The following design standards shall be construed as minimum requirements. More stringent standards may be applied due to the unique characteristics and circumstances of any individual development lot, as the city unilaterally deems to be appropriate and necessary to ensure that each and every development produces sound and orderly growth and improves public health, safety and welfare throughout the city.
(A) Development shall conform to the Comprehensive Plan; Zoning Code, Statewide Urban Design and Specifications (SUDAS) as adopted and amended by the city; and all other applicable city and state regulations. Hickman Road, Merle Hay Road and a portion of Douglas Avenue are controlled access streets to which access is allowed only by city ordinance in accordance with § 99.053, or by obtaining a permit from the Iowa Department of Transportation (herein, “IDOT”).
(B) Development shall not endanger health, safety or general welfare of the public or of persons residing or working on nearby properties, and shall not impair an adequate supply of light and air to nearby properties.
(C) Development shall be designed to locate and configure buildings and other structures, and other site improvements within a development lot in a manner that will not unduly diminish or impair the use and enjoyment of nearby properties. Development shall provide and maintain in perpetuity buffer yards, landscaping, and screening; access controls; pedestrian, bicycle and mass transit accommodations; turn lanes, medians and traffic signalization; directional signs and pavement markings; on-site lighting; adequate drainage and sewage systems; sufficient water supply for both fire protection and domestic consumption; and all other on- and off-site improvements that the city finds to be necessary when approving a site plan in order to implement this code.
(D) Vehicle access and circulation shall be designed and configured to minimize and reduce traffic congestion and safety hazards, including but not limited to compliance with the following.
(1) Driveways and approaches shall conform to all city codes and specifications, including but not limited to width and configuration; providing nominal minimum spacing of 600 feet between full movement accesses and of 300 feet between any access and right-turn only or other limited-movement accesses to public arterial and collector streets; aligning with existing drives or designated access points on the opposing frontage; providing cross-access easements to allow accesses to public streets to be shared by multiple properties; and by adding right and left turn lanes to the public street unless such requirement is waived by the City Engineer.
(2) Existing drives and approaches that do not fully comply with current codes or specifications shall be brought into compliance to the maximum practical extent according to the extent of modification or redevelopment of existing site improvements, with order of priority for compliance given to providing a separation of not less than 300 feet from all street intersections as measured from the centerline of the intersecting street to the centerline of the closest access point; compliance with a 300-foot minimum spacing between access points, including those located on other properties; and if the preceding criteria cannot be met, by aligning with existing drives or designated access points on the opposing frontage and reducing the total number of accesses by eliminating existing accesses and creating cross-access easements to allow accesses to be shared by multiple properties. Be it provided that, the requirements of this division (D)(2) shall not be applied in a manner that denies a property from retaining a single existing legally nonconforming access drive on each street frontage.
(3) (a) Driveway approaches for nonresidential and multi-family residential developments shall be configured to have two exit lanes with a minimum width of 12 feet and one entrance lane with a minimum width of 14 feet, separated by a raised median having a minimum width of two feet that may be of a mountable, half-height curb design, unless the City Engineer determines that an alternative design is acceptable or required. Lanes shall be marked and directional arrows and traffic signs provided as deemed appropriate by the City Engineer, and all traffic direction signs and markings shall be maintained in perpetuity.
(b) Accesses that are restricted to right-turn only or other limited traffic movements shall incorporate a raised median within the driveway approach if the public street does not have a raised median or other physical means of preventing the prohibited traffic movements, or if the City Engineer deems a raised median or other traffic control installations to be necessary for such purposes. If the median or other traffic control provisions do not satisfactorily limit vehicular access in the manner that was required or intended, the City Engineer may require any such median or traffic control provision to be modified or replaced with another design or method of control, or for the access to be eliminated entirely.
(c) Gated entrance drives shall be constructed with sufficient storage capacity to prevent queuing vehicles from encroaching into a public street right-of-way or from obstructing any sidewalk or bicycle trail or lane, but in all cases shall have not less than 75 feet of queuing space between the gate and said points.
