Wise words? Not sure, but I'll try to summarize the gist of it.
Pressure and velocity are interrelated. Water has a vapor pressure that's mainly a function of temperature. If the ambient static pressure drops below this value, some of the water will spontaneously flash to vapor. In doing so, it increases greatly in volume and momentarily raises the ambient static pressure which prevents all the stuff from flashing at once.
In a hydraulic system you've got a static pressure based on gravity, ie the pressure will be higher at the bottom of the case than at the top. You also have the ambient atmospheric pressure, which depends mainly on temperature and altitude. Once you start things moving the situation gets interesting.
The lowest static pressure in the system exists within the pump housing. The water gets pressure from the impeller literally by radial acceleration. Higher flow rates mean higher velocities within the pump. Higher temperatures mean lower vapor pressure. High restrictions ahead of the pump rob pressure that would help keep the fluid liquid.
One universal solution to cavitation is to throttle back on the pump discharge. This obviously reduces system flow and slows down the average velocity in the system. Another solution is a "water tower", basically a column of water tall enough to raise the static pressure in the system such that cavitation does not occur at the desired flow rate/temperature. Yet another is a pressure reducing valve that also artificially raises the overall system pressure. In this last one, a valve sits between a high pressure source and the flow loop and maintains a minimum static pressure.
In my old job, we used the "water tower" approach with hot oil systems to handle the expansion associated with heating ~5000 gallons of oil from room temperature to 550°F. The expansion tank pulled double duty taking up excess fluid and raising overall pressure. We also used the reducing valve approach with pressurized water systems heated to a maximum of ~375°F. These hot water systems would pump ~300 gpm of water that was maintained in a liquid state at these elevated temperatures.
Anyway, getting back to your question, industrial pumps typically state a value known as NPSHr, or Net Positive Suction Head required. This value varies according to flow (roughly rising with flow squared, imagine that). NPSHr represents the amount of positive head that must exist at the pump suction to avoid cavitation. NPSHa is the actual value available and equals ambient atmospheric pressure - V^2/2g +/- the static head applied by virtue of the pump elevation vs water surface elevation. There's also the matter of pump intake resistance, which some makers factor into their respective NPSHr values and others require you to factor into the NPSHa value.
I have no hard evidence to back up the next statement, but consider it "gut instinct". With joe-typical pond pump, cavitation is not likely provided you have a straight run of at least five diameters (preferably a little more) heading into the suction AND you do not reduce tubing diameter below the pump's intake diameter AND actual flow is less than ~2/3 of zero head flow.
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