The ordinance codified in this Article Ill-A shall be known and cited as the Highway Corridor Overlay District Ordinance of Riverdale, Iowa". The district created hereunder is intended to establish a physically attractive pattern of development on certain major entrance corridors into the City of Riverdale, to protect these areas from the negative effects of incompatible development and to protect the traffic carrying of important highways within the city.

The regulations set forth in this chapter, or set forth elsewhere in this title when referred to in this chapter, are the regulations in the "HCOD" highway corridor overlay district. The HCOD highway corridor overlay district shall apply to all property in the City of Riverdale which is within 400 feet of either side of the right of way of U.S. Route 67 (State Street), as well as property within 400 feet of the right of way of Valley Drive from U.S. Route 67 (State Street) to Fenno Road.

Permitted uses shall be all uses allowed in the underlying zoning districts. All future rezonings in the "HCOD" highway corridor overlay district other than single family residential shall be limited to "C-1" local shopping district, "C-2" community shopping district, "M-1" light industrial district, and "M-2" heavy industrial district, as these districts allow the degree of review and control necessary to achieve the goals of the "HCOD" highway corridor overlay district and allow a complete range of allowable uses for low density residential to retail to industrial. Any property which is zoned "C" commercial district within the HCOD highway corridor overlay district prior to January 1, 2001, shall be permitted to continue its use under this Article I11-A without change, so long as the property is not expanded or developed further or so long as its use is not changed. In those instances, the property must conform to one of the four allowed zoning districts within this Section 36.03.

This chapter shall not apply to single family detached homes or single family subdivisions.

If there is a conflict between the requirements of the "HCOD" highway corridor overlay district under this Article Ill-A and the provisions of any applicable zoning district for any property, the requirements of this Article Ill-A shall govern and prevail for such property.

All requirements of the underlying zoning districts concerning building height, lot area, and yard depths shall remain applicable with the following exceptions:

a)   A twenty-five foot landscape buffer shall be required on all major arterial or minor arterial streets. Parking lot circulation may cross the landscape buffer area but parking may not be developed within the required setback. On all other streets, a similar ten foot landscape buffer shall be required. In cases where other provisions of the zoning ordinance requires more restrictive standards, the more restrictive standards shall apply.

b)   All immediate structures for non-residential uses shall be set back from any immediately contiguous property used for residential development a minimum of twenty-five feet for a one and one-half story building (maximum height fifteen feet) and forty feet for a two story building (maximum height twenty-five feet). Structures shall be set back an additional one foot for each foot of building height over twenty-five feet to a maximum setback of seventy feet from any immediately contiguous residential property line or residential zone. Property separated by public rights-of-way shall not be considered immediately contiguous property.

The zoning board of adjustment may grant variances in cases where the above setback regulations (subsections A and B) unduly impact the developability of any lot subdivided for development prior to the passage of this chapter. The Board may consider the feasibility of complying with the additional setback requirements based upon all of the following:

1.   Existing lot size.

2.   Compatibility with adjacent development.

3.   Locational and topographical factors

All uses and buildings permitted within the "HCOD" highway corridor overlay district shall comply in total with the following performance standards:

A)   Open Space and Landscaping Requirements.

The total ground area devoted to open space for natural landscape and landscape beautification shall not be less than fifteen percent on any development site within the "HCOD" highway corridor overlay district. Such open spaces will be free of all drives, parking areas, structures, buildings, except for those walkways, monuments, and ornamental features considered to be necessary and essential to the central landscape theme. In the case of underlying zones which require more restrictive standards, the more restrictive standard shall apply.

Additional plantings, and larger caliper sizes and heights may be required to achieve the goals of this chapter. This landscaping shall be designed to minimize the adverse effects of long expanses of wall, exposed parking, and service areas.

Tree planting shall include a combination of evergreen and deciduous trees and shrubs. In the required front yard, canopy trees shall have a minimum caliper of two and one-half inches, multi-stem clumps shall have a minimum height of ten feet, understory trees shall have a minimum height of five feet, deciduous shrubs shall have a minimum height of twenty-four inches, and evergreen shrubs shall have a minimum height of eighteen inches.

"Caliper" shall be defined according to the standards of the American Association of Nurserymen.

Where fences are necessary for commercial projects, masonry, wrought iron/aluminum, moisture resistant wood (other than stockade) and hedges are encouraged. If visible from a public street, galvanized chain link fences are not to be allowed unless complemented by continuous tall shrubbery completely obscuring the fence.

B)   Arcbitectural Standards.

Buildings within the "HCOD" highway corridor overlay district shall be constructed of quality materials that have strength and permanence. Permanence means that buildings will age without deteriorating, given a minimum level of maintenance. The development shall recognize the strength and permanency of stone, brick, concrete, and steel as opposed to the frailty of light gauge sheet metal and constant maintenance of wood veneer. While no specific materials are disallowed, certain materials will be approved for exterior use only if they are an integral part of a design of unusual merit. Among those materials are architectural metal wall panels, plywood and composition siding such as hardboard. Other materials may be appropriate in one use or situation but be totally inappropriate in another.

