Rate of Evaporation from an UG CMP detention system

[EITZM]

If I have an existing UG CMP detention system that is holding water with no methods of routing or infiltration till 3/4 full. I was wondering what the rate of evaporation from this UG CMP detention system is there some sort of a calculation to estimate the evaporation from this underground detention system?

 

[jgailla]

If you mean an underground corrugated metal pipe detention system, the rate of evaporation would be effectively zero.
You would probably get some leakage over time, the amount of which depends on how it is constructed.