Understanding Tides

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Judging from questions I get from readers, tides cause more confusion among coastal anglers than any other subject does. 
One of the questions I hear most often goes something like this: “I saw where the low tide was going to be at 11:15, but the water was up above the boat dock. How could the tide be so high during the low tide period?”
To answer this and any other question about tides, it is best to take a good look at what tides are and exactly what forces cause them.Tides are the periodic rise and fall of all ocean waters. They are caused in two different ways: gravity upon the water from the moon and sun, and gravity upon the water from the earth. My mentor, the late Ed Holder, told me that the easiest way to understand how these tidal movements work is to compare them to a wave.
“In essence a tide is a large, slow-moving wave that starts off in the ocean, moves through a pass and ends up in the back of a bay or upland into a river system. And it’s all influenced by the elements,” he said.
Remember that most waves are influenced by wind and tides are no different. This is why some low tides are not always so low.
A strong southerly wind pushes a lot of water into a bay system, causing unusually high tides, even sometimes during periods when moon or solar patterns call for low tides. Conversely, north winds will push water out of an ecosystem. That is why during the fall we get such low tides. “Blue northers” in conjunction with a strong tidal pull will really drain an area and help to cleanse coastal marshes.
Moving on, but still keeping with the idea of viewing the tide as a wave, it’s very important for anglers to understand that tidal strength at points away from the immediate coastline won’t be as strong as those at a pass near the Gulf.
“You’ve got to realize that like any wave, a tide weakens as it move inland,” Holder said. ”So your strongest tide will be near the Gulf and the weakest will be far into the bay or river.”
When I used to do tide charts for the Port Arthur News, their tides were given for the Old Coast Guard station at Sabine Pass. 
However, at Stewts Island, on the north end of Sabine Lake, what is a three-foot tidal change at the pass may be reduced to somewhere between two and two and a half feet.
And 10 miles up the river at the Interstate 10 Bridge at the Neches River, it might be only a one foot change. But you will need to remember, the wave weakens as it moves farther inland.

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