Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 30
have any ordinances or policies in place that protect views from privately-owned property within this area of the City.
The analysis in this section, as related to lighting impacts, is based, in part, on the Lighting Study, prepared September 17, 2024, by Watchfire. It is included as Appendix A, Lighting Study. a) Have a substantial adverse effect on a scenic vista? Less than Significant Impact. The Project site is located on a developed valley floor immediately north of SR 60 and far below the ridgelines of the San Gabriel Mountains, which are located approximately nine miles to the north. The Diamond Bar General Plan EIR recognizes the San Gabriel Mountain distant range as valued vistas that can be seen from public corridors, such as Grand Avenue east of S. Diamond Bar Boulevard and N. Diamond Bar Boulevard north of SR 60. Although the General Plan EIR does not designate formal “scenic vista points,” Development Code Section 22.16.130 (View Protection) and the Citywide Design Guidelines require new development to respect important view elements by controlling height, bulk, and siting. Existing views in the Project area are limited to the surrounding existing intervening development, trees, and the elevated SR 60 freeway and its soundwall. Views of distant hills would not be impacted by installation of the proposed electronic billboard, due to its location, orientation and existing intervening development.
With mandatory compliance with the Development Code and the design standards for billboard signage in the proposed Development Code Amendment, the proposed Project would not adversely affect views at the nearby school, residential, and light industrial uses. The proposed design standards include provisions related to placement of billboards, including minimum distances from residential uses, limitations on the height of the billboard and the maximum screen size, limitations on the amount of illumination to limit light spillover, and other operational characteristics of the electronic billboard, such as the minimum duration of image display times and transitions. Based on the foregoing analysis, the future development of a billboard on the southwestern portion of the Project site would not have a substantial adverse effect on scenic vistas, and a less-than-significant impact would occur.
Mitigation Measures: No mitigation measures are required. b) Substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, and historic buildings within a state scenic highway?
No Impact. The nearest officially designated State scenic highway is a portion of State Route 91, approximately 11 miles south of the Project site.2 The nearest eligible State scenic highway is a portion of State Route 57, located approximately one mile southeast of the Project site. The Project site does not contain any scenic resources and is not located adjacent to or within view of a designated State scenic highway. As such, the Project would not substantially damage scenic resources within a State scenic highway; no impacts would result.
2 California Department of Transportation (Caltrans), California State Scenic Highway System Map. Available at:
https://caltrans.maps.arcgis.com/apps/webappviewer/index.html?id=465dfd3d807c46cc8e8057116f1aacaa.
Accessed June 11, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 31
Mitigation Measures: No mitigation measures are required. c) In non-urbanized areas, substantially degrade the existing visual character or quality of public views of the site and its surroundings? (Public views are those that are experienced from publicly accessible vantage point). If the project is in an urbanized area, would the project conflict with applicable zoning and other regulations governing scenic quality? Less Than Significant Impact. Implementation of the Project would result in the construction and operation of a dual-faced, digital/LED billboard with associated infrastructure connections. The Project would be located in an urbanized area. The Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is generally urbanized and developed with school, residential, and light industrial uses. The visual character of the SR 60 freeway corridor in the vicinity of the Project site is established by views of the concrete freeway sound wall, tall light standards and signage, solar panel covered canopies over the school-bus yard parking areas, and adjacent commercial and light-industrial buildings. Therefore, the installation and operation of a digital billboard on the site would not conflict with the light industrial nature of the Project area and environs located adjacent to the freeway corridor.
To demonstrate the appearance of the proposed electronic billboard in the surrounding vicinity, photo simulations were prepared exhibiting the views of the billboard from seven key vantage points; refer to Figure 13, Photo Simulation Viewpoint Locations.
View 1 is facing east looking directly at the Project site from S. Lemon Avenue at the intersection of the westbound SR 60 on-ramp; refer to Figure 14, Photo Simulation Viewpoint 1. The billboard would be prominent from this vantage point (approximately 130 feet away); however, it would generally be located above the line of sight of motorists.
View 2 is facing south looking directly at the Project site from S. Lemon Avenue at the intersection of Earlgate Street and driveway of the WVUSD offices and school bus yard, which is the access point to the proposed Project site; refer to Figure 15, Photo Simulation Viewpoint 2. The billboard and its supporting structure would be prominent from this vantage point (approximately 440 feet away); however, due to the angles of the screens as mounted, the illuminated faces of the electronic billboard screens are not prominent facing south.
View 3 is facing north looking directly at the Project site from S. Lemon Avenue, south of SR 60, and just south of the intersection of Golden Springs Drive; refer to Figure 16, Photo Simulation Viewpoint 3. The billboard would not be prominent from this vantage point, due to distance (approximately 890 feet away) and the intervening trees and structures. It would appear as another point of light in the distance, blending into the urban character of the vicinity, due to the existing developed and commercial nature of this location, as well as the distance and intervening trees and structures in the field of view.
View 4 is facing northeast from Flintgate Drive, just west of the intersection of Calpet Drive, and immediately south of the SR 60 eastbound offramp; refer to Figure 17, Photo Simulation Viewpoint 4. The billboard would be visible but not prominent from this vantage point, due to distance (approximately 625 feet away) and intervening trees and structures, as well as the elevated SR 60 freeway. The billboard would appear as a larger point of light in the distance, due to the proximity of SR 60 and the existing developed, commercial nature of the area, as well as the distance and intervening trees and structures in the field of view.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 32
View 5 is facing west from Glenwick Avenue, south of the intersection of Moonlake Street; refer to Figure 18, Photo Simulation Viewpoint 5. The billboard would be visible from this location and introduce a more prominent illuminated object in the night sky, as trees and other structures are not present at the end of this cul-de-sac (approximately 550 feet away). Farther north on Glenwick Avenue, visibility of the billboard would be limited at the street level, due to intervening structures, including the proximity of SR 60 and its prominent soundwall. In addition, illumination from trucks and other vehicles traveling along SR 60 are visible from Glenwick Avenue.
View 6 is from the westbound lanes of SR 60; refer to Figure 19, Photo Simulation Viewpoint 6. The billboard would be prominent from this roadway, which is the primary intended viewpoint. Public views in the area are already limited, due to the presence of sound walls and intervening trees and structures.
In addition, the proposed billboard would only be visible for a few seconds to a moving car, and views of distant mountains and hillsides would still be available from motorists traveling along the roadway.
View 7 is from the eastbound lanes of SR 60; refer to Figure 20, Photo Simulation Viewpoint 7. The billboard would be prominent from this roadway, which is the primary intended viewpoint. Public views in the area are already limited, due to the presence of sound walls and intervening trees and structures.
In addition, the proposed billboard would only be visible for a few seconds to a moving car, and views of distant mountains and hillsides would still be available from motorists traveling along the roadway.
City staff is required to review the proposed design of the billboard as part of the approval process, and design parameters will be imposed by the City based on Development Code Chapter 22.36, Sign Standards. Additional limitations would be placed on the proposed in accordance with the proposed Development Code Amendment Section 22.36.120 – Standards for Specific Types of Signs, as described above, in Section 2.5 of the Project Description. The proposed electronic billboard would be located less than 400 feet from the edge of the freeway right-of-way. The proposed billboard would not be located within 800 feet of any other billboards, static or digital. The proposed billboard would not be located within 400 feet of any residential parcels, as the closest residential uses are approximately 500 feet away, east of Glenwick Avenue. The proposed electronic billboard would be situated less than 75 feet above the nearest SR 60 travel elevation. The total height of the electronic billboard would be 90 feet tall with an additional seven feet of decorative/architectural features, for a total of approximately 97 feet in height.
The height of the proposed electronic billboard would be in compliance with the provisions of the proposed Development Code Update which limits billboards to 75 feet above the nearest freeway travel elevation, plus 10 additional feet for decorative/architectural features which would not consist of advertising space. The nearest SR 60 travel elevation is located approximately 21.5 feet from the base of the billboard; therefore, the total maximum permitted height is 96.5 feet, or 106.5 feet including decorative elements. Therefore, the proposed Project would comply with the Development Code Update height limitations.
The screen faces of the electronic billboard would not exceed 48 feet wide by 14 feet in height and would consist of two sign faces in a V-shape that would not exceed 45 degrees between the planes of the two sign faces. Architectural features would not function as additional sign faces would be designed as integral components of the sign structure. As discussed below, under Threshold 4.1(d), the luminance of the proposed electronic billboard would be controlled to prevent light spillover onto adjacent properties, roadways and the night sky, with maximum luminance not exceeding 0.3 foot-candles above ambient levels. Furthermore, the sign would present a static image for eight seconds, with no motion, animation, flashing or other visual effects, with instantaneous transitions between images.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 33
As such, the proposed Project would be consistent with the requirements of the Outdoor Advertising Act, the City’s Development Code, as amended, as well as the light industrial character of the area. Installation of the proposed electronic billboard would not result in the substantial degradation of the existing visual character or quality of the site and its surroundings, nor would it conflict with applicable zoning or other regulations governing scenic quality. Therefore, impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. d) Create a new source of substantial light or glare which would adversely affect day or nighttime views in the area?
Less Than Significant Impact. Under existing conditions, the Project site is developed with WVUSD administrative offices and school bus parking and maintenance uses. Exterior lighting is present within neighboring commercial areas beyond SR 60 to the south, residential uses to the east, and industrial uses to the west of the Project site. Lighting posts are located along the SR 60 corridor adjacent to the Project site. The proposed Project would result in an increase in ambient light generation via the projection of images on an LED interface that would be visible to motorists traveling on the SR 60 freeway. Due to the height of the proposed billboard, all or a portion of the LED display also would be visible from nearby properties, including the residential neighborhoods; refer to Figure 14 through Figure 20.
Light measurements utilize foot-candles as a unit of lighting intensity, which is the amount of light produced by a single candle when measured from one foot away. For reference, a 100-watt light bulb produces 137 foot-candles from one foot away, 0.0548 foot-candles from 50 feet away, and 0.0137 footcandles from 100 feet away.
According to the Project’s Lighting Study, the manufacturer of the electronic billboard, Watchfire, has adopted brightness standards endorsed by both the International Sign Association (ISA) and Outdoor Advertising Association of America (OAAA). These standards were the result of detailed analysis and recommendations for lighting control and are based on accepted practices by the Illuminating Engineering Society of North America (IESNA) for evaluating and controlling “light trespass”. The proposed electronic billboard would meet the requirements set forth by both associations, based on these studies and recommendations, which results in a lighting impact of less than 0.3 foot-candles above existing ambient light levels when viewed from a 90-degree angle and at a distance of 200 feet from the center of the sign face. This would also satisfy the City’s requirements as provided in the Development Code, as amended, related to maximum permitted lighting impact.
As provided in the Lighting Study, due to the LED screens lighting direction and intensity, the nearest residential uses would not experience an increase in ambient light as a result of operation of the proposed electronic billboard. Illumination from LED screens would decrease in intensity with distance, and at 500 feet, no resulting light spillover would occur, as the broadcast of light from the LED screens would not reach residential uses which are all more than 500 feet away from the sign. To the east of the Project site, along the east side of Glenwick Avenue, ambient light levels at residential uses would not increase; refer to Figure 21, Broadcast of Light at Distances and Angles - East Face. To the west of the Project site, along Flintgate Drive and Calpet Drive, ambient light levels at the residential uses would not increase; refer to Figure 22, Broadcast of Light at Distances and Angles - West Face. The existing residential neighborhoods already experience ambient lighting from several sources, including porch and landscape lighting, security lighting at the WVUSD yard and nearby school, illumination from vehicle headlights on SR 60 and within
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 34
the neighborhood, streetlights, and nearby commercial uses and parking lots. The addition of the electronic billboard would not exceed ambient lighting conditions that already occur in the area.
