Pipe Working Pressure Calculation. Calculated Bursting/Yield Pressure

Dear sir,
can any body help me to solve this complete pipe flow analysis For velocity & pressure, kindly help me this is a kind request.
The 12000 m long Steel pipe with 33 MM thickness is fixed with 4 degree slope, each pipe measurement :-- Pipe inlet 12 diameters a circular pipe, length of pipe 100 m long and pipe outlet is also 12 diameters but out of 12 diameters circular pipe 9 meters are closed and just 3 diameters opened , internal surface of the pipe is smooth, entire pipe 12 m depth is always full of flowing and running water @ 20m3/sec as inflows and 20m3/sec as outflows.(1) What is the velocity in the entire pipe including inlet velocity and outlet velocity plus the pressure in the entire pipe length with inlet and outlet pressure.
now my real question is if there are 120 such identical pipes of 100 m long with 12 diameters is fixed in a cascade with 4 degree slope ,where pipe after pipe is fixed, will the water velocity and pressure be the same and identical in all individual pipes in a 12000 m long drinking water pipeline with 4 degree slope.
with regards

Reported as probable homework question.

And if it is not homework: http://www.eng-tips.com/

Since we are unsure where the OP is from I, for one, would refrain from replying since it appears we might be supplying information/calculations for an actual engineering project or plan set. If the OP can’t do his/her own calcs, they have no business going ‘outside’ for values they can’t verify.

Don’t think I’m gonna stamp those plans - or build from them.

First of all, no one here is going to give you an answer to such a detailed and unique question. This is due to liability, of course. Secondly, while a number of calculations would probably give you a reasonable answer, the *best *approach is to use FEA modeling software specifically designed for flow applications.