Tom,

Maybe the water management district in your area has a table similar to this one?
http://www.srwmd.state.fl.us/DocumentView.asp?DID=43

It would make things easier if you would update your profile to include your city.

__________________
Jerry Peck, Construction / Litigation Consultant
Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
www.AskCodeMan.com