The proposed electronic billboard’s LED screens automatically adjust brightness levels relative to the changes in ambient light levels, so that the screens are appropriately dimmed or brightened based around daily sunrise and sunset. The LED screens are also designed to limit the vertical impact of light output; thereby preventing impacts to vertical ambient lighting and preserving night skies. The LED screens are also automatically and remotely controlled should the sign malfunction. The electronic billboard’s operator and manufacturer would be immediately notified, with protocols in place to have the sign go dark if needed.
Therefore, operation of the proposed electronic billboard would be in compliance with all City of Diamond requirements, including the design parameters as provided in Development Code Chapter 22.36, Sign Standards. Additional limitations would be placed on the proposed in accordance with the proposed Development Code Amendment Section 22.36.120 – Standards for Specific Types of Signs, as described above, in Section 2.5 of the Project Description.
With respect to glare, there are no glare-inducing aspects or components on the proposed electronic billboard. There are no reflective materials on any part of the billboard or its superstructure that could include glare.
Therefore, operation of the proposed electronic billboard would not create a new source of substantial light or glare which would adversely affect day or nighttime views in the area, and impacts would be less than significant.
Mitigation Measures: No mitigation measures are required.
1 2
3 4
5 6
7 Le
mon Ave
Golden Springs Dr
Gernside Dr
S Lemon Ave
Rapidview
Dr
Earlgate St
E Walnut Dr N
Will
ow
Bud Dr
Glenwick Ave
Flintgate Dr
Lycoming St
Hern Dr
Kelfield Dr
Calpet Dr
Northampton St
Greenside Dr
Ada
m
sgrove Ave
Hollow Pine Dr
Blenarm Dr
D
a
r
i
us Ave
Kingla
ke Dr
Belbury Dr
Moonlake St
Damietta Dr
E Climber Dr
Earlgate St
Clorinda Dr
Yellow Brick Rd
60 WVUSD ELECTRONIC BILLBOARD PROJECT
DIAMOND BAR, CALIFORNIA
Figure 13. Photo Simulation Viewpoint Locations
Project Parcel (APN 8760-015-901)
Proposed Electronic Billboard Location
Photo Simulation Location
Sources: Los Angeles County GIS; MAXAR Imagery 1/29/2024, Map Date: July 28, 2025.
R
0 150 300
Feet
WVUSD ELECTRONIC BILLBOARD PROJECT
DIAMOND BAR, CALIFORNIA
Figure 14. Photo Simulation Viewpoint 1
July 28, 2025.
BEFORE
AFTER
WVUSD ELECTRONIC BILLBOARD PROJECT
DIAMOND BAR, CALIFORNIA
Figure 15. Photo Simulation Viewpoint 2
July 28, 2025.
BEFORE
AFTER
WVUSD ELECTRONIC BILLBOARD PROJECT
DIAMOND BAR, CALIFORNIA
Figure 16. Photo Simulation Viewpoint 3
July 28, 2025.
BEFORE
AFTER
_
WVUSD ELECTRONIC BILLBOARD PROJECT
DIAMOND BAR, CALIFORNIA
Figure 17. Photo Simulation Viewpoint 4
July 28, 2025.
BEFORE
AFTER
_
WVUSD ELECTRONIC BILLBOARD PROJECT
DIAMOND BAR, CALIFORNIA
Figure 18. Photo Simulation Viewpoint 5
July 28, 2025.
BEFORE
AFTER
WVUSD ELECTRONIC BILLBOARD PROJECT
DIAMOND BAR, CALIFORNIA
Figure 19. Photo Simulation Viewpoint 6
July 29, 2025.
BEFORE
AFTER
WVUSD ELECTRONIC BILLBOARD PROJECT
DIAMOND BAR, CALIFORNIA
Figure 20. Photo Simulation Viewpoint 7
July 29, 2025.
BEFORE
AFTER
WVUSD ELECTRONIC BILLBOARD PROJECT
DIAMOND BAR, CALIFORNIA
Figure 21. Broadcast of Light at Distances
and Angles - East Face
Source: Watchfire 09/17/2024
Map Date: July 28, 2025.
WVUSD ELECTRONIC BILLBOARD PROJECT
DIAMOND BAR, CALIFORNIA
Figure 22. Broadcast of Light at Distances
and Angles - West Face
Source: Watchfire 09/17/2024
Map Date: July 28, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 45
4.2 Agriculture and Forestry Resources
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Convert Prime Farmland, Unique
Farmland, or Farmland of Statewide
Importance (Farmland), as shown on the
maps prepared pursuant to the Farmland
Mapping and Monitoring Program of the
California Resources Agency, to nonagricultural use?
X
b. Conflict with existing zoning for
agricultural use, or a Williamson Act
contract?
X
c. Conflict with existing zoning for, or cause
rezoning of, forest land (as defined in Public
Resources Code section 1222(g)) or
timberland (as defined in Public Resources
Code section 4526)?
X
d. Result in the loss of forest land or
conversion of forest land to non-forest use? X
e Involve other changes in the existing
environment which, due to their location or
nature, could result in conversion of
Farmland, to non-agricultural use or
conversion of forest land to non-forest use?
X
a) Convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use?
No Impact. According to the California Department of Conservation, the Project site and surrounding area are considered Urban and Built-Up Land; therefore, installation of an electronic billboard at the proposed Project site would not convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance.3 Therefore, the Project would not involve the conversion of Farmland to a non-agricultural use. No impact would occur.
3 California Department of Conservation, California Important Farmland Finder. Available at:
https://maps.conservation.ca.gov/DLRP/CIFF/. Accessed May 13, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 46
b) Conflict with existing zoning for agricultural use, or a Williamson Act contract? No Impact. According to the California Department of Conservation, the Project site and surrounding area are considered Urban and Built-Up Land. Furthermore, the Project site and areas nearby are zoned as Light Industry (I), and the site is not zoned for agricultural use, nor is the site under a Williamson Act contract. Thus, the Project would not conflict with existing zoning for agricultural use or a Williamson Act contract. No impact would occur.
Mitigation Measures: No mitigation measures are required. c) Conflict with existing zoning for, or cause rezoning of, forest land (as defined in Public Resources Code section 12220(g)), timberland (as defined by Public Resources Code section 4526), or timberland zoned Timberland Production (as defined by Government Code section 51104(g))? No Impact. The Project site and areas nearby are zoned as Light Industry (I) and do not contain forest land (as defined in PRC Section 12220(g)), timberland (as defined in PRC Section 4526), or timberland zoned Timberland Production (as defined by Government Code Section 51104(g)). The Project site is currently developed and consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles and does not contain any forest land. Thus, the proposed Project would not conflict with existing zoning for, or cause rezoning of, forest land, timberland, or timberland zoned Timberland Production. No impact would occur.
Mitigation Measures: No mitigation measures are required. d) Result in the loss of forest land or conversion of forest land to non-forest use? No Impact. The Project site does not contain forest land, as it is currently developed and consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles and does not contain any forest land. Thus, the proposed Project would not result in the loss of forest land or conversion of forest land to non-forest use. No impact would occur.
Mitigation Measures: No mitigation measures are required. e) Involve other changes in the existing environment, which, due to their location or nature, could result in conversion of Farmland, to non-agricultural use or conversion of forest land to non-forest use?
No Impact. As discussed above, the proposed Project would not involve other changes in the existing environment that could result in the conversion Farmland to a non-agricultural use or conversion of forest land to a non-forest use. Therefore, no impact would occur.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 47
4.3 Air Quality
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Conflict with or obstruct implementation of
the applicable air quality plan? X
b. Result in a cumulatively considerable net
increase of any criteria pollutant for which
the project region is non-attainment under
an applicable federal or state ambient air
quality standard?
X
c. Expose sensitive receptors to substantial
pollutant concentrations? X
d. Result in other emissions (such as those
leading to odors) adversely affecting a
substantial number of people?
X
a) Conflict with or obstruct implementation of the applicable air quality plan? No Impact. As part of its enforcement responsibilities, the United States Environmental Protection Agency (EPA) requires that each state with nonattainment areas prepare and submit a State Implementation Plan (SIP) that demonstrates the means to attain the federal standards. The SIP must integrate federal, State, and local plan components and regulations to identify specific measures to reduce pollution in nonattainment areas, using a combination of performance standards and market-based programs.
Similarly, under State law, the California Clean Air Act (CCAA) requires an air quality attainment plan to be prepared for areas designated as being in nonattainment with federal and State ambient air quality standards. Air quality attainment plans outline emissions limits and control measures to achieve and maintain these standards by the earliest practical date.
The Project site is located within the South Coast Air Basin (SCAB), which is under the South Coast Air Quality Management District’s (SCAQMD) jurisdiction. The SCAQMD is required, pursuant to the Federal Clean Air Act (FCAA), to reduce emissions of criteria pollutants for which SCAB is in non-attainment. To reduce such emissions, the SCAQMD adopted the 2022 Air Quality Management Plan (AQMP) in December 2022 as an update to the 2016 AQMP. The 2022 AQMP establishes a program of rules and regulations directed at reducing air pollutant emissions and achieving State and national air quality standards. The AQMP is a regional and multi-agency effort including the SCAQMD, the California Air Resources Board (CARB), the Southern California Association of Governments (SCAG), and the EPA. The 2022 AQMP’s pollutant control strategies are based on the latest scientific and technical information and planning assumptions, including SCAG’s Connect SoCal (2020-2045 RTP/SCS), updated emission inventory
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 48
methodologies for various source categories, and SCAG’s growth forecasts.4 SCAG’s growth forecasts were defined in consultation with local governments and with reference to local general plans. The proposed Project is subject to the SCAQMD’s AQMP.
• Consistency Criterion No. 1: A proposed project would not result in an increase in the frequency or severity of existing air quality violations, or cause or contribute to new violations, or delay the timely attainment of the AQMP’s air quality standards or the interim emissions reductions. • Consistency Criterion No. 2: A proposed project would not exceed the AQMP’s assumptions or increments based on the years of the project build-out phase.
Implementation of the proposed Project would entail the installation of a digital billboard, the installation and operation of which would not result in an increase in the frequency or severity of existing air quality violations, nor would it cause or contribute to new violations that would inhibit attainment of air quality standards specified in the AQMP. Construction and installation are anticipated to occur over a five- to seven-day period and the resulting generation of emissions would not exceed the SCAQMD’s adopted thresholds for construction emissions. Additionally, operation of the project would not result in regional criteria pollutant emissions that would exceed the applicable Air District thresholds. Refer to impact b), below, for further detail.
Additionally, the proposed Project would not affect any regional population, housing, and employment projections prepared for the City of Diamond Bar by SCAG and, therefore, would not exceed the assumptions in the AQMP. As a result, the proposed Project would not conflict with, or obstruct the implementation of, the applicable air quality plan, and no impacts would occur.
Mitigation Measures: No mitigation measures are required. b) Result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non-attainment under an applicable federal or state ambient air quality standard? Less Than Significant Impact. Air quality impacts/emissions associated with a project can be placed into two categories: temporary (short-term) or long-term emissions. Temporary (short-term) emissions are generally associated with the demolition, grading, and construction activities of a project while long-term emissions are associated with the day-to-day operation, use, and area emissions from activities such as vehicle use, consumer product use, and energy generation/consumption.
The Project would be required to follow all standard SCAQMD rules and requirements with regards to fugitive dust control. Fugitive dust emissions are commonly associated with land clearing activities, cut and fill grading operations, and exposure of soils to the air and wind. SCAQMD Rule 403 requires that fugitive dust is controlled with best-available control measures so that the presence of such dust does not remain visible in the atmosphere beyond the property line of the emission source. In addition, SCAQMD Rules 402 and 403 require implementation of dust suppression techniques to prevent fugitive dust from creating a nuisance off-site.
