3.72 ft, NGVD29). 218 Annual Beach Monitoring Report September

51 Figure 2.1: Beach volume changes on Hilton Head Island, SC between May 217 and June 218 surveys. Areas filled in 216 and 217 are shown in grey. 218 Annual Beach Monitoring Report September

52 Figure 2.11: Beach volume changes on Hilton Head Island, SC between May 217 and June 218 surveys. 218 Annual Beach Monitoring Report September

53 Table 2.5: Hilton Head Island Beach Volume Change Summary (May 217 to June 218). May 217 to June 218 Calibogue Sound South Beach South Island Monument Range Reach Length (ft) Average Volume Change (cy/ft) Above +3.7' Above.' DOC LEG to HIA 1, ,2-6 HIA to HIB 1, ,4 4,6 3,8 HIB to HI , 15,2 147, Subtotal 3, Above HI1 to HI1A ,6 7,2 68,8 HI1A to HI1B ,5-2,4 8,2 HI1B to HI1C , -6,7-2,9 HI1C to HI ,3-1,8-24,7 HI2 to HI2A HI2A to HI3 1, ,1 1,8 15,4 HI3 to HI4 3, , 69,2 157,9 Subtotal 7, Volume Change (cy) Above +3.7' Above.' Above DOC ,2 21, 177,2 34,2 67,1 24,2 HI4 to HI5 3, ,2 113,7 229,2 HI5 to HI6 2, ,1 83,6 136,5 HI6 to HI7 3, ,2 9,7 136, HI7 to HI8 2, ,9 33,7 47,5 HI8 to HI9 2, , 15,7 23,4 HI9 to HI1 1, , HI1 to HI11 2, , 5,8 8,2 Whole Island Central Island North Island Subtotal 17, ,3 342,3 58,5 HI11 to HI12 1, ,5 9,7 HI12 to HI13 2, ,1-24,9-12,4 HI13 to HI14 2, ,2-32,9-32,1 HI14 to HI15 1, ,7-25,8-32,1 HI15 to HI16 2, ,2-28,9-34, HI16 to HI , -8,1-1,9 HI17 to HI18 1, , -8,7-13,7 HI18 to HI19 2, ,5-8,3-14,6 HI19 to HI19A 2, ,8-17,2-22,4 HI19A to HI2 1, ,6-1,8-11,8 HI2 to HI21 1, ,7-15, -14,6 HI21 to HI22 2, ,9-6,6-7,6 HI22 to HI23 1, ,5-3,7-5,1 HI23 to HI24 1, ,4 2,2 3,6 HI24 to Folly ,1 3,6 4,1 Subtotal 28, ,2-185,1-193,9 Folly to HI25 1, ,1 13,3 8,9 HI25 to HI26 3, ,3 35,4 28,9 HI26 to HI27 3, ,3 23, 28,2 HI27 to HI27A , 3,5 2,9 HI27A to HI27B ,7 HI27B to HI ,3-2,5-5,1 Subtotal 1, , 72,8 6,1 218 Annual Beach Monitoring Report September Continued on next page

54 Table 2.5 (con t): Hilton Head Island Beach Volume Change Summary (May 217 to June 218). May 217 to June 218 The Heel Monument Range Reach Length (ft) Average Volume Change (cy/ft) Above +3.7' Above.' Above Volume Change (cy) Above +3.7' Above.' Above DOC DOC HI28 to HI28A ,6-2,3-4,3 HI28A to HI28B ,3-1,3-2,6 HI28B to HI28C ,3-2,8-4,7 HI28C to HI28D ,4-3,6-6,7 HI28D to HI ,3-7,6-15, HI29 to HI29A ,9-2,6-45,5 HI29A1 to HI29A ,1-11,8-26,5 HI29A2 to HI29A ,8-1,8-7,3 HI29A3 to HI29B ,5-2,7-8,1 HI29B to HI29C ,3-6, -12,3 HI29C to HI29D ,1-3, -8,5 HI29D to HI29E ,4-2,1 Whole Island Port Royal Plantation Fish Haul Creek Inner Port Royal Sound Subtotal 5, HI29E to HI29F ,2-3,6 6 HI29F to HI ,9-7,6-15,3 HI3 to HI3A ,1 4,1-6 HI3A to HI , 9,9 13,4 HI31 to HI31A ,7 1,3 1 HI31A to HI31B ,8-2,2-5,9 HI31B to HI ,7 HI32 to FHC 1, , 12, Subtotal 6, ,2 5,3 FHC to FH , -41,2-42,7 FH1 to FH , -12,7-13,3 FH2 to HI ,8-6,8-7,5 HI33 to FH ,9-4,8-5,4 FH4 to FH ,5-4,5-5,5 FH5 to FH ,7 6,9 7,9 FH6 to FH ,8 13,4 16,1 FH7 to FH ,8 9,4 FH8 to HI ,2 2,7 HI34 to FH ,5-3,4-3,4 FH1 to FH ,4-3,3-3,3 FH11 to FH , -2, FH12 to FH ,4-1,4 FH13 to HI HI35 to HI36 1, ,2-4,4 HI36 to HI37 1, ,6-3,2 HI37 to HI38 1, ,3 HI38 to HI39 1, ,2 1,3 Subtotal 5, ,8-64,9-143,6 6, Subtotal 3, ,9-52,2-48,8 8-4,7-3, TOTAL 88, ,8 21,6 638,7 218 Annual Beach Monitoring Report September

55 2.5 June 218 Beach Condition relative to Recommended Minimum Beach Condition (RMBC) This section presents a summary of shoreline changes that occurred along the island relative to the RMBC (generally April 1997) and June 218. The RMBC is assumed to represent the beach conditions prior to the inception of the Town s beach renourishment program, and the June 218 survey represents the most current conditions as of the time of this monitoring report. Results based upon comparison of these two surveys represent the total net change to the island s beach as a result of the renourishment program. Figure 2.12 depicts the February 216 (pre-renourishment) and June 218 position of the Mean High Water (MHW) shoreline (+3.7ft NGVD29) along the Calibogue Sound, South Beach, South Island, and Central Island shorelines relative to a Recommended Minimum Beach Condition (RMBC 15 ). Figure 2.13 depicts the position of the MHW shoreline relative to the RMBC along the North Island, The Heel, Port Royal Plantation, and Inner Port Royal Sound shorelines for the same period. The RMBC was defined in 24 by Olsen Associates, Inc. and is generally based upon the pre-1997 beach fill shoreline position and beach condition. Shoreline position changes at each monument are listed in Table 2.6, with average shoreline position changes for each beach segment, as well as the entire island. As of June 218, the average position of the MHW for the monitored shoreline was ft seaward of the RMBC. The June 218 MHW shoreline position was seaward of the RMBC (where there is a defined RMBC) for all but two transects over the entire island, HHI- A and HHI-B. The shoreline, which has eroded beyond the RMBC, has never been nourished as part of the Town s beach nourishment program. The position of the June 218 shoreline relative to the RMBC is greatest at the terminal ends of the island, South Beach and The Heel, due to natural shoreline and inlet dynamics. Over this period, there was a maximum advance of ft at HHI-33, and maximum recession of ft at HHI-B. As of June 218, relative to the RMBC, the Calibogue Sound shoreline (HHI-A to HHI-1) was ft seaward of the RMBC, on average, due to the strong effect of HHI-1 ( ft). Aside from HHI-1, HHI-A and HHI-B are at approximately the position of the RMBC, -3.5 and ft, respectively. The stability of these two monitoring locations exemplify why this portion of Calibogue Sound has not been included in beach fill projects, to this day. 15 The RMBC was established as a basis to evaluate the condition of the island s beaches relative to an assumed minimum width that the Town might want to consider (based on the April 1997 survey). The defined RMBC was never formally adopted by the Town. In this instance, it is simply used as a basis for discussion of conditions as they relate to a historical condition Annual Beach Monitoring Report September 218

