Guidelines for Tower Placement and Appearance

This chapter presents design guidelines for the placement and appearance of wireless communications facilities. The guidelines will be used by the MPC staff in evaluating use on review applications for telecommunications towers. They also provide the designers of telecommunications facility networks with suggested siting techniques.

The guidelines are advisory and adherence to them is not a legal requirement.

Knox County is an area with challenging topography and landscapes ranging from intensely urban to isolated and rural. Not all wireless facility siting issues can be anticipated, and network designers are encouraged to use creativity in proposing design solutions that are not included as illustrations in this document. Proposals that are in substantial compliance with the principles outlined below should be approved. Failure to comply with the design guidelines does not necessarily mean that the applicant has not met the legal requirements of the zoning ordinance regarding visual impacts. The Planning Commission reserves the right to approve proposals that differ from the guidelines but provide a superior design solution which meets the intent of this plan and the zoning ordinance. Furthermore, the Planning Commission may approve proposals that represent the most practical design for the situation.

Principles:

VIEW PROTECTION
The proposed facility should not burden other properties with adverse visual impacts, nor should the facility detract from the character of the Knoxville-Knox County landscape.

LAND USE COMPATIBILITY
The proposed facility should not interfere with the use and enjoyment of other properties and should be consistent with the character of land use and development of the area around its location.

DESIGN COMPATIBILITY
The proposed facility design, including its form, height and color, should be compatible with the surrounding area.

OPPORTUNITY AREAS, SENSITIVE AREAS & AVOIDANCE AREAS
Three types of areas are described in the guidelines, based on their potential suitability for wireless facilities: opportunity areas, sensitive areas, and avoidance areas. (It should be noted that co-location of antennae on existing towers or alternate tower structures is encouraged in all areas, including avoidance areas.)

Opportunity areas are the most likely to provide good sites for the widest range of telecommunications installations, including towers. Exhibit 3 shows examples of opportunity areas, including interstate highway corridors, industrial parks, shopping centers, large agricultural tracts, and other locations where properly designed facilities could fit into the landscape reasonably well and would be unlikely to become a blighting influence on the surrounding neighborhood.

Sensitive Areas, such as high density housing districts, sites within 500 feet of low density residential areas, and community facilities such as churches, cemeteries, playing fields and recreation centers, require more care in site selection, facility design and screening. Issues such as safety, visibility, property values or land use compatibility are more likely to arise in these areas than in opportunity areas. Exhibits 4 and 5 show examples.

Avoidance Areas are the least preferred locations for wireless telecommunications towers. Low-density residential districts, ridge tops, historic sites, scenic highways, and most public parks are included in this category. Exhibit 6 shows examples.

LAND USE/WIRELESS FACILITIES MATRIX

The Land Use/Wireless Facilities Matrix (Exhibit 7) uses a three-tiered classification system, based on site characteristics and the type of telecommunications facility being considered. The three classifications are "encouraged", "neutral" and "discouraged". Site/facility combinations classified as encouraged will have the least impact on existing or future development patterns and landscapes. Installations that fall into the neutral category may be very acceptable, or may raise issues related to safety, property values, visibility, or land use compatibility, depending on the development pattern, topography, and the specific plans for the wireless facilities. Care in site selection, facility design, and screening are needed to ensure compliance with the zoning ordinance. Installations classified as discouraged are the least likely to comply with the intent of the zoning ordinance and this plan, unless the facilities are disguised or effectively screened.

As shown by the matrix, some type of wireless communications facility may be approved in all three site classifications. Though the matrix is designed as a general guide to siting decisions, there will be instances where new towers will be acceptable in a sensitive area or avoidance area with proper siting, appropriate design or effective screening.

The matrix is advisory. The Planning Commission may approve installations that are inconsistent with the matrix; however, the Commission should be satisfied that the intent of the ordinance is met and that the applicant is in substantial compliance with the spirit of the guidelines.

 

 

SITING PREFERENCES

The following siting alternatives are encouraged.

  1. CO-location on existing towers, buildings or other appropriate structures.
  2. On sites where existing topography, vegetation, buildings, or other structures, screen facilities to the extent that the visibility from other properties is minimal.
  3. Sites where "Stealth" or alternative tower structures, which have the appearance of structures that are customarily part of the landscape, can be located.
  4. Areas where lower monopoles with low profile antenna arrays will blend in with common utility structures.
  5. Highway commercial, industrial, or isolated, undeveloped areas where taller monopoles do not detract from neighborhood environments or natural landscapes.
  6. Isolated sites where lattice or guyed towers are out of public view.

 

CO-LOCATION

CO-location of antennae on existing towers or alternative tower structures is almost always the least intrusive and most economical siting solution. The following photographs show antennae located on existing structures, including rooftops, utility structures, and advertising signs. Sign-mounted antennae should be mounted below the sign face or placed inside the pole.

co-location collage

 

SCREENING

One of the most effective screening techniques involves locating towers among stands of mature trees so that the base and a large part of the tower will be hidden from view. Careful analysis of wooded sites is needed to determine the best screening strategy. Distance, perspective, topography and the height and extent of tree cover between the tower and sensitive views or land uses determine the effectiveness of screening. Planting new trees to screen anything but the equipment cabinet and perimeter fencing has very limited effectiveness. In some cases, however, planting Leland Cypress or other fast growing, tall trees at the edge of a larger property hosting a tower will create some screening. Buildings or topographic features can also provide screening.

 

SITING ON A RIDGE

This principle applies to sites on ridges and mountains identified on the United States Geological Survey (USGS) quadrangle maps.

  1. Avoid skylining towers
  2. Use a backdrop to reduce visibility
  3. Locate towers below the ridgeline, not exceeding 30 feet above the ridge top tree line. Ridge top tree line is defined as the height of the tallest tree within 100 feet either side of the place where the tower exceeds the height of the ridgeline.

 

SEPARATION

Locating multiple towers on the same site may create an unattractive "tower farm" appearance. This may be less of a concern in areas that are out of the public view or are already impacted by other forms of visual clutter, and it may be necessary to locate towers in multiples if no acceptable alternative exists. Spacing towers far enough apart to help achieve more complete coverage is preferable. However, towers may need to be located or clustered together to allow carriers to provide coverage.

 

COLOR

Use galvanized coating, gray, light blue or similar colors for towers with a sky backdrop, and brown or forest green if they are in a wooded area.

 

EQUIPMENT HOUSING

Screen the equipment housing with fences, vegetation or other techniques.

 

SITING STEALTH STRUCTURES

The proposed stealth structure should be appropriate for the context of its surroundings. For example, a silo structure appropriate in a farming area would be inappropriate in a more urban setting. The equipment housing should be integrated into the structure, or buried underground.