4 Although SCAG has prepared a more recent RTP/SCS, the 2020-2045 RTP/SCS is used because the 2022 AQMP is based on this version of the RTP/SCS. Evaluations related to greenhouse gas emissions are based on the current RTP/SCS.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 49
Operational activities associated with the proposed Project would result in criteria pollutant emissions strictly from energy source emissions from the Project’s electricity demand and mobile source emissions, as a result of billboard maintenance visits (six to eight times per year). Additionally, construction activities would be minor and last approximately seven days. The CalEEMod model was utilized to estimate Project construction-related and operational emissions. Refer to Appendix B, Air Quality and Greenhouse Gas Emissions Modeling, for the modeling detail.
Estimated maximum construction-related emissions associated with operation of the Project are summarized in Table 4.3-1, Maximum Construction-related Criteria Pollutant Emissions (Maximum Pounds per Day). These emissions include all worker vehicle, vendor vehicle, hauler vehicle, and off-road construction vehicle emissions. For the purposes of this analysis, the construction schedule is estimated to occur in late 2025. The length of the construction/installation schedule was provided by the Project applicant.
Construction emissions associated with the Project would not worsen ambient air quality, create additional violations of federal and State standards, or delay the SCAQMD’s goal for meeting attainment standards in the SCAB.
Table 4.3-1
Maximum Construction-related Criteria Pollutant Emissions (Maximum Pounds per Day) Construction VOC NOx CO SOx PM10 PM2.5
Maximum
Emissions 1.1 10.6 10.7 <1.0 2.8 1.5
SCAQMD
Threshold 75 100 550 150 150 55
Exceed
Threshold? No No No No No No
Source: CalEEMod v.2022.1
Notes: SCAQMD Rule 403 Fugitive Dust control measures applied based on values within the CalEEMod model.
Volatile organic compounds = VOC; oxides of nitrogen = NOx; carbon monoxide = CO; sulfur dioxide = SOx; particulate matter less than 10 microns in diameter = PM10; and particulate matter less than 2.5 microns in diameter = PM2.5.
Estimated operation-related emissions associated with operation of the Project are summarized in Table
4.3-2, Maximum Regional Operational Criteria Pollutant Emissions (Maximum Pounds per Day). For the purposes of this analysis, the first year of operation is estimated to occur in 2025. Operation-related emissions include the electricity required to power the billboard, as well as up to approximately eight vehicle trips per year associated with Project maintenance.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 50
Table 4.3-2
Maximum Regional Operational Criteria Pollutant Emissions (Maximum Pounds per Day) Operation VOC NOx CO SOx PM10 PM2.5
Maximum
Emissions <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
SCAQMD
Threshold 55 55 550 150 150 55
Exceed
Threshold? No No No No No No
Source: CalEEMod v.2022.1
Notes: SCAQMD Rule 403 Fugitive Dust control measures applied based on values within the CalEEMod model.
Volatile organic compounds = VOC; oxides of nitrogen = NOx; carbon monoxide = CO; sulfur dioxide = SOx; particulate matter less than 10 microns in diameter = PM10; and particulate matter less than 2.5 microns in diameter = PM2.5.
Overall, Project-related construction and operation emissions would not exceed the SCAQMD’s criteria pollutant emissions thresholds, as provided in Table 4.3-1 and Table 4.3-2, above. Therefore, the proposed Project would result in less than significant impacts related to criteria pollutant emissions.
Since the Project would not exceed any of the SCAQMD’s thresholds of significance, given the Project’s size and type, the Project would not contribute substantially to an existing or projected air quality violation, as explained in further detail under Response 4.3(a). Further, by complying with the SCAQMD standards, the Project would not contribute to a cumulatively considerable net increase of any criteria pollutant for which the Project region is non-attainment under an applicable federal or State ambient air quality standard (including releasing emissions which exceed quantitative thresholds for ozone precursors). Therefore, Project impacts related to regional air quality would be less than significant.
Mitigation Measures: No mitigation measures are required. c) Expose sensitive receptors to substantial pollutant concentrations? Less Than Significant Impact. Sensitive receptors are members of the population that are particularly sensitive to the effects of air pollutants, such as children, the elderly, and people with illnesses. Examples of land uses where sensitive receptors are typically located include residences, schools, hospitals, and daycare centers. The Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is generally urbanized and developed with freeway, school, residential, and light industrial uses. Walnut Elementary School ls located approximately 700 feet to the north of the Project site. Therefore, there are no sensitive uses within 500 feet of the Project site.
As described in Threshold b), above, Project installation and operation would not produce emissions above SCAQMD’s regional thresholds of significance. In addition, due to the nature of the Project (proposed stationary digital billboard), its trip generation would be nominal, consisting of one two-way trip approximately six to eight times per year for billboard maintenance. A maximum of one two-way trip approximately six to eight times per year could not result in a carbon dioxide (CO) “hotspot” that could lead to an exceedance of the State’s CO standards. Accordingly, no substantial pollutant concentrations would result from the Project’s installation or operation, and impacts would be less than significant to sensitive receptors.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 51
d) Result in other emissions (such as those leading to odors adversely affecting a substantial number of people?
Less Than Significant Impact. The proposed Project would involve the installation and operation of an electronic billboard, which is not a land use typically associated with emitting objectionable odors.
Potential temporary odor sources associated with the installation of the proposed Project may result from construction equipment exhaust and the application of asphalt (if needed after installation of the electronic billboard). Construction-related odor emissions would be temporary, short-term, and intermittent in nature and would cease upon completion of the respective phases of construction. In addition, these types of odors are common in construction activities and are not considered to be offensive or objectionable to a large portion of the population. Furthermore, there are no sensitive receptors within 500 feet of the Project installation site. As such, odor emissions associated with construction activities is considered less than significant. The Project’s construction-generated refuse would be stored in covered containers and removed at regular intervals in compliance with the City of Diamond Bar Municipal Code Section 8.16.800, Permitted Waste, which states the requirements for construction and demolition waste. The proposed Project would also be required to comply with SCAQMD Rule 402 to prevent occurrences of public nuisances related to odors. Operation of the Project would not generate any odors. Therefore, odors associated with installation and operation of the Project would be less than significant.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 52
4.4 Biological Resources
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Have a substantial adverse effect, either
directly or through habitat modifications,
on any species identified as a candidate,
sensitive, or special status species in local
or regional plans, policies, or regulations,
or by the California Department of Fish and
Game or U.S. Fish and Wildlife Service?
X
b. Have a substantial adverse effect on any
riparian habitat or other sensitive natural
community identified in local or regional
plans, policies, regulations or by the
California Department of Fish and Game or
U.S. Fish and Wildlife Service?
X
c. Have a substantial adverse effect on state
or federally protected wetlands (including,
but not limited to, marsh, vernal pool,
coastal, etc.) through direct removal, filling,
hydrological interruption, or other means?
X
d. Interfere substantially with the movement
of any native resident or migratory fish or
wildlife species or with established native
resident or migratory wildlife corridors, or
impede the use of native wildlife nursery
sites?
X
e. Conflict with any local policies or
ordinances protecting biological resources,
such as a tree preservation policy or
ordinance?
X
f. Conflict with the provisions of an adopted
Habitat Conservation Plan, Natural
Community Conservation Plan, or other
approved local, regional, or state habitat
conservation plan?
X
a) Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service?
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 53
No Impact. Implementation of the Project would result in the installation and operation of a digital billboard. The Projectsite consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is heavily urbanized and developed with the SR 60 corridor, school uses, residential, and light industrial uses. The Project site does not contain any native habitat or sensitive plant species or vegetation that serve as habitat to sensitive animal species.
Accordingly, no impacts to sensitive species would occur.
Mitigation Measures: No mitigation measures are required. b) Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service?
No Impact. The Project site does not contain riparian habitat or other sensitive natural communities identified in local or regional plans, policies, regulations, or by the California Department of Fish and Wildlife (CDFW) or the U.S. Fish and Wildlife Service (USFWS). Accordingly, no impact to riparian habitat would occur.
Mitigation Measures: No mitigation measures are required. c) Have a substantial adverse effect on state or federally protected wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means?
No Impact. The Project site does not contain any wetlands. Accordingly, the proposed Project would have no impact on federally protected wetlands as defined by Section 404 of the Clean Water Act (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means.
Mitigation Measures: No mitigation measures are required. d) Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites?
Less Than SignificantImpact. Implementation of the Project would result in the installation and operation of an electronic billboard on a portion of an existing asphalt-covered parking lot, and the area surrounding the Project site is heavily urbanized and developed with freeway, school, residential, and light industrial uses. Under existing conditions, the Project site does not provide habitat for native species, is not part of a terrestrial wildlife movement corridor, and does not serve as a native wildlife nursery site.
Outside of the electronic billboard installation area, on the other side of the cinder block wall along S.
Lemon Avenue, two mature pine trees will be removed. In their place, two 24-inch box Crape Myrtle trees will be planted. The currently degraded landscaped strip between the driveway entry off S. Lemon Avenue to the property and the SR 60 corridor would be enhanced with mulch.
Should nesting birds be located within the two pine trees prior to their removal, mandatory compliance with the federal Migratory Bird Treaty Act (MBTA) would preclude impacts to nesting birds in the unlikely event that nesting birds are present. The MTBA includes construction avoidance measures designed to prevent disturbance of migratory birds, particularly during nest season (typically February 1 to September
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 54
15), and may require preconstruction surveys, scheduling work outside of nesting season, and no-work buffers around active nests, as well as other measures. Accordingly, implementation of the proposed Project would not interfere with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or with the use of native wildlife nursery sites. Impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. e) Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance?
Less Than Significant Impact. As previously discussed, two pine trees would be removed during the Project’s construction or operation phases; however, these are not considered protected trees by the City of Diamond Bar pursuant to DBCC Section 22.38.030. Removal of these trees would be undertaken in accordance with City of Diamond Bar requirements.
There are no other local policies or ordinances protecting biological resources that are applicable to the proposed Project; accordingly, the Project would not conflict with any local policies or ordinances protecting biological resources would occur as a result of Project implementation, and impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. f) Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? No Impact. According to the CDFW, there are no Habitat Conservation Plans, Natural Community Conservation Plans, or other approved local, regional, or state habitat conservation plans applicable to the Project site.
5 Accordingly, the Project has no potential to conflict with any of the above, and no impact would occur.
Mitigation Measures: No mitigation measures are required.
5 California Department of Fish and Wildlife, 2023. California Regional Conservation Plans Map. Available at:
https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=68626&inline. Accessed May 13, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 55
4.5 Cultural Resources
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Cause a substantial adverse change in the
significance of a historical resource
pursuant to § 15064.5?
X
b. Cause a substantial adverse change in the
significance of an archaeological resource
pursuant to § 15064.5?
X
c. Disturb any human remains, including
those interred outside of dedicated
cemeteries?
X
The analysis in this section is based, in part, on the Cultural Resources Technical Report, Walnut Valley Unified School District Electronic Billboard Project, City of Diamond Bar, Los Angeles County, California, prepared in July 2025, by South Environmental. It is included as Appendix C, Cultural Resources Report. a) Cause a substantial adverse change in the significance of a historical resource pursuant to § 15064.5?
No Impact. A cultural resources technical report was prepared for the proposed Project, which included the results of a California Historical Resources Information Center (CHRIS) records search of the Project site and a 0.5-mile radius, a California Native American Heritage Commission (NAHC) Sacred Lands File (SLF) search, and archival research. No pedestrian survey was performed due to complete site paving, which precluded ground surface visibility. There are no historical structures or resources on the larger Project improvement area. Furthermore, according to the General Plan Resource Conservation Element, there are no registered historic resources in the City, including the Project site. Therefore, the Project would not cause a substantial adverse change in the significance of a historical resource pursuant to CEQA Guidelines Section 15064.5. No impact would occur.
Mitigation Measures: No mitigation measures are required. b) Cause a substantial adverse change in the significance of an archaeological resource pursuant to § 15064.5?
