Is there any material to put down that you got get slammed with putting a retention pond ect? Asphalt millings and they want a retention pond...What other material would work?
It must depend on your area or city. Crushed asphalt and crushed concrete don't count towards the total impervious area for us. And that area can be up to an acre per parcel before you need a retention pond.
I'd probably start by visiting the city planning department.