ThursHighLightGlare-Version2-VMedits-Jun30
Light & Glare Technical Report
Thurston Highlands
Master Planned Community
July 2007
Robert W. Droll Landscape Architect, PS
4405 7th Avenue SE, Suite 203
Lacey, WA 98503
360.456.3813
Fax 360.493.2063
Table of Contents
A. INTRODUCTION 1
B. AFFECTED ENVIRONMENT 2
1. Site of Proposed Project 2
2. Existing Light & Glare – Thurston Highlands Site 2
3. Existing Light & Glare – Surrounding Properties 3
C. POTENTIAL CONSTRUCTION IMPACTS 3
D. POTENTIAL DEVELOPED-CONDITION IMPACTS 4
1. Build Alternatives 4
2. Phase 1 Development 5
3. No Action Alternative 6
E. MITIGATION MEASURES 6
1. Incorporated Plan Features 6
2. Applicable Regulations and Commitments 7
3. Other Recommended Mitigation Measures 7
F. SIGNIFICANT UNAVOIDABLE ADVERSE IMPACTS 8
G. REFERENCES 9
List of Tables
Table 1 Recommended levels of illumination – outdoor areas 2
List of Figures
Figure 1 Conceptual rendering of streetscape corridor at night, Thurston Highlands site….… 5
Figure 2 Phase 1 conceptual land use plan – detail, northeast corner 6
Light & Glare
INTRODUCTION
Adverse impacts of light and glare are, in most cases, the result of an increase in ambient light levels at various locations near the source of the light, or a visual impact created
by a new light source in areas that were previously not illuminated – as seen from a distant location. For example, locations near a light source may be impacted by glare if bright
lights are used at the source. Or, locations distant from a light source may experience adversely impacted views due to a significant amount of glare in the night sky. As another example,
views from sparsely developed hillsides in the suburbs of a large city are adversely impacted from significant “sky glow” – dull, orange-brown light – emanating from the large metropolis
several miles away.
To understand the effects of light and glare, it is helpful to be familiar with some of the terminology associated with lighting. Following is a list of definitions.
Lumen: A quantitative unit of measurement referring to the total amount of light energy emitted by a light source, without regard to the direction of its distribution.
Lux: The International Standard (SI) measure for illuminance of a surface; one lux is equal to one lumen per square meter, or one lux equals 0.093 footcandles.
Footcandle (fc): The U.S. unit of measurement referring to incident light; footcandles can be derived from lumens (1 footcandle=1 lumen/square foot).
Candlepower: The unit of intensity of a light source in a specific direction.
Illuminance: Incident light, or light striking a surface; illuminance is commonly called light level and is expressed as lumens per square foot (footcandles), or lumens per square meter
(lux).
Luminance: Light leaving a surface, whether due to the surface’s reflectivity, or because it is the surface of a light-emitting object (such as a light bulb).
Light Depreciation: Lamp output (lumens) that lessens over its effective life; illumination will be reduced further due to an accumulation of dirt and grime on the lamp and fixture.
Cutoff Light Distribution: A term used in reference to the optical design of light fixtures; proper placement of lamps can effectively eliminate intense, high-angle lighting.
Glare: The effect of brightness or differences in brightness within the visual field sufficiently high to cause annoyance, discomfort or loss of visual performance.
Direct Glare: Glare produced by a direct view from an observer of light sources.
Spill Light: Light from a source that does not strike the area intended for illumination.
Light Trespass: An occurrence of spill light extending beyond the property line of the owner of a light source, and onto or above another owner’s property.
Sky Glow: The haze or glow of light emitted above the lighting installation that reduces an observer’s ability to view the darkened sky; it can be a combination of light emitted directly
from the source, reflected upward from an illuminated surface, and reflected from airborne particles between the light source and the illuminated surface.
The following table provides recommended levels of illumination for outdoor facilities or areas.
Table 1. Recommended levels of illumination – outdoor areas.