56 The South Beach shoreline (HHI-1 to HHI-4) is seaward of the RMBC by an average of ft, which is in part due to the recent beach fill projects in 216 and 217. The greatest advance in South Beach was ft at HHI-1A, whereas the smallest advance was by ft at HHI-4. The South Beach shoreline has historically benefitted from the nearshore shoal field and associated landward sand transport. Along the island s Atlantic shorefront, from HI-4 to Alder Lane in South Forest Beach (at approximately HI-11), the South Island segment MHW shoreline was ft seaward of the RMBC, on average, as of June 218. The greatest distance between the June 218 MHW and RMBC was at HHI-11 ( ft). All transects in this reach were greater than +1. ft seaward of the RMBC and have generally been stable to accretional with accretion becoming greater from south to north. The MHW shoreline position along the Central Island segment (Alder Lane (HHI-11) to The Folly (HHI-24)) was, on average, ft seaward of the RMBC. The distance between the RMBC and June 218 MHW was fairly consistent alongshore, with the greatest offset of ft at HHI-18 and the smallest offset of ft at HHI-15. Along the North Island shoreline (The Folly (HHI-24) to HI-28), the distance between the RMBC and the June 218 MHW shoreline position was ft, on average. The smallest distance between the RMBC and June 218 MHW position was ft at HHI-25 and greatest was ft at HHI-28. These distances increase from south to north, reflecting the benefit to the shoreline from the 216 renourishment and 211/12 shore stabilization project. The MHW shoreline position along The Heel (HI-28 to HI-29E) is about ft seaward of the RMBC, with a maximum distance of +8.8 ft at HI-29C and minimum of ft at HHI-29. This average is composed of distances at only four transects, however, as the remainder of the monuments within this segment did not exist at the time that the RMBC was established. This portion of The Heel is where the northward movement of a sand mass from Joiner Bank has attached itself to Hilton Head Island (Section 2.6.3), in addition to the benefit from the 216 project. The June 218 MHW shoreline position along the Port Royal Plantation shoreline (HHI- 29E to Fish Haul Creek), was ft seaward of the RMBC, on average. Distances from the RMBC to June 218 MHW shoreline reflect the movement of the sand mass into Port Royal Sound from Joiner Bank. Distances from the RMBC ranged from a minimum of ft at HHI-32 to ft at HHI-29F. Along the Inner Port Royal Sound segment (Fish Haul Creek to HI-39), the RMBC is established only for monuments HHI-33 through HHI-35, which are roughly the limits of the 218 Annual Beach Monitoring Report September

57 26/7 Fish Haul/Spa project shoreline. The RMBC for this segment is the pre-construction (September 26) condition. Here, the June 218 MHW shoreline position was ft seaward of the RMBC, on average. This average is carried by the attachment of the sand spit at HHI-33, where the distance from MHW to the RMBC was ft. 218 Annual Beach Monitoring Report September

58 218 Annual Beach Monitoring Report September Figure 2.12: Mean High Water shoreline position along Hilton Head Island relative to the Recommended Minimum Beach Template.

59 218 Annual Beach Monitoring Report September Figure 2.13: Mean High Water shoreline position along Hilton Head Island relative to the Recommended Minimum Beach Template.

60 Table 2.6: Hilton Head Island MHW Change Summary (RMBC to February 218). 216 Fill 217 Fill 216 Fill Seg Calibogue Sound South Beach South Island Central Island Alongshore Shoreline Position (ft) Alongshore Shoreline Position (ft) Distance (ft) at MHW (+3.7 ft, NGVD) Distance (ft) at MHW (+3.7 ft, NGVD) Mon from Lands End RMBC* Jun-18 Change Seg Mon from Lands End RMBC* Jun-18 Change Braddock Cove Creek The Folly HI-A 1, HI-25 57, HI-B 2, HI-26 61, HI-1 3, HI-27 64, , HI-27A 65, HI-1 3, HI-27B 66, HI-1A 4, HI-28 67, HI-1B 4, , HI-1C 5, HI-28 67, HI-2 5, HI-28A 67, HI-2A 6, HI-28B 68, HI-3 7, HI-28C 68, HI-4 1, HI-28D 68, , HI-29 69, HI-4 1, HI-29A1 7, HI-5 13, HI-29A2 7, HI-6 16, HI-29A3 7, HI-7 19, HI-29B 71, HI-8 21, HI-29C 71, HI-9 23, HI-29D 71, HI-1 25, HI-29E 71, HI-11 27, , , , HI-29E 71, HI-11 27, , HI-29F 72, HI-12 29, , HI-3 73, HI-13 31, HI-3A 74, HI-14 34, HI-31 75, HI-15 36, HI-31A 75, HI-16 39, HI-31B 76, HI-17 4, HI-32 77, HI-18 41, , HI-19 43, Fish Haul Creek HI-19A 46, HI-33 79, HI-2 47, HI-34 81, HI-21 49, HI-35 82, HI-22 52, HI-36 83, HI-23 54, HI-37 85, HI-24 55, HI-38 86, , HI-39 87, The Folly 9, North Island The Heel Port Royal Plantation Inner Port Royal Sound 87, Fill 216 Fill Annual Beach Monitoring Report September

61 2.6 Detailed Discussion of Areas of Interest This section highlights areas of the island shoreline that are experiencing beach change that is either highly dynamic or not historically typical primarily through the analysis period from February 216 to June 218. For comparison, historical surveys are also included for each area. As such, addressing these areas of the island may require special consideration beyond that of a periodic renourishment Lands End Figures 2.14 and 2.15 depict the shoreline in the vicinity of the Lands End Groin on Calibogue Sound at Braddock Cove Creek from December 23 to April 218. Photography is shown for eight conditions, (1) December 23, (2) March 27, (3) January 29 (prior to rehabilitation of the groin), (4) April 21 (immediately following groin rehabilitation), (5) May 213, (6) April 216, (7) May 217, and (8) May 218. Lines displayed in the figures track the vegetation line as delineated by inspection of each set of aerial orthophotographs. The timeline is broken into two sets to reduce line clutter. From December 23 to April 21, the shoreline south (left in the photo) of the groin had accreted, sand with a fairly consistent location of the vegetation line. The retreat of the vegetation line on the southern side near the groin from January 29 to April 21 was due to construction activities during groin improvements. On the north side of the groin (right in the photo) the shoreline constantly eroded, while, at the same time, the vegetation line marginally advanced. South of the groin, from April 21 to April 216, the shoreline experienced accretion, but then eroded from April 216 to April 218. The vegetation line was relatively stable until Hurricane Matthew struck in October of 216, which caused the approximately 5-foot retreat between April 216 and May 217. Since May 217, the vegetation line has appeared to be moving seaward toward the pre-matthew position. North of the groin, there has been continuous erosion of the shoreline, up to seawall exposure in some areas. In previous monitoring reports, it has been proposed that this erosion has been caused primarily by the SIDA dredging project from December 213 to March 214, and groin improvements, to a lesser extent (Olsen Associates, Inc. July 217). Despite shoreline loss, vegetation has been growing on the northern side of the groin since by at least May 217. The propagation of vegetation may be highly beneficial to this area since it may allow for accretional entrapment of sediment and future return of the shore. Also see Appendix C for additional monitoring photographs. 218 Annual Beach Monitoring Report September