(4) On-site circulation aisles, drives, drive-up facilities, delivery and loading berths and maneuvering aisles therefore, and parking shall be designed and arranged so as to not cause or encourage vehicles to queue or maneuver into a street right-of-way or a common private access drive.
(E) (1) A continuous raised portland cement concrete (“PCC”) curb having a minimum height of six inches shall be constructed on the perimeters of all parking areas, delivery and loading berths, circulation aisles, access drives and landscape islands to control drainage and vehicles. Said curbing shall be installed not less than two feet beyond minimum landscape and buffer yard setbacks to prevent parked vehicles from encroaching into said minimum landscape setbacks or buffer yards, and said two feet of overhang width may be counted as part of the minimum depth of adjoining parking stalls. Landscape islands within parking areas shall have a minimum dimension of ten feet and a minimum area of 300 square feet. Grades within parking lot bays shall not exceed a 5% maximum slope.
(2) Parking areas, circulation aisles and access drives shall be maintained free and clear of potholes, spalling, joint failures, full-depth fracturing or failures and significant surface irregularities or defects. Paved areas shall be resurfaced or overlaid from time to time as found to be necessary by the Engineering or Community Development Departments to maintain a surface that is reasonably smooth and free from tripping hazards, and that is not unsightly because of repeated patching and repairs. The Engineering or Community Development Departments may require structural problems or defects, as may be evidenced by potholes or full-depth failures, to be repaired by full-depth replacement of pavement.
(F) Public sidewalks shall be constructed along the frontages of all streets and common private access drives. On-site pedestrian and bicycle circulation systems shall be constructed of PCC or other city-approved materials in landscaped corridors that connect the development to public sidewalks and pathways and to mass transit stops, and shall be maintained to provide safe, convenient and attractive pedestrian and bicycle access. Walks shall have a minimum width of four feet in all cases, and a minimum width of six feet when adjacent to parking to provide for vehicle overhang, and shall be fully compliant with SUDAS standards as adopted and amended by the city.
(G) (1) Development shall be designed with adequate water mains and fire hydrants, sanitary sewers, storm sewers and surface water flowage channels, and storm water detention to protect the public health, safety and welfare and to prevent the overload of any existing public infrastructure. Development may be required to extend or expand public infrastructure, or to be delayed until such extension or expansion can be funded and constructed by the city or other public body, if deemed necessary by the city.
(2) Impervious surfaces shall not be allowed to drain into a street or common access drive. Driveway approaches shall have sufficient crown, and a crown of not less than eight inches above the gutter elevation in any case, to control street drainage and prevent storm runoff from leaving the right-of-way. Paved areas shall not be designed to sheet-drain into pervious areas, or to be conveyed by open gutters or channels except in the case of on-site stormwater management systems such as those that are designed to facilitate the absorption or infiltration of runoff, or if it is not possible to collect and pipe runoff from the paving in an on-site storm sewer system due to the lack of public storm sewer and extraordinarily flat topography that voids all reasonable alternatives. Provisions shall be made and maintained for surface passage of runoff from storms that exceed the design capacity of the storm sewer system, without causing flooding or damage to public streets or nearby properties. Surface water flowage easements shall be provided over such areas of flow, using the city’s standard forms of easement. Storm sewer and surface water flowage easements shall be provided using the city’s standard forms of easement over any drainageways that convey any off-site runoff through the lot, of sufficient dimensions to cover the flow from a storm having a 1% chance of occurrence in any single year.
(3) Storm detention shall not be located within minimum required buffer yards or landscape setbacks, unless the detention is located within a subsurface structure of sufficient depth below the surface to allow required landscaping to be planted and maintained over such buried detention. Storm detention shall not be located within parking areas, loading areas or drives unless the detention pool’s maximum depth is less than six inches. Low flows shall be piped through detention basins whenever possible, and a paved trickle channel shall be provided to convey the low flows if piping is not practical, to facilitate maintenance of the basin unless the basin is expressly designed to facilitate the absorption or infiltration of runoff. Storm detention shall not be located within a FEMA-designated 1 % floodplain.