The city council may establish design guidelines to help guide the decisions by the Planning and Zoning Commission and to aid petitioners with design considerations.

C)   Restricted Uses.

There are some uses that require additional restrictions within the "HCOD" highway corridor overlay district to lessen their negative impact and make them more compatible with the goals of this chapter. The following uses are restricted:

1.   Automobile salesroom or showroom, or new or used car sales or vehicle storage lots. Design principles shall be incorporated into the design of auto dealerships which minimize the unattractive aspects of large areas of parked cars. One-car-deep display areas along arterial and collector streets and freeways shall be permitted. Display rows shall be screened from public rights-of-way with an eighteen inch earth berm. Additional rows of cars shall be separated from the initial row by a shrubbery hedge that completely conceals the view of these additional rows of cars from the public right-of-way. Five percent of the balance of the parking lot shall be landscaped and permeable in the form of islands and peninsulas. Signs applied to, located in, or painted onto vehicle bodies or windshields on cars in the display area are prohibited with the exception of factory invoices. The use of pennants and tinsel are prohibited. Elevated or tilted vehicle display platforms are prohibited. An earth berm or other form of landscape buffer shall be located around the sides and rear of the property to shield the view of stored cars from adjoining residences and streets, if any. Berming and landscaping may be required to shield the view from commercial areas depending on sight lines. Lighting design shall be integrated with the design of the dealership. Non-glare, cut off luminaries shall be required so that lighting does not spill over onto adjacent properties. The leasing or renting of trucks intended for short term lease of less than seven days shall be prohibited either as a primary or an accessory use.

2.   Public garages, service stations, car washes, repair shops, auto parts installation shops, auto service malls, and other similar uses. Building forms and materials shall emphasize masonry and be compatible with nearby retail buildings. Canopies over pumps and their supports shall have no lettering, logos, or striping, and shall be integrated with the building design. The use of pennants and tinsel are prohibited. Car wash structures shall be a minimum of fifty feet from any residential property line or residential zone. Outdoor storage shall be confined to areas enclosed by masonry walls. Stacks of tires, oil cans, and promotional items are not permitted. Garage bays shall be concealed from view from adjacent streets and parking lots whenever possible. The leasing or renting of trucks intended for short term lease of less than seven days shall be prohibited either as a primary or an accessory use.

3.   Outdoor Retailing. Outdoor retailing areas, such as garden centers, shall be orderly and attractive, with low screening walls concealing merchandise, except plant materials, from view.

4.   Contractor's yards and other similar uses involving the outside storage of materials and/or vehicles and equipment. Contractor's yards and other similar uses shall be orderly with screening walls, berms, and landscape buffers to completely screen them from adjacent properties and public roads.

5.   Outdoor Vending Machines. For the purposes of this chapter, outdoor vending machines shall also be considered outdoor retailing. Such vending machines shall be screened from public rights-of-way.

D)   Environmental Performance Standards.

Complete abatement, elimination, or reduction of all generally offensive characteristics such as odors, gases, noise, vibration, pollution of air or water or soil, excessive lighting intensity, hazardous activity, etc. which may be detrimental to the general welfare of the community shall be accomplished. The standards for compliance with this paragraph shall be as follows:

1.   Air Pollution. The use shall not emit any smoke, dust, odorous gases, or other matter in such quantities as to be readily detectable at any point beyond the perimeter of the site area.

2.   Noise. Riverdale Municipal Code, Chapter 53, "Riverdale Noise Control Ordinance," shall be used to regulate noise within the "HCOD" highway corridor overlay district.

3.   Vibration. The use shall not include vibration which is discernible without instruments on any adjoining lot or property.

4.   Site Lighting and Glare. All lights, other than street lights, shall be so situated and installed as to reflect away from adjacent streets and residential areas. Light and pole designs shall be compatible with the overall design of the building(s) and site. In large parking lots, poles are to be located within the landscape islands. The scale of the parking area shall be considered in the selection of pole height and spacing. Pole height shall decrease, where possible, near property lines and in low intensity use areas to further reduce glare. Uplighting trees and fountains, accent lighting on shrubs and entrances, and silhouette lighting may be used to create special effects.

5.   Traffic Hazard. The use shall not involve any activity substantially increasing the movement of traffic on public streets to a point that capacity and safety limitations are exceeded unless procedures are instituted to limit traffic hazards and congestion.