62 2.6.2 South Beach As seen in Figure 2.16, the southern terminus of the island has historically been a dynamic shoreline reach since at least March 28. This shoreline is characterized by the existence and movement of a large sand wave around the toe of the island. Between March 28 and May 218, there has been significant shoreline accretion between HHI-1 and HHI-2 as the sand lobe has moved from south to north, with a resulting erosional impact between HHI- 2 and HHI-3. Sand placement during the 216 and 217 projects in South Beach and South Island appears to have helped nourish this segment by sand diffusion; however, continued migration of the sand wave may facilitate future renourishment needs. As noted in past beach monitoring reports, the sand movement along South Beach and Calibogue Sound continues to move into and along Calibogue Sound. Between February 216 and June 218, the greatest advance was by ft at HHI-1, and the greatest retreat was by ft at HHI-1B in the vicinity of HHI-1 and HHI The Heel A portion of The Heel shoreline reach, between HHI-28C and HHI-29A2, at the north end of the island that was restored in 211/12 has experienced continued erosion, which is directly south (left side of picture) of the terminal groin. This has been occurring since completion of the 211/12 project, as illustrated in Figure From 213 to 216, the formation of a spit-like bar can be seen on the northern (right side of picture) side of the terminal groin. This feature was most likely able to form because of the sand shoals moving landward from Joiner Bank and attaching near HHI-29F. After construction of the 216 renourishment, the southern side of the groin began to erode between HHI-29 and HHI-29A2. North of the groin has been relatively stable, with moderate accretion between stations HHI-29F and HHI-3. Also see Appendix C for additional monitoring photographs Fish Haul Creek The Fish Haul Creek/Spa shoreline has experienced significant shoreline changes which are characterized by the growth of a sand spit from south to north. Until 216, the mouth of Fish Haul Creek had drained northward near the location of the breakwaters. From April 216 to May 218, the sand spit has grown landward and attached to the breakwater farthest inside Port Royal Sound. As of May 218, the mouth of the creek can be seen to be draining to the east-northeast and bypasses the breakwaters. In the current 218 position, the breakwaters have become landlocked by the migration of the sand spit, and the area shoreward of the spit may have the opportunity to fill in with sand. Since construction of the breakwaters there has also been associated vegetation growth in the area, which will assist in further stabilization of the shoreline. 218 Annual Beach Monitoring Report September

63 Figure 2.14: Aerial orthophotography depicting evolution of shoreline conditions around the Lands End Groin on the Calibogue Sound shoreline of Hilton Head Island, adjacent to Braddock Cove Creek. 218 Annual Beach Monitoring Report September

64 May 218 Figure 2.15: Aerial orthophotography depicting evolution of shoreline conditions around the Lands End Groin on the Calibogue Sound shoreline of Hilton Head Island adjacent to Braddock Cove Creek. 218 Annual Beach Monitoring Report September

65 Figure 2.16: Shoreline change along the South Beach shoreline segment of Hilton Head Island. 218 Annual Beach Monitoring Report September

66 Figure 2.17: Shoreline change along The Heel shoreline segment of Hilton Head Island. 218 Annual Beach Monitoring Report September

67 Figure 2.18: Shoreline change along the Fish Haul/Spa shoreline segment of Hilton Head Island. 218 Annual Beach Monitoring Report September

68 3. ADDITIONAL DISCUSSION FEATURES 3.1 Fish Haul Creek Marsh Grass In accordance with the South Carolina Department of Health and Environmental Control (SC DHEC) Office of Coastal Resource Management (OCRM), Critical Area Permit & Coastal Zone Consistency Certification permit (PN: W) Special Condition #9 for the Fish Haul Creek segment of the 216 Island-wide Beach Renourishment Project, the Town quantified the acreage of Spartina vegetation prior to the project and immediately after the project to determine if mitigation for impacts to Spartina [was] needed. The Fish Haul/Spa segment of the project was permitted separately from the rest of the 216 Renourishment under permit number W. Prior to construction of the 216 project, the Fish Haul area contained approximately 4.84 acres of marsh vegetation seaward of the beach and within project limits from FH-5 to HHI-35 (surveyed 9 June 216). The post-construction survey (surveyed 25 July 216) of this area revealed that approximately.56 acres of marsh grass were buried during the beach fill placement, resulting in a post-project total of 4.28 acres remaining. Figure 3.1 provides an illustration of the evolution of marsh grass vegetation found within the 216 fill limits along Fish Haul Creek. In May 217, there were approximately 3.6 acres of marsh grass (estimated by aerial photography), which was a -.68-acre reduction of marsh grass since July 216. Based on aerial imagery, part of the loss in vegetation appears to have been influenced by the migration of the sand spit (also discussed in Section 2.6.4). Since the spit has been moving northward along the shoreline and progressing towards attachment to the breakwaters, the reduction in water flow through the area and additional sand may have negatively affected some of the existing grass. As of May 218, there were approximately 3.51 acres of marsh grass (estimated by aerial photography) along the same reach of Fish Haul Creek, which was a reduction of -.9 acres since May 217. Again, it appears that his reduction has been influenced by the attachment of the sand spit to the breakwaters. 218 Annual Beach Monitoring Report September

69 Figure 3.1: Marsh grass vegetation change along Fish Haul/Spa shoreline segment of Hilton Head Island. 218 Annual Beach Monitoring Report September

70 3.2 Joiner Bank Another area of interest is Joiner Bank, offshore southeast of the northern terminus of Hilton Head Island, in the Atlantic Ocean. Joiner Bank is generally a large, linear shoal system that boarders the entrance of Port Royal Sound. Since at least the late 198s, portions of Joiner Bank have shown to slowly move towards Hilton Head Island. Up until 1999, the proximity of Joiner Bank to The Heel had provided shielding from wave energy, which allowed for The Heel to accumulate sand and for the vegetation to grow seaward. After 1999, the bank that had been migrating toward the island began to attach to the Port Royal Sound shoreline and was no longer shielding The Heel. As a result, The Heel became highly erosional, which necessitated the shore stabilization project of 211/12 (Olsen Associates, Inc., 212). As seen in Figures 3.2 and 3.3, part of Joiner Bank has been progressively growing to the north and migrating to the west from 211 (month not available) to May 218. The area of the bank was delineated by where the sand-water interface became clearly visible in the aerial photographs. An approximate surface area of the bank was estimated, as provided in Table 3.1; however, it should be noted that the actual size of the bank would be larger than the reported number since these areas are based off of the visible portions of the bank. Additionally, the June 212 and May 215 aerials did not capture the entire feature, so the true value would be higher than that reported. The acreage is not determined as a standard management practice, but rather for comparison and potentially future planning purposes. Table 3.1 Approximate visible area of Joiner Bank between 211 and May 218. Date of Aerial Acreage of Joiner Bank (ac.) *June *May May * Aerial image did not capture all of Joiner Bank Between 211 and May 218, Joiner Bank appears to have been growing in surface area. As of May 218, Joiner Bank has become narrower and more elongated than in earlier reported years. The bank may stay intact and continue to accumulate sand, as was seen in the 198s and 199s, and eventually become emergent. Based on the history of the Joiner Bank feature, there is a possibility for the shoal to migrate towards The Heel, repeating the cycle that was seen in the late 198s and 9s. 218 Annual Beach Monitoring Report September

