Loading...
1992-319 CZM Section II (4.0) 4.0 COASTAL ZONE MANAGEMENT DATA BASE Collier County technical reports TR84-4, Coastal Zone Management units: Data Inventory and Analysis, and TR84-5, Coastal Zone Management units: Atlas (see section 2.1), have identified discrete management units of the County's coastal barrier systems. Resource management units are delineated for the coastal zone on three different levels. On the broadest, system-wide basis, the entire coastal zone of Collier County is divided into eight estuarine units. These units, termed coastal drainage districts, reflect historic sheetflow pathways (or close to them) from the interior of the county to the Gulf of Mexico. The drainage districts established for Collier County encompass all parts of the county's estuarine system, brackish marshes, mangrove forests, open bays, seagrass beds, and associated uplands. The coastal barriers of Collier County are also included in the above-mentioned system-wide drainage districts. They form the next level of organization of the Collier County coastal management units. From the Lee County Line to Cape Romano, the 37 miles of shoreline is divided into ten coastal barrier units, each of which is bounded to the north and south by a tidal pass. These units are then broken down into 37 sub-units known as beach segments, that represent areas distinct from one another and possess similar physical features (erosion rates), land use characteristics (parks vs public) and resource attributes (Figure 4-1) . 4.1 COASTAL BARRIER UNIT 1. BAREFOOT BEACH Barefoot Beach is the northernmost barrier unit in Collier county. It has experienced long-term accretion since 1885. Near the County line, the shoreline has accreted as much as 350 feet since 1885, with only minor short-term erosional trends. Erosion that occurred in the central sector of Barefoot Beach after 1927 (40 ft.) was related to the northward migration and closure of Little Hickory Pass, and the deep existing channels on the bays ide suggest that there is a strong possibility that this former tidal channel may reopen in the near future. cyclic periods of erosion interspersed by accretion have been the trend in the south sector, adjacent to Wiggins Pass. Four beach segments occur within the Barefoot Beach coastal barrier unit (Figure 4-2). II -73- unit Recommendations: 1. Future structures should be elevated on pilings. 2. Use of fill should be prohibited. 3. Establish a dune protection zone with centralized crosswalks. The zone should be approximately 100 feet in width, and all Australian pines should be removed. 4. All efforts should be made to protect any remaining coastal hammock. 4.1.1 Beach segment #1. LELY BEACH Length: 4,220 feet Beach Access: County park at the end of Bonita Beach Road Hazard Potential: MODERATE TO HIGH. Relatively low density development would lower hazard potential. A wide setback exists and the shoreline has a more or less stable history. Management and Recommendations: Future structures should be elevated on pilings; the use of fill is not recommended and should be prohibited. An integrated dune protection zone should be established, with centralized crosswalks constructed for sharing beach access by property owners. The existing dune protection zone should be widened to 100 feet. All efforts should be made to protect and restore the remaining coastal hammock. The coastal strand vegetation was nearly all cleared during the late 1970's and a feeble attempt at replanting using coconut palms has been made; restoration of strand habitats should be undertaken whenever possible. The recreational value as well as storm protection is expected to continue to decline in this area. 4.1.2 Beach segment #2. LITTLE HICKORY HAULOVER Length: 4,110 feet Beach access: No direct access Hazard Potential: EXTREMELY HIGH. The low beach elevations allow great potential for storm breaching of the beach and subsequent reformation of an ephemeral inlet. II -74- Management and Recommendations: Construction will occur in the central portion of an active coastal ridge zone on foundations and fill, with subsequent destruction and clearing of coastal vegetation. Dune restoration is needed, with an extension of the preserved area from the present 20-30 ft. to a more realistic 60-80 ft. As in the previous segment, future construction should be limited to piling-based houses. See other recommendations as in segment #1. 4.1.3 Beach segment #3. LELY BAREFOOT BEACH Length: 3,930 feet Beach access: New county park - Barefoo~ tleach Preserve Hazard Potential: MODERATE TO HIGH. The wide ridge system and dense natural vegetation coupled with the protective ebb tidal delta ensures relative stability of the highest coastal ridges. Management and Recommendations: Maintain as much as possible of the area as a true Preserve, to protect the minimally disturbed habitats found here. Desire for more beach areas for active recreation could threaten the ecology of this preserve. Australian pines should be removed. There should be no dredging of Wiggins Pass without first assessing potential effects on nearby beaches. 4.1.4 Beach segment #4. BAREFOOT BEACH STATE PRESERVE Length: 4,020 feet Beach access: New county park - Barefoot Beach Preserve Hazard Potential: MODERATE TO HIGH. The wide ridge system and dense natural vegetation coupled with the protective ebb tidal delta ensures relative stability of the highest coastal ridges. Management and Recommendations: Maintain the area as a Preserve, without changing status, in order to protect the minimally disturbed habitats found here. Restrict access to boats only. Allow native vegetation to continue growth. Desire for more beach areas for active recreation could II -75- threaten the ecology of this preserve. There should be no dredging of Wiggins Pass without first assessing potential effects on nearby beaches. 