Crab Island, Destin Florida
Just the name itself is synonymous with mystery and excitement and beloved by all who have come here and graced its crystal clear waters and snorkeled along its sand bars. But what do we really know about Crab Island? Interesting when I researched the topic I found that there just wasn’t a lot of data or scientific studies that I could dive into that gave me flow charts, tidal current analysis or information that I could use to advance my own hypothesis or credit another individual for scientific observations that could help us understand this very complex natural phenomenon and how to protect it for future generations. So, in the hunt for knowledge, I decided to research it myself and give past, present and future insight to the subject for those of you who may be interested while also making the general public aware of how today’s activities and marine improvements will likely impact this natural marvel we have all come to love in the coming decades.
Going back as far as the first records of the island, the locals here referred to the island as “Bird Island”. Why, you may ask? Well, simply put because it was dry land that many different species of native birds frequented throughout the day and rested upon in the evenings. The island was well established with vegetation, sea grasses, sea oats and even tidal pools which many fish undoubtedly used for ambushing incoming and outgoing schools of fish as well as possible spawning grounds for many different species.
But as wonderful as the island was, it was just a landmark for the local fishing fleets looking to navigate through the treacherous East Pass out to the rich hunting grounds of the Gulf Coast. In a haste to create a sustainable and navigatable channel for the ever growing number of fishing charters, the U.S. Army Corps of Engineers decided to step in and embark on a 36 year old endeavor to dredge and secure the canal for commercial activity.
According to a 1992 report by the U.S. Army Corps of Engineers, the East Pass of Destin was first dredged in 1931 to remove sand and make it safer to navigate. The pass was dredged a total of 22 times between April 1931 and December 1967, when construction on the jetties started.
According to the report, during the 1950s vessel traffic through East Pass ranged from 4,000 to 6,000 trips per year. And despite regular dredging, “East Pass was considered to be generally unsatisfactory for navigation. Shoaling was rapid, and channel depths reverted to 7 to 8 feet shortly after each dredging.” So to “enhance navigation and reduce the annual maintenance,” a proposal to build jetties to protect the mouth of the pass was birthed in 1963. (thedestinlog)
The Jetties are comprised of over 61,000 tons of cover stone and 24,000 tons of blanket material brought down by barge from Kentucky.
Have the jetties served their purpose?
“It made (traversing in and out of the the pass) more doable,“ said retired charter boat Capt. Kelly Windes. “It’s not perfect but there were times that you absolutely could not come and go before the jetties.”
The jetties have “definitely made it safer,” Windes said, who fished for more than four decades out of Destin.
However, Windes did say there are days “you still can’t come and go, because of lack of dredging because it’s too shallow.”
“It was suppose to give us a deep channel,” Gentry said. “But I don’t remember it making a big difference for us. (thedestinlog)
So what affects have these “improvements” made on the marine environment and how has that altered the state of the island as we know it today?
This is one of the earliest aerial photos of the East Pass, post construction of the bridge but prior to further dredging by the Army Corps of Engineers. You can clearly see the current and how the ebbs and flows have shifted the sands in such a way that it would be conducive for an island to exist on the north side of the pass at this time. Although it is difficult to see, the island is in fact dry with the currents surrounding the island and not conflicting with its topography.
Dredging Takes its Toll
Interestingly, when researching the history of Crab Island, all accounts seem to point to Hurricane Eloise as the leading cause to the islands disappearance. Not to undermine the significance of that event, which I will get to later, I do disagree that this is the “leading” cause to its deterioration. In fact, the evidence speaks a different truth. Notice from the photo above how the dredging of the East Pass by the Army Corps of Engineers has started to drastically alter the Ebbs and Flow of the current. The Ebb and Flow (also called ebb flood and flood drain) are two phases of the tide or any similar movement of water.
The ebb is the outgoing phase, when the tide drains away from the shore; and the flow is the incoming phase when water rises again. Each phase of the construction of the Jetty’s and corresponding dredging takes a huge toll on the way these flows navigate the channel thus altering the current and therefore whatever sand or non permanent structure could impede its natural inclination; which is to find the quickest path from point A to point B. To give an illustration, take a water hose and turn it on, unobstructed. Notice that the pressure is manageable with the flow of water expelled not very abrasive at all. However, put your thumb over 3/4 of the end of the hose and the pressure increases making the outbound water abrasive and forceful. The same can be said with these canals and how these Jetty’s are “funneling” the water to a narrower opening building up the pressure and volume needing to ebb and flow through it. But to understand the ebb and flow, maybe we should look at what volume of water is needing to navigate this little opening.
