Open space/ LEED boundary

I am working on a project that is part of a leasehold located within an executive airport property. The building is surrounded by asphalt (driveways & runways) on 2 sides, and large areas of existing turf grass on the other two that the owner intends to develop at a later date, therefore making it not possible to state that these areas would be preserved for the life of the building. There is, however, a large area of dry detention covered in turf grass that is across the runway/driveway on the north side of the new building that will remain open forever. Would it be acceptable to incorporate this area into our LEED boundary and claim it as open space as long as the intervening asphalt is included as well?