Pipe Locator

[Joss10]

I am having some problems to trace and then identify properly flow-lines (see attached photo), could someone give me an adise about what is the more appropriate method to do that, I know the experience of the operator is crucial but also the equipment used.
Thanks.

 

[BigInch]

Gloves, shovel, pump comes to mind.
Maybe there are other methods, conductivity and resistance, IR, ultrasonic, sonic, pressure/flow pulsing...

I hate Windowz 8!!!!