|

Beach policy unrealistic; buildings must be moved

Clifford Olson
Contributing Columnist
opinion@lbknews.com

As a seasonal renter at 380 North Shore Road for the past two years (Jan-Feb-Mar), I have had ample opportunity for daily observations of the north end of Longboat Key – both pre and post placement of sand.  As a geologist with a Masters Degree in Sediment logy (the deposition and erosion of

When structures protrude past the natural shoreline, beach maintenance can grow difficult and expensive.

sands and clays) from the University of Cincinnati, I understand the forces that have (and will continue to) shape this area.

Simply stated, putting a building on a beach on a barrier island is a bad idea. Precautions can be taken (i.e. adequate set back from the beach or adequate elevation of the structure) but these are only precautions – one must realize the shoreline will migrate ‘in and out’ causing the width of the beach to change.

The solution is also simply stated, remove those structures that are threatened and acknowledge that they should not have been put there in the first place.  This is a very practical . . . and from a geologic standpoint . . . obvious solution.  However to the people whose beach has shrunk or have a house ‘threatened’ by waves, this is untenable.  They want the beach ‘fixed’.

Last year, Longboat Key spent $5 million on a ‘fix’ by placing 150,000 cubic yards of sand on the north end of Longboat Key.  I’d estimate that 80% of that sand is gone (or at least not where Longboat Key wanted it to stay).

This year I’ve read that, Longboat Key wants permission to place groins at the north end of the Key to ‘anchor’ the existing sand and (presumably) buy more sand to restore the beach.

Unfortunately, while the issue of beach re-nourishment seems simple . . . pile more sand in the eroded areas and anchor it if possible . . . it is much more complex.  To help understand this complexity, I’d like to present a ‘geologic view’ with the hope that Longboat Key reconsiders their approach of ‘beach maintenance’ and acknowledge that allowing developers free reign, has led to the placement of buildings in locations that are untenable (i.e. adjacent to a tidal channel).  In addition, continuing to spend money on sand/engineering solutions is foolish (even Longboat Key doesn’t have enough money to change what the Gulf will eventually dish out).

Longboat Key should remove the offending buildings and associated roadway.

 

Background – Interested Parties

In order to help understand the issue of beach re-nourishment and groins, one needs to realize that there are a number of parties, each with their own perspective, providing insight into this issue. It’s not that anyone is ‘right or wrong’; it’s just that each party is approaching the issue based on their particular desires or training.

So far (based on the news articles I’ve read), we’ve heard from the:

• Town Commission that looks at beaches as a maintenance issue (similar to road repair) – Gulf side structures should have a viable, broad beach between the structure and the water.

• Homeowners on the Gulf side that have a similar approach as the Town Commission – the beach is not the same (generally less) as when I purchased the house and it should be fixed (wider beach).

• Engineers that are asked to provide ‘beach maintenance’ – engineers by definition provide solutions to problems and this usually means ‘building something’ (think of the Corps of Engineers).

• Academics, (via a recent article in the Longboat Key News) presented excerpts from an academic study on the futility of groins to stabilize beaches on the Atlantic coast.

• The status quo or ‘go slow’? The only person urging caution is Joe McClash from the Manatee Board of County Commissioners.

Now for a geologic point of view.

 

Discussion – Geologic Forces and Longboat Key

Longboat Key is one of several barrier islands that separate Sarasota Bay from the Gulf of Mexico.  That means that it is composed of sand and due to the action of the waters of the Gulf, this sand is in constant motion thanks to the: lateral off-shore currents, tidal forces and waves.  The end result is that sand on Longboat Key is in constant motion.

Longboat Key (and the other Keys that form the Gulf side of Sarasota Bay) is the result of offshore Gulf currents that move laterally along the coast, from north to south.  The result is a ‘smooth sinuous shoreline’ that is passing sand from the north to the south.  This is well illustrated both by high altitude photographs and the extensive southern sweep of the western channel shoal of Longboat Pass.

Separating the barrier islands are tidal channels; Longboat Pass is a one of these. Each day, the waters of Sarasota Bay rise and fall several feet due to tides. While this may not sound like much, multiply this by the twenty or so square miles of water in Sarasota Bay and one gets tens of millions of cubic feet of water that moves in and out via the tidal channels – at least twice, but more frequently, four times a day.  When one considers that Longboat Key is ten miles long (i.e. a ten mile long barrier that the tide must flow around), one can begin to understand the strength of the currents in the channels.

An additional consideration of the tidal channel is that the sides (and bottom) are composed of sand – an unconsolidated material (rock is a bound or consolidated material).  This results in a flexible conduit, one that is subject to monthly or annual movement but over the course of many years stays roughly in the same area. (Actually, it’s quite amazing that given the amount of water that is moved each day and the flexibility of sand that the channel stays in one place for so long).  Aerial photographs starting in 1940’s and charts as far back as the 1880’s show that the approximate location of Longboat Pass has not changed in over 100 years but that individual flow paths are highly variable.