Area/Facility
Illumination Level (footcandle)
Building entries, active use
5.0
Building entries, infrequent use
1.0
Bikeways, residential
0.2
Gardens, general
0.5
Open areas
2.0
Parking lots
1.0
Playgrounds
5.0
Roadways, residential collector roads
0.6
Roadways, residential local roads
0.4
Safety/surveillance lighting
0.9
Signage
20.0 to 50.0
Skate court
10.0
Sports: baseball
10.0 to 15.0
Sports: basketball
10.0
Sports: football/soccer (Class III – 5,000 to 10,000 spectators)
30.0
Sports: softball
7.0 to 10.0
Sports: tennis/volleyball
10.0
Walkways, parks
0.5
Walkways, pedestrian stairways
20.0 to 50.0
Walkways, residential roadside areas
0.2
Source: Robert W. Droll, Landscape Architect, PS.
AFFECTED ENVIRONMENT
1. Site of Proposed Project
The Thurston Highlands site is approximately 1,240 acres in size, within the Yelm city limits. The irregularly-shaped site is zoned MPC (Master Planned Community) and extends nearly
8,000 linear feet – east to west – at its widest point. The heart of the project site is approximately 1.5 miles west of the center of downtown Yelm (from the intersection of South
1st Street/Yelm Avenue).
2. Existing Light & Glare – Thurston Highlands Site
The Thurston Highlands property is currently undeveloped and is characterized by former Weyerhauser managed forest land, numerous hillocks, ridges and ravines. Several types of vegetative
habitats are located on the property, including approximately 74 acres of wetlands and a dominant, monotypic forest comprised of replanted Douglas fir. Former logging roads meander
throughout most areas of the site, with several of these roads accessing parcels
to the east. The Centralia Power electrical transmission line easement, a treeless swath 100 feet wide and a little more than one mile in length, traverses the western side of the property.
As there is no development on the Thurston Highland property at this time, there are no existing sources of light or glare on, or emitting from, the site. There is the potential for
maintenance vehicles to travel along the powerline access road or any of the existing logging roads on the site during evening or nighttime hours. This could result in light from headlights
or spotlights within the Highlands. However, nighttime maintenance activity is not likely and, at the time of this writing, no such use has been determined or recorded.
3. Existing Light & Glare – Surrounding Properties
Land uses adjacent to the Thurston Highlands site include the Fort Lewis Military Reservation (to the west and northwest), rural residential properties (to the north, south and southeast),
and the Tahoma Terra Master Planned Community (to the east), which is currently developing at an urban density. Impacts of light and glare from these and other surrounding properties
are noticeable from higher points of elevation on the Thurston Highlands site; predominantly from a ridge on the south-central portion of the site. From this vantage point, several
light sources have been observed from adjacent properties (most notably, the Fort Lewis Military Reservation), as well as from downtown Yelm. The light source from Fort Lewis included
helicopters with high-intensity spotlights and numerous flares that were part of a nighttime parachuting exercise estimated to be approximately 3 miles west of the Thurston Highlands
property on the night of this observation. During maneuvers bright spotlights from the helicopters briefly swept across the site and numerous flares lit up the sky above the site.
No information is available to confirm how often these nighttime military exercises occur, or how intensive or variable the maneuvers may be in affecting the Thurston Highlands site
with light and glare. This is confidential military information.
Other sources of light have been seen from the Highlands at night (from the same ridge as described above), but without directly impacting the property with light or glare. These
sources include a “sky glow” of light reflecting off low cloud cover, coming from the direction of downtown Yelm (approximately 1.5 miles to the northeast); and bright lights from the
football stadium at Yelm High School (approximately one mile to the northeast).
POTENTIAL CONSTRUCTION IMPACTS
Regardless which conceptual land use alternative is selected for implementation, it is likely that area residents in newly-established neighborhoods in the Tahoma Terra development east
of the Highlands site would observe different types of illumination on construction sites within the Thurston Highlands property during Phase 1 Development. Sources of lighting may
include nighttime security lighting, or illumination from the headlights of vehicles or construction equipment in early morning or late afternoon hours during winter months. Sources
of glare may include reflections from plastic or synthetic coverings used to cover stockpiles and stored construction material. During evening or early morning hours, lights associated
with construction activity could potentially be seen from other properties as well, depending on the extent of forest clearing and grading changes to the topography on the Highlands
site. Lights from construction activity may also temporarily affect resident wildlife, specifically in the ‘H’ wetlands areas located in the northeastern corner of the site (see Figure2).