4.2 COASTAL BARRIER UNIT 2. VANDERBILT BEACH Compared to adjacent areas, the Vanderbilt Beach barrier unit was experienced significant erosion (up to 200 feet in its coastal sector) since 1885. Land clearing and isolated seawall construction in the one-mile-Iong Vanderbilt Beach subdivision caused an acceleration of erosion after 1950. Recession of the mean high water line and vegetation line occurred between 1952 and 1962 at about twice the rate of that in adjacent, undisturbed areas. There has been a general trend of shoreline recession in the entire Vanderbilt Beach unit since 1962. The Vanderbilt Beach coastal barrier unit is comprised of five beach segments (Figure 4-3). unit Recommendations: 1. Develop a management plan that takes into account the cumulative effects of shoreline stabilization, as well as compatible integration with neighboring projects. 2. No encroachment of upland protective structures should be permitted any further seaward than those already present, or to the presently existing vegetation line. 3. New structures should be designed to cause minimal damage and interference with natural beach processes. 4. A dune protection zone should be established that calls for preservation and reconstruction. 5. Dune walkovers are needed where foot traffic continues to impose stress on remaining coastal strand vegetation. 6. Selected Australian pines need to be removed. 7. Careful restrictions to minimize impact on several specimens of seagrapes are also needed. 8. Land run-off from condominiums behind mangrove swamps may produce eutrophication and should be carefully monitored. 4.2.1 Beach Segment IS. WIGGINS BEACH Length: 1,800 feet Beach Access: Delnor Wiggins State Park Hazard Potential: MODERATE TO HIGH. The narrow beach ridge could be breached by a tropical storm. However, the wide ridge system and dense vegetation in II -76- Management and Recommendations: conjunction with a protective ebb tidal delta might ensure relative stability of the highest coastal ridges. Dune preservation and reconstruction is needed, owing to intensive foot traffic across ridge. Coastal strand vegetation in decline owing to foot traffic and Australian pine invasion. Selective removal of Australian pines required. 4.2.2 Beach Segment #6. DELNOR WIGGINS STATE PARK Length: 4,210 feet Beach Access: State Park Hazard Potential: MODERATE TO HIGH. As in segment #5, the relatively wide ridge system with natural vegetation and a protective ebb tidal delta will provide some stability to the highest coastal ridges, but the narrow beach ridge could be easily breached during a tropical storm. Management and Recommendations: Dune preservation and reconstruction is needed. Intensive foot traffic continues to impose stress on remaining coastal strand vegetation. Selected Australian pine removal needed; careful restrictions to minimize impact on several specimens of seagrapes are also needed. Land run-off from condominium complex behind mangrove swamp may produce eutrophication, and should be carefully monitored. 4.2.3 Beach segment #7. VANDERBILT BEACH Length: 7,040 feet Beach Access: six access points at various locations Hazard Potential: SEVERE. A narrow building setback and inadequate, exposed, return walls are exacerbating long-term recession and erosion, thereby increasing the potential for damage incurred during tropical storms. Management and Recommendations: Produce an engineered plan that addresses the cumulative effects of shoreline stabilization in past years, as well as compatible II -77- integration with neighboring projects. No encroachment of upland protective structures shall be permitted any farther seaward than those already present or to the presently existing vegetation line. New structures must be designed to cause minimal damage and interference with natural beach processes. 4.2.4 Beach segment #8a. PELICAN BAY NORTH Length: 5,340 feet Beach Access: North end of unit Hazard Potential: EXTREMELY HIGH TO SEVERE. The narrow barrier ridge could be completely eroded in a major storm, or at least inundated and disDlaced landward. Potential hazards are greatest in the filled area to the northwest. Multifamily zoning also in the north area will increase threat to population. Management and Recommendations: Dune restoration, management, and protection needed at northern end of segment using an integrated management plan. Access to dunes should be severely restricted. Preservation of remaining coastal hammock mandatory. 4.2.S Beach segment #Sb. CLAM PASS NORTH Length: 7,940 feet Beach Access: None, unless Clam Pass is shallow or closed. Hazard Potential: HIGH. The narrow barrier ridge could be completely eroded in a major storm. See segment #8a. Management and Recommendations: The existing beach facility is constructed too close to the receding shore; landward relocation of this facility should be considered. Any additional facilities should be set substantially landward. Moreover, by restricting recreation to the open beach, the coastal forest-mangrove strand on this segment should be treated as a wildlife preserve for both animal life and rare plant habitats. South of the pass Australian pine invasion has restricted development of a fully functional dunejwashover zone. Therefore the Australian pines should be removed. II -78- 4.3 COASTAL BARRIER UNIT 3. PARK SHORE The north sector of the Park Shore unit has been relatively stable since 1885. In fact, certain areas have shown accretion. Historically, north Park Shore has received sand eroded and transported south from the Vanderbilt Beach unit. In contrast to the northern sector, the southern 1.3 miles of the Park Shore unit have experienced erosion since 1927. Erosion continued in this area until the shoreline was stabilized by the construction of seawalls and jetties. The north jetty at Doctors Pass trapped sand being transported to the south in the littoral drift, resulting in 10 to 50 feet of accretion since 1973. There are four beach segments contained within the Park Shore coastal barrier unit (Figure 4-4). unit Recommendations: 1. In unaltered areas between seawalls where continued scarp recession necessitates corrective action, the front line of the existing structure should be integrated with the adjacent existing scarp, using a combination of sand fill, stabilizing vegetation, and rock boulders. 