71 Figure 3.2: Joiner Bank evolution between 211 and 214 near Hilton Head Island, SC. 218 Annual Beach Monitoring Report September

72 Figure 3.3: Joiner Bank evolution between May 215 and May 218 near Hilton Head Island, SC. 218 Annual Beach Monitoring Report September

73 3.3 Bay Point Shoals Borrow Area Bay Point Shoals was used during the 216 Island-wide Renourishment Project as the borrow area for The Heel, Port Royal Plantation, and Fish Haul Creek shorelines. As part of project monitoring requirements, the borrow area would be surveyed annually for the first 3 years following project completion. The post-project survey was taken on 5 January 217 by McKim & Creed of Wilmington, NC. The most recent hydrographic survey of Bay Point Shoals as of the time of this report was taken in June 218 by Arc Surveying & Mapping, Inc. of Jacksonville, FL. Figure 3.4 illustrates the bathymetry of Bay Point Shoals immediately post-project and in June 218, and it also outlines the Permitted Limit and Dredge Limit of the 216 project. Figure 3.5 shows the general change of bathymetry over the same time frame, with cooler colors representing accretion and warmer colors as erosion. Over this period, the dredged area of Bay Point Shoals accreted by +37,5 cy. The majority of accretion occurred in the southeastern portion of the borrow site, which was dredged twice over the course of the 216 project. The permitted area accreted by +246, cy which is 61,5-cy less than the dredged area, indicating that there was a net loss from the region outside of the dredge area but within the permitted area. It can be seen that there was sediment lost from the southeastern portion of the shoal, which likely filled in the dredged area after construction. From January 217 to June 218, the net change was an erosion of -14,6 cy. To accompany the previous figures, Figures 3.6 and 3.7 provide cross-sectional views of Bay Point Shoals. Sand loss over this time period may be associated with the change in bathymetry and general movement of sediment across the shoal. 218 Annual Beach Monitoring Report September

74 Figure 3.4: Bay Point Shoals bathymetry as of post-216 construction (left) and June 218 (right). 218 Annual Beach Monitoring Report September

75 Figure 3.5: Bay Point Shoals bathymetry change from post-216 construction to June Annual Beach Monitoring Report September

76 A A' Permitted Limit Erosion Accretion January 217 June Distance Along Transect (ft) B B' Accretion Erosion Permitted Limit Distance Along Transect (ft) Figure 3.6: Cross-sectional view of Bay Point Shoals along sections A-A (northwest) and B-B (southeast). 218 Annual Beach Monitoring Report September

77 C C' Permitted Limit Accretion Erosion January 217 June Distance Along Transect (ft) Figure 3.7: Cross-sectional view of Bay Point Shoals along section C-C (longitudinal). 218 Annual Beach Monitoring Report September

78 4. SUMMARY This monitoring report has examined the most recent survey data results from June of 218 and compared them to several other available collection periods which include February 216, May 217, and the RMBC (based on the April 1997 survey) to analyze shoreline and beach volume changes. Since the previous monitoring report (February 216), the island has seen two beach projects, the 216 Island-wide Beach Renourishment and the 217 South Island Emergency Beach Fill, and has experienced the effects of Hurricanes Matthew and Irma. Due to the addition of these two projects and two hurricanes, this monitoring report was unique from previous reports in the sense that it generally reflects the changes to the island over the course of two years. As of June 218, the only narrow portion of the beach was a segment of Calibogue Sound between near HHI-A, which has never received sand placement since the inception of the Town s beach management program. Areas of the island which have presented as net erosional over the past two years are portions of: Calibogue Sound, South Beach, North Island, and The Heel. In the Calibogue Sound and South Beach reaches, the retreat of the MHW and volume loss areas have been associated with the movement of a large sand mass along the shoreline into Calibogue Sound. This movement has caused significant erosion between HHI-1B and HHI- 1C, as well as resulting accretion between HHI-1 and HHI-1A. Likewise, the north end of the island has experienced a similar change as a portion of Joiner Bank has attached itself near HHI- 29F along The Heel shoreline segment. North Island, which was not nourished in 216 or 217, had only one marginally erosional area at HHI-25, but was surrounded by areas that benefitted from southerly directed transport from The Heel. Between February 216 and June 218, the MHW shoreline experienced major changes along the entire beach due to the 216 and 217 beach projects and the effects of Hurricanes Matthew and Irma, most notably. On average, over the entire shoreline, the MHW advanced approximately ft (weighted 16 ) over the roughly two-year period, with the greatest advance of ft at FH-6 and the greatest retreat of ft at FH-2. Shoreline advance occurred along all reaches except one. Two reaches, North Island (HHI-25 to HHI-28) and Inner Port Royal Sound (HHI-35 to HHI-39), experienced average shoreline recession during this period; however, these areas also did not receive any direct sand placement from either of the two projects. Three primary regions are shown to have experienced a retreat of the MHW and a loss of beach volume during this period: Calibogue Sound and South Beach (HHI-A to HHI-B and HHI-1A to HHI-1C), North Island (HHI-27 to HHI-HHI-28), and The Heel (HHI-29D to 16 The average MHW change was calculated by using the change computed at each monitoring station and is weighted by the distance between each monitoring station (e.g. a longer reach represents more of the average) Annual Beach Monitoring Report September 218

79 HHI-29E); however, it should be noted that none of these reaches received direct sand placement during either of the projects. Between February 216 and June 218, the shoreline along all segments of Hilton Head Island gained a net +3,326,6 cy (+37.7 cy/ft) 17. The largest increase in beach volume was by +272,6 cy (+87.1 cy/ft) between HHI-3 and HHI-4, while the greatest loss was -18,1 cy ( cy/ft) between HHI-29E and HHI-29F. Foremost, it is noted that between February 216 and June 218 Hilton Head Island received direct sand placement during the 216 Island-wide Beach Renourishment Project and 217 South Island Emergency Beach Fill Project. Because of the projects, the majority of changes are attributed to the addition of sand to the system by the two projects. The projects masked the significant sand losses that occurred during Hurricanes Matthew and Irma as well as other natural sand losses. Increases in total beach volume were greatest along the Atlantic-fronting reaches of Central Island, South Island, and South Beach. The only area to have lost sand during this time was the Inner Port Royal Sound (HHI-35 to HHI-39) shoreline, which also did not receive beach fill over this period. In addition to the discussion of overall beach conditions and change, other topics were explored. These are (1) the condition of marsh grass at Fish Haul Creek, (2) the apparent reformation of Joiner Bank, and (3) the conditions of Bay Point Shoals borrow area. Each of these were evaluated to document changes which have not typically been included in past monitoring reports, but may provide useful insight to future planning: Fish Haul Creek Marsh Grass Since completion of the 216 project, there has been a reduction of marsh grass coverage, likely due to the attachment of a sand spit to the breakwaters. This feature has landlocked the grass and reduced the water flow due to the position of the new mouth cut out by Fish Haul Creek. There were approximately 3.51 ac of marsh grass as of June 218, compared to the 4.84 ac prior to the 216 project. Joiner Bank The offshore feature has been progressively growing since at least 211 and currently shows approximately 3.7 ac as determined by aerial imagery. The bank has become thinner and longer than it has been in previous years. Bay Point Shoals Borrow Area Since completion of the 216 project, the Bay Point Shoals borrow area has gained +37,5 cy of sand within the area dredged in 216. The southeast portion of the shoals outside the dredge and permitted limits have deflated to some extent. This deflation may be related to the movement of sand from that portion of the overall shoal to the dredged area. 17 Unless stated otherwise, the volume changes in this report were computed from the seaward edge of the most seaward dune feature evident in the beach profile data to the apparent location of beach profile closure Annual Beach Monitoring Report September 218