Full build-out of any of the land use alternatives would include development of additional residential neighborhoods, streets, and retail commercial and professional office areas. Sources
of lighting during additional construction on the Thurston Highlands site would potentially be seen from established neighborhoods or commercial areas on the Highlands site, as well
as from adjacent properties. It is likely that certain institutional settings (e.g., schools and parks) would be constructed after the establishment of residential neighborhoods. Residences
adjacent to these sites may experience temporary light and glare impacts during construction operations.
POTENTIAL DEVELOPED-CONDITION IMPACTS
Site planning for the Thurston Highlands Master Planned Community was in a conceptual phase at the time of this writing. Alternative conceptual land use plans schematically depict possible
locations and features of various elements of the Thurston Highlands Master Planned Community that likely will produce light and glare, such as residential lots, commercial areas, village
centers, streets and street corridors, and institutional facilities (e.g., schools, parks, a fire station, and a Regional Sports Complex). No final determinations had been made at the
time of this writing as to the specific layout and size of various built features (e.g., building structures, streets, parks), or other significant schemes that may impact light and
glare, such as type and size of fixtures, or landscape plantings to be used for screening. Consequently, the light and glare impact analysis is somewhat generalized.
Build Alternatives
Development of any one of the conceptual land use alternatives would introduce a substantial number of new sources of light and glare that would be generated from several different sources.
Lighting from new residences (interior and exterior lights); institutional facilities; retail commercial and office facilities; plazas; street lights and vehicles along local and collector
roads; and pedestrian-oriented lights along sidewalks, pathways or bikeways all may contribute to a combination of light and glare throughout the Thurston Highlands property. The most
significant source of light and glare will likely be the proposed Regional Sports Complex. Sports field lighting will require the use of higher wattage lights mounted on taller standards
than elsewhere on the Thurston Highlands property. The use of taller poles will allow lights to be directed downward onto the fields, in order to minimize the amount of glare and light
trespass from these fixtures.
Adverse impacts of light and glare would likely differ somewhat between the three conceptual land use alternatives. In the Preferred Alternative, impacts of light and glare would be
most concentrated in commercial areas. Impacts in residential neighborhoods would vary, depending on housing densities. In the Traditional Development Alternative, impacts would be
more wide-spread throughout the Master Planned Community, where single-family neighborhoods and small-scale neighborhood convenience areas would be the norm. In the Urban Village Alternative,
compact areas of high-density residential uses interspersed with commercial uses around a village square, as well as more two- and three-story buildings, would likely create sky glow.
Adverse impacts from light and glare would be reduced in surrounding areas, where lower residential densities and a larger expanse of open space would provide more vegetative buffer
between the Master Planned Community and surrounding neighborhoods.
Figure 1. Conceptual rendering of streetscape corridor at night, Thurston Highlands site
Source: SCA Consulting Group.
2. Phase 1 Development
The Phase 1 conceptual site plan would create approximately 1,008 dwelling units (single-family detached and multi-family) on approximately 350 acres, in the northeastern portion of
the Thurston Highlands property (see Figure 1). Phase 1 development under any build alternative is anticipated to be traditional neighborhood development, for compatibility with the
adjacent Tahoma Terra neighborhood to the east. Higher-density residential development and a village center are proposed west and south of the traditional neighborhood, in future phases
of the Thurston Highlands Master Planned Community.
The extent of light and glare that would be experienced by the first residents of the Phase 1 development will depend on the level of development of streets and street corridors, walkways
and number of dwelling units. Sources of off-site light and glare will include the adjacent Tahoma Terra neighborhood to the east (depending on the amount of vegetative buffer between
each development), and nighttime lighting in the developed community closer to and including downtown Yelm. Likewise, a minimal amount of spill light may fall onto Tahoma Terra property
from the Thurston Highlands site, depending on landscape treatments along the common property line.
Figure 2. Phase 1 conceptual land use plan – detail, northeast corner of Thurston Highlands site
Source: Robert W. Droll, Landscape Architect, PS.
3. No Action Alternative
There would be no new sources of light and glare impacts under the No Action Alternative if no development were to occur.
E. MITIGATION MEASURES
Incorporated Plan Features
Thurston Highland Master Planned Community conceptual land use plan development does not yet describe proposals for lighting. Lighting plans would be evaluated during review of project-specific
development proposals under the Final Master Site Plan. Proposals would include minimizing the amount of glare, light trespass and sky glow generated by lighting from residential neighborhoods
and streets, pedestrian and vehicular corridors, commercial and village centers, and the Regional Sports Complex through a combination of measures. These measures may include:
State-of-the-art lighting system components and controls used for maximum efficiency and effect.