6.   Storm Water Detention and Erosion Control. The use and development of the use will comply with the soil erosion, sediment control, and storm water runoff control standards and specifications of the Scott County Soil Conservation District and the general principles of the Subdivision Ordinance of Riverdale, Iowa, including Section 30.12 of such ordinance. All development with a disturbed site in excess of one acre shall submit a copy of State of Iowa Department of Natural Resources Permit with accompanying plans. On sites less than one acre, an erosion control plan shall be required if, in the opinion of the city engineer, it is necessary to protect off-site properties. An approved grading plan shall be required prior to the commencement of any grading.

7.   Overtax Public Utilities and Facilities. The use shall not involve any activity substantially increasing the burden on any public facilities or utilities, unless provisions are made for necessary adjustments.

8.   All utilities provided as new installation shall be underground and comply in full with the regulations set forth in Article V, Required Improvements, of the Subdivision Ordinance of the City of Riverdale, Iowa.

E)   Off-Street Parking and Loading.

The required number of spaces shall remain the same as that of the underlying zoning districts. In all cases, parking lots created in the "HCOD" highway corridor overlay district shall be constructed with concrete or asphalt curbing. In all cases, parking areas shall be screened from any public right-of-way or adjacent residential area by proper siting, the use of earth berms and vegetation. Earth berms shall be a minimum of three feet in height (with the exception of those on automobile sales display rows) and shall be supplemented with substantially mature trees and shrubs which have year-round effectiveness. Service areas, loading docks, and garbage facilities shall be located properly and screened as well. Landscaped parking islands and peninsulas shall be included in lot layout to reduce the visual impact and produce shade. In parking lots of twenty or more spaces, an area equal to five percent of the total parking lot area must be landscaped and permeable. This shall not include perimeter plantings. This requirement may be waived in the case of industrial properties where interior landscaping may interfere with the necessary movement of trucks and other equipment.

F)   HCOD Highway Corridor Overlay District.

Signage shall be consistent with the central aesthetic theme of the "HCOD" highway corridor overlay district; sign materials shall be permanent or long lasting in quality. The lighting of signs shall be non-intrusive with back lighting or other methods of indirect lighting required. Project and business identification signage .shall be limited solely to wall signs, monument signs, ground signs and awnings. Billboards are prohibited within the "HCOD" highway corridor overlay district regardless of the underlying zoning.

1.   Wall Signs. Wall signs shall be limited in size by the regulations of the underlying district. Signs painted on a wall shall be prohibited.

2.   Freestanding Ground Signs. For the purposes of this chapter, a freestanding ground sign shall mean a sign placed directly on the ground the allowed height of which shall be determined by land use. All such signs shall have monument-type bases of masonry construction. A comparable alternate base material may be used upon written approval of the design review committee or by the city council where signage requires final development plan approval. Sign setbacks shall be equivalent to those found in the underlying zoning district.

a)   Large Retail Stores and Shopping Centers. For the purposes of this subsection, a large retail store or shopping center shall be defined as a single retail store or multiple store center located on a site that is eight acres or more in size. Such store or center shall be allowed one ground sign a maximum of twenty-five feet in height for center identification with a maximum sign area of four hundred square feet. Center identification signs can state the name of the shopping center and a major tenant or tenants.

Pad sites or out lots incorporated into large shopping centers shall be limited to one ground sign a maximum of fifteen feet in height with a maximum of one hundred square feet of sign area.

All other signage shall consist of building mounted signage consistent with the regulations of the underlying zoning district.

b)   Small Retail Stores and Shopping Centers. For purposes of this section, a small store or shopping center shall be defined as any single retail store or multiple store center located on a site that is less than eight acres in size. A retail store shall also be limited to those structures in which the primary use is for retail sales to the public. Such store or tenant shall be limited to one ground sign a maximum of fifteen feet in height with a maximum sign area of one hundred square feet.

All other signage shall consist of building mounted signage consistent with the regulations of the underlying zoning district.

c) Travel Related Uses. For purposes of this subsection, travel related uses are those uses that are used primarily by the motoring public and are limited to hotel/motel, service or gas stations and restaurants. Such uses shall be limited to one freestanding ground sign fifteen feet in height with a maximum sign area of one hundred square feet.

All other signage shall consist of building mounted signage consistent with the regulations of the underlying zoning district.

d) All Other Commercial. Industrial, . and Institutional Uses. All other commercial, industrial, and institutional uses shall be limited to one freestanding ground sign not to exceed six feet in height with the maximum area determined by the zoning district. All other signage shall comply with the regulations of the underlying zoning district.

e) Subdivision, Apartment Complex Signs. Subdivision, townhouse, condominium, and apartment complex signs, regardless of zoning district, shall be limited to monument signs with a maximum height of four feet, a maximum sign area of thirty-two feet, and a minimum front yard setback of five feet.

f) Billboard Signs. Billboards are prohibited within the "HCOD" highway corridor overlay district regardless of the underlying zoning.

g) The use of tinsel and pennants or other attention-getting devices other than approved signage are prohibited in the "HCOD" highway corridor overlay district other than for a thirty-day period immediately following the granting of an occupancy permit for a new business.