Less Than Significant Impact with Mitigation Incorporated. The Project site is located within a region historically used for agriculture and lies adjacent to the former course of a stream that has been heavily altered by development including SR 60, directly adjacent to the south. Historical aerial photographs and maps confirm the presence of cultivated fields and proximity to San Jose Creek and Diamond Bar Creek.
Environments like this near creeks are preferred for prehistoric habitation due to access to fresh water, plant and animal resources, and transportation routes.
No archaeological resources were identified within the Project site through the CHRIS records search, background research, or NAHC SLF search. While the environmental setting indicates inherent moderate
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 56
archaeological potential, the documented disturbance history and absence of recorded cultural resources within the immediate Project vicinity support a determination of low sensitivity for buried archaeological deposits. The shallow depth of documented fill materials suggests that any near-surface archaeological deposits would likely have been disturbed by historical land use activities.
Nevertheless, there is the potential for accidental discovery of archaeological resources during grounddisturbing activities. The Project would be required to comply with City of Diamond Bar General Plan Resource Conservation Cultural and Historic Resources Policies, including Policy RC-P-42, Archaeological Resources, which provides procedures for the management of archaeological materials on-site during development projects. Policy RC-P-43 seeks to preserve discovered archaeological resources in place to maintain the relationship between the artifacts and their archaeological context, where feasible. Policy RC-P-44 provides that preservation can be achieved through measures such as avoidance and other protections.
Should ground disturbing activities during Project construction encounter archaeological resources, incorporation of Mitigation Measures CUL-1, which identifies procedures for the unanticipated discovery of archaeological resources if it occurs during the Project’s ground disturbing activities. Through compliance with the General Plan Resource Conservation policies and implementation of Mitigation Measures CUL-1, the Project’s potential impacts to archaeological resources would be reduced to levels that are less than significant.
Mitigation Measures:
CUL-1: Should archaeological resources (sites, features, or artifacts) be exposed during construction activities for the proposed Project, all construction work shall immediately stop until a qualified archaeologist, meeting the Secretary of the Interior’s Professional Qualification Standards, can evaluate the significance of the find and determine whether or not additional study is warranted.
Depending upon the significance of the find, the archaeologist may simply record the find and allow work to continue. If the discovery proves significant under CEQA, additional work such as preparation of an archaeological treatment plan, testing, or data recovery may be warranted. c) Disturb any human remains, including those interred outside of dedicated cemeteries? Less Than Significant Impact with Mitigation Incorporated. According to the General Plan Resource Conservation Element, there are no dedicated cemeteries within the Project site or surrounding area and there is no information to suggest that the site has any undiscovered human remains. Implementation of the Project would result in the installation and operation of an electronic billboard. The Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is heavily urbanized and developed with freeway, school, residential, and light industrial uses. The existing asphalt-covered parking lot has been altered by previous ground disturbance associated with school development. Due to the extensive ground disturbance that has occurred on the Project site and in the surrounding area associated with construction of the existing residential developments, the potential for the proposed Project to disturb previously undiscovered human remains is highly unlikely.
Nevertheless, there is the potential for accidental discovery of unanticipated human remains during ground-disturbing activities. Should ground disturbing activities during Project construction inadvertently encounter buried human remains, incorporation of Mitigation Measure CUL-2, which provides procedures
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 57
related to the treatment of the unanticipated discovery of human remains, would ensure that the Project’s potential impacts to buried remains would be reduced to levels that are less than significant.
Mitigation Measures:
CUL-2: In accordance with Section 7050.5 of the California Health and Safety Code, if human remains are found, the County Coroner shall be notified within 24 hours of the discovery. No further excavation or disturbance of the site or any nearby area reasonably suspected to overlie adjacent remains shall occur until the County Coroner has determined, within two working days of notification of the discovery, the appropriate treatment and disposition of the human remains. If the remains are determined to be Native American, the Coroner shall notify the NAHC in Sacramento within 24 hours. In accordance with California PRC, Section 5097.98, the NAHC must immediately notify those persons it believes to be the Most Likely Descendant (MLD) from the deceased Native American. The MLD shall complete their inspection within 48 hours of being granted access to the site. The MLD would then determine, in consultation with the property owner, the disposition of the human remains.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 58
4.6 Energy
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Result in potentially significant
environmental impact due to wasteful,
inefficient, or unnecessary consumption of
energy resources, during project
construction or operation?
X
b. Conflict with or obstruct a state or local
plan for renewable energy or energy
efficiency?
X
a) Result in potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources, during project construction or operation? Less Than Significant Impact. The means to achieve the goal of conserving energy include decreasing overall energy consumption, decreasing reliance on natural gas and oil, and increasing reliance on renewable energy sources. In particular, the proposed Project would be considered “wasteful, inefficient, and unnecessary” if it were to violate State and federal energy standards and/or result in significant adverse impacts related to a project’s energy requirements, energy inefficiencies, energy intensiveness of materials, cause significant impacts on local and regional energy supplies or generate requirements for additional capacity, fail to comply with existing energy standards, otherwise result in significant adverse impacts on energy resources, or conflict or create an inconsistency with applicable plan, policy, or regulation.
Southern California Edison (SCE) provides electricity, and Southern California Gas Company (SoCal Gas) provides natural gas for the City, including the Project site; however, there would be no natural gas use required for Project installation or operation.
6 Implementation of the Project would result in the
installation and operation of a dual-faced, electronic/LED billboard with associated infrastructure connections. The Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is heavily urbanized and developed with freeway, school, residential, and light industrial uses.
The proposed Project would use a limited amount of energy resources for the operation of the digital billboard (e.g., electricity), for on-road vehicle trips (six to eight times per year) for maintenance (e.g. gasoline and diesel fuel) generated by the Project (both during project construction and operation), and from off-road construction/installation activities associated with the Project (e.g. diesel fuel). Each of these activities would require the use of energy resources. This usage of energy resources would be extremely small-scale, in the context of the surrounding community, and would not be wasteful, inefficient, or unnecessary, due to the nature of the Project. By its nature, LED lighting is considered 6 City of Diamond Bar, n.d. Utilities. Available at:
https://www.diamondbarca.gov/BusinessDirectoryII.aspx?lngBusinessCategoryID=23. Accessed June 9, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 59
energy efficient. The Project would be responsible for conserving energy, to the extent feasible, and would be required to comply with Statewide and local measures regarding energy conservation, such as Title 24 building efficiency standards, as applicable.
The proposed Project would be in compliance with all applicable federal, State, and local regulations regulating energy usage. SCE manages a mix of energy resources used to provide electricity for its customers and is actively implementing the Statewide Renewable Portfolio Standard (RPS) to expand its use of renewable energy (e.g. solar and wind). As of 2023, SCE’s eligible renewable power mix was 37.6 percent, which is consistent with the RPS requirements.7 This also compares favorably with the statewide average eligible renewable power mix in 2023, of 36.9 percent. In addition, statewide programs, such as vehicle emissions and low-carbon fuel standards, would boost fuel efficiency in passenger cars and heavyduty trucks.
As a result, the Project would not result in any significant adverse impacts related to Project energy requirements, energy use inefficiencies, and/or the energy intensiveness of materials by amount and fuel type for each stage of the Project including construction, operations, and maintenance. SCE has sufficient capacity to serve the proposed Project. The Project would be required to comply with all existing energy efficiency standards and would not result in significant adverse impacts on energy resources. Therefore, the proposed Project would not result in a wasteful, inefficient, or unnecessary of energy resources during Project installation or operation. Impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. b) Conflict with or obstruct a state or local plan for renewable energy or energy efficiency? Less Than Significant Impact. The proposed Project involves the construction of a dual-faced, electronic/LED billboard with associated infrastructure connections. The manufacturer of the electronic billboard would set the screens to a maximum daytime brightness level of 7,500 nits and a maximum nighttime brightness level of 300 nits. The area around the Project site would see an almost undetectable difference in ambient light after installation of the digital led billboards. The manufacturer of the electronic billboard has adopted brightness standards endorsed by both the International Sign Association (ISA) and Outdoor Advertising Association of America (OAAA). Furthermore, the City of Diamond Bar Building and Safety Division would review Project plans for compliance with the CBC and Title 15 of the City Code, as well as the Lighting Report’s recommendations, as part of the building permit and plan check process. LED technology is inherently low-energy, and the screens would meet UL Greenleaf certifications set forth by Title 24 of the California Code of Regulations, and operation of the electronic billboard would require approximately 200 amps of operating power. This amount of electrical usage is negligible within SCE’s overall portfolio. As such, the Project would not conflict with or obstruct a state or local plan for renewable energy or energy efficiency; impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. 7 Southern California Edison. 2023. 2023 Power Content Label. Available:
https://www.energy.ca.gov/filebrowser/download/7362. Accessed July 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 60
4.7 Geology and Soils
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Directly or indirectly cause potential
substantial adverse effects, including the
risk of loss, injury, or death involving:
1) Rupture of a known earthquake fault, as
delineated on the most recent AlquistPriolo Earthquake Fault Zoning Map issued by the State Geologist for the area
or based on other substantial evidence
of a known fault? Refer to Division of
Mines and Geology Special Publication
42. X
2) Strong seismic ground shaking? X
3) Seismic-related ground failure,
including liquefaction? X
4) Landslides? X
b. Result in substantial soil erosion or the loss
of topsoil? X
c. Be located on a geologic unit or soil that is
unstable, or that would become unstable as
a result of the project, and potentially result
in on-or off-site landslide, lateral spreading,
subsidence, liquefaction or collapse?
X
d. Be located on expansive soil, as defined in
Table 18-1-B of the Uniform Building Code
(1994), creating substantial direct or
indirect risks to life or property?
X
e. Have soils incapable of adequately
supporting the use of septic tanks or
alternative waste water disposal systems
where sewers are not available for the
disposal of waste water?
X
f. Directly or indirectly destroy a unique
paleontological resource or site or unique
geologic feature?
X
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 61
This section is based in part on the Foundation Engineering Investigation Proposed Billboard 880 S. Lemon Avenue, Diamond Bar, California (Geotechnical Report), September 4, 2024, prepared by Rybak Geotechnical, Inc., and included as Appendix D, Geotechnical Report. The Geotechnical Report addresses geologic and soil conditions for the Project site.
a) Directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving:
1) Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? Refer to Division of Mines and Geology Special Publication 42.
No Impact. The Alquist-Priolo Earthquake Fault Zoning Act was passed in 1972 to mitigate the hazard of surface faulting to structures for human occupancy. The Alquist-Priolo Earthquake Fault Zoning Act’s main purpose is to prevent the construction of buildings used for human occupancy on the surface trace of active faults. The Alquist-Priolo Earthquake Fault Zoning Act requires the State Geologist to establish regulatory zones, known as “Alquist-Priolo Earthquake Fault Zones,” around the surface traces of active faults and to issue appropriate maps. If an active fault is found, a structure for human occupancy cannot be placed over the trace of the fault and must be set back from the fault (typically 50 feet). According to the City’s General Plan Public Safety Element and California Department of Conservation Data Viewer, the Project site is not within an Alquist-Priolo Fault Zone as defined by the State of California in the Earthquake Fault Zoning Act.
8 Additionally, the Geotechnical Report notes that the potential for fault rupture is remote. Therefore, the Project would not directly or indirectly cause potential substantial adverse effects involving rupture of a known earthquake fault, and there would be no impact.
Mitigation Measures: No mitigation measures are required. 2) Strong seismic ground shaking?
Less Than Significant Impact. The Project site is located in a seismically active area of southern California that has historically been affected by moderate to occasionally high levels of ground motion. As a result, it is likely the Project site has and would continue to experience ground shaking from proximate fault activity as well as some background shaking from other seismically active areas of the Southern California region. The intensity of ground shaking on the Project site would depend upon the earthquake’s magnitude, distance to the epicenter, and geology of the area between the Project site and epicenter.