80 5. REFERENCES Dean, R.G. and Dalrymple, R.A. (24). Coastal Processes with Engineering Applications. Cambridge University Press. Pages 134 and 216. National Geodetic Survey (NGS). NOAA Tides and Currents. Center for Operational Oceanographic Products and Services (CO-OPS). Olsen Associates, Inc. (1992). Beach Restoration Project, Monitoring Report Year 1 -. Report prepared for the. Olsen Associates, Inc., Jacksonville, FL, January Olsen Associates, Inc. (1999). Beach Nourishment Project Post- Construction Report. Report prepared for the. Olsen Associates, Inc., Jacksonville, FL, November Olsen Associates, Inc. (2) Beach Renourishment Project, Monitoring Report No.2 Report prepared for the. Olsen Associates, Inc., Jacksonville, FL, April 2. Olsen Associates, Inc. (24). FEMA Transect Formulation for the Town Hilton Head Island, SC (From Primary Dune to Toe of Beach). Report prepared for the. Olsen Associates, Inc., Jacksonville, FL, December 15, 24. Olsen Associates, Inc. (28). 26/7 Beach Renourishment Project, Post-Construction Engineering Summary Report. Report prepared for the Town of Hilton Head Island, SC. Olsen Associates, Inc., Jacksonville, FL, April 28. Olsen Associates, Inc. (212). Port Royal Sound Shoreline Restoration and Stabilization Project Post-Construction Engineering Summary Report. Report prepared for the. Olsen Associates, Inc., Jacksonville, FL, December 212. Olsen Associates, Inc. (217). Hilton Head Island Post-Hurricane Matthew Condition Assessment: October 216. Report prepared for the Town of Hilton Head Island, SC. Olsen Associates, Inc., Jacksonville, FL, February 217. Olsen Associates, Inc. (217). Hilton Head Island 216 Annual Beach Monitoring Report. Report prepared for the. Olsen Associates, Inc., Jacksonville, FL, July 217. Olsen Associates, Inc. (218). Hilton Head Island Post-Hurricane Irma Condition Assessment: September 217 Survey. Report prepared for the Town of Hilton Head Island, SC. Olsen Associates, Inc., Jacksonville, FL, June Annual Beach Monitoring Report September

81 APPENDIX A HISTORICAL BEACH PROFILE PLOTS The monitoring profile surveys conducted in February 216, October 217, and May 218 were performed by Arc Surveying & Mapping, Inc. (Arc), of Jacksonville, FL. 218 Annual Beach Monitoring Report A-1

82

83 216 to 218 Beach Monitoring Report July 218 A-3 Figure A.2: Measured beach profiles at monument HIA - Hilton Head Island, South Carolina HHI-A Calibogue Sound Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

84 216 to 218 Beach Monitoring Report July 218 A-4 Figure A.3: Measured beach profiles at monument HIB - Hilton Head Island, South Carolina HHI-B Calibogue Sound Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

85 216 to 218 Beach Monitoring Report July 218 A-5 Figure A.4: Measured beach profiles at monument HI1 - Hilton Head Island, South Carolina HHI-1 South Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

86 216 to 218 Beach Monitoring Report July 218 A-6 Figure A.5: Measured beach profiles at monument HI1A - Hilton Head Island, South Carolina HHI-1A South Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

87 216 to 218 Beach Monitoring Report July 218 A-7 Figure A.6: Measured beach profiles at monument HI1B - Hilton Head Island, South Carolina HHI-1B South Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

88 216 to 218 Beach Monitoring Report July 218 A-8 Figure A.7: Measured beach profiles at monument HI1C - Hilton Head Island, South Carolina HHI-1C South Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

89 216 to 218 Beach Monitoring Report July 218 A-9 Figure A.8: Measured beach profiles at monument HI2 - Hilton Head Island, South Carolina HHI-2 South Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

90 216 to 218 Beach Monitoring Report July 218 A-1 Figure A.9: Measured beach profiles at monument HI2A - Hilton Head Island, South Carolina HHI-2A South Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

91 216 to 218 Beach Monitoring Report July 218 A-11 Figure A.1: Measured beach profiles at monument HI3 - Hilton Head Island, South Carolina HHI-3 South Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

92 216 to 218 Beach Monitoring Report July 218 A-12 Figure A.11: Measured beach profiles at monument HI4 - Hilton Head Island, South Carolina HHI-4 South Beach, South Beach Lane Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

93 216 to 218 Beach Monitoring Report July 218 A-13 Figure A.12: Measured beach profiles at monument HI5 - Hilton Head Island, South Carolina HHI-5 South Island, South Beach Lane Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

94 216 to 218 Beach Monitoring Report July 218 A-14 Figure A.13: Measured beach profiles at monument HI6 - Hilton Head Island, South Carolina HHI-6 South Island, Sea Pines Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

95 216 to 218 Beach Monitoring Report July 218 A-15 Figure A.14: Measured beach profiles at monument HI7 - Hilton Head Island, South Carolina HHI-7 South Island, Sea Pines Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

96 216 to 218 Beach Monitoring Report July 218 A-16 Figure A.15: Measured beach profiles at monument HI8 - Hilton Head Island, South Carolina HHI-8 South Island, Sea Pines Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

97 216 to 218 Beach Monitoring Report July 218 A-17 Figure A.16: Measured beach profiles at monument HI9 - Hilton Head Island, South Carolina HHI-9 South Island, Sea Pines Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

98 216 to 218 Beach Monitoring Report July 218 A-18 Figure A.17: Measured beach profiles at monument HI1 - Hilton Head Island, South Carolina HHI-1 South Island, South Forest Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

99 216 to 218 Beach Monitoring Report July 218 A-19 Figure A.18: Measured beach profiles at monument HI11 - Hilton Head Island, South Carolina HHI-11 Central Island, South Forest Beach, Alder Lane Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

100 216 to 218 Beach Monitoring Report July 218 A-2 Figure A.19: Measured beach profiles at monument HI12 - Hilton Head Island, South Carolina HHI-12 Central Island, South Forest Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

101 216 to 218 Beach Monitoring Report July 218 A-21 Figure A.2: Measured beach profiles at monument HI13 - Hilton Head Island, South Carolina HHI-13 Central Island, Coligny Circle Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

102 216 to 218 Beach Monitoring Report July 218 A-22 Figure A.21: Measured beach profiles at monument HI14 - Hilton Head Island, South Carolina HHI-14 Central Island, North Forest Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

103 216 to 218 Beach Monitoring Report July 218 A-23 Figure A.22: Measured beach profiles at monument HI15 - Hilton Head Island, South Carolina HHI-15 Central Island, North Forest Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

104 216 to 218 Beach Monitoring Report July 218 A-24 Figure A.23: Measured beach profiles at monument HI16 - Hilton Head Island, South Carolina HHI-16 Central Island, North Forest Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

105 216 to 218 Beach Monitoring Report July 218 A-25 Figure A.24: Measured beach profiles at monument HI17 - Hilton Head Island, South Carolina HHI-17 Central Island, Shipyard Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

106 216 to 218 Beach Monitoring Report July 218 A-26 Figure A.25: Measured beach profiles at monument HI18 - Hilton Head Island, South Carolina HHI-18 Central Island, Palmetto Dunes Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

107 216 to 218 Beach Monitoring Report July 218 A-27 Figure A.26: Measured beach profiles at monument HI19 - Hilton Head Island, South Carolina HHI-19 Central Island, Palmetto Dunes Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

