The Planned Unit Development Zoning District is designed to provide a framework within which a developer, upon his/her/its initiation, can relate the type, design and layout of residential and/or commercial uses to a particular site and particular demand for housing and/or other local commercial facilities in a manner consistent with the preservation of property values within established areas. The section also provides an added degree of flexibility in the building design and land use arrangement so that a mixture of uses and provision of common open space can be provided. The zoning district is intended to accommodate developments with mixed or varied uses, on sites with unusual topography or unique settings within the community, or on land which exhibits difficulty or costly development problems or sites that contain natural features such as wetlands or woodlots that are important for the City to retain in order to protect its character. This zoning classification shall not be granted where it is sought primarily to avoid the imposition of standards and requirements of other zoning classifications rather than to achieve the stated purposes herein set forth. The following regulations are the minimum requirements for the promotion and protection of the public health, safety and welfare. Some uses permitted in this district are required to comply with specific design standards.