There are no active faults within the City; however, there are several major active faults located in the region. According to the General Plan Public Safety Element, the San Andreas Fault Zone, which has the greatest potential to cause damage in the region, is 26 miles northeast of the City. Other active local faults that are greater risk to the City include Whittier, San Jose, Sierra Madre, and San Gabriel. Rupture of any of these faults, or of an unknown fault in the region, could cause seismic ground shaking.
Implementation of the Project would result in the installation and operation of an electronic billboard.
The Projectsite consists of an existing asphalt-covered parking lot used for WVUSD school buses and other 8 California Department of Conservation, Geologic Hazards Data Viewer. Available at:
https://maps.conservation.ca.gov/geologichazards/. Accessed June 10, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 62
vehicles, and the area surrounding the Project site is heavily urbanized and developed with freeway, school, residential, and light industrial uses. A geotechnical investigation was conducted to evaluate subsurface conditions and site seismic hazards and perform geotechnical engineering for the proposed Project. The evaluation included review of available geotechnical background information pertaining to the site; laboratory testing of the on-site soil materials; and a summary of findings, conclusions, and recommendations for the development of the proposed Project. The Geotechnical Report concluded that development of the Project, as proposed, is feasible and safe from a geotechnical standpoint, provided the site-specific recommendations are followed during design, construction, and maintenance of the Project. The Geotechnical Report provides site-specific seismic, geotechnical design, and construction recommendations based on the results of the subsurface evaluation and laboratory testing, geotechnical analysis, and a review of referenced geologic materials. Site-specific recommendations address the monopole foundation design, installation, and maintenance. These recommendations reference California Building Code (CBC) seismic design standards in place at the time of report preparation.
The City of Diamond Bar has adopted the CBC (City Code Section 15.00.310), with amendments, which prescribes regulations for the erection, construction, enlargement, alteration, repair, improving, removal, conversion, demolition, occupancy, equipment, use, height, area and maintenance of all buildings and structures. The CBC includes standards related to soils and foundations, structural design, building materials, and structural testing and inspections to minimize hazards during a seismic event. The Project would be required to comply with the applicable regulations in the CBC, which would reduce potential impacts associated with strong seismic ground shaking, as well as the Geotechnical Report prepared for the Project site as it pertains to the proposed electronic billboard structure. The City of Diamond Bar Building and Safety Division would review Project plans for compliance with the CBC and City Code, as well as the Geotechnical Report’s recommendations as part of the building permit and plan check process.
Therefore, compliance with the City’s established regulatory framework and standard engineering practices and design criteria, which would be verified through the City’s development review process, would ensure potential impacts associated with strong seismic ground shaking at the Project site would be less than significant.
Mitigation Measures: No mitigation measures are required. 3) Seismic-related ground failure, including liquefaction? Less Than Significant Impact. Liquefaction is a phenomenon where earthquake-induced ground vibrations increase the pore pressure in saturated, granular soils until it is equal to the confining, overburden pressure. Engineering research of soil liquefaction potential indicates that generally three basic factors must exist concurrently in order for liquefaction to occur. These factors include:
• A source of ground shaking, such as an earthquake, capable of generating soil mass distortions. • A relatively loose silty and/or sandy soil.
• A relatively shallow groundwater table (within approximately 50 feet below ground surface) or completely saturated soil conditions that will allow positive pore pressure generation.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 63
The Project site is mapped by the California Geologic Survey as being within a zone of potentially liquefiable soils.9
However, the liquefaction analysis conducted as part of the Geotechnical Report prepared for the Project site indicates that the soils underlying the Project site are not prone to liquefaction. Impacts associated with seismic-related ground failure due to liquefaction would be less than significant. Implementation of site-specific geotechnical recommendations and compliance with applicable building regulations, would further ensure that impacts related to seismic-related ground failure, including liquefaction, would be less than significant.
Mitigation Measures: No mitigation measures are required. 4) Landslides?
No Impact. Landslides are mass movements of the ground that include rock falls, relatively shallow slumping and sliding of soil, and deeper rotational or transitional movement of soil or rock. Geologic hazards associated with landslides are not anticipated, as the Project site is not located within an area identified by the California Geologic Survey as having potential for seismic slope instability.10 Additionally, the Geotechnical Report concludes that due to the relatively level nature of the Project site, the potential for seismically-induced landsliding is considered remote. As such, no impacts related to landslide would occur.
Mitigation Measures: No mitigation measures are required. b) Result in substantial soil erosion or the loss of topsoil? Less Than Significant Impact. Although construction activities associated with the proposed Project could expose soils to potential short-term erosion by wind and water, the Project would be required to comply with water quality measures included in City Code Section 8.12.1610, City of Diamond Bar Storm Water Management and Discharge Control Ordinance, which include conditions and requirements established by the City related to the reduction or elimination of storm water runoff pollutants during construction and operational phases of the Project. The Project would also be required to comply with CBC (City Code Section 15.00.310), as amended, which prescribes regulations for the erection, construction, enlargement, alteration, repair, improving, removal, conversion, demolition, occupancy, equipment, use, height, area and maintenance of all buildings and structures. Following compliance with the established regulatory framework identified in the Diamond Bar Municipal Code regarding stormwater and runoff pollution control, potential impacts associated with soil erosion and the loss of topsoil would be less than significant.
Mitigation Measures: No mitigation measures are required. 9 California Department of Conservation, Geologic Hazards Data Viewer. Available at:
https://maps.conservation.ca.gov/geologichazards/. Accessed June 10, 2025. 10 California Department of Conservation, California Geological Survey (CGS), Earthquake Zones of Required Investigation. Available at: https://maps.conservation.ca.gov/cgs/EQZApp/. Accessed June 10, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 64
c) Be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on-or off-site landslide, lateral spreading, subsidence, liquefaction or collapse?
Less Than Significant Impact. Potential landslide, lateral spreading, soil stability, and liquefaction hazards are addressed above under the discussion and analysis of Thresholds a) and b). As discussed under Thresholds a) and b), with mandatory compliance with applicable requirements and standards of the CBC, impacts due to landslides and liquefaction would be less than significant and mitigation is not required.
Additionally, the entirety of the Project site is fully developed and the likelihood of the Project to be subject to unstable soils is low. The billboard column is proposed to be secured to an assumed fix installed at a depth of approximately 31 feet below the adjacent site grade. Based on the foregoing analysis, and with mandatory compliance with the CBC requirements, impacts due to unstable soil conditions that could result in on- or off-site landslides, lateral spreading, subsidence, liquefaction, and collapse would be less than significant.
Mitigation Measures: No mitigation measures are required. d) Be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial direct or indirect risks to life or property? Less Than Significant Impact. Expansive soils are defined as soils possessing clay particles that react to moisture changes by shrinking (when dry) or swelling (when wet). As discussed in Response 4.7(a), the Project site is not mapped by the California Geological Survey (CGS) as being within a zone of potentially liquefiable soils. In addition, according to the Geotechnical Report, the results of the liquefaction analyses indicate that the soils underlying the Project site are not prone to liquefaction.
Further, the Geotechnical Report states that the site’s existing fill was encountered to a total depth of six inches. The existing fill consists of silty sand, which is gray-brown, slightly moist, dense, and contains some gravel. The underlying alluvial soils encountered consist of sand, silty sand, clayey sand, and sandy clay, which are brown, yellow-tan, moist to wet, dense and hard, and cemented. While the Geotechnical Report does not discuss expansive soils specifically, it did conclude that groundwater was encountered at a depth of 25.5 feet. As the Project site is considered to be grossly stable and would be required to comply with the established regulatory framework, standard engineering practices, and design criteria, including the CBC (or DBCC Section 15.00.310), Project implementation would not directly or indirectly increase risk to life or property due to the presence of expansive soils, and impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. e) Have soils incapable of adequately supporting the use of septic tanks or alternative waste water disposal systems where sewers are not available for the disposal of waste water? No Impact. The proposed Project is an electronic digital billboard and would not utilize septic tanks or alternative wastewater disposal systems, as it would not connect to any water or wastewater infrastructure. Accordingly, there would be no impact.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 65
f) Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature?
Less Than Significant Impact with Mitigation Incorporated. The City’s General Plan Resource Conservation Cultural and Historic Resources Policies includes Policy RC-P-47, Paleontological Resources, which establishes a procedure for the management of paleontological materials found on-site during a development. The Project site is not known to contain a unique paleontological resource or contain a unique geologic feature. Nevertheless, there is a possibility that a paleontological resource could be discovered during ground-disturbing activities. As such, compliance with City General Plan policies related to paleontological resources, as well as implementation of Mitigation Measure GEO-1, which includes procedures for discovery of paleontological resources, would ensure that potential impacts would be less than significant.
Mitigation Measures:
GEO-1: If evidence of subsurface paleontological resources is found during construction, excavation and other construction activity in that area shall cease and the construction contractor shall contact the City of Diamond Bar Community Development Director or designee. With direction from the Community Development Director, a paleontologist certified by the County of Los Angeles shall evaluate the find prior to resuming grading in the immediate vicinity of the find. If warranted, the paleontologist shall prepare and complete a standard Paleontological Resources Mitigation Program for the salvage and curation of the identified resources.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 66
4.8 Greenhouse Gas Emissions
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Generate greenhouse gas emissions, either
directly or indirectly, that may have a
significant impact on the environment?
X
b. Conflict with an applicable plan, policy or
regulation adopted for the purpose of
reducing the emissions of greenhouse
gases?
X
GREENHOUSE GASES
Various gases in the Earth’s atmosphere, classified as atmospheric greenhouse gases (GHGs), play a critical role in determining the Earth’s surface temperature. Solar radiation enters Earth’s atmosphere from space, and a portion of the radiation is absorbed by the Earth’s surface. The Earth emits this radiation back toward space, but the properties of the radiation change from high-frequency solar radiation to lower-frequency infrared radiation.
Naturally occurring GHGs include water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3). Several classes of halogenated substances that contain fluorine, chlorine, or bromine are also GHGs, but they are, for the most part, solely a product of industrial activities. Although the direct GHGs, including CO2, CH4, and N2O, occur naturally in the atmosphere, human activities have changed their atmospheric concentrations.
Greenhouse gases, which are transparent to solar radiation, are effective in absorbing infrared radiation.
As a result, this radiation that otherwise would have escaped back into space is now retained, resulting in a warming of the atmosphere. This phenomenon is known as the greenhouse effect. Among the prominent GHGs contributing to the greenhouse effect are carbon dioxide (CO2), methane (CH4), ozone (O3), water vapor, nitrous oxide (N2O), and chlorofluorocarbons (CFCs).
REGULATORY FRAMEWORK
U.S. Environmental Protection Agency Endangerment Finding The U.S. Environmental Protection Agency’s (EPA) authority to regulate GHG emissions stems from the U.S. Supreme Court decision in Massachusetts v. EPA (2007). The Supreme Court ruled that GHGs meet the definition of air pollutants under the existing FCAA and must be regulated if these gases could be reasonably anticipated to endanger public health or welfare. Responding to the Court’s ruling, the EPA finalized an endangerment finding in December 2009. Based on scientific evidence it found that six GHGs (CO2, CH4, N2O, hydrofluorocarbons [HFCs], perfluorocarbons [PFCs], and sulfur hexafluoride [SF6]) constitute a threat to public health and welfare. Thus, it is the Supreme Court’s interpretation of the existing FCAA and EPA’s assessment of the scientific evidence that form the basis for the EPA’s regulatory actions.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 67
Senate Bill 32
In 2016, the California State Legislature adopted Senate Bill (SB) 32 and its companion bill AB 197, and both were signed by Governor Brown (Office of Governor Edmund G. Brown Jr., 2016). SB 32 and AB 197 amend California Health and Safety Code Division 25.5, establish a new GHG reduction target of 40 percent below 1990 levels by 2030, and include provisions to ensure the benefits of State climate policies reach into disadvantaged communities.
