In my hometown, a residential property under 10,000 sq. ft can have 1000 sq ft of "outbuilding". A property greater than 10,000 sq. ft can have 1200 sq ft of "outbuilding". All "outbuildings" combined, so garage, gazebo, and crappy sheet-steel or plastic Home Depot "garden shed" all count toward the outbuilding limit. In addition to the "outbuilding" limit, there's also an "impermeable surface" limit: You have to have a certain amount of drainage available as a percentage of total square feet. So a gravel driveway is OK, a paver-block driveway might be, but a blacktop or concrete driveway may not be, depending on how much area it covers.
I tried to have a garage built at my old house. i didnt sit on a ton of land, but other people had put garages in years past. I ran into "impervious surfaces" and "storm water management" like you did. I was going to have to do the variance thing as well, and i was told i should take a lawyer, and an engineer to the hearing. The zoning officer told me "i think this would fly", meaning my proposal for my garage basically drawn out the best i could on a computer. I think the number was about $12,000. Thats what it was going to cost just to find out
if i could build a garage. Oh, and in my area it couldnt be bigger than 400 sq ft. Numbers of $50,000 rolled around for what it would cost in the end to build it, if i could, with the variance, then the impervious surfaces, and stormwater management.....about half of the 50K was to be spent before the garage could even be built.
In the end, it was cheaper to move, so i did.