108 216 to 218 Beach Monitoring Report July 218 A-28 Figure A.27: Measured beach profiles at monument HI19A - Hilton Head Island, South Carolina HHI-19A Central Island, Palmetto Dunes Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

109 216 to 218 Beach Monitoring Report July 218 A-29 Figure A.28: Measured beach profiles at monument HI2 - Hilton Head Island, South Carolina HHI-2 Central Island, Palmetto Dunes Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

110 216 to 218 Beach Monitoring Report July 218 A-3 Figure A.29: Measured beach profiles at monument HI21 - Hilton Head Island, South Carolina HHI-21 Central Island, Palmetto Dunes Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

111 216 to 218 Beach Monitoring Report July 218 A-31 Figure A.3: Measured beach profiles at monument HI22 - Hilton Head Island, South Carolina HHI-22 Central Island, Palmetto Dunes Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

112 216 to 218 Beach Monitoring Report July 218 A-32 Figure A.31: Measured beach profiles at monument HI23 - Hilton Head Island, South Carolina HHI-23 Central Island, Palmetto Dunes Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

113 216 to 218 Beach Monitoring Report July 218 A-33 Figure A.32: Measured beach profiles at monument HI24 - Hilton Head Island, South Carolina HHI-24 Central Island, Singleton Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

114 216 to 218 Beach Monitoring Report July 218 A-34 Figure A.33: Measured beach profiles at monument HI25 - Hilton Head Island, South Carolina HHI-25 North Island, Bradley Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

115 216 to 218 Beach Monitoring Report July 218 A-35 Figure A.34: Measured beach profiles at monument HI26 - Hilton Head Island, South Carolina HHI-26 North Island, Bradley Beach Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

116 216 to 218 Beach Monitoring Report July 218 A-36 Figure A.35: Measured beach profiles at monument HI27 - Hilton Head Island, South Carolina HHI-27 North Island, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

117 216 to 218 Beach Monitoring Report July 218 A-37 Figure A.36: Measured beach profiles at monument HI27A - Hilton Head Island, South Carolina HHI-27A North Island, Port Royal Plantation February 216 May 217 October 217 May 218 Volume Calculation Limit

118 216 to 218 Beach Monitoring Report July 218 A-38 Figure A.37: Measured beach profiles at monument HI27B - Hilton Head Island, South Carolina HHI-27B North Island, Port Royal Plantation February 216 May 217 October 217 May 218 Volume Calculation Limit

119 216 to 218 Beach Monitoring Report July 218 A-39 Figure A.38: Measured beach profiles at monument HI28 - Hilton Head Island, South Carolina HHI-28 North Island, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

120 216 to 218 Beach Monitoring Report July 218 A-4 Figure A.39: Measured beach profiles at monument HI28A - Hilton Head Island, South Carolina HHI-28A The Heel, Port Royal Plantation February 216 May 217 October 217 May 218 Volume Calculation Limit

121 216 to 218 Beach Monitoring Report July 218 A-41 Figure A.4: Measured beach profiles at monument HI28B - Hilton Head Island, South Carolina HHI-28B The Heel, Port Royal Plantation February 216 May 217 October 217 May 218 Volume Calculation Limit

122 216 to 218 Beach Monitoring Report July 218 A-42 Figure A.41: Measured beach profiles at monument HI28C - Hilton Head Island, South Carolina HHI-28C The Heel, Port Royal Plantation February 216 May 217 October 217 May 218 Volume Calculation Limit

123 216 to 218 Beach Monitoring Report July 218 A-43 Figure A.42: Measured beach profiles at monument HI28D - Hilton Head Island, South Carolina HHI-28D The Heel, Port Royal Plantation February 216 May 217 October 217 May 218 Volume Calculation Limit

124 216 to 218 Beach Monitoring Report July 218 A-44 Figure A.43: Measured beach profiles at monument HI29 - Hilton Head Island, South Carolina HHI-29 The Heel, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

125 216 to 218 Beach Monitoring Report July 218 A-45 Figure A.44: Measured beach profiles at monument HI29A1 - Hilton Head Island, South Carolina HHI-29A-1 The Heel, Port Royal Plantation February 216 May 217 October 217 May 218 Volume Calculation Limit

126 216 to 218 Beach Monitoring Report July 218 A-46 Figure A.45: Measured beach profiles at monument HI29A2 - Hilton Head Island, South Carolina HHI-29A-2 The Heel, Port Royal Plantation February 216 May 217 October 217 May 218 Volume Calculation Limit

127 216 to 218 Beach Monitoring Report July 218 A-47 Figure A.46: Measured beach profiles at monument HI29A3 - Hilton Head Island, South Carolina HHI-29A-3 Port Royal Sound, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

128 216 to 218 Beach Monitoring Report July 218 A-48 Figure A.47: Measured beach profiles at monument HI29B - Hilton Head Island, South Carolina HHI-29B Port Royal Sound, Port Royal Plantation February 216 May 217 October 217 May 218 Volume Calculation Limit

129 216 to 218 Beach Monitoring Report July 218 A-49 Figure A.48: Measured beach profiles at monument HI29C - Hilton Head Island, South Carolina HHI-29C Port Royal Sound, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

130 216 to 218 Beach Monitoring Report July 218 A-5 Figure A.49: Measured beach profiles at monument HI29D - Hilton Head Island, South Carolina HHI-29D Port Royal Sound, Port Royal Plantation February 216 May 217 October 217 May 218 Volume Calculation Limit

131 216 to 218 Beach Monitoring Report July 218 A-51 Figure A.5: Measured beach profiles at monument HI29E - Hilton Head Island, South Carolina HHI-29E Port Royal Sound, Port Royal Plantation February 216 May 217 October 217 May 218 Volume Calculation Limit

132 216 to 218 Beach Monitoring Report July 218 A-52 Figure A.51: Measured beach profiles at monument HI29F - Hilton Head Island, South Carolina HHI-29F Port Royal Sound, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

133 216 to 218 Beach Monitoring Report July 218 A-53 Figure A.52: Measured beach profiles at monument HI3 - Hilton Head Island, South Carolina HHI-3 Port Royal Sound, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

134 216 to 218 Beach Monitoring Report July 218 A-54 Figure A.53: Measured beach profiles at monument HI3A - Hilton Head Island, South Carolina HHI-3A Port Royal Sound, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

135 216 to 218 Beach Monitoring Report July 218 A-55 Figure A.54: Measured beach profiles at monument HI31 - Hilton Head Island, South Carolina HHI-31 Port Royal Sound, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

136 216 to 218 Beach Monitoring Report July 218 A-56 Figure A.55: Measured beach profiles at monument HI31A - Hilton Head Island, South Carolina HHI-31A Port Royal Sound, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

137 216 to 218 Beach Monitoring Report July 218 A-57 Figure A.56: Measured beach profiles at monument HI31B - Hilton Head Island, South Carolina HHI-31B Port Royal Sound, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

138 216 to 218 Beach Monitoring Report July 218 A-58 Figure A.57: Measured beach profiles at monument HI32 - Hilton Head Island, South Carolina HHI-32 Port Royal Sound, Port Royal Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

139 216 to 218 Beach Monitoring Report July 218 A-59 Figure A.58: Measured beach profiles at monument FH1 - Hilton Head Island, South Carolina FH-1 Fish Haul Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

140 216 to 218 Beach Monitoring Report July 218 A-6 Figure A.59: Measured beach profiles at monument FH2 - Hilton Head Island, South Carolina FH-2 Fish Haul Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

