NCEES water sample prob #506

[Waterworld]

I managed to solve for Ha and got the problem right. But I can't understand the solution method to get Hb.

Has anyone else figured this one out?

Thanks

 

[Badger]

I managed to solve for Ha and got the problem right. But I can't understand the solution method to get Hb. Has anyone else figured this one out?

Thanks

The question says to ignore the losses in the 24" line between the parshall flume and the weir.

So the elevation of the water surface at Pt B will be the same as the water surface over the sharp crested weir.

Q=3.0MGD = 4.64cfs use sharp crested weir formula with L =4ft

Hb^(3/2) = Q/(3.33L) Hb = 0.49'

Elevation of water surface at pt B = 100.20' +0.49'=100.69'

It would be a lot more complicated if it gave the length and type of 24" pipe, I probably couldn't solve it in six minutes then.

Good luck

 

[RJs]

This problem is revised in the NCEES errata list.

 

[Waterworld]

This problem is revised in the NCEES errata list.

Thanks