Three Reservoir Problem

This problem includes three reservoirs connected by three pipes with an additional external flow demand at the common junction of the three pipes. The highest reservoir has a water surface elevation of 100.0 M, the middle reservoir water surface elevation is 85.0 M and the lowest reservoir has a water surface elevation of 60.0 M.

The pipe from the highest reservoir has a length of 2000 M and an inside diameter of 300mm. The pipe from the middle reservoir has a length of 1500 M and inside diameter of 250mm and the pipe from the lowest reservoir has a length of 3000 M and inside diameter of 250mm. The absolute pipe roughness of each pipe is 0.0005 m.

We are required to determine the discharge in each pipe.    

Fig 1: Three Reservoir Problem.