141 216 to 218 Beach Monitoring Report July 218 A-61 Figure A.6: Measured beach profiles at monument HI33 - Hilton Head Island, South Carolina HHI-33 Fish Haul, FH-3 Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

142 216 to 218 Beach Monitoring Report July 218 A-62 Figure A.61: Measured beach profiles at monument FH4 - Hilton Head Island, South Carolina FH-4 Fish Haul Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

143 216 to 218 Beach Monitoring Report July 218 A-63 Figure A.62: Measured beach profiles at monument FH5 - Hilton Head Island, South Carolina FH-5 The Spa Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

144 216 to 218 Beach Monitoring Report July 218 A-64 Figure A.63: Measured beach profiles at monument FH6 - Hilton Head Island, South Carolina FH-6 The Spa Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

145 216 to 218 Beach Monitoring Report July 218 A-65 Figure A.64: Measured beach profiles at monument FH7 - Hilton Head Island, South Carolina FH-7 The Spa Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

146 216 to 218 Beach Monitoring Report July 218 A-66 Figure A.65: Measured beach profiles at monument FH8 - Hilton Head Island, South Carolina FH-8 The Spa Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

147 216 to 218 Beach Monitoring Report July 218 A-67 Figure A.66: Measured beach profiles at monument HI34 - Hilton Head Island, South Carolina HHI-34 Mitchelville Beach Park, FH-9 Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

148 216 to 218 Beach Monitoring Report July 218 A-68 Figure A.67: Measured beach profiles at monument FH1 - Hilton Head Island, South Carolina FH-1 Mitchelville Beach Park Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

149 216 to 218 Beach Monitoring Report July 218 A-69 Figure A.68: Measured beach profiles at monument FH11 - Hilton Head Island, South Carolina FH-11 Mitchelville Beach Park Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

150 216 to 218 Beach Monitoring Report July 218 A-7 Figure A.69: Measured beach profiles at monument FH12 - Hilton Head Island, South Carolina FH-12 Mitchelville Beach Park Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

151 216 to 218 Beach Monitoring Report July 218 A-71 Figure A.7: Measured beach profiles at monument FH13 - Hilton Head Island, South Carolina FH-13 Mitchelville Beach Park Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

152 216 to 218 Beach Monitoring Report July 218 A-72 Figure A.71: Measured beach profiles at monument HI35 - Hilton Head Island, South Carolina HHI-35 Mitchelville Beach Park, FH-14 Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

153 216 to 218 Beach Monitoring Report July 218 A-73 Figure A.72: Measured beach profiles at monument HI36 - Hilton Head Island, South Carolina HHI-36 Hilton Head Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

154 216 to 218 Beach Monitoring Report July 218 A-74 Figure A.73: Measured beach profiles at monument HI37 - Hilton Head Island, South Carolina HHI-37 Hilton Head Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

155 216 to 218 Beach Monitoring Report July 218 A-75 Figure A.74: Measured beach profiles at monument HI38 - Hilton Head Island, South Carolina HHI-38 Hilton Head Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

156 216 to 218 Beach Monitoring Report July 218 A-76 Figure A.75: Measured beach profiles at monument HI39 - Hilton Head Island, South Carolina HHI-39 Hilton Head Plantation Minimum Beach Condition (April 1997) February 216 May 217 October 217 May 218 Volume Calculation Limit

157 APPENDIX B SHORELINE AERIALS Digital aerial photography was flown on 5 April 216 and 1 May 218 by Kucera International, Inc., of Willoughby, OH 218 Annual Beach Monitoring Report B-1

158 Figure B.1: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Skull Creek Flood Ebb 218 Annual Beach Monitoring Report B-2 Skull Creek Flood Ebb 216 MHWL - Green Line 218 MHWL - Blue Line Matchline - Page 2 Matchline - Page 3 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 2 Matchline - Page 3

159 Figure B.2: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Matchline - Page 2 Matchline - Page Annual Beach Monitoring Report B-3 Matchline - Page 2 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Matchline - Page 3 Matchline - Page 4 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 3 Matchline - Page 4

160 Figure B.3: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Matchline - Page 3 Matchline - Page Annual Beach Monitoring Report B-4 Matchline - Page 3 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Matchline - Page 4 Matchline - Page 5 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 4 Matchline - Page 5

161 Annual Beach Monitoring Report B-5 Matchline - Page 4 Matchline - Page 5 Matchline - Page 4 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.4: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Matchline - Page 5 Matchline - Page 6 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 5 Matchline - Page 6

162 218 Annual Beach Monitoring Report B-6 37 Matchline - Page 5 Matchline - Page 6 37 Matchline - Page 5 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.5: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, Matchline - Page 6 Matchline - Page 7 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 6 Matchline - Page 7

163 The Spa FH7 The Spa FH7 FH6 FH8 FH6 FH8 218 Annual Beach Monitoring Report B-7 35 (FH14) (FH9) FH13 FH12 FH1 34 FH11 Matchline - Page 6 Matchline - Page 7 Fish Haul Breakwaters 35 (FH14) (FH9) FH13 FH12 FH1 34 FH11 Matchline - Page 6 Matchline - Page 7 Fish Haul Breakwaters 216 MHWL - Green Line 218 MHWL - Blue Line Figure B.6: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 FH4 FH5 Matchline - Page 7 Matchline - Page 8 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft FH4 FH5 Matchline - Page 7 Matchline - Page 8

164 218 Annual Beach Monitoring Report B-8 Matchline - Page 7 Matchline - Page 8 2,99, E 148, N Matchline - Page 7 Matchline - Page 8 2,99, E 148, N 216 MHWL - Green Line 218 MHWL - Blue Line Figure B.7: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, Matchline - Page 8 Matchline - Page 9 32 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 8 Matchline - Page 9

165 218 Annual Beach Monitoring Report B B 31A Matchline - Page 8 Matchline - Page B 31A Matchline - Page 8 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.8: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, A Matchline - Page 9 Matchline - Page 1 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft 3A Matchline - Page 9 Matchline - Page 1

166 218 Annual Beach Monitoring Report B-1 3A 3 29F Matchline - Page 9 Matchline - Page 1 3A 3 29F Matchline - Page 9 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.9: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, E 29E 29D 29D 2 29C 29B Matchline - Page 1 Matchline - Page C 29B GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 1 Matchline - Page 11

167 218 Annual Beach Monitoring Report B-11 29B 29A-1-3 Matchline - Page 1 Matchline - Page D 28C 29B 28D 28C 29 29A-1-3 Matchline - Page 1 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.1: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, B 28B 28A 28A Matchline - Page 11 Matchline - Page 12 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 11 Matchline - Page 12

168 The The 218 Annual Beach Monitoring Report B B 27A Matchline - Page 11 Matchline - Page B 27A Matchline - Page 11 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.11: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, Barony Islander Beach Park Matchline - Page 12 Matchline - Page 13 Barony Islander Beach Park GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 12 Matchline - Page 13

169 218 Annual Beach Monitoring Report B-13 Islander Beach Park Islander Club Matchline - Page 12 Matchline - Page 13 Islander Beach Park Islander Club Matchline - Page 12 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.12: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, Folly Field Beach Park 26 Folly Field Beach Park Sea Cloisters Matchline - Page 13 Matchline - Page 14 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Sea Cloisters Matchline - Page 13 Matchline - Page 14

170 218 Annual Beach Monitoring Report B-14 Bradley Beach s Surf Watch Matchline - Page 13 Matchline - Page 14 Bradley Beach s Surf Watch Matchline - Page 13 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.13: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Burke 25 Matchline Page 14 Matchline Page 15 Burke 25 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline Page 14 Matchline Page 15

