Numbers around Artificial Irrigation

Taking into account a house related irrigation facility for the sake of simplicity, there are few key quantities to keep in mind.

Related to the pipelines
A.)Nominal Water Flow. (litres per minute)
E.g. 45 l/min.
B.)Working Pressure. (kiloPascal or Bar)

E.g. 3,5 Bar.

C.)Maximal Water Flow. (litres per minute)

E.g. 60 l/min.

D.)Diametral Section. (millimetres)

E.g. 25 mm.

Related to the sprinklers
E.)Range. (metres)
E.g. 5 m.
F)Area of coverage. (square metres)
E.g. 8mx8m.

source: Hunter Industries, Guida alla progettazione. Impianto di irrigazione per spazi verdi residenziali.

Which is the best way to describe watering facilities?

Building plants to provide irrigation, is a matter of engineering.
The precise branch is hydraulic engineering, which belongs to the civil engineering area. As a matter of fact, it is possible to uniquely describe a facility or a system, with a document. A report is used to describe modifications, tests, or maintenance. For the system as a whole, a project relation would be the reference.
Here is an example from a project to improve the Crow Irrigation Project, located in North America, USA.