# Geographers/Geologists: Waterfall flow per second? **URL:** \ **Category:** Factual Questions\ **Created:** [October 17, 2011, 10:20pm UTC](https://boards.straightdope.com/t/geographers-geologists-waterfall-flow-per-second/599972 "2011-10-17T22:20:32Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [October 17, 2011, 10:20pm UTC](https://boards.straightdope.com/t/geographers-geologists-waterfall-flow-per-second/599972/1 "2011-10-17T22:20:32Z")
I was reading the [wikipedia page](http://en.wikipedia.org/wiki/Tahquamenon_Falls) on Tahquamenon Falls and it states that > [@](#): > > During the late spring runoff, the river drains as much as 50,000 US gallons (190,000 L) of water per second, making the upper falls the third most voluminous vertical waterfall east of the Mississippi River, after Niagara Falls and Cohoes Falls, both in New York State . But…there is a lower Tahquamenon Falls as well. Shouldn’t that have at least the same volume per second since it’s lower on the same stream? I can understand it if waterfall volume were measured as the average amount of water _that is in the waterfall at any given time_. But it’s not. It’s invariably given as flow _per second_, but the fact that the Wiki page only distinguishes the upper falls makes me think I might have that wrong (or, alternatively, that the Wiki page was poorly written.) Related question: if waterfall flow per second is indeed just a measure of the flow of the stream itself, is there a listing of waterfalls by average volume contained in the waterfall at any one time? Because the grandeur/immenseness of a waterfall is, to me, some product of both its height _and_ the average volume of the flow of its stream. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 17, 2011, 10:25pm UTC](https://boards.straightdope.com/t/geographers-geologists-waterfall-flow-per-second/599972/2 "2011-10-17T22:25:56Z")
I suppose it’s possible that the river forks somewhere before the lower falls, diverting some of the flow. And in principle, if it ran through a particularly arid region, you could lose some to evaporation in between, though that seems implausible in the eastern US. Other than that, though, you’re right, the lower falls should have at least as much flow as the upper. ---
**Author:** ![Giles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giles/32/60_2.png) [@Giles](https://boards.straightdope.com/u/Giles)\ **Post date:** [October 17, 2011, 10:49pm UTC](https://boards.straightdope.com/t/geographers-geologists-waterfall-flow-per-second/599972/3 "2011-10-17T22:49:04Z")
> [@Chronos](#): > > I suppose it’s possible that the river forks somewhere before the lower falls, diverting some of the flow. The river splits in two at the lower falls, so the lower falls are essentially two separate series of waterfalls separated by an island. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [October 17, 2011, 11:52pm UTC](https://boards.straightdope.com/t/geographers-geologists-waterfall-flow-per-second/599972/4 "2011-10-17T23:52:45Z")
> [@Giles](#): > > The river splits in two at the lower falls, so the lower falls are essentially two separate series of waterfalls separated by an island. You’re right, I’m surprised I didn’t think of that. The picture was in my link and everything. I still think volume per second is a pretty lame measure of the size of a waterfall\* since by that method the former [Saint Anthony Falls](http://en.wikipedia.org/wiki/Saint_Anthony_Falls) would be one of the largest falls in the US. Although I think that as a rough measure I could simply multiply the height by the volume of a falls to give a measure of “grandeur”. (But of course the question would remain of what to do about split falls, and non-completely-plunge style falls of all shapes.) \*not saying anyone here said that.