104 INLET DYNAMICS Tidal inlets — Floridians often call them Inlet Locations passes, especially on the west coast — are the most dynamic and visible features of South- and Status west Florida’s boating geography. Inlets are Fifteen inlets are currently used by boaters to transit points of entry and egress between the Gulf of between Gulf and bay waters in this Southwest Florida Mexico and inland waterways. They are also a chal- region: Gasparilla, Boca Grande, Captiva, Redfish, lenge to navigate, because of their shifting nature, strong Matanzas, Big Carlos, New, Big Hickory, Wiggins, Clam, ebb and flood currents, and changing wave action. Waves Doctors, Gordon, Big Marco, Capri, and Caxambas Passes propagating into an opposing current in inlets increase in (Map 1). Table 1 lists distances for traversing the outside height and decrease in length. The result is steeper waves (Gulf of Mexico) and inside (Intracoastal and Inland Wa- that are more difficult to navigate. terways) routes, as well as the intervening access chan- Offshore shoals continually shift because of the mov- nels. Outside route distances for mariners are longer, but ing beach sand, so it is challenging to keep markers in the travel time under favorable conditions is usually less, best water. Local watermen often leave the buoyed chan- especially for high-performance cruisers. An exception to nel, guided by knowledge of local conditions that enables the distance rule is from Gordon Pass to Caxambas Pass, them to pick the best water and avoid uncharted obstruc- where the inside route is considerably longer due to run- tions. A basic understanding of how inlets come into be- ning the Gordon River. Cruising sailboats often choose ing and evolve can aid all mariners to cope with the seem- the outside route for better winds and to avoid bridges ing vagaries of Florida’s vital passes. with restricted openings. Boca Grande, Matanzas, Gordon, Capri, and Big Marco Passes are federally authorized navigation inlets, periodically surveyed and dredged by the Army Engineers, in cooperation with the West Coast Inland Navigation District (WCIND), Lee and Collier Counties, and the City of Naples. Though not generally navigable, Big Hickory Pass was dredged once, in the late 1970s, to in- crease tidal flushing. Wiggins, and Doctors Passes are maintenance dredged for navigation by Collier County and the City of Naples. Another four inlets–Redfish, Blind (currently closed), Clam, and Caxambas have been dredged either as a by product of beach renourishment or for water quality improvement. The remaining inlets — Gasparilla, Captiva, Big Carlos, New, Little Marco, and Hurricane — are natural, unimproved passes. Aids to navi- gation are maintained at all the inlets, except Gasparilla, Captiva, Big Hickory, Clam, Little Marco, Hurricane, and Big Marco. New and Big Hickory Passes have fixed–span bridges near their mouths, and Big Carlos has a lift bridge that opens on demand between 8 a.m. and 7 p.m., but is otherwise locked down. Five inlets have closed during the past century on this reach of the Southwest Florida coast: Little Gasparilla, Blind, Un-named (south of Big Carlos), Little Hickory, and John’s (Map 1). Current and historic inlets have Rotonda West (circular shape on left side of photo), view south with Stump Pass formed, closed, and reopened, due to natural processes as in foreground, Gasparilla Pass in upper right, Charlotte Harbor in background. well as human intervention. Such events directly affect the amount of water flowing through an inlet during a tidal cycle, referred to as a tidal prism. Dredging inlet “A” can rob some of the tidal prism from inlet “B”, situated several miles down the coast. Similarly, the tidal prism of an inlet may be affected by changing the area of the bay adjacent to it; an inlet may close due to an abundance of sediment and strong longshore drift coupled with a small tidal prism. Considerable debate continues regarding the effects on tidal prism and the related closing of inlets caused by the dredging and filling of mangrove and marsh environ- ments along bay margins. Little disagreement exists, how- ever, about the potential for storm overwash of the bar- rier islands and the creation of new inlets. Eight sites along this stretch of the coast are particularly vulnerable to storm overwash (the “potential” inlet sites on Map 1). They are prone to overwash because of the narrow width of the barrier island, low elevation, and orientation to storm- wave attack. Map 1. Inlets of the Southwest Florida region. 