The purpose of the planned unit development is to encourage the total planning of developments consistent with comprehensive planning policies by achieving flexibility from customary platting and zoning standards. The intent is to avoid rigidity associated with traditional approaches to land use and permit applicant and zoning authority to tailor specific desirable development design to a particular tract of land. It is intended that planned unit developments be used on projects of a residential, commercial, industrial or institutional nature.

Planned unit development procedures are available for both single-use and mixed-use projects. Hence, criteria for two types of planned unit developments have been provided. Both are subject to the performance standards of this chapter.

Written Description Required. Each application shall include a written narrative explaining general concept and intent for the usage of land within the planned unit development; how the design is consistent with the comprehensive planning goals; and any other pertinent information not readily identifiable on map form.

Map Required. An accurately drawn map that has a scale of not less than 200 feet to the inch shall be required. The map shall contain at least the following information: the boundaries of the site; names and dimensions of all streets bounding or touching the site; the proposed location and height of all buildings and structures proposed to be located on the site; proposed locations and dimensions of all open space; proposed public dedications; location and design of off-street parking facilities showing points of ingress to and egress from the site; the location, direction and bearing of any major physiographic features such as railroads, drainage canals, streams and other shorelines; and, existing topographic contours at intervals of not less than five feet together with any proposed plans for grading, drainage and landscaping. Should such plans be for a residential planned unit development, the requirements of a preliminary plat as described in the city's platting regulations shall be required in addition to the above information.

Soils and Surface Geology. Planned unit development applications shall show where lands within the site have high frost heave potential or are subject to slippage as determined by the Soil Conservation Service soils capability rating and that the project has been planned so that the improvements will not be subject to geologic hazards or soil conditions that would damage such improvements or cause environmental degradation.

Drainage. Planned unit development applications shall show that the development has been designed to accommodate runoff amounts equivalent to a 50-year design storm or a 100-year flow if located within the 100-year floodplain. Disposal of storm water onto adjacent facilities shall be limited to no more than those facilities will accommodate based on an engineering design analysis including existing flows. Such amount and determination shall be on the basis of full development of the affected properties. Accommodation of runoff, both on and off the development site, shall be to preserve natural patterns and facilities to the greatest extent feasible. Applications shall also show how grading and contouring will affect drainage and runoff patterns.

Architectural Considerations. Planned unit development applications shall describe what steps are being taken to maintain architectural compatibility with the surrounding area.

Plan for Extension of Utilities Required. Applications shall include a plan and program for the extension of such utilities as power, telephone, water and sewer that are required by the development. Evidence shall be provided that there exists or soon will exist sufficient demand for utility extensions.

Transportation. Applications shall include an on-site and off-site traffic engineering analysis; an evaluation of the likely impacts upon the affected sections of adjacent road systems including the nature and amount of traffic likely to be generated by the development; and the effect this traffic would have on the physical conditions or level of services and safety on existing and proposed roadways and highways. The application shall also show how parking areas have been designed to maximize efficient utilization of land.

Consistency of Location, Use and Design with Comprehensive Plan. The application shall show how the proposed project design and location meets the goals and objectives of the comprehensive plan. Provisions and uses described in the comprehensive plan which apply to the area in which the PUD is proposed shall be considered by the planning commission and may be a basis for the imposition of additional requirements or for the denial of the application.

Reference to Underlying Zoning District. Single-use planned unit developments are permitted only when allowed in the underlying zoning district. Approval of the single-use PUD does not nullify the use requirements of the underlying zoning district.

Approval of Proposed Uses Within a Mixed-Use PUD Required. While a full range of uses may be allowed within a mixed-use PUD, the uses must be approved by the planning commission and must be consistent with the comprehensive planning policies for that area. Mixed-use planned unit developments are permitted only when allowed in the underlying zoning district.

Mobile/Manufactured Home Parks by PUD. Density standards for mobile/manufactured home parks designed by PUD shall be the same as the underlying zoning district.

Yards. The requirements for yard setbacks in the underlying zoning district in which the PUD is proposed shall apply to all exterior boundary lines of the site. Interior yard setback requirements may vary upon approval of the planning commission.

Open Space. Residential planned unit developments shall have a minimum of 30 percent of the total area of the planned unit development dedicated or reserved as common open space land. The open space shall be permanently restricted as to use and size. The planning commission shall assure that adequate measures are provided to manage the open space.

Height of Buildings. For buildings and structures exceeding 30 feet in height there shall be maintained a distance from side to rear boundaries equal to the required yard plus one foot for each one foot such building exceeds the height of 30 feet.

Densities. The number of dwelling units in residential planned unit developments shall not exceed the number derived by dividing the total area of the number of dwelling units per acre permitted in the underlying zoning district multiplied by a factor of 1.30.

Permitted Site Coverage. Permitted site coverage may not exceed 40 percent of the total area for the planned unit development.