Written by the TreasureGuide for the exclusive use of the Treasure Beaches Report.
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| Groin Illustration from Living-Shoreline.pdf (above). Groin Advantages and Disadvantages from same web site (below). |
A few days ago I talked, about erosion control structures known as groins. I mentioned how they can produce some very productive metal detecting spots. I've made a lot of finds by hunting near groins. Many of my finds came from spots near groins.
The above graphic of a groin and the descriptive text is from living-shoreline.pdf. Living-Shoreline.pdf presents the same kind of summary information for seven different types of erosion control methods. They include vegetation, edging, sills, beach renourishment, beach renourishment with vegetation, breakwaters and groins. Like the above summary for groins, the advantage and disadvantages for each type of method is listed. Those summaries provide some pretty good tips for metal detecting. For example, under the benefits for groins, you'll see that one of the disadvantages is the erosion of adjacent areas.
So. groins, like most erosion control structures, actually shifts the sand. Find the low spot and detect there. Some of my best hunting days have been around an old groin.
One particular dip between groins produced five pieces of gold in a very small dip. I showed that particular spot in an old post. Here is the link. The Treasure Beaches Report Direct From Florida's Treasure Coast.: 8/23/13 Old Silver Coin Spots From the Past, Hurricane Season Said To Be Far From Over, and Big Tidal Wave Like with groins, any erosion control structure will produce some areas to check with your metal detector. The sand will be shifted to one area and away from another.
There was a saying I gave some years ago. It is, "Follow the sand but don't catch it." Whenever the sand is building somewhere, it is coming from another place. You'll want find and hunt the areas where the sand left.
That applies to drifting sand bars too.
After the hurricanes of 2004 that did so much damage to the west side of Indian River Drive, they put huge concrete block revetments along the west bank of the Indian River. If you saw those very heavy linked block walls, you might have thought they were impossible to move, but the walls have already fallen in many places and blocks have broken free in many places.
Bruce Lee said, "Be water, my friend." Water is persistent. It flows - over, under or around. It finds the weak spots.
And the sand in front of the revetments has eroded. The water lowered the sand level in front of the revetments and then attacked the weak spot under the revetments, washing it out and causing the block walls to fall and break under their own rigid weight.
The water is now deeper in front of the revetments. When water is presented with a solid surface it bounces off and the force goes elsewhere, but the initial contact area also becomes worn even if very slowly. The block walls of the revetments reflected the wave energy back into the shallows in front of the walls and washed the sand away. You can't stop the water: it will just go somewhere else.
Take a look at each type of erosion control measure described and think about what will happen to it over time. Think about where the erosion will occur (there will be erosion) and where the good metal detecting spots will be.
Here is the link again.
I previously posted about groins. Here is one good post showing how groins, as one example, shifts the sand. The Treasure Beaches Report Direct From Florida's Treasure Coast.: 2/24/14 Report - Iron Flakes or Silver, Driftwood, & Groins and Beach Dynamics
In that post I gave the following diagram along with some pointers for finding the hot spot when groins are involved.
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U.S. Coin Production Hits Eight-Month High in January As 2026 Semiquincentennial Coins DebutSee U.S. Coin Production Jumps in January as 2026 Coins Debut
Reports of the new 2026 Semiquincentennial coins have been reported found in circulation. Keep your eyes open. I haven't noticed any yet.
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A couple days ago I mentioned a stunning gold find. Concerning that Steve from Iowa said...
> Thanks for publishing that story about the beautiful finds in Panama. I
> will be visiting that site on Monday while driving to Pedasi in Panama
> for a surfing/metal detecting trip. I visited it last year and it is
> fascinating. Big mounds and excavations. It is a mortuary city site
> where many remarkable finds have been made. Thanks again!
Traveling with a metal detector is always fun, but often you won't be allowed to metal detect where you'd love too. Despite not being able to detect in places like that, I can't help looking around and thinking about where things should be found. You can still do some eye-balling, even when you can't remove items. You might be surprised by what you'll see. You might notice shards, shell or stone tools or even an occasional metal item.
As I've said before wind or rain erosion can expose things too.
If you are an avid detectorist, it is difficult to turn it off. I used to do it in stores too.
For example, in department stores, glance under the edges of the display cabinets where earrings studs, loose stones and little things can easily get lost.
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The surf charts are unexciting now. The winds are from the south.
We are still having afternoon negative low tides.
Good hunting,
Treasureguide@comcasst.net