In expansion of the statement of community development objectives contained in Article III, § 160-6, it is hereby declared to be the intent of this article with respect to the R-7 Residential District to establish reasonable standards of performance and promote the desirable benefits which single-family detached dwellings will have in those areas of the Township that are presently served or planned to be served by public sewer and water. Furthermore, it is the intent of this article to encourage a creative approach to the use of land, a more desirable visual character in residential areas, the creation of usable open space corridors throughout the Township and more efficient development patterns in terms of roads and utilities where applied for as a conditional use to the Board of Supervisors. Specifically, this article is intended to provide for a variation in the normally required lot sizes in the R-7 Residential District so that desirable open space, tree cover, historic sites, recreation areas, scenic vistas, stream valleys or other lands for public purposes are preserved within these developments for the benefit of the residents of the development and in furtherance of the general welfare of Whitpain Township.