Light fixture shielding systems to emit light down to areas intended to be illuminated, and not into surrounding areas of the community.
Use of lighting design principles that focus on appropriate selection of fixtures, levels of lighting, and mounting heights to limit potential impacts to surrounding neighborhoods.
Proper selection of painted or treated surfaces for standards and fixtures to minimize the amount of reflected light glare generated.
Consideration regarding the location and orientation of athletic fields in relation to adjoining residential properties.
Landscape plantings to provide visual screening, particularly around the edges of the Regional Sports Complex and along property boundaries.
Applicable Regulations and Commitments
Construction-related noise would be regulated by Washington Administrative Code (WAC) 173-60. Work hours would be limited to allowable hours provided under state and local laws. Subject
to some restrictions on the duration of maximum allowable noise levels, WAC 173.60.050 exempts noise related to construction activity between the hours of 7:00 AM to 10:00 PM. Provided
that no variance is sought to allow nighttime work, these hours of operation would minimize the amount of lighting associated with construction activity – particularly during winter
months. Temporary variances may potentially be sought from these limits, if periods of nighttime construction become necessary during the course of the work.
Yelm City Code and the Development Agreement to be created for the Master Planned Community will address lighting requirements and types of lighting fixtures that will ensure efficient
and aesthetic lighting throughout the Thurston Highlands development.
Other Recommended Mitigation Measures
The following list provides additional guidelines that could be followed for the design and implementation of lighting standards that will minimize impacts of light and glare on residents
of the Thurston Highlands Master Planned Community, as well as residents and/or passers-by on adjacent properties.
Street lighting provided for vehicular and pedestrian circulation should meet standards equal to or greater than those typically required by the City of Yelm.
Lighting for building exteriors, parking lots, and all vehicular and pedestrian circulation should be designed with sensitivity to surrounding and/or adjacent neighborhoods.
Exterior lighting fixtures should use appropriate shielding to reduce light spill into surrounding areas.
Lighting fixtures should be carefully located and oriented to avoid glare or light trespass into surrounding or adjacent neighborhoods.
Development standards could place limits on hours of operation of lighted athletic fields at the Regional Sports Complex.
Timers and other lighting controls should be incorporated, if possible, into the lighting design to assure that light fixtures would be turned off when no longer needed.
Street lighting standards should not exceed a maximum height, to reduce spill light and light trespass (e.g., light standards in residential areas should not exceed 35 feet in height).
Walkway and trail lighting should have a maximum height of 15 feet; use of bollard or ground lighting could be used as an alternative to lighting on poles.
No up-lighting of environmental features or building facades should be allowed.
Low-reflectivity materials should be incorporated on building surfaces to reduce the amount of glare.
Landscape features such as street trees should be incorporated in neighborhood streetscapes to diffuse light and glare.
F. SIGNIFICANT UNAVOIDABLE ADVERSE IMPACTS
Development of the Master Planned Community under any of the conceptual land use alternatives would substantially increase the amount of light and glare on the Thurston Highlands property.
The impact of this change likely would be interpreted differently by different observers, with some objecting to a significant level of light and glare where there was none before.
Others may be accepting of additional light and glare introduced with urban development of the site, provided it is implemented with as much sensitivity to surrounding environments
as possible. The Thurston Highlands property is within the City of Yelm Urban Growth Area, and thus is anticipated to develop as an urban community, whether at this time or in the foreseeable
future.
REFERENCES
Harris, Charles W. and Nicholas T. Dines, Editors. 1998. Time-saver standards for landscape architecture. McGraw-Hill Publishing Company. New York, NY. Pages 540-2/3, 540-12/13.
Shanewise, Steve. Principal, The Coot Company, Olympia, WA. May 2007. Personal communication with Alan Rice, Robert W. Droll Landscape Architect, PS, re: observed light and glare from
specific viewpoints on the Thurston Highlands site.
Sparling. June 2006. Preston athletic fields and community park lighting study. Prepared for Preston Park, L.L.C., Preston, WA. Pages 2-3.
Thurston County GeoData Center. City of Yelm parcel identity and mapping, at http://www.geodata.org/online.htm.