2. New structures must be designed to have minimal interference with natural beach processes. 3. Reconstruction after a major storm should be restricted to the landward side of the Collier County Coastal Setback Line. 4.3.1 Beach segment #9. CLAM PASS BEACH Length: 3,440 feet Beach Access: Via Clam Pass Park boardwalk Hazard Potential: EXTREMELY HIGH. Complete inundation or ephemeral tidal pass formation could occur during an intense tropical storm. Management and Recommendations: The groin should be removed. The existing beach facility to the north is constructed too close to the receding shoreline and should be considered for landward relocation; any additional facilities should be set farther landward. Any disturbance to vegetation will be inimical to the dune areas; both upland and dune vegetation will be protected. II -79- 4.3.2 Beach segment # 10. NORTH PARK SHORE Length: 4,800 feet Beach Access: Access at the North end of Gulfshore Boulevard. Hazard Potential: MODERATE. A relatively wide setback and an artificial dune constructed in 1981 contributes to a lowered hazard. Management and Recommendations: A multifaceted program is needed for this area, and includes the following: 1. Permanently remove the groins; 2. Protect seaward edge of existing vegetation from foot traffic; 3. Establish pedestrian by-passes wherever possible; 4. Acquire rights for public use of existing accesses; 5. In unaltered areas where continued scarp recession necessitates corrective action, the front line of the existing structure should be integrated with the adjacent existing scarp, using a combination of sand fill, stabilizing vegetation, and rock boulder; 6. Any new structure must be designed to have minimal interference with natural beach processes; 7. Reconstruction after major storms shall be restricted to landward of the County Coastal Setback Line. 4.3.3 Beach Segment #11. SOUTH PARK SHORE Length: 3,310 feet Beach Access: None Hazard Potential: EXTREMELY HIGH TO SEVERE. Dense high-rise construction and minimal setbacks will ensure a high potential for MAJOR DESTRUCTION AND PROPERTY DAMAGE in a full strike hurricane or even a moderate tropical storm. Management and Recommendations: Protection of remnant vegetation in front of retaining wall from foot traffic by construction of beach access stairs at north and south ends. See also recommendation for segment #10. II -80- 4.3.4 Beach segment #12. THE MOORINGS Length: 5,750 feet Beach Access: Via Horizon Way, Vedado Way and Via Miramar Hazard Potential: HIGH. Poorly integrated seawalls and minimal setbacks increase the potential for severe damage during even a moderate storm. Management and Recommendations: See recommendations for segments #10 and #11. Horizon Way has an artificial dune with a rock core. 4.4 COASTAL BARRIER UNIT 4. NAPLES HEADLAND The northern mile of the Naples headland has experienced the most pervasive trend of erosion in Collier County. The beach in the area has receded up to 300 feet since 1927. The shoreline receded 30 to 40 feet after the construction of jetties at Doctors Pass in 1960. This erosion occurred as a result of a sand deficit caused by the jetties in the Park Shore barrier unit. The shoreline of Central Naples was relatively stable in the early 1900's but began to fluctuate about the middle of the twentieth century. In the last 50 years, continual erosion has occurred between 5th Avenue South and 10th Avenue South. This shoreline was hardened by the construction of seawalls and closely spaced groins about 1950. The shoreline of South Naples has fluctuated landward and seaward as much as 200 feet since 1885. Three long timber pile groins, numerous more closely-spaced rock groins, and nearly continuous seawalls were constructed in South Naples during the 1950's. Shoreline data r~veal that the timber pile groins have promoted 20-60 feet of accretion in their immediate vicinity since construction. Erosion occurred between 1962 and 1973 in the vicinity of Gordon Pass. In 1986, with funding assistance from DNR, the city removed offshore portions of about 25 deteriorated timber groins. There are five beach segments contained within the Naples Headland coastal barrier unit (Figure 4-S). unit Recommendations: 1. Protect coastal vegetation and reconstruct dunes. 2. No encroachment of any upland protective structures should be permitted seaward of the existing vegetation line. 3. Any new structures should be designed to interact with natural beach processes. II -81- 4. Repair of structures should be allowed only after alternatives for redesign or repositioning have been exhausted. 5. Reconstruction of inhabited structures after major storm damage must be restricted to areas behind the City's Coastal Setback Line. 6. Seawall conditions need to be examined, and alternatives to misalignment be considered after storm damage. 7. The volume of the ebb tidal delta at Gordon Pass should be monitored and the location of dredge disposal be adjusted accordingly. 8. All efforts should be made to protect any remaining coastal hammock. 