Question
My county requires to have a two foot dirt border around my in ground pool and patio.  I am loosing the dirt around the pool and want to add drainage rocks, what is the proper way to do that so the dirt doesn't disappear?

Answer
Do you mean a 2-foot BERM? - A lump of earth that is supposed to contain a portion of water sloshing out of the tub/pool/patio?  I'd suggest you talk to a local landscape contractor, as I am not familiar with this type of requirement.  

Drain rock is used when you want to remove water in a subterrain fashion, or if there is no other overland or piped escape route available.  It silts up over time with particles that migrates within the water, so measures can be taken to slow this process (IF that is what you are looking to do)

~Marc