I live beside a bay which is about 6 miles long by 2 miles wide. When the tide comes in, does it come in equally on each side of the bay? If so does that mean that the water level falls in the centre of the bay or rises; or do I need to get a life?
The water level in a small area such as a bay will rise or fall by the same amount over the entire area. However, the ground underneath will likely be irregular. That means that the water may flow higher onto one particular section of the beach than others. Even so, the total height of the water will be equal throughout.
I don’t think Exapno’s answer is correct. Tides are much more complicated than that, particularly in narrow bays like the OP mentions. They actually flow like very large waves.
As part of a case I am involved in at the moment we have heard evidence of two tidal gauges about a mile or so apart which show differences of about 3-4 inches in tidal max tidal height and 5-10 minutes difference in time.
The configuration of the bottom and shoreline can result in currents at various angles to the general tidal flow. Water is a certain amount of viscosity so it can temporarily “pile up” until enough pressure difference exists in increase the flow out of the “pile.” This ought to result in differences in tidal time and height at various locations in such an inlet.
That’s right. A bay with a wedge shape can collect the tide coming in at the wide end and squeeze it together as it flows to give a faster and higher rush of water at the narrow end. See “tidal bore” on Wikipedia. The Bay of Fundy has extremely high tides because of resonance with the Gulf of Maine, according to the article I linked. Essentially, the water sloshes back and forth between them with a push each time from the Atlantic tides, giving Fundy tides as high as 12 to 16 meters.
Besides what’s ben said, there can be a ‘seiche’ in a lake or semi-enclosed basin. Wikipedia has some cool examples. It’s the surge back and forth you see in a bathtub for a minute when you just got out, or in a lake activated by the wind. A seiche would also hinder the bay from all rising evenly as the tide comes in.
The tidal gauge at the entrance of San Francisco Bay peaks at a different height and time than the one down the San Mateo County coast, and they both measure the same Pacific tide.
Rivers where the water is rapidly rising = noticeably higher in the middle.
Rivers where the water is rapidly falling = noticeably lower in the middle.
YES , but you already knew that!
I don’t know. Sitting outside on a nice day, sipping a good beer, watching the tide flow in, and letting your mind wander. That sounds like a life to me.
Otis Redding already said it best:
spingears, I see a pattern of unhelpful posts in GQ from you. If I see one more such post, you will be suspended.
You have been warned.
-xash
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