Wastewater dicharge rates

[vu4678]

I have a water discharge rates comming from the Power plant will be entering the storm drain system I was trying to model this in hydroCad would be Link Manual imput be the best choice for this application

 

[Kamelothman]

does anyone knows where did the peak factor formula P=5.75/p^0.2 came from i cant find any referrence ??? please help