re: Question regarding property that is considered wetlands?

I have been dealing with this exact situation in SW LA. The process is tedious and very slow. I purchased my property in early January and actually just got my permit from the Corps today. I bought 7 acres and it was determined that 22% was wet but that it was intermingled throughout the whole property so technically I didn't have any dry land according to them. Your first step is to file an application with the Corps and then it is a back and forth process that they will walk you through. Your offset is purchased through a mitigation bank depending on the type of wetland your property is...mine was bottom land hardwoods. The cost was around $18k/acre, but they sell partial acreage.
The corps has their own formula for offset, but basically you would figure the area that you would impact (driveway, house including usable yard) and multiply it by the wetland percentage of the area that you are using. I would get a square footage total and divide it by the square footage in an acre to get the percentage of acreage that I needed to offset. Based on the type construction you are doing, the Corps will set a multiplier to it....it could by 1 to 1, 1.5 to 1, 2 to 1, or even higher. That is how much offset you would pay.