Assembly Bill 1279
Assembly Bill (AB) 1279, passed in 2022, declares the State’s objective to achieve net zero greenhouse gas emissions as soon as possible, but no later than 2045, and to achieve and maintain net negative greenhouse gas emissions thereafter. This is in addition to, and does not replace or supersede, Statewide greenhouse gas emissions reduction targets.
Senate Bill 375
SB 375 (Stats. 2008, ch. 728) (SB 375) was built on AB 32 (California’s 2006 climate change law). SB 375’s core provision is a requirement for regional transportation agencies to develop a Sustainable Communities Strategy (SCS) in order to reduce GHG emissions from passenger vehicles. The SCS is one component of the existing Regional Transportation Plan (RTP). The SCS outlines the region’s plan for combining transportation resources, such as roads and mass transit, with a realistic land use pattern, in order to meet a State target for reducing GHG emissions. The strategy must take into account the region’s housing needs, transportation demands, and protection of resource and farmlands.
Additionally, SB 375 modified the State’s Housing Element Law to achieve consistency between the land use pattern outlined in the SCS and the Regional Housing Needs Assessment allocation. The legislation also substantially improved cities’ and counties’ accountability for carrying out their housing element plans. Finally, SB 375 amended CEQA (Pub. Resources Code, Section 21000 et seq.) to ease the environmental review of developments that help reduce the growth of GHG emissions.
South Coast Air Quality Management District Threshold Development SCAQMD has established recommended significance thresholds for GHGs for local lead agency consideration (“SCAQMD draft local agency threshold”). SCAQMD has published a five‐tiered draft GHG threshold which includes a 10,000-metric ton of CO2e per year for stationary/industrial sources and 3,000 metric tons (MT) of carbon dioxide equivalent (CO2e) per year significance threshold for residential/commercial projects.
The current draft thresholds consist of the following tiered approach:
(a) Tier 1 consists of evaluating whether or not the project qualifies for any applicable exemption under CEQA.
(b) Tier 2 consists of determining whether or not the project is consistent with a greenhouse gas reduction plan. If a project is consistent with a qualifying local greenhouse gas reduction plan, it does not have significant greenhouse gas emissions. (c) Tier 3 consists of screening values that are intended to capture 90 percent of the GHG emissions from projects. If a project’s emissions are under the screening thresholds, then the project is less than significant. SCAQMD has presented two options that lead agencies could choose for screening values. Option #1 sets the thresholds for residential projects
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 68
to 3,500 MTCO2e/year, commercial projects to 1,400 MTCO2e/year), and the mixed use to 3,000 MTCO2e/year. Option #2 sets a single numerical threshold for all non-industrial projects of 3,000 MTCO2e/year and 10,000 MTCO MTCO2e/year for industrial projects.
Lead agencies are able to choose either option but must be consistent. A project’s construction emissions are averaged over 30 years and are added to a project’s operational emissions. If a project’s emissions are under one of the following screening thresholds, then the project is less than significant:
(d) Tier 4 has the following options:
1. Option 1: Reduce emissions from business as usual by a certain percentage; this percentage is currently undefined
2. Option 2: Early implementation of applicable AB 32 Scoping Plan measures
3. Option 3: Year 2020 target for service populations (SP), which includes residents and employees: 4.8 MTCO2e/SP/year for projects and 6.6 MTCO2e/SP/year for plans
4. Option 3, 2035 target: 3.0 MTCO2e/SP/year for projects and 4.1 MTCO2e/SP/year for plans
(e) Tier 5 involves mitigation offsets to achieve target significance threshold.
In December 2019, the City of Diamond Bar adopted its own local GHG reduction plan titled Diamond Bar Climate Action Plan 2040.11 Therefore, to determine whether the proposed Project’s greenhouse gas emissions are significant, this analysis assesses how the Project aligns with the City’s Climate Action Plan under Tier 2. However, since the Diamond Bar Climate Action Plan 2040 does not establish specific project level GHG thresholds, for purposes of analysis herein, the proposed Project would be considered to have a significant adverse impact on GHG emissions if it would generate GHG emissions that exceed the SCAQMD’s proposed 3,000 MTCO2e per year screening threshold for all land use types (Tier 3).
SCAG’s Connect SoCal: Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS) The Southern California Association of Governments (SCAG) is the metropolitan planning organization (MPO) for the region in which the City of Diamond Bar is located. In 2024, SCAG adopted Connect SoCal 2024 (also referred to as the Regional Transportation Plan/Sustainable Communities Strategy [RTP/SCS]), the 2024-2050 RTP/SCS, which is an update to the previous 2020-2045 RTP/SCS (Connect SoCal 2020).
Connect SoCal 2024 carries forward policy direction established in Connect SoCal 2020, as well as more recent Regional Council actions that address emerging issues facing the region. Connect SoCal 2024 outlines a vision for a more resilient and equitable future, with investment, policies and strategies for achieving the region’s shared goals through 2050. As with the previous RTP/SCS, Connect SoCal 2024 is a long-term plan for the southern California region that details investment in the transportation system and development in communities. SCAG worked closely with local jurisdictions to develop Connect SoCal 2024, which incorporates current demographics and anticipated future population, household, and employment growth patterns based, in part, upon local growth forecasts, projects and programs, and includes complementary regional policies and initiatives. Connect SoCal 2024 outlines a forecasted 11 City of Diamond Bar, 2019. Diamond Bar Climate Action Plan 2040. Available at:
https://www.diamondbarca.gov/DocumentCenter/View/7071/Diamond-Bar-Climate-Action-Plan-2040pdf?bidId=.
Accessed June 10, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 69
development pattern that demonstrates how the region can sustainably accommodate needed housing.
In addition, Connect SoCal is supported by a combination of transportation and land use strategies that outline how the region can achieve California’s GHG-emission-reduction goals and federal Clean Air Act requirements.
2022 Scoping Plan Update
In accordance with AB 32, the CARB developed the first Scoping Plan in 2008 to outline the State’s strategy to achieve 1990 level emissions by year 2020. In May 2014, the CARB released and adopted the First Update to the Climate Change Scoping Plan to identify the next steps in reaching AB 32 goals and evaluate the progress that has been made between 2000 and 2012. A newer version of the Scoping Plan was then adopted by the CARB in December 2017 (entitled California’s 2017 Climate Change Scoping Plan). Lastly, the most recent version of the Scoping Plan was adopted by the CARB in November 2022 (entitled Final 2022 Scoping Plan for Achieving Carbon Neutrality) (2022 Scoping Plan), which was designed consistent with the long-term GHG reduction targets embedded in AB 1279. Since adoption of the 2008 Scoping Plan and the subsequent updates in 2014, 2017, and 2022, State agencies have adopted programs identified in the plan, and the Legislature has passed additional legislation to achieve the GHG reduction targets.
Statewide strategies to reduce GHG emissions include the Low Carbon Fuel Standard, California Appliance Energy Efficiency regulations, California Building Standards (e.g., CALGreen and the 2022 Building and Energy Efficiency Standards), zero carbon electricity by 2045, and changes in the corporate average fuel economy standards (e.g., Pavley I and California Advanced Clean Cars). a) Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment?
Less Than Significant Impact. Operational activities associated with the proposed Project would result in emissions of CO2, CH4, and N2O strictly from energy source emissions due to the Project’s electricity demand and mobile source emissions as a result of billboard maintenance visits (six to eight times per year). Additionally, construction/installation activities would be minor and last approximately seven days.
The CalEEMod model was utilized to estimate Project construction-related and operational emissions.
Refer to Appendix B, Air Quality and Greenhouse Gas Emissions Modeling, for full detail.
Estimated maximum construction-related GHG emissions associated with operation of the Project are summarized in Table 4.7-1, Maximum Construction-related GHG Emissions (Mitigated Average Metric Tons/year). These emissions include all worker vehicle, vendor vehicle, hauler vehicle, and off-road construction vehicle GHG emissions. For the purposes of this analysis, the construction schedule is estimated to occur in late 2025. The length of the construction schedule was provided by the Project applicant. It should be noted that this schedule is an approximation and may change over time.
Table 4.7-1
Maximum Construction-related GHG Emissions (Metric Tons/year) Year Bio-CO2 NBio-CO2 Total CO2 CH4 N2O R CO2e
2025 0 4.5 4.5 <0.1 <0.1 <0.1 4.5
Source: CalEEMod version 2022.1
Biogenic carbon dioxide = Bio-CO2; non-biogenic carbon dioxide = NBio-CO2; total carbon dioxide = total CO2; nitrous oxide = and N2O; refrigerant emissions = R; and carbon dioxide equivalent = CO2e.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 70
As shown above in Table 4.7-1, construction emissions are approximately 4.5 MTCO2e. The SCAQMD recommends that construction GHG emissions are amortized over 30 years. Therefore, amortized construction emissions would be approximately 0.2 MTCO2e.
Estimated operation-related GHG emissions associated with operation of the Project are summarized in Table 4.7-2, Maximum Operational GHG Emissions (Mitigated Average Metric Tons/year). For the purposes of this analysis, the first year of operation is estimated to occur in 2025. Operation-related emissions include the electricity required to power the billboard, as well as the up to approximately eight two-way vehicle trips per year associated with Project maintenance.
Table 4.7-2
Maximum Operational GHG Emissions (Metric Tons/year)
Year Bio-CO2 NBio-CO2 Total CO2 CH4 N2O R CO2e
2025 1.7 11.9 13.7 0.2 <0.1 <0.1 18.4
Source: CalEEMod version 2022.1
Biogenic carbon dioxide = Bio-CO2; non-biogenic carbon dioxide = NBio-CO2; total carbon dioxide = total CO2; nitrous oxide = and N2O; refrigerant emissions = R; and carbon dioxide equivalent = CO2e.
As shown in Table 4.7-2, maximum annual operational GHG emissions would be only 18.4 MTCO2e.
SCAQMD recommends that a project’s operational GHG emissions should be combined with a project’s amortized construction emissions, to compare to the SCAQMD’s interim threshold of 3,000 MTCO2e per year for GHGs individual projects. When combined with the amortized construction emissions, total GHG emissions would be approximately 18.6 MTCO2e.
The SCAQMD maintains an interim threshold of 3,000 MTCO2e per year for GHGs individual projects, inclusive of both construction and operational activities. Overall, Project-related construction and operational GHG emissions (approximately 18.6 MTCO2e) would produce GHG emissions well below the SCAQMD’s interim threshold of 3,000 MTCO2e per year. Therefore, the proposed Project would result in less than significant impacts related to GHG emissions.
Mitigation Measures: No mitigation measures are required. b) Conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases?
No Impact. As discussed in Threshold a) above, the Project would not generate GHG emissions above the SCAQMD draft screening level threshold of 3,000 MTCO2e per year that is utilized to evaluate the significance of a small non-industrial project’s GHG emissions.
Additionally, activities associated with the Project would be subject to all applicable federal, state, and regional requirements adopted for the purpose of reducing GHG emissions, including, but not limited to:
CBSC Title 24 Energy Standards (also known as CALGreen); AB 1493; Executive Orders S-3-05 and B-30-15; AB 32; SB 1368; SB 97; SB 32 (2016); and the applicable policies of the City’s General Plan that reduce GHG emissions. As such, the Project would be reviewed for consistency with the Diamond Bar Climate Action Plan 2040, including Appendix C, Policy CR-P-56, which encourages dedicated parking and charging stations for electric vehicles. The proposed Project would use energy efficient LED lighting consistent with the Climate Action Plan’s Appendix D project-level measures and would not deter EV-readiness for maintenance activities. Additionally, the Project would not conflict with the SCAG’s adopted Connect
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 71
SoCal 2024, as well as the CARB’s 2022 Scoping Plan. There are no other plans, policies, or regulations adopted for the purpose of reducing GHG emissions that are applicable to the Project area. Therefore, the Project would not conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of GHGs, and there would be no impact in this regard.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 72
4.9 Hazards and Hazardous Materials
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Create a significant hazard to the public or
the environment through the routine
transport, use, or disposal of hazardous
materials?
