'Water-Hammer' occurs when water changes direction or stops. When the mass of water is required to stop or change direction the inertia of the water causes things to break.  In high-pressure high volume pipelines it can get interesting.  

I would suggest good blocking for hard turns and the power station itself.  In short, any there is an abrupt change.  Also, you should have a valve at the head and foot of the project. To fill, have both valves closed. Open the head valve slowly and let the pipe fill. Once you believe the pipe is full, leave the top valve open and fully open the lower valve to get all the air out.  You will want to open and close the valves slowly when doing so.  Especially at the final stop or start of flow. According to my calculations you will have approximately 11,000 pounds of water (500lf of 4" pipe).

Good luck,

Ron

Can you calculate the RPM and the Diameter of the Turgo ?.

Joe can assist you there, well,

It may be necessary to have a special Turgo plate.

Since you are planning to use a Smart Drive and the distance is 500 Feet let me suggest NOT to modify the S&D windings and leave them as coming from the factory.

Use 3 transformers to bring the Voltage down to the necessary voltage ( 65 to 85 Volts) and use a MX60 to attain the maximum power available.

A bit more expensive but the power harvesting would be at its maximum.

To get the 1000 watts you will need to run the S&D at around 1100 RPM, so get a motor(1.0, 0.8 or 0.60 Size ) that gives the output voltage the transformers need.

This way the transmission loses would be at a minimum and a # 12 Size, 3 wire will do the job, wire that is a commodity throughout the world

Regards