4.4.1 Beach segment #13. NAPLES NORTH Length: 8,430 feet Beach Access - Moorings Residents' Beach, Lowdermilk Park and four street access points. Hazard Potential: EXTREMELY HIGH. Similar to conditions noted in Moorings segment, and is further exacerbated by continued erosion expected to occur in the future. Management and Recommendations: Remove non-functional groins and minimize any further structural intrusion onto beach. 4.4.2 Beach segment #14. CENTRAL NAPLES Length: 4,300 feet Beach Access: Nine points located at the street ends. Hazard Potential: HIGH. continued sharp beach recession during storms, limited setbacks, and the age, condition and poor integration of adjoining seawalls present an immediate hazard during even moderate storms. Construction on foundation rather than on pilings has vastly increased the potential for major structural damage during hurricane tides or storm surges. Management and Recommendations: Protect coastal vegetation and reconstruct dunes in segments #14-16. No encroachment of any "upland protection structure" should be permitted seaward of the existing vegetation line. Any new structures must be designed to interact with natural beach processes. Repair of these structures should be allowed only II -82- after alternatives for redesign or repositioning have been exhausted. 4.4.3 Beach segment #1S. OLD NAPLES Length: 5,320 feet Beach Access: Fifteen points located at the street ends. Hazard Potential: EXTREMELY HIGH TO SEVERE. Some seawalls are over 30 years old and their collapse could upset neighboring bulkheads. Seawall age, condition and integration is poor. Residential homes are built on foundations rather than pilings. Storm surge damage would be extremely high. Management and Recommendations: Similar to the previous segment. Riprap rock and revegetation would aid in beach stabilization by enhancing dune formation. See recommendations for segment #14. 4.4.4 Beach Segment #16. NORTH PORT ROYAL Length: 6,400 feet Beach Access: Two beach walks with parking on Gordon Drive, Avenue South, and 21st Avenue South, and at the end of 32nd 33nd Avenue South. Hazard Potential: MODERATE. Wide setbacks, preservation natural vegetation, and the effects of pile groins aid in mitigating hazard. SOUTHERN SECTION THE HAZARD MAY BECOME SEVERE. 18th and of some timber IN THE HIGH TO Management and Recommendations: Primarily revegetation management with an irrigation system. Sailboat mooring and hawser attachments in the dune zone should be discouraged by the property owners. See other recommendations as in previous segments of this unit. 4.4.S Beach Segment #17. SOUTH PORT ROYAL Length: 6,250 feet Beach Access: None Hazard Potential: SEVERE. Seven long seawalls exposed at high tides and frequently to storm tides, plus closely-spaced groin fields, discourage natural II -83- beach processes from operating. Moderate to intense storms could contribute to seawall failure. House construction on foundations instead of pilings would increase hazard severity. Management and Recommendations: Seawall conditions must be carefully examined, and alternatives to misalignment be considered after heavy damage has occurred. The volume of the ebb tidal delta at Gordon Pass should be monitored, and the location of dredge disposal be adjusted accordingly. Other recommendations similar to that in previous segments of this unit. 4.S COASTAL BARRIER UNIT S. KEEWAYDIN ISLAND Over the long term (1885 to 1981) the northern extreme of Keewaydin Island exhibited an accretional trend. Some of the accreting sand was supplied from a north-south drift divide that occurred approximately 0.75 miles south of Gordon Pass. In 1962, 1967, 1970, 1980, and 1986 sand dredged from the ebb tidal shoals of Gordon Pass was placed on North Keewaydin Island. A two mile stretch of beach immediately south of the drift divide has undergone continual erosion since 1885. Numerous tidal passes have opened and closed along this segment. The most recent in this area (John's Pass) closed by overwash and infilling of the throat during the 1930's. This segment could again become a tidal pass site in the near future if erosion continues at the present rate. Central and South Keewaydin Island have benefited over the past 100 years from the erosion occurring to the north. Central Keewaydin Island grew southward over 1.5 miles during the same period. The terminal end of an accreting spit is normally the widest. As the spit continues to grow, erosion will begin to occur in the vicinity of the previous termini. This effect is apparent on south Keewaydin Island, where, since 1962, approximately 200 feet of erosion has occurred along a 1.5 mile stretch of beach directly north of the accreting spit. There are five beach segments in this barrier unit (Figure 4-6). unit Recommendations: 1. Any future development in this area should be of low impact, stilt cottage construction, as far away from the beach as possible. II -84- 2. property owners should be encouraged to remove Australian pines and retain all native dune and beach vegetation. 3. No structural stabilization of the shore should be undertaken. 4. Owners will be warned as to hazard potential prior to any construction. 5. Preserve established setbacks. 6. Encourage vegetational management. 7. Establish and maintain narrow isolated foot trails. 4.S.1 Beach segment #18. NORTH KEEWAYDIN ISLAND Length: 4,110 feet Beach Access: None (private property) Hazard Potential: EXTREMELY HIGH TO SEVERE. Natural or man-induced changes in the nearshore area are responsible for massive fluctuations in the shoreline. Management and Recommendations: The undeveloped portions of this segment have been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in Unit P16, Keewaydin Island. