# Watching the tide flow away **URL:** \ **Category:** Factual Questions\ **Created:** [March 30, 2006, 4:37pm UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556 "2006-03-30T16:37:06Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![hop\_along](https://avatars.discourse-cdn.com/v4/letter/h/f08c70/32.png) [@hop\_along](https://boards.straightdope.com/u/hop_along)\ **Post date:** [March 30, 2006, 4:37pm UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556/1 "2006-03-30T16:37:06Z")
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? ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [March 30, 2006, 5:07pm UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556/2 "2006-03-30T17:07:14Z")
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. ---
**Author:** ![Princhester](https://avatars.discourse-cdn.com/v4/letter/p/3e96dc/32.png) [@Princhester](https://boards.straightdope.com/u/Princhester)\ **Post date:** [March 31, 2006, 12:10pm UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556/3 "2006-03-31T12:10:07Z")
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. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [March 31, 2006, 5:29pm UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556/4 "2006-03-31T17:29:25Z")
> [@Princhester](#): > > 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. ---
**Author:** ![rjk](https://avatars.discourse-cdn.com/v4/letter/r/ed655f/32.png) [@rjk](https://boards.straightdope.com/u/rjk)\ **Post date:** [April 1, 2006, 4:40am UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556/5 "2006-04-01T04:40:31Z")
> [@David Simmons](#): > > 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”](http://en.wikipedia.org/wiki/Tidal_bore) on Wikipedia. The [Bay of Fundy](http://www.valleyweb.com/fundytides/) 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. ---
**Author:** ![MaryEFoo](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@MaryEFoo](https://boards.straightdope.com/u/MaryEFoo)\ **Post date:** [April 1, 2006, 5:07am UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556/6 "2006-04-01T05:07:07Z")
Besides what’s ben said, there can be a ‘seiche’ in a lake or semi-enclosed basin. [Wikipedia](http://en.wikipedia.org/wiki/Seiche) 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. ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [April 1, 2006, 7:45am UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556/7 "2006-04-01T07:45:43Z")
Rivers where the water is rapidly rising = noticeably higher in the middle. Rivers where the water is rapidly falling = noticeably lower in the middle. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [April 1, 2006, 5:12pm UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556/8 "2006-04-01T17:12:23Z")
> [@hop along](#): > > or do I need to get a life? YES , but you already knew that! ---
**Author:** ![Gary\_Robson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gary_robson/32/3448_2.png) [@Gary\_Robson](https://boards.straightdope.com/u/Gary_Robson)\ **Post date:** [April 1, 2006, 10:27pm UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556/9 "2006-04-01T22:27:23Z")
> [@hop along](#): > > …or do I need to get a life? 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. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [April 1, 2006, 10:42pm UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556/10 "2006-04-01T22:42:01Z")
Otis Redding already said it best: > [@](#): > > Sittin’ in the mornin’ sun > I’ll be sittin’ when the evenin’ come > Watching the ships roll in > And then I watch 'em roll away again, yeah > > I’m sittin’ on the dock of the bay > Watching the tide roll away > Ooo, I’m just sittin’ on the dock of the bay > Wastin’ time ---
**Author:** ![xash](https://avatars.discourse-cdn.com/v4/letter/x/c6cbf5/32.png) [@xash](https://boards.straightdope.com/u/xash)\ **Post date:** [April 4, 2006, 6:49am UTC](https://boards.straightdope.com/t/watching-the-tide-flow-away/350556/11 "2006-04-04T06:49:58Z")
> [@spingears](#): > > YES , but you already knew that! **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** General Questions Moderator