The Choctawhatchee Bay is NOT a little body of water. It is a significant body of water encompassing nearly 13,856 km2 (5,350 mi2) and spans portions of northwest Florida and southern Alabama. It connects to Santa Rosa Sound in Fort Walton Beach, Florida to the west and to St. Andrews Bay in Bay County to the east, via the Gulf Intracoastal Waterway, the East Pass in Destin is the ONLY outlet of the Bay flowing directly into the Gulf of Mexico.
Now imagine that volume of water being forced through a tiny pinhole (Destin’s East Pass) multiple times a day and what long term impact that could have on the surrounding islands, sand bars and habitats.
What prevents marine erosion and what are the contributing causes?
Sea Grass and other terrestrial plants play a significant role in the marine topography around a coastline and is heavily protected by The Florida Department of Environmental Protection’s Beaches Programs, within the Office of Resilience and Coastal Protection. However, theres a couple natural and unnatural factors at play here that contribute to erosion as it pertains to Crab Island.
Because freshwater inflow and poor flushing heavily influence Choctawhatchee Bay, the bay exhibits extremes of fresh water, which are marine conditions that may contribute naturally to declines and expansions of seagrass beds. While it appears that the bay has supported varying amounts of seagrass in the last 50 yr, seagrass areas have declined in several locations since the 1950s.
The health of the bay and its seagrass beds is being threatened by increased development in the Choctawhatchee Bay watershed. Increasing numbers of people desire to be
on or near the water, whether for living, recreation, or both. As environmentally attractive and sensitive lands are more heavily used, stress on the resources, including sensitive habitats such as seagrass beds, is increasing.
The lack of protection of these terrestrial plants as it relates to Crab Island has further compounded the situation. I will admit, as will most natives to the area, that I have been out to Crab Island countless times digging my feet into its sand and swimming within its tranquil water. But, that has had a significant negative impact on its deterioration as the growing number of tourists desire to do the same. These grass beds are being uprooted and the infrastructure that is desperately trying to remain intact is slowly being destroyed. Simply put, if the grass beds deteriorate, the island will cease to exist. But what proof do I have of this?
Disaster Strikes the Emerald Coast: Bird Island Lost
On September 23rd, 1975 Hurricane Eloise struck Destin.
According to weather.gov thousands of trees were toppled and utility lines were knocked down across the area. 85-90% of the buildings between Fort Walton Beach and Panama City, FL (on the Gulf side of Highway 98) were severely damaged or destroyed. At least 150 buildings were destroyed or un-repairable, 75 motel foundations were destroyed and 400 other buildings were damaged in that area.
Storm surge was extensive along the coast with observations of storm tide (storm surge + tide) as high as 10.6 feet in Destin, FL with higher values further to the east of the track of Eloise. Eloise severely damaged several piers across the panhandle, including the destruction of the relatively newly built Okaloosa Island Pier. Beaches were destroyed and dunes were undermined. 30-70 feet of sand dune width was eroded during Eloise. Storm surge washed away structures and streets across northwest Florida as can be seen in the before and after photos below. More than 30 boats moored in Destin, FL were destroyed or sunk with some reportedly “stacked like toys” according to the NOAA Assessment.
This natural disaster was the tipping point for what little sea grass and sea beds remained that clung on to their decades of growth preventing any massive shift of sand caused by human interaction. This was the catalyst that pushed a few decades worth of erosion, caused by the East Pass expansion efforts, to take place immediately and for the powers at be to predictably blame the Hurricane as the root cause for the erosion. But, this was just the tip of the iceberg. I do not believe this was the root cause of the erosion as I have aforementioned in my research above.
Crab Island Today
Looking at the completion of our city’s master plan for the development of the East Pass Channel, the Getty’s and further preventative measures taken around Norriego Point, you can now finally see the huge impact it has played on what remains of Crab Island. Notice how the forced volume of water is starting to shift the island; even displacing it to the East in what appears to be a new island in the beginning stages of development.
Now consider how crowded Crab Island is year after year and what impact that is having on its sea grass growth and you can quickly see that this beloved natural attraction, that is an icon of Destin, may only be a memory in the not too distant future.