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated undeveloped coastal barriers. In addition, as of October I, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. Any future development in this area should be of low impact, stilt cottage construction, as far away from the beach as possible. Property owners should be encouraged, or if applicable, required to remove Australian pines, and retain all native dune and beach vegetation. No structural stabilization of the shore will be undertaken. property owners will be informed of this beach segment's hazard potential prior to commencement of any construction activities. II -85- 4.S.2 Beach segment #19. JOHNS HAULOVER Length: 5,060 feet Beach Access: Unlimited, however, only by boat. Hazard Potential: SEVERE. Complete overwash of the barrier ridge occurs seasonally. Formation of emphemeral tidal passes could occur in at least 4 places along this segment. Management and Recommendations: This segment has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in Unit P16, Keewaydin Island. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated undeveloped coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. Development in this area is strongly discouraged because of narrow barrier width and past tidal pass history. No stabilization structures will be permitted on the shoreline. Property owners will be informed of this beach segment's hazard potential prior to commencement of any construction activities. 4.S.3 Beach segment #20. CENTRAL KEEWAYDIN ISLAND Length: 14,360 feet Beach Access: By boat Hazard Potential: HIGH. It is expected that the accretional trend seen over the last century will slow considerably or stop altogether in the near future. Management and Recommendations: This segment has been classified as an Undeveloped Barrier under P.L. 97-348, the 1982 federal Coastal Barrier Resources Act; it is included in Unit P16, Keewaydin Island. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated undeveloped coastal barriers. In II -86- addition, as of October 1, 1984, no Federally subsidized flood insurance coverage is available for any coastal barriers classified as such. Any future development in this area should be of low impact, stilt cottage construction, as far away from the beach as possible. Property owners are encouraged, or if applicable, required to remove Australian pines, and retain all native dune and beach barrier vegetation. No structural stabilization of the shore will be undertaken. Property owners will be informed of hazard potential prior to commencement of any construction activities. 4.S.4 Beach segment #21. SOUTH KEEWAYDIN ISLAND Length: 8,080 feet Beach Access: By boat Hazard Potential: MODERATE TO HIGH. An accretional trend and relatively wide barrier ridges limits the hazards in this segment. Management and Recommendations: This segment has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in unit P16, Keewaydin Island. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated undeveloped coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. Preserve established setbacks. Encourage or require vegetation management, including the removal of Australian pines. Establish and maintain narrow isolated foot trails. Property owners will be informed of this beach segment's hazard potential prior to commencement of any construction activities. II -87- 4.S.S Beach Segment #22. HURRICANE SPIT Length: 7,000 feet Beach Access: by boat Hazard Potential: SEVERE. The low elevations, young geophysical age, and large effects of tidal influences on this segment suggest that drastic fluctuations of the shoreline are probable. Management and Recommendations: This segment has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in Unit P16, Keewaydin Island. This Act prohibits the use of most federal funds (e.g.; financial assistance for new utility and transportation facilities) for projects on designated undeveloped coastal barriers. In addition, as of October 1, 1984 no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. Seawall conditions must be carefully examined, and alternatives to misalignment must be considered after heavy damage has occurred. The volume of the ebb tidal delta at Gordon Pass should be monitored and the location of dredge disposal be adjusted accordingly. Other recommendations similar to that of previous segments. Considerations need to be made by property owners for possible ephemeral pass formation during storms. No development will be permitted on the active south end. Property owners will be informed of hazard potential prior to the commencement of any construction activities. 4.6 COASTAL BARRIER UNIT 6. COCONUT ISLAND Once 3.8 miles long, Coconut Island was breach~d by storms at one location and at another in 1965. The accreting southern end of Keewaydin Island overlapped the historic northern segment of Coconut Island by growing around its leeward side. The northern segment of Coconut Island was later renamed Little Marco Island. The remnants of Coconut Island presently comprise two small barrier islands, North Coconut and South Coconut, which total approximately 1.5 miles in length. II -88- Coconut Island has been the site of continuous erosion since 1885. The shoreline of North Coconut Island has receded approximately 1,200 feet since 1885 without any significant periods of accretion occurring during this time. From 1973 to 1981, North Coconut Island receded as much as 200 feet, or over 20 feet per year, making it one of the fastest naturally eroding areas in Collier County. This unit contains two beach segments (Figure 4-7). unit Recommendations: 1. Construction activity is discouraged. 2. This coastal barrier unit has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in unit P16, Keewaydin Island. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated undeveloped coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. 