Until such time as a Soil Conservation and Water Quality Plan is implemented to the satisfaction of the Department of Permitting, Inspections, and Enforcement, existing farms in the Chesapeake Bay Critical Area Overlay Zones are required to maintain a minimum twenty-five (25) foot vegetated filter strip landward from tidal waters, tidal wetlands, and streams (excluding drainage ditches), or from the edge of tidal wetlands, whichever is further inland, and further provided that: The filter strip shall be composed of either trees with a dense ground cover, or other appropriate vegetation, and shall be so managed as to provide water quality benefits and habitat protection. Noxious weeds, including Johnson grass, Canada thistle, and multiflora rose, which occur in the filter strip, may be controlled by authorized means; and The filter strip shall be expanded by a distance of four (4) feet for every one percent (1%) of slope, for slopes greater than six percent (6%).