(4) Fire hydrants shall be provided in the number and locations required by the Water Utility and Fire Department, whether they are to be added to a public water main or located on the lot. On-site water mains that supply one or more fire hydrants shall be a minimum of eight inches in diameter, or larger if increased size is determined to be necessary to provide necessary fire flows. Hydrants shall be supplied with appropriate connections as may be specified by the Water Utility and Fire Department. All hydrants and valves shall be maintained in good working order. Due diligence shall be taken to prevent on-site mains and appurtenances from leaking, and any leaks or breaks that occur shall be repaired immediately, wherever they may be located beyond the public main.
(H) (1) Development shall be designed with regard for existing topography and drainage patterns, by blending lot grading smoothly into the land forms on adjoining properties and by controlling runoff. If it is necessary to discharge surface runoff onto an adjoining property, provisions shall be made to maintain the general drainage pattern as it existed prior to development and to dissipate erosive energy from any concentrations of runoff.
(2) An attempt should be made to preserve mature upland forestation and other natural vegetation and geological features, while recognizing developments’ need to substantially regrade lots and install infrastructure to comply with all city codes and regulations, and that the probability for the survival of trees and other existing vegetation post-development may be greatly diminished by such necessary site modifications and disturbances. Where preservation does not appear to be practical, development landscaping should select overstory tree species that will create or reestablish the dominant tree species that would be native to the environ.
(3) All soil erosion, whether by wind, water, mechanical or other means, shall be controlled in accordance with all applicable standards and regulations.
(4) Vegetated areas shall have a 2% minimum slope to maintain positive drainage throughout the lot, unless subsurface drainage is provided.
(I) Wood, vegetation and other organic materials of any kind shall not be buried in any portion of a development lot. Debris, junk, and rubbish of all kinds, whether organic or inorganic, shall not be left or deposited on any street and shall be completely removed from the development lot prior to issuance of a final certificate of occupancy and zoning compliance for a development.
(J) (1) No overhead or exposed wiring shall be allowed, and all utility services shall be placed underground. The installation or maintenance of lighting that could be confused with warning or emergency lights or traffic controls shall be unlawful.
(2) All lighting, except warning or emergency lights and traffic signals, shall consist of cutoff fixtures that are designed and installed in a manner that prevents light from spilling beyond any property line, and such fixtures shall also be designed and installed in a manner that sufficiently obscures the light source to prevent glare into public streets or nearby residential areas. Lighting shall be designed and maintained to avoid pockets of very high or low levels of illumination. Lighting fixtures shall not be mounted on poles, buildings or other structures at a height of more than 30 feet, as measured from the grade to the top of the fixture, unless glare and spill can be satisfactorily controlled.
(3) Spotlights and floodlights shall not be allowed, except for architectural highlighting, such as to wash a wall or illuminate architectural details, and if allowed for such purpose the fixtures shall be carefully aimed to prevent glare or light spill.
(4) A light level of one minimum average maintained horizontal foot candle, as measured at the average point of illumination between the brightest and darkest areas and at a height of four to five feet above the ground surface, may be required within parking areas and circulation drives, and over walks and trails, if found to be necessary to preserve public safety or prevent crime.
(K) (1) Dumpsters and refuse containers shall be completely enclosed by an opaque wall or fence that is fitted with complete gates over points of access, and the dumpsters and containers shall be kept completely covered at all times to prevent materials from blowing or washing out of the enclosure, and from being accessed by birds or other animals.
(2) Transformers, air handling and other ground-mounted mechanical units, power generators, other utility or service areas pedestals or apparatus, and large storm water detention basins shall be treated with landscaping, berms, walls or other decorative elements to mitigate their utilitarian appearance if they are visible from public ways or nearby residential areas. Building wall extensions or other structural screens may be required help control noise from loading and unloading operations and to screen loading and delivery berths, and outdoor storage if allowed by the Zoning Code, from view from public ways and nearby residential areas.
(L) The inclusion of sign information on or as part of a site plan submittal shall not be construed to grant approval of any sign or to waive any requirement of the Sign Code.
(1999 Code, Title VII, Ch. 12, § 3) Penalty, see § 157.99