Waves are the final component of sand movement; not the waves that lap the beach on a sunny day, but storm waves.  Storm waves occur during storm events (obviously), so they are infrequent and their severity unpredictable – and they are responsible for 95%+ of all sand moved by waves.

The result of these three forces is a series of: long / narrow sinuous islands – with undulating shore lines, separated by channels (connecting the Bay to the Gulf) that only experience major changes during storm events (i.e. storm waves can move a tremendous amount of sand in a short period of time and open a new path or dramatically affect an existing one).

None of this is an issue until a town allows buildings to be placed in the path of these forces.

 

Discussion – Development and Longboat Key

Starting in the 60’s and 70’s, Longboat Key started seeing large-scale development along the Gulf beaches and the people doing this work wanted ‘houses with a view’.  This means a ‘house on the beach’ and the house is built (usually) ‘a prudent distance from the shore’.  Unfortunately, ‘a prudent distance from the shore’ is defined by some combination of: the developer, the Town and the perspective owner – with only the most casual regard for the fact that a beach (the intersection of the Gulf waters and the shore) and the channel migrate with time.  Since building foundations are fixed, problems are bound to arise if an area of the beach shrinks . . .  leaving succeeding Town Officials and homeowners to try to correct the situation (the developer having made their money is long gone).

The picture illustrates the current problem; a building placed too close to the water, a bulkhead placed to protect the foundation and the shoreline responding to the geologic forces of the Gulf.

So that leaves Longboat Key with a problem:

• People wanting wide beaches (or at least as wide as when the building was built),

• Buildings that were built too close to the beach (a beach that can move in or out by dozens of feet over a decade),

• A town with a desire (and at least in the short term, the money) to ‘stabilize’ or ‘re-nourish’ a particular stretch of beach and

• Firms (consulting and dredging) that are more than happy to sell the idea of ‘beach stability and maintenance’.

 

Conclusion

I would suggest that Longboat Key reconsider their approach of ‘beach maintenance’ and acknowledge that allowing developers free reign has led to the placement of buildings in locations that are untenable (i.e. adjacent to a tidal channel).

In addition, continuing to spend money on sand/engineering solutions is foolish (even Longboat Key doesn’t have enough money to change what the Gulf will eventually dish out).  Longboat Key should remove the offending buildings and associated roadway.

 

Tags: , , , , ,

Longboat Key News

7 Responses for “Beach policy unrealistic; buildings must be moved”

  1. Doug Riemer says:

    I moved to Longboat in 1974 and left in 1997 — greed and status had pretty well wiped out the community were used to call “The key of happiness.” When I briefly returned last year, I found that process complete. Longboat Key is the most elegant mausoleum, but a place to come to die, not to live, nonetheless. I fled to Venice, which remains a very sweet town.

    The issue the author raises is true, though not stated clearly — it’s an uneven battle between the huge forces of nature and the puny power of the monied elite to protect their castles, which truly should be understood to be “sand castles.”

    Most of the comments voiced concerns about being betrayed, suggesting the writers have a right to their sand castles. The Town will most certainly grant their wishes and continue to fight, winning some battles but certainly losing the war. Remember the old Chiffon
    commercial” “It’s not nice to fool Mother Nature” The inevitable storm comes at the end.

  2. Mckinnon says:

    What planet is this guy from?? Displace hundreds of homeowners and families?? Yeah, that’s what we do in this country – when there’s a threat, we pack up and leave. Not! We work to find solutions.

  3. Anne Arsenault says:

    This is such an about-face to the plans and policies that Longboat Key has had for the years I’ve lived here that it feels like a betrayal. Do you want all of us who live on a beach to move? What about the promises in writing to add white sand to a dark beach? If LBK quits in its promises to help those of us who live legally on a beach, then its reputation will be so poor that no one will buy here.

  4. Bill Cue says:

    Even a moderate hurricane could make many more buildings too close to the shoreline. Maybe there are ways to inexpensively reclaim sections of the beach without costly dredging. Maybe the town could hire a non-dredging oriented engineering company to suggest cost effective alternatives.

  5. Karen Feeney says:

    This seems like prudent advice for the Town!

  6. Karen Feeney says:

    This seems like prudent advice for the Town!

  7. LBK visitor since 1947 says:

    While this article/post is pretty much on the money, as far as it goes, it is just the beginning of the story, and especially the history.

    LBK, and the other keys were just fine until FEMA came into being; since then, all the beautiful islands have been “screwed up,” royally and otherwise by overbuilding, grossly so in the main. There is no way in heaven or earth that any of the keys of Florida, no matter how fully flouridated, can support the amount of people and construction with which they are burdened, physically and socially, and it’s about time to begin the transition back to how it was before FEMA.

    Anything else is futile and infantile and a gross discredit to to the intelligence of everyone involved.

Leave a Reply