All bodies of water have tides, even your bathtub. Measuring it is another story. Lake Superior has tides of 2" and it's 340 miles long. Winnipesaukee's tides can't be 3".
Ocean tides caused by the moon are slightly more than one foot. It's the funneling and resonance effect that causes the higher tides here in New England. Using this 12" figure divided by the earth's radius and multiplying by the length of Winnipesaukee, this gives the tides here about 1/16th inch, about the thickness of a nickel. This is only 0.005 feet and is not measurable on the USGS gauge at Weirs Beach.
When it's high tide in one part of the lake, it's low tide at the other end. Both Center Harbor and Alton can't be in sync with the tides of Portsmouth. One could, but not both.
While the tide height is not noticeable, some water does move back and forth each tide cycle of 12 1/2 hours. This causes enough water movement so that water may not freeze in narrow passages, such as between islands.
Another effect causes the height to fluctuate is seiching. A strong northwest wind would blow some water from Center Harbor towards Alton. This raises the water in Alton and lowers it in Center harbor. When the wind stops, the water sloshes back and forth for a while. The effect is usuall less than an inch but it probably is what causes the fluctuations seen on the USGS graph of water height.
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I see a constant flow of the surface water passing by my dock -- always to the east -- in fair weather. What's that about? Coriolis Effect?
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I'm guessing here, but since the prevailing winds are from the west, it moves the surface water to the east. I assume the deeper water is moving to the west to replace it.