105 106 Route distances between inlets. a. Gulf of Mexico (outside) route to inlet (sea buoy) entrance (distances in statute miles). New Boca Big Big Big Ppass/Inlet Satum Gasparill Chaptiva Rsedfis Matanza (Little Wmiggins Csla Dnoctor Giordo Capr Caxambas Grande Carlos Hickory Marco Carlos) Stump (Volume One) 71.0 176. 234. 287. 541. 579. 640. 632. 617. 732. 705. 891. 829. 972. 95. G0asparilla 7. 97.1 137. 280. 444. 572. 543. 535. 610. 635. 608. 794. 822. 875. 88. B1oca Grande 116. 9. 82.6 171. 335. 465. 434. 426. 501. 526. 599. 684. 713. 766. 79. C7aptiva 274. 167. 8. 21.6 277. 304. 376. 367. 442. 467. 530. 526. 655. 607. 71. R3edfish 237. 220. 161. 2. 214.5 342. 313. 305. 480. 404. 478. 563. 692. 644. 68. M8atanzas 581. 474. 315. 257. 24. 79.6 86. 150. 135. 250. 223. 219. 348. 490. 43. B4ig Carlos 549. 532. 473. 314. 362. 7. 10.3 34. 77. 192. 165. 251. 380. 332. 36. N7ew (Little Carlos) 670. 563. 404. 346. 393. 83. 1. 16.7 64. 161. 134. 220. 259. 301. 35. B4ig Hickory 642. 535. 476. 317. 365. 100. 37. 1. 47.9 99. 162. 158. 287. 239. 33. W3iggins 637. 620. 561. 402. 450. 195. 76. 69. 4. 40.8 87. 163. 292. 244. 28. C1lam 712. 605. 546. 487. 434. 270. 142. 171. 98. 4. 39.2 88. 117. 260. 23. D3octors 735. 628. 569. 500. 458. 293. 165. 194. 102. 82. 3. 56.7 194. 146. 20. G0ordon 801. 794. 634. 576. 523. 269. 231. 260. 178. 193. 87. 5. 82.9 171. 14. C9apri 899. 882. 723. 665. 612. 358. 320. 259. 267. 282. 167. 194. 8. 28.3 5. B2ig Marco 922. 815. 756. 697. 644. 480. 352. 381. 299. 214. 290. 126. 131. 2. 3.5 C7axambas 975. 868. 709. 741. 698. 433. 306. 335. 343. 268. 243. 270. 184. 55. 3. b. Intracoastal waterway (inside) route to inlet access channel (distances in statute miles). New Boca Big Big Ppass/Inlet Satum Gasparill Chaptiva Rsedfis Matanza (Little Wiggins Grande Carlos Hickory Carlos) Stump (Volume One) 75.5 105. 203. 278. 417. 565. 507. 680. 65. Gasparilla 7.5 85.0 155. 220. 460. 417. 550. 532. 58. Boca Grande 105.5 8. 75.5 122. 362. 319. 452. 434. 50. Captiva 253.0 155. 7. 57.0 214. 362. 304. 387. 42. Redfish 258.0 250. 102. 5. 119.7 267. 209. 382. 37. Matanzas 427.7 420. 372. 274. 19. 79.4 93. 112. 18. Big Carlos 565.1 467. 319. 312. 247. 7. 29.5 47. 10. New (Little Carlos) 517.6 510. 462. 364. 299. 95. 2. 22.4 8. Big Hickory 650.0 552. 404. 307. 332. 192. 44. 2. 5.8 Wiggins 635.8 538. 580. 482. 317. 178. 120. 88. 5. d. Inlet and access channels from Gulf to Intracoastal c. Inland waterway (inside) to access channel (distances in statute miles). (distances in statute miles). Plass/Inlet Isnlet Channe IlCW/IW Acces Tota Pnass/Inlet Giordo Coapr Bsig Marc Caxamba Stump (Vol.1) 18.5 03. 2. Gasparilla 02.9 11. 2. Gordon 190.6 190. 21. Boca Grande 48.3 01. 5. Capri 10.6 03.3 11. Captiva 22.5 17. 3. Redfish 19.1 10. 3. Big Carlos 130.9 0. 11.0 Matanzas 10.1 01. 1. Caxambas 231.9 101. 11. Big Carlos 10.8 08. 1. New (Little Carlos) 04.9 03. 1. Big Hickory 05.6 01. 1. Wiggins 00.6 06. 0. Clam 0.2 0.2 Doctors 0.3 0.3 Gordon 00.8 18. 1. Capri 00.7 07. 0. Big Marco 20.1 01. 2. Caxambas 14.4 58. 6. e. Outside route, including runs from and to the ICW/IW (distances in statute miles). New Boca Big Big Big Ppass/Inlet Satum Gasparill Chaptiva Rsedfis Matanza (Little Wmiggins Csla Dnoctor Giordo Capr Caxambas Grande Carlos Hickory Marco Carlos) Stump (Volume One) 151.4 273. 360. 322. 555. 633. 684. 625. 760. 794. 717. 895. 962. 986. 104. Gasparilla 11.4 156.3 243. 205. 438. 516. 567. 508. 643. 677. 790. 777. 845. 869. 97. Boca Grande 233.5 16. 137.4 199. 421. 500. 551. 592. 536. 661. 684. 761. 739. 853. 91. Captiva 350.7 243. 17. 99.3 321. 400. 451. 492. 436. 561. 584. 661. 639. 753. 81. Redfish 342.6 235. 139. 9. 298.6 376. 327. 369. 403. 438. 551. 538. 606. 720. 78. Matanzas 505.2 498. 491. 361. 28. 130.5 181. 122. 167. 291. 214. 392. 369. 483. 51. Big Carlos 633.5 526. 520. 490. 356. 10. 49.4 53. 170. 104. 128. 205. 373. 396. 44. New (Little Carlos) 614.3 507. 501. 471. 337. 141. 4. 45.1 89. 122. 146. 223. 391. 314. 43. Big Hickory 665.8 558. 552. 422. 389. 192. 51. 4. 60.6 131. 154. 231. 209. 323. 41. Wiggins 700.2 693. 596. 466. 423. 137. 150. 86. 6. 59.6 81. 196. 263. 287. 35. Clam 744.6 637.