X
b. Create a significant hazard to the public or
the environment through reasonably
foreseeable upset and accident conditions
involving the release of hazardous
materials into the environment?
X
c. Emit hazardous emissions or handle
hazardous or acutely hazardous materials,
substances, or waste within one-quarter
mile of an existing or proposed school?
X
d. Be located on a site which is included on a
list of hazardous materials sites compiled
pursuant to Government Code Section
65962.5 and, as a result, would it create a
significant hazard to the public or the
environment?
X
e. For a project located within an airport land
use plan or, where such a plan has not been
adopted, within two miles of a public
airport or public use airport, would the
project result in a safety hazard or
excessive noise for people residing or
working in the project area?
X
f. Impair implementation of or physically
interfere with an adopted emergency
response plan or emergency evacuation
plan?
X
g. Expose people or structures, either directly
or indirectly, to a significant risk of loss,
injury or death involving wildland fires?
X
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 73
a) Create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials?
Less Than Significant Impact. Implementation of the Project would result in the installation and operation of an electronic billboard. Once installed, the digital billboard would not involve routine on-site storage, mixing, or use of hazardous substances. Occasional maintenance would involve the handling of small quantities of materials (e.g., swapping LED modules or minor electrical components); however, LED parts are not hazardous and would be handled using normal trash disposal or e-waste procedures, as applicable.
Since there would be no ongoing process associated with the Project that would routinely use or store hazardous materials, compliance with existing federal, State, and local regulations governing transport, handling, and disposal ensures potential hazards would be minimized to a less than significant level.
Mitigation Measures: No mitigation measures are required. b) Create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment?
Less Than Significant Impact. Installation of the proposed electronic billboard would occur over the course of five to seven days, utilizing standard construction equipment with small quantities of fuels and lubricants. Work would occur within an existing asphalt bus yard with limited ground disturbance (a drilled foundation and a shallow utility trench), which reduces exposure pathways. Contractors must store, handle, and clean up any spills in accordance with applicable regulations and standard BMPs. During operation, the electronic billboard does not use or emit hazardous materials; occasional maintenance is limited to swapping electrical/LED components, which are not considered hazardous and would be handled under routine solid-waste or e-waste procedures. Given the small quantities of materials involved, the brief construction period, and required compliance with federal, State, and local regulations, reasonably foreseeable upset or accident conditions would not create a significant hazard. Impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. c) Emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school? Less Than Significant Impact. The Project site is located on property owned by WVUSD and houses administrative offices and parking lot and maintenance yard for WVUSD school buses. The Project site is adjacent to Walnut Elementary School (841 S. Lemon Avenue), which is located within one-quarter mile of the site. Additionally, Discovery World Montessori (801 South Brea Canyon Road) is located approximately 0.5 mile from the Project Site. Project installation activities would use limited construction equipment for a total of up to seven days. Installation and operation of the electronic billboard does not include the potential for hazardous emissions, nor would the handling of hazardous materials, substances or waste occur as part of the Project. Accordingly, the proposed Project has no potential to emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school. Impacts would be less than significant.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 74
d) Be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5 and, as a result, would it create a significant hazard to the public or the environment?
No Impact. Implementation of the Project would result in the installation and operation of an electronic billboard. The site is not located on a hazardous materials site compiled pursuant to Government Code Section 65962.5.12 Therefore, there would be no impact.
Mitigation Measures: No mitigation measures are required. e) For a project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project result in a safety hazard or excessive noise for people residing or working in the project area? No Impact. The nearest airport to the Project site is the Brackett Field Airport which is located approximately 7.6 miles northeast of the Project site. According to the General Plan EIR, the City is not located within the area of influence of any nearby airports, nor is the site within an airport land use plan.
Accordingly, there would be no impact related to airports.
Mitigation Measures: No mitigation measures are required. f) Impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan?
No Impact. The Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway, school, residential, and light industrial uses. The Project would not include any full-time employees or result in increased traffic or activities at the site with the potential to interfere with an emergency response plan or emergency evacuation plan. Due to the inherently small-scale nature and location of the proposed electronic billboard Project, there would be no physical interference with an adopted emergency response plan or emergency evacuation plan. Additionally, all billboard installation activities would occur on-site, and no roadway closures would be required. There would be no impact.
Mitigation Measures: No mitigation measures are required. g) Expose people or structures, either directly or indirectly, to a significant risk of loss, injury or death involving wildland fires?
No Impact. The Project site consists of an existing asphalt-covered parking lot, and the area surrounding the Project site is urbanized and developed. According to the CAL FIRE Fire Hazard Severity Zone Map, the Project site is not located within a very high fire hazard severity zone (VHFHSZ), nor is the site within or 12 State Water Resources Control Board, GeoTracker. Available at:
https://geotracker.waterboards.ca.gov/map/?CMD=runreport&myaddress=880+s+lemon+ave%2C+diamond+bar.
Accessed August 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 75
near a State Responsibility Area.13 The Project would be required to comply with all City and Los Angeles County Fire requirements for fire prevention and safety measures, including site access. Additionally, due to the inherently small-scale nature and location of the proposed electronic billboard within and surrounded by urban built-up land, the proposed Project would not expose people or structures to a significant risk of loss, injury or death involving wildland fires. There would be no impact.
Mitigation Measures: No mitigation measures are required. 13 California Department of Forestry and Fire Protection (CalFire), FHSZ Viewer. Available at:
https://osfm.fire.ca.gov/what-we-do/community-wildfire-preparedness-and-mitigation/fire-hazard-severity-zones.
Accessed June 5, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 76
4.10 Hydrology and Water Quality
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Violate any water quality standards or
waste discharge requirements or
otherwise substantially degrade surface or
ground water quality?
X
b. Substantially decrease groundwater
supplies or interfere substantially with
groundwater recharge such that the project
may impede sustainable groundwater
management of the basin?
X
c. Substantially alter the existing drainage
pattern of the site or area, including
through the alteration of the course of a
stream or river or through the addition of
impervious surfaces, in a manner which
would:
X
1) Result in substantial erosion or siltation
on- or off-site? X
2) Substantially increase the rate or
amount of surface runoff in a manner
which would result in flooding on- or
offsite?
X
3) Create or contribute runoff water which
would exceed the capacity of existing or
planned stormwater drainage systems
or provide substantial additional
sources of polluted runoff?
X
4) Impede or redirect flood flows? X
d) In flood hazard, tsunami, or seiche zones,
risk release of pollutants due to project
inundation?
X
e) Conflict with or obstruct implementation of
a water quality control plan or sustainable
groundwater management plan?
X
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 77
a) Violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or ground water quality?
Less Than Significant Impact. Installation of the proposed Project would involve the drilling of an approximately 31-foot deep, 5-foot-wide borehole and the installation of the billboard’s support superstructure. This process would be completed within one day. All excavated materials would be removed from the site by dump trucks. It is anticipated that approximately 32 cubic yards of soil would be exported, requiring about four truckloads. Once the post installation hole is ready, the column would be installed and concrete would be poured, completing the foundation-related ground disturbance.
Excavated soil would not remain on-site and would immediately be transported to the nearest approved receiving landfills. Given the Project’s minimal impact area and the fact that excavated soil would immediately be transported off-site, no substantial physical features associated with the construction of a digital billboard would lead to erosion or substantial contribution of polluted storm water runoff that would result in violation of any water quality standards or waste discharge requirements.
Minimal on-site trenching would be required to connect electrical utilities, and all soil removed during this time would be returned back to its original location. Additionally, because the area is already paved under existing conditions, the long-term operation of the digital billboard would not substantially increase the quantity or rate of storm water runoff, nor would it substantially increase pollutant concentrations in storm water runoff from the site. Additionally, the Project would not produce wastewater discharge.
Therefore, water quality impacts associated with installation and operation activities would be less than significant.
Mitigation Measures: No mitigation measures are required. b) Substantially decrease groundwater supplies or interfere substantially with groundwater recharge such that the project may impede sustainable groundwater management of the basin? No Impact. No structures that would require the use of water are being proposed as part of the Project.
Furthermore, the site is currently completely paved over, and there would be no measurable increase in impervious surfaces associated with the Project that could interfere with groundwater recharge. No groundwater wells are located on the Project site. Therefore, implementation of the proposed Project would not deplete groundwater supplies.
As part of the Geotechnical Report, a subsurface exploration was conducted on July 17, 2024, consisting of one boring to a depth of 51.5 feet excavated with the aid of a truck-mounted auger drilling machine.
Groundwater was encountered at a boring depth of 25.5 feet. Because the drilled foundation is anticipated to extend to approximately 31 feet below grade, potential contact with groundwater during drilling could occur; therefore, procedures for managing any encountered groundwater are discussed under subsection (e), below.
Upon review of historical documents, the Geotechnical Report found that the historically highest groundwater level below the subject site was on the order of 20 feet below existing site surface grade.
The Geotechnical Report directs the foundation excavation to be at least 10 feet in depth below the existing surface grade; therefore, groundwater may be encountered during construction of the Project. If water is encountered during installation of the electronic billboard, the Geotechnical Report includes instructions to use a tremie to place concrete into the bottom of the hole. Under current conditions, the portion of the Project site where the billboard would be installed is on a portion of an existing parking lot.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 78
In addition, installation and operation of the billboard would not involve any water consumption, and no net change in area-wide water consumption would occur as a result of Project implementation.
Accordingly, there would be no impacts related to depletion of groundwater supplies or interference with groundwater recharge.
Mitigation Measures: No mitigation measures are required. c) Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would:
1) Result in substantial erosion or siltation on- or off-site? Less Than Significant Impact. Implementation of the Project would result in the installation and operation of an electronic billboard. The Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway, school, residential, and light industrial uses. Ground disturbance would be limited, and runoff would continue to be conveyed to the existing drainage course. As part of the Project, two pine trees along S. Lemon Avenue would be removed, and in their place, two 24-inch box Crape Myrtle trees would be planted. These conditions would not result in substantial erosion or siltation on- or offsite. Impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. 2) Substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or offsite?
Less Than Significant Impact. The Project does not add measurable impervious area, as it would consist of installation of a monopole foundation on an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway, school, residential, and light industrial uses. Ground disturbance would be limited, and runoff would continue to be conveyed to the existing drainage course. Therefore, the rate or amount of runoff would not increase to a level that would cause flooding on- or off-site. Impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. 3) Create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff?
Less Than Significant Impact. Since the Project’s runoff would continue to be conveyed to the existing drainage course and the impervious area would not meaningfully change, the Project would not exceed storm drain capacity. Operation of a digital billboard does not introduce new process water or substantial pollutant sources. The City of Diamond Bar’s Public Works review of the site’s drainage documentation would confirm continued compliance with existing capacity and design standards. Impacts would be less than significant.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 79
4) Impede or redirect flood flows?
Less Than Significant Impact. There is no stream or river on or near the Project site. The foundation of the proposed electronic billboard would not alter the site’s existing hydrology, and no on-site drainage would be conveyed to adjacent parcels, unless that is the natural drainage course. As such, the project would not impede or redirect flood flows. Impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. d) In flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation? No Impact. Tsunamis are sea waves that are generated in response to large-magnitude earthquakes, which can result in coastal flooding; however, at its closest point, the Pacific Ocean is over 23 miles away.
Seiches are the oscillation of large bodies of standing water, such as lakes, which can occur in response to ground shaking; however, the closest water body is Puddingstone Reservoir, which is over six miles away.
As such, the Project site is not located within a flood hazard, tsunami, or seiche zone.14, 15 Therefore, no impacts associated with risk of pollutants due to project inundation would occur.
