English to French Tech/Engineering Construction / Civil Engineering direct mounted

How do you say stage-storage curve in French.
This has to do with storage of drain water during storms. It involves measuring the volume of water in a retention pond

The english definition of a stage-storage curve is as follow:

A stage-storage curve defines the relationship between the depth of water and storage volume in a storage facility. The volume of storage can be calculated by using simple geometric formulas expressed as a function of depth