4.6.1 Beach segments #23. SEA OAT, CANNON, AND COCONUT ISLANDS Length: 2,900 feet Beach Access: By boat only Hazard Potential: SEVERE ON ALL BUT THE STABLE UPLAND PORTIONS OF CANNON ISLAND. Massive unremitting erosion and low elevations have created extreme hazards in the majority of this segment. All portions of the segment would be susceptible to substantial flooding during a severe tropical storm. Management and Recommendations: This segment has been classified as an Undeveloped Coastal Barrier Under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in Unit P16, Keewaydin Island. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated undeveloped coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. II -89- construction on this segment is strongly discouraged. Limited construction is possible but all details should be carefully reviewed to guarantee that this unique island is not subjected to adverse impact. In 1987 the majority of Cannon Island was purchased by the state of Florida under the CARL program. Property owners will be informed of this beach segment's hazard potential prior to commencement of any construction activity. 4.7 COASTAL BARRIER UNIT 7. MARCO ISLAND Shoreline changes along Marco Island have been extremely variable. ~hanges in position of the shore have generally exceeded 300 feet since 1885. The inlet shoreline on the south side of Big Marco Pass (North Hideaway Beach) has eroded 300 feet since that date. This recession was a result of the shift of the main ebb channel to the south, i.e., against North Marco Island. The continued erosion of South Coconut Island, which protects North Hideaway Beach from direct wave attack, could cause increased recession in the future. The position of the northwestern Marco Island shoreline has fluctuated widely in response to the changing shape of the ebb tidal delta at Big Marco Pass. Between 1885 and 1962 the northern 1.75 miles of Marco Island received sand released from the ebb tidal delta and accreted 900 feet. Since 1962, however, North Marco Island has become the site of massive, pervasive erosion. Shoreline recession rates ranging from 30 to 40 feet per year have occurred there since 1962. These rates have not been exceeded anywhere else in Collier County. The shoreline of North Central Marco Island has shifted both landward and seaward since 1885. It currently is in an erosional phase, having eroded 215 feet since 1962. A 700-foot-long seawall, which was constructed in the central portion of the sector in the early 1970's, has exacerbated erosion in the area. In the period from 1973 to 1981 approximately 60 feet of erosion has taken place. Coastal strand vegetation on either side of the seawall was cleared during the mid-1970's to allow development. Consequently, the seawall became more exposed to wave swash, causing increased wave reflection and turbulence. This, in turn, increased erosion during storm periods. Approximately 40 feet of recession occurred north of the seawall in a matter of hours during the "No Name" storm of June, 1982. II -90- The central 1.5 miles of Marco Island have accreted steadily since 1885. The southern half-mile of the island has, however, been eroding since 1927. This southern area of erosion was limited to the extreme southwestern tip of Marco Island until the mid-20th century, when the trend of erosion began to spread northward. Increased erosion of the southern part of the island was related to the construction of a seawall "compound" directly adjacent to Caxambas Pass in the early 1950's. There are six beach segments contained within the Marco Island barrier unit (Figure 4-S). unit Recommendations: 1. The County strongly encourages dune enhancement and restoration of elevated crosswalks. 2. No other structures should be allowed seaward of the Coastal Construction Control Line. 3. continue to encourage landward relocation and realignment of seawalls after storm damage, and require public seawall by-pass walkways where high tide beach is non-existent, if the recommendation is to rebuild the seawall. 4. Following renourishment, a dune protection zone should be established and crosswalks should be constructed. 5. Beach raking is discouraged. 4.7.1 Beach segment #24. HIDEAWAY BEACH NORTH Length: 8,650 feet Beach Access: None (private property) Hazard Potential: SEVERE. Further inlet throat migration could cause accelerated erosion. Management and Recommendations: Encourage retention of native vegetation in unaltered natural areas. Ensure sufficient setback of structures from the water line, through enforcement of County setback requirements, especially toward the southeast end near the curve in Big Marco Pass. Property owners will be informed of this beach segment's hazard potential prior to commencement of any construction activities. 4.7.2 Beach segment #2S. HIDEAWAY BEACH WEST Length: 6,750 feet Beach Access: Tigertail Beach II -91- - _.._"-,-_.._- _..."...-,._.__._._-~~ Hazard Potential: LOW TO MODERATE. The dynamics of the ebb tidal delta in Big Marco Pass control shoreline changes in this segment. At present Sand Dollar Island protects this beach segment from direct wave energy. Management and Recommendations: The public area should be managed for use as a passive beach and nature appreciation park. Every effort should be made to minimize impact and to restore and maintain native vegetation. Regrowth of previously removed Australian pine will be removed. 4.7.3 Beach segment #26. NORTH MARCO SPIT Length: 4,390 feet Beach Access: None Hazard Potential: EXTREMELY HIGH. A trend of erosion has been aggravated by the exposure of approximately 1,500 feet of uninterrupted seawall to the daily swash of waves. Continued erosion is likely. Management and Recommendations: continue landward relocation and realignment of seawalls after storm damage; require pUblic seawall by-pass walkways where high tide beach is non-existent. 