In the irrigation industry, matched precipitation rate (MPR) is a term that is used to calculate the amount of precipitation in a given area is uniform.
In order to be "matched" all sprinkler heads in a given zone must have the same rate of precipitation.
This can be achieved by matching the gallonage of a standard rotor to its arc and reducing range accordingly (i.e. 2 gallons at 90 degrees, 4 gallons at 180 degrees, or 8 gallons if the head does a full circle) or by using MPR nozzles or sprinklers.
The primary benefit and main goal of MPR sprinklers is to prevent water waste from run-off while still ensuring that the area receives adequate moisture.
[1][2][3] The mathematical formula for determining precipitation rate is (GPM x 96.3 ÷ area) = PR The first MPR nozzles, the MP Rotator, were produced by Nelson Irrigation in 2003, and acquired by Hunter Industries in 2007.