Water Resources - Hydrograph Flow Rate in Hydrology

Great hydrology problem that could hit you on the civil PE exam. Practice makes perfect.
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Thanks for checking things out!

[@Asahel717]

Your videos are very nicely done. They are a big help. Thank you.

[@D.H.CE_FL]

Thank you! Goes to show you that my process of elimination approach would not work. I was assuming the value would fall between that 22 and 7, thus eliminating 6 and most likely 8.

[@orfeosilvano]

Lol i was doing the same thing and didn't work. haha

[@oleopathic]

Same here. :(

[@ashleyc1399]

Hello, I can't find excess precipitation anywhere in the civil reference handbook, is it not in there?

[@MtEverest_Hotspur]

Quick question: Why can't I use trapezoidal formula to calculate the volume of hydrograph here?

[@oleopathic]

Ncees pe hb 1.1, p. 393.
Use graph as a guide. Good problem for PE. Thanks you.

[@vincentaroux]

graph helps visualize the problem but not sure how it helps guide you to the solution. not sure this would show up on CBT? unless they expect you to think of the histogram approach shown in the CERM and generate the equations yourself by examination?

[@oleopathic]

​​@@vincentaroux this problem is close to a PE-type problem. If you think about the graph it becomes easier to remember how Q, t, and V are related. That's the 1st step. All else follows this premise.
CERM is about useless at this point as it cannot be brought to exam. Still, if CERM is your only source of theory & practice then it's good.
There are other materials, more practical than the CERM in 2023, which might he used.

[@gbelai]

This is a runoff hydrograph problem. Area under a runoff hydrograph curve gives the total volume of flow.

[@noorasi1]

Good question parshva, I was also wondering the same

[@CivilEngAcademy]

Because you were only asked to find it between hours 3 and 4 which is just 1 hour. If they asked to find it for the first 5 hours then you'd use 5. Hope that helps! If you'd like to more check out the review course we made for everyone at www.civilpereviewcourse.com

[@asifnoor355]

Thanks for answering... Your videos are excellent...great work...thanks a lot

[@임태균-t6h]

is this kind of question can be shown in pe civil construction exam?

[@CivilEngAcademy]

Not on your depth but possibly on the breadth.

[@bobbob-uo7vj]

Keep up these videos

[@parshva.]

why dont you use t = 5 hrs?

[@CivilEngAcademy]

See above, but I'll copy and past it: Because you were only asked to find it between hours 3 and 4 which is just 1 hour. If they asked to find it for the first 5 hours then you'd use 5. Hope that helps! If you'd like to more check out the review course we made for everyone at www.civilpereviewcourse.com

[@SouthBayEngr]

Civil Engineering Academy yes but you’re using total volume of the water shed and total runoff....so shouldn’t you use total
Time I.e. 5 hours

[@raphaelr87]

​@@SouthBayEngr The explanation is not clear. They should consider 5 hours, as you said. They did not explain that you are considering a "precipitation average" times the area to find your total volume. The average means the sum of all precipitation divided by number of hours (5 in this case). So, the total precipitation is actually 5 times the average. So, you would have to multiply 0.893 cm by 5 to get the total precipitation, needed to calculate the total volume. Then, the total flow, is the total volume divided by 5 hours. So, in the balance, it is like that 5 never existed. But, it was there and that was the reason why, which was not explained in the video. Coincidentally they got the same solution by just using one hour instead, which seems to be an incorrect approach.
Alternatively, they could have said the average precipitation would lead to an "average volume" per hour and "average flows" per hour and then use one hour as they did, but it seems more complicated than just converting the average precipitation in total precipitation.

[@bonegrubber]

I'm not here to understand.. only on how to get the answer and get out of the PErgartory I've been stuck in for years

[@oleopathic]

​@@bonegrubber thats a good one: pe-rgatory.

[@LaRoJita]

Thank you!

[@jacobparra6878]

So I did it the wrong way, but I still got the correct answer lol

[@bigmonkeyballer]

Failing upwards!

[@vivekkumar-jl6ef]

jammmeeen pr aa jaao bhai

[@er.heyyakshu]

Hindi me batao