I am planning a gravity drip irrigation system fed from a large cistern that is 55 inches tall from the faucet to the overflow tube.
This will yield a significant variation in water pressure between empty and full. For example, one bed is 63 inches below the faucet, yielding 2.3 psi when empty and 4.3 when full; another is 125 inches below, for 4.5–6.5 psi.
How can one deal with variable head of this scale in a gravity drip system? I want to be able to water roughly the same amount without too much hassle whether the cistern is full or nearly empty.
I am aware of pressure regulators and pressure compensating emitters but have not been able to locate any that work at the low pressures from gravity. I have found multiple options for non-compensating emitters and drip line at these pressures.