Required recreational facilities and amenities: Calculation of the open space area for compliance with Subsection C above shall not include the footprint of impervious improvements for the use of the community owners, invitees and permitted guests, such as a clubhouse, pool, tennis courts and other amenities. Improvements including, but not limited to, grading, pervious and impervious trails, walking paths, stormwater management facilities, emergency access roads, underground utilities, fences and retaining walls may be located within the calculable open space areas. The ongoing maintenance of recreational facilities shall be the responsibility of the homeowners' association pursuant to the declaration of restrictive covenants and easements or a recreation facilities management plan.