Written by the TreasureGuide for the exclusive use of treasurebeachesreport.blogspot.com.
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| Tires In Indian River Lagoon. ( I pulled the vegetation-covered one out of the water. ) |
Hours, days, weeks, months, decades, centuries are all units of time that can be appropriate for describing beach sand cycles. By "beach sand cycles" I mean the cycles of beach accretion and erosion on specific beaches. Besides sand, other objects wash in and out in cycles of varying length.
A beach might erode for an hour, day or week before filling in again, but there are what I would call long-term and short-term cycles. To give an example, Bathtub beach and Fort Pierce South Jetty beach will continue to erode for years, decades and even centuries. There are stationary obstacles that cause the erosion, such as the rocks and houses in one case, and the jetty in the other case. Despite the long term trend of erosion, there will also be shorter term cycles when the sand actually builds a little in those locations and then erodes back again. So even though a beach might generally erode for a week or so, there can also be daily or hourly fluctuations.
But not only does the sand come and go in cycles, there are also periods of time when other objects, such as coins, come or go, and those periods are not perfectly correlated with the sand cycles. I've explained why that is in the past. I have been observing this lately in the Indian River Lagoon.
There is, believe it or not, a bit of a beach along the west side of the lagoon, and like other beaches, it comes and goes. The waves do not get as high as they do on the ocean, but at times they reach a foot or more. They usually hit the west bank of the lagoon.
I consider the beach along the west bank to provide a small scale model of an ocean beach, admitting that there are some differences - one being the average size of the waves and another being the tidal change of current. As you probably know, the water flows into and out of the lagoon with the tides.
Since I drive up Indian River Drive frequently, I keep watch the lagoon to see what is happening there. You might remember that I once said that the west bank of the lagoon was littered with a mass of bottles after the 2004 hurricanes. There was a solid thick line of bottles along the west bank - some fairly old. After the hurricanes, the erosion caused so much damage to the banks and Indian River Drive that they put sheets of connected concrete blocks along the west bank between Fort Pierce and Jensen to hold the banks in place. That project must have taken about two years, as I recall. After a few years ( I don't remember exactly how many ) the bottles disappeared. The source of many of the bottles was also cut off. Many came from the banks where people used to discard their garbage before the days of garbage collection, but the banks and anything on the banks was now covered by concrete sheets. So there were few bottles left in the water and on the small beach, and it appeared that no more would be washed onto the beach or into the lagoon from the banks.
After a very long period of very few bottles other than new trash thrown from cars, boats or whatever, the bottles began to reappear again couple of years ago. Not only bottles, but old tires too. The old tires are have been washing in, especially the last few weeks.
I've been watching the tires appear and move in towards the beach. Also I've been tracking a few other objects, but the tires are plentiful and easy to track. Tires are increasing in areas where there were some before but are showing up where I have scarcely ever seen them in the past fourteen years.
I'm not really much interested in how tires or bottles move in the lagoon, except for what it can teach me about the movement of objects in general in the water and on a beach. I believe there are some important lessons to be learned there.
I always say that one of the big factors that determines how objects move in the water and on a beach, besides the density, is the shape of the object. Bottles and tires obviously have very different shapes and both are very different from coins. Both are very interesting, but the big hole in the middle of a tire collects sand as does the space that would be filled with air when the tire is inflated. It becomes very heavy and all that sand inside puts a drag on it. You'll be surprised how hard it is to move a tire filled with sand in shallow water. They become very heavy. yet in recent days and weeks the tires in the lagoon have been moving at a rate of at least a few feet per day. Remember, the surf in the river seldom gets over a foot, yet these flocks of tires are migrating to the beach, and they haven't done that to this extent since before 2004.
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| Area Where Tires Have Been Accumulating For Years. |
While coins are obviously different from tires, there are periods when coins move, just like there are periods when tires and bottles move. So what is the thing that prevented the tires from appearing for so long before they recently showed up and started moving in towards the beach. I can't answer that precisely right now, but the obvious answer is that they were previously buried. Just like coins they won't move as long as they are buried - not unless all the sand they are under is moved too.
In the past I've mentioned the tons of sand in front of the ocean beaches and how it will protect the coins and keep them from being washed up onto the beach. That sand has also protected most of the ocean beaches from eroding much over the past couple of years.
When talking about the junk washing in, one person who spends a lot of time wind-surfing in the lagoon, said there is no sea weed in the lagoon right now - at least not where he goes. His thought was that the stuff that was normally under the vegetation was now free and getting washed in.
I noticed that many of the bottles that have been showing up lately were covered with barnacles and vegetation. So are the tires. Unfortunately I haven't been fishing or out in the water in the lagoon enough lately to say if the sea weed is just buried or if it has died or what, but sand has been moving in for the past couple of months and building bars. That is happening while the bottles and tires are moving in.
The lesson today is not about tires or bottles. The point I am trying to emphasize is the various periods when different things, including sand, bottles and coins move. They move at different times, and as I've said in previous posts, according to the force of water and other factors, including the density and shape of the objects in question.
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What do you call a flock of tires? Anything you want I guess. I'd say a "bunch" or a "mess."
The surf along the Treasure Coast is up to three to five feet today and expected to stay the same tomorrow. The tides are decent.
Happy hunting,
TreasureGuide@comcast.net