171 218 Annual Beach Monitoring Report B-15 Bur 25 The Folly 24 Matchline Page 14 Matchline Page 15 Bur 24 The Folly 25 Matchline Page 14 Matchline Page MHWL - Green Line 218 MHWL - Blue Line Figure B.14: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Hilton Head Resort Beach Cabana Singleton Beach Matchline - Page 15 Matchline - Page 16 Hilton Head Resort Beach Cabana Singleton Beach GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 15 Matchline - Page 16

172 218 Annual Beach Monitoring Report B Matchline - Page 15 Matchline - Page Matchline - Page 15 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.15: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, Matchline - Page 16 Matchline - Page 17 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 16 Matchline - Page 17

173 218 Annual Beach Monitoring Report B Matchline - Page 16 Matchline - Page Matchline - Page 16 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.16: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Matchline - Page 17 Matchline - Page 18 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 17 Matchline - Page 18

174 218 Annual Beach Monitoring Report B-18 2 Dune House 19A Marriot Beach & Golf Resort Matchline - Page 17 Matchline - Page 18 2 Dune House 19A Marriot Beach & Golf Resort Matchline - Page 17 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.17: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Villamare Villamare Disney Beach Club Captains Walk Matchline - Page 18 Matchline - Page 19 Disney Beach Club Captains Walk GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 18 Matchline - Page 19

175 2, 6, 8 E 8, 11 Matchline - Page 19 Matchline - Page 2 N 218 Annual Beach Monitoring Report 18 Matchline - Page 19 Matchline - Page 216 MHWL - Green Line 218 MHWL - Blue Line GRAPHIC SCALE Captains Walk Hampton Place 18 Matchline - Page 19 Matchline - Page B , 4 ft E 8, 11 2, 2 Windsor Place Windsor Court Matchline - Page 19 Matchline - Page 2 N GRAPHIC SCALE Captains Walk 19 Hampton Place Figure B.18: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Windsor Court 2 Windsor Place 4 ft

176 Shipyard Beach Club Shipyard Beach Club Oceanwood Oceanwood 218 Annual Beach Monitoring Report B-2 on 18 Windsor Place Barrington Court Somerset 17 Leamington Beach Pavilion Matchline - Page 19 Matchline - Page 2 on 18 Windsor Place Barrington Court Somerset 17 Leamington Beach Pavilion Matchline - Page 19 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.19: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, , N 2,84, E 116, N 2,84, E Matchline - Page 2 Matchline - Page 21 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 2 Matchline - Page 21

177 Figure B.2: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 anwood Matchline - Page 2 Matchline - Page 21 anwood 218 Annual Beach Monitoring Report B-21 Matchline - Page 2 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Matchline - Page 21 Matchline - Page 22 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 21 Matchline - Page 22

178 ge 21 Matchline - Pa ge 22 Matchline - Pa 218 Annual Beach Monitoring Report Matchline - Page 22 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Breakers 14 GRAPHIC SCALE Sea Crest Condos ft ge 21 Matchline - Pa ge 22 Matchline - Pa Matchline - Page 22 Matchline - Page 23 B-22 North Forest Beach Coligny Beach Park North Forest Beach Breakers 14 Figure B.21: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Coligny Beach Park GRAPHIC SCALE Sea Crest Condos ft

179 216 MHWL - Green Line 218 MHWL - Blue Line 218 Annual Beach Monitoring Report Matchline - Page 22 Matchline - Page 23 Matchline - Page 23 Matchline - Page 24 B-23 Breakers Coligny Beach Park 13 Holiday Inn Oceanfront Ocean One A Place at the Beach Shorewood Villas Seaside Villas GRAPHIC SCALE 2 4 ft O Hilton Head Adventure D Matchline - Page 22 Matchline - Page 23 Breakers Coligny Beach Park 13 Holiday Inn Oceanfront Ocean One A Place at the Beach Shorewood Villas Figure B.22: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Seaside Villas Matchline - Page 23 Matchline - Page 24 GRAPHIC SCALE 2 4 ft O Hilton Head Adventure D

180 218 Annual Beach Monitoring Report B-24 Matchline - Page 23 Matchline - Page 24 Adventure Inn Ocean Dunes Villas Marriott Grande Ocean Resort Alder Lane Beach Park Matchline - Page 23 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Adventure Inn Ocean Dunes Villas Marriott Grande Ocean Resort Alder Lane Beach Park Figure B.23: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, , N 2,73, E 19, N 2,73, E Matchline - Page 24 Matchline - Page 25 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 24 Matchline - Page 25

181 Annual Beach Monitoring Report B-25 Matchline - Page 24 Matchline - Page 25 Matchline - Page 24 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.24: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Matchline - Page 25 Matchline - Page 26 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 25 Matchline - Page 26

182 8 8 Sea Pines Sea Pines 7 7 Sea Pines Beach Clu Sea Pines Beach Clu 218 Annual Beach Monitoring Report B-26 Matchline - Page 25 Matchline - Page 26 16, N 2, Matchline - Page 25 Matchline - Page 26 16, N 2, 216 MHWL - Green Line 218 MHWL - Blue Line Figure B.25: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Matchline - Page 26 Matchline - Page 27 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 26 Matchline - Page 27

183 7 7 Sea Pines Beach Club Sea Pines Beach Club Monarch at Sea Pines Monarch at Sea Pines Turtle Lane Club Turtle Lane Club Annual Beach Monitoring Report B-27 Matchline - Page 26 Matchline - Page 27 Matchline - Page 26 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.26: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Matchline - Page 27 Matchline - Page 28 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 27 Matchline - Page 28

184 Annual Beach Monitoring Report B-28 Matchline - Page 27 Matchline - Page 28 13, N 2,6 Matchline - Page 27 Matchline - Page 28 13, N 2,6 216 MHWL - Green Line 218 MHWL - Blue Line Figure B.27: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Matchline - Page 28 Matchline - Page 29 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 28 Matchline - Page 29

185 Figure B.28: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, Matchline - Page 28 Matchline - Page Annual Beach Monitoring Report B-29 Matchline - Page 28 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line Matchline - Page 29 Matchline - Page 3 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 29 Matchline - Page 3

186 Figure B.29: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 Matchline - Page 29 Matchline - Page Annual Beach Monitoring Report B-3 Matchline - Page 29 Matchline - Page MHWL - Green Line 218 MHWL - Blue Line 3 3 2A Matchline - Page 3 Matchline - Page 31 2A GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 3 Matchline - Page 31

187 218 Annual Beach Monitoring Report B C 1B hline - Page 3 atchline - Page C 1B hline - Page 3 atchline - Page MHWL - Green Line 218 MHWL - Blue Line Figure B.3: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 1A 1A s s 1 Matchline - Page 31 Matchline - Page 32 1 GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft Matchline - Page 31 Matchline - Page 32

188 218 Annual Beach Monitoring Report B-32 1 B Beachside Tennis Villas Matchline - Page 31 Matchline - Page 32 South Beach Club Sound Villas 14, N 2,53, E 1 B Beachside Tennis Villas Matchline - Page 31 Matchline - Page 32 South Beach Club Sound Villas 14, N 2,53, E 216 MHWL - Green Line 218 MHWL - Blue Line Figure B.31: Spring 216 shoreline conditions (upper) Photo: April 5, 216 Spring 218 shoreline conditions (lower) Photo: May 1, 218 A A Lands End Lands End GRAPHIC SCALE 2 4 ft GRAPHIC SCALE 2 4 ft