4.7.4 Beach segment #27. CENTRAL MARCO Length: 7,260 feet Beach Access: None Hazard Potential: MODERATE TO HIGH. A trend of accretion moderates the erosion hazard although the potential for severe flooding over the low elevations of Marco Island is always present. Management and Recommendations: Enhancement and restoration of the existing dune zone and the construction of elevated crosswalks. No other structures should be allowed seaward of the County Coastal Setback Line on this segment. II -92- 4.7.S Beach segment #2S. SOUTH MARCO ISLAND Length: 2,820 feet Beach Access: None Hazard Potential: SEVERE. Poor vegetation management has enhanced the erosional trend in this segment and erosion is expected to continue. Management and Recommendations: Protect dune resources and maximize building setbacks along the south segment. 4.7.6 Beach segment #29. POINT MARCO Length: 2,210 feet Beach Access: Approximately 500 feet north of Caxambas Pass Inlet; however, no parking is available. Hazard Potential: SEVERE. practically no natural beach remains in this segment. Revetment protection of upland property could be dislodged in a major storm. Management and Recommendations: The entire offshore system should be carefully studied prior to any future attempts to further stabilize this area. Rock riprap at the base of seawalls should be maintained periodically where rocks have been lost due to wave action. 4.S COASTAL BARRIER UNIT S. KICE ISLAND Kice Island has receded steadily since 1885. On the average the shoreline has eroded 400 feet over this period. This barrier unit contains one beach segment (Figure 4-9). unit Recommendations: 1. This coastal barrier unit has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated undeveloped coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. Maintain current status. II -93- 4.8.1 Beach segment #30. KICE ISLAND Length: 16,000 feet Beach Access: By boat only Hazard Potential: SEVERE. Complete overwash of barrier unit seasonal. Management and Recommendations: This segment has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in Unit 15, Cape Romano. This act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projectson designated undeveloped coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. Maintain current status. COASTAL BARRIER UNIT 9. MORGAN ISLAND Morgan Island has experienced a history of erosion and sand redistribution since 1885. The trend along the northern half has been erosion and landward migration. This has resulted in a recession of 150 feet since 1927. The shoreline on the southern half of the island fluctuated 300 feet landward and 200 feet seaward during the cyclic formation and destruction of an accreting spit. Tidal passes have periodically opened, migrated, and closed on Morgan Island throughout the 1960's. Based on the history of shoreline change in the area it can be expected that, as in the past, the spit will disappear during the passage of some future moderate to intense tropical storm. Three beach segments occur within this unit (Figure 4-9). unit Recommendations: 1. This coastal barrier unit has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated undeveloped coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. 2. There should be close scrutiny of any proposed site development or land alteration in this area. II -94- 3. construction of structures is discouraged due to hazard potential. . 4. All proposed structures will be considered temporary, for short term use, and should be constructed on pilings. 5. No stabilization of the shoreline will be permitted. 4.9.1 Beach segment #31. NORTH MORGAN ISLAND Length: 5,880 feet Beach Access: By boat only Hazard Potential: HIGH. A low elevation and an accelerating erosion rate produce transient shoreline conditions. Management and Recommendations: This segment has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in Unit 15, Cape Romano. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. There should be close scrutiny of any proposed site development or land alteration in this area. Construction of permanent structures is strongly discouraged due to hazard potential. All proposed structures should be considered temporary, for short term use, and should be constructed on pilings. No stabilization of the shoreline will be permitted. 4.9.2 Beach segment #32. SOUTH MORGAN ISLAND Length: 3,600 feet Beach Access: By boat only Hazard Potential: SEVERE. The category to which this beach segment has been assigned summarizes the hazard. Continued migration and potential formation of ephemeral passes makes this segment extremely unstable. II -95- Management and Recommendations: This segment has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in unit 15, Cape Romano. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. No construction or shoreline stabilization will be permitted on this segment due to its extreme instability and severe hazard potential. 4.9.3 Beach segment #33. MORGAN SPIT Length: 3,800 feet Beach Access: By boat only Hazard Potential: SEVERE. Recently accreted spits such as this one exemplify land forms that are extremely tenuous and which could disappear during a single storm. Management and Recommendations: This segment has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in Unit 15, Cape Romano. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. 4.10 COASTAL BARRIER UNIT 10. CAPE ROMANO ISLAND Cape Romano Island formed in response to the interaction of predominantly south and southeasterly winds and a large subtidal sand supply in the Cape Romano shoals. These winds transported sands around Cape Romano and deposited it on Cape Romano Island. The acute intersection of Morgan Island and Cape Romano Island forms a classic cape feature. The shoreline of the apex of the II -96- Cape accreted seaward 700 feet from 1927 to 1952, and then eroded 800 feet from 1952 to 1981. Further to the northeast the shoreline has been relatively stable. The Cape Romano coastal barrier unit contains two beach segments (Figure 4-9). unit Recommendations: 1. This segment has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in unit 15, Cape Romano. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. 2. Public lands should be maintained in their natural state. 3. There should be close scrutiny of any proposed development or alteration of land in private ownership. 4. Only structures and/or activities designated to minimize adverse impacts on adjacent public lands will be permitted. 5. Private lands should be acquired if offered. possible areas of County acquisition. 4.10.1 Beach segment #34. CAPE ROMANO Length: 3,840 feet Beach Access: By boat Hazard Potential: LOW TO MODERATE. The orientation of Cape Romano Island away from the predominant approach of waves, has contributed to the historical stability of the area. Management and Recommendations: This segment has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in unit 15, Cape Romano. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated coastal barriers. In addition, as of October 1, 1984, no federally subsidized flood insurance coverage is available for any coastal barriers classified as such. II -97- Public lands will be maintained in their natural state. There should be close scrutiny of any proposed development or alteration of land in private ownership. Only structures and/or activities designated to minimize adverse impact on adjacent public lands will be permitted. Private lands should be acquired if offered. Possible areas of County acquisition. 4.10.2 Beach segment #3S. CAPE ROMANO SPIT Length: 10,800 feet Beach Access: By boat Hazard Potential: LOW TO MODERATE. As with the previous segmentation; the orientation away from predominating wave approach has contributed to the spit's stability. Management and Recommendations: This segment has been classified as an Undeveloped Coastal Barrier under P.L. 97-348, the 1982 Federal Coastal Barrier Resources Act; it is included in unit 15, Cape Romano. This Act prohibits the use of most federal funds (e.g., financial assistance for new utility and transportation facilities) for projects on designated coastal barriers. No federally subsidized flood insurance coverage is available for any coastal barriers classified as such. Public lands should be maintained in their natural state. There should be close scrutiny of any proposed development or alteration of land in private ownership. Only structures and/or activities designated to minimize adverse impact on adjacent public lands will be permitted. Private lands should be acquired if offered. Possible areas of County acquisition. II -98- 21 22 20 KEEWAYDIN ISLAND Hurricane Pass Big Marco Pass COCONUT' 23 ISLAND GROUP MARCO ISLAND 24 25 26 27 28 ~ Caxambas Pass Gullivan Pass MORGAN ISLAND GROUP 30~ 31 ~ 34 ~~~~NO 32 _ 33 35 ISL AND KICE ISLAND Blind Pass Figure 4-1: Collier County Coastal Barrier Units, Beach Segments, and Tidal Passes (from Harvey et al., 1984 - Part 2). II -99- I~ - I ------- (~ r .. . , ,,' ,'- ..- "> . . . .~.'-'~A . " <:\,.' , . .~ J~~ ~-~ 1... . ",<. <.(~}_:..' J ( e " o '.;" ..' " ~~..;.:::. ......' .'- .' .' ~ 2* ~~: ~ ",,", ....... . ,,' /- ". .- lI>oo - .- . --- Le1y Beach Beach Seqmen,ti No. 2 - // . Little -Hickory Hau"l"over' --- Beach: Seqment No''- 3" - Beach Segment No..'4 . 'Bee.ch '5e'g'm"e"lit . No. J.-'. ... Lely' Ba'refoot Beach Barefoot !leach State Preserve .' . o 1 . .- " ~ Ii' / G u 1 /' / Figure 4-2: Coastal et al., Barrier Unit 1- 1984). Barefoot Beach (from Harvey II -100- ~!ii,;~:~~\t~;,i;i~,: x .r'.' . , .... 't.:. I_~ '"- =. ........._?" .- ~ . lei Park '- , 33 f, ~ii~~ "'-,\ @ Qr~" . r-. " ' ..'J , ,.. I " . . , ) " ( . '.'1' / >, n \ . ; 11 ! i . '" . . , . I~ . ;: c;) / . ! , 9 Figure 4-3: Coastal Barrier unit 2. Vanderbilt Beach (from Harvey et al., 1984 - Part 2). II -101- D"' \ o ~ " ~ , 9 c::: ." f" , " ~ ( ~. ~.1 . , t-< g: ! ..:. n 0 ~ '.1>>' "'j l:!f} .. ~ - I :<' / cti 5' rt . ~ r~ 0:" )0 5"g 011> . ~ ~f,t .f} 0 '00 1 g> " !:l- I , "'j I " \ n ~ \ \ II> = , .~ , \ , ! , \, , \ \ -I Figure 4-4: Coastal Barrier unit 3. Park Shore (from Harvey et al., 1984 - Part 2). II -102- M ~~ , !i \ >.; I ...... (") ! ~~! .. . . = .~ ! . <. i. ~ . ,-,:; ~ . ,'-"; ."'r,,.......--. ~ ;-..~..~'i.'... 'a:;! :;. .::C"., . ~ .:1" ~ o "r.t. . . ~ ~ ~~ . \" (j\ \ \ I \ \ I c;..~t..'" 0;; . .... . .....::.. .. , :.. :..t... . ....... .~ ,., : . .. .. ~ . . . . i ;'.. .t!;. ~. . " . --:"A::- I I I I i I . , ! \.f" .~ ". ~ ~. .'\ 1~:3 ( ..... ~ ". les:~ . '" -t ~t 1 }<).j ~. .r" ~"~1 .. ":,.....,16: J ~ . - ,.-..:.. . i-V~ , \..\~,-~~ \ lo~Jr \ t.~, ) : J:ro;-,!-;: -) ){1.:2) ~ Figure 4-5: Coastal Barrier unit 4. Naples Headland (from Harvey et al., 1984 - Part 2). II -103- [~ I; i . r'l 0 < ~ . : , . ~ [ .,,~ " o ~ ~ " < i" . . H: M; .F."' : is: li ". \ \ Figure 4-6: Coastal Barrier unit 5. Keewaydin Island (from Harvey et al., 1984 - Part 2). ,. " ~ . . II -104- Beach Segment No. 23 Coconut Island .;....-..,..,.,.. Figure 4-7: Coastal Barrier unit 6. Coconut Island Group (from Harvey et al., 1984 - Part 2). II -105- "'~'._-'---"--'-------'-r-"'-"- \Z~ z'" o e. O. "0- . ~ . 0 . " ( . '" ,. '" 3 . . . , 0 ~ " :c z'" .. 00 0- . 0 0 ~ ,. . '" , . .. 0 0 . " 0 ~ ,. '" 0 . " \g' I""" 00 " . . !} I, ; ~ N 0 0 n r'" . 00 " . . " 0 N ,. . '" ... , 0 :c ~ . N 0 " 0 " ... . ... . , 0- ;'ff '-'. ~ ( , 1\ ~f.~ . ~ V ~I~ n~\l g o - Barrier unit 7. 1984 - Part 2). Marco Island (from Harvey Figure 4-8: Coastal et al., II -106- (J.,,. ., 8 , .., S ~;.b~~ ,~ ~. \ 13 '\ , ,~ I .. '! i. .::.~~'''\~:st1.~t:~~~, " " Figure 4-9: Coastal Complex (from Harvey Barrier units 8, 9, and 10. Cape Kice Island, Morgan Island, and et al., 1984 Part 2). Romano cape Romano II -107-