Mitigation Measures: No mitigation measures are required. e) Conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan?
Less Than Significant Impact. The Geotechnical Report concludes that groundwater was encountered at a depth of 25.5 feet below the Project site. Upon review of historical documents, the Geotechnical Report found that the historically highest groundwater level below the Project site was on the order of 20 feet below existing site surface grade. The Foundation Engineering Investigation directs the foundation excavation to be at least 10 feet in depth below the existing surface grade; therefore, groundwater may be encountered during installation of the electronic billboard.
The applicable water quality control plan is the Water Quality Control Plan for the Los Angeles Region (Region 4) Basin Plan, which designates beneficial uses, sets water quality objectives for surface and ground waters, and includes implementation programs. The proposed electronic billboard construction would comply with Basin Plan provisions and any required Regional Water Board approvals. If water is encountered during installation of the proposed electronic billboard, the Geotechnical Report recommends the use of a tremie to place concrete into the bottom of the hole. This would avoid any conflict with the Basin Plan.
Additionally, the Project does not propose the installation of any wells and would not otherwise interfere with the implementation of any adopted water quality control plan or a sustainable groundwater 14 Federal Emergency Management Agency (FEMA), Flood Map Service Center: Search by Address. Available at:
https://msc.fema.gov/portal/search?AddressQuery. Accessed June 11, 2025. 15 California Department of Conservation, California Tsunami Maps and Data, Available at:
https://www.conservation.ca.gov/cgs/tsunami/maps. Accessed June 11, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 80
management plan. The Project site overlies the adjudicated Puente Groundwater Basin. 16 Under California
Water Code Section 10720.8, adjudicated basins are not subject to the Sustainable Groundwater Management Act (SGMA) requirement to prepare a Groundwater Sustainability Plan (GSP) and are administered by a court-appointed Watermaster, who must submit annual reports to the California Department of Water Resources (DWR) pursuant to Section 10720.8(f). Since the Project does not involve groundwater extraction, recharge, or an installation of a new well, there is no applicable GSP to conflict with, and the Project would not obstruct Watermaster administration of the basin. Due to limited scope of ground disturbance, brief period of construction, and adherence to the Geotechnical Report recommendations and applicable existing regulations, the Project would not conflict with or obstruct implementation of any water quality control or groundwater management plan. Impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. 16 Walnut Vally Water District, 2021. Urban Water Management Plan, Figure 4- Puente Basin Location. Available at:
https://walnutvalleywater.gov/wp-content/uploads/2023/03/FINAL-Walnut-Valley-Water-District-2020- UWMP.pdf. Accessed August 1, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 81
4.11 Land Use and Planning
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Physically divide an established
community? X
b. Cause a significant environmental impact
due to a conflict with any land use plan,
policy, or regulation adopted for the
purpose of avoiding or mitigating an
environmental effect?
X
a) Physically divide an established community?
No Impact. The Project site is zoned Light Industry (I). The Light Industry zoning designation is applied to areas appropriate for light industrial/manufacturing uses including research and development, officebased industrial uses in an "industrial park" setting, business support services, and commercial uses requiring larger sites than are available in the commercial zoning districts. Implementation of the Project would result in the construction and operation of a digital billboard. The Projectsite consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway, school, residential, and light industrial uses. The proposed Project would not physically divide or separate the residential neighborhood within the surrounding area, as there are no residential uses within the Project improvement area Thus, no impact would occur in this regard.
Mitigation Measures: No mitigation measures are required. b) Cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect? Less Than Significant Impact. The land use plans, policies, and regulations applicable to the proposed Project include the City’s General Plan and the City’s Zoning Code/Municipal Code. Each of these plans, policies, and regulations is discussed below.
Analysis of Consistency with the City of Diamond Bar General Plan The Project site has a General Plan land use designation of School (S). The School land use designation is intended for school facilities. The Project site is located on property owned by WVUSD and houses administrative offices and parking lot and maintenance yard for WVUSD school buses. The Project improvement area is adjacent to Walnut Elementary School (841 S. Lemon Avenue), which is located within one-quarter mile of the site. No schools or students are present at the Project site. No General Plan land use amendment is proposed. Implementation of the Project would result in the installation and operation of the proposed electronic billboard. The proposed digital billboard use would not conflict with General Plan land use and zoning for the Project site. The Project would be consistent with City’s General Plan Land Use and Economic Development Element policies that avoid or mitigate environmental effects, including Policy LU-P-1, which calls for sensitive transitions to minimize impacts on adjacent, less intensive
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 82
uses, and Policies LU-P-4 through LU-P-6, which require mitigation of land use and circulation effects and the provision of adequate public services and fair-share improvements. The proposed electronic billboard’s siting within an existing asphalt-covered parking lot, static LED display with automatic dimming, and negligible traffic demand would not interfere with these policies. In addition, the Project would comply with Policy LU-P-34 by evaluating and avoiding noise and air quality effects associated with proximity to SR-60, including use of lighting controls to prevent glare.
Analysis of Consistency with the City of Diamond Bar Development Code The Project site is zoned Light Industry (I). The Light Industry zoning designation is applied to areas appropriate for light industrial/manufacturing uses including research and development, office-based industrial uses in an "industrial park" setting, business support services, and commercial uses requiring larger sites than are available in the commercial zoning districts. Implementation of the Project would result in the installation and operation of an electronic billboard. The Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway, school, residential, and light industrial uses.
Development Code Amendment
The City of Diamond Bar will require adoption of a Development Code Amendment to allow the Project to operate subject to a conditional use permit. The Development Code (Title 22 of the Diamond Bar City Code) would be amended to modify the following sections: Section 22.10.30 – Commercial/Industrial District Land Uses and Permit Requirements; Section 22.36.080 – Prohibited Signs; Section 22.36.120 – Standards for Specific Types of Signs; and Section 22.80.020 – Definitions of Specialized Terms and Phrases. Upon adoption, the proposed Project would be required to comply with the standards established in the amended Development Code.
The following sets forth the proposed revisions to each affected section of the Development Code:
Section 22.10.30 – Commercial/Industrial District Land Uses and Permit Requirements, would be amended to permit “billboards” as a conditionally permitted use in the City’s I (Light Industry) zones.
Section 22.36.080 – Prohibited Signs, would be amended to allow off-site signs, as specified.
Section 22.36.120 – Standards for Specific Types of Signs, would add a new subsection for billboards, as follows:
Billboards. Billboards may be permitted by conditional use permit and a development agreement on properties located within the I zone, subject to the following limitations:
(1) No billboard shall be located more than 400 feet from the edge of a freeway right-of-way, measured from the nearest point of the sign structure to the nearest point of the right-of-way boundary.
(2) No billboard shall be located within 800 feet of any existing billboard, regardless of whether the proposed billboard is static or digital. In addition, no digital billboard shall be located within 2,000 feet of any existing digital billboard. Distance shall be measured in a straight line between the bases of the respective billboard structures.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 83
(3) No billboard shall be located within 400 feet of any parcel that is zoned or used for residential purposes. Distance shall be measured in a straight line from the closest point of the residentiallyzoned or residentially-used parcel boundary to the base of the proposed billboard. (4) The maximum height of a billboard shall not exceed 75 feet, measured as the vertical distance from the highest point of the sign structure to the finished surface elevation at the edge of the nearest freeway travel lane. This measurement shall be taken along a line drawn perpendicularly from the base of the sign structure to the tangent of the nearest freeway lane. A decorative or architectural element may extend up to 10 feet above the maximum height, provided it does not contain any additional display area or advertising content. (5) The maximum area of any individual sign face shall not exceed 672 square feet. Each sign face shall be limited to a maximum length of 48 feet and a maximum height of 14 feet. No billboard shall contain more than one sign face per direction of travel, and vertical stacking of sign faces on the same side of a structure is prohibited.
(6) Architectural features such as framing, decorative borders, or structural shrouds that do not contain any advertising content shall be permitted above, below, or around the sign face and shall not count toward the maximum allowable sign area, provided they are designed as integral components of the sign structure and do not function as additional sign faces. (7) No billboard shall contain more than two sign faces. Where two sign faces are configured in a Vshaped or angled arrangement, the angle between the faces shall not exceed 45 degrees as measured between the planes of the two sign faces.
(8) All illuminated billboards shall be equipped with automatic light-sensing technology to adjust brightness in response to ambient lighting conditions. Maximum luminance shall not exceed 0.3 foot-candles above ambient levels, measured at a distance of 250 feet perpendicular to the center of the sign face.
All luminance measurements shall be verified at a horizontal distance of 250 feet perpendicular to the sign face. A photometric analysis shall be submitted with the permit application and shall include certification by a qualified lighting professional or electrical engineer confirming compliance with these standards.
All illumination shall be directed to avoid light spillover onto adjacent properties, roadways, or into the night sky. Sign lighting shall not cause glare or impair visibility for motorists, and shall remain static, without flashing, strobing, or rapidly changing brightness. (9) Digital billboards shall display static images only. Each image shall remain on the screen for a minimum duration of eight (8) seconds. Transitions between images shall be instantaneous, without any motion, animation, flashing, or other visual effects.
Section 22.80.020 – Definitions of specialized terms and phrases, would add a new definition of billboards, as follows:
(10) Billboard. A freestanding sign structure that is designed and used to display off-site advertising copy, including commercial and non-commercial messages that direct attention to a business, product, service, activity, event, or location not located on the same premises as the sign. A billboard may display either static billboard or digital billboard, as defined below. Billboards do
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 84
not include on-site business identification signs, civic information signs, or temporary political signs.
a. Digital Billboard. A billboard that displays off-site advertising copy using electronic changeable copy technology, such as light-emitting diodes (LEDs) or similar digital display methods. The content may change remotely and at programmed intervals but shall comply with limitations on message duration and visual effects as set forth in this Title. b. Static Billboard. A billboard that displays a fixed image or message, typically through printed or painted panels. The copy does not change electronically and remains static until physically replaced.
Upon approval of the Development Code Amendment, the Project would not conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect; therefore, impacts would be less than significant.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 85
4.12 Mineral Resources
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Result in the loss of availability of a known
mineral resource that would be of value to
the region and the residents of the state?
X
b. Result in the loss of availability of a locallyimportant mineral resource recovery site delineated on a local general plan, specific
plan or other land use plan?
X
a) Result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state?
No Impact. According to the City’s General Plan EIR, there are no mineral resources identified within the City, including the Project site.17 Implementation of the Project would result in the installation and operation of an electronic billboard. The southwestern portion of the Project site, where the proposed Project would be installed, consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles. The Project site does not include any known mineral resources. No impact would occur.
Mitigation Measures: No mitigation measures are required. b) Result in the loss of availability of a locally-important mineral resource recovery site delineated on a local general plan, specific plan or other land use plan? No Impact. The Project site is not designated as a locally important mineral resource recovery area in the City’s General Plan, any specific plan, or other adopted land use plan. Therefore, the proposed Project would not result in the loss of availability of a designated local mineral resource site. No impact would occur.
Mitigation Measures: No mitigation measures are required. 17 City of Diamond Bar, September 2019. Diamond Bar EIR 2040 Public Review Draft.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 86
4.13 Noise
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Generation of a substantial temporary or
permanent increase in ambient noise levels
in the vicinity of the project in excess of
standards established in the local general
plan or noise ordinance, or applicable
standards of other agencies?
X
b. Generation of excessive groundborne
vibration or groundborne noise levels? X
c. For a project located within the vicinity of a
private airstrip or an airport land use plan
or, where such a plan has not been adopted,
within two miles of a public airport or
public use airport, would the project
expose people residing or working in the
project area to excessive noise levels?
X
Existing Noise Conditions
Existing Study Area Ambient Noise Conditions
Implementation of the Project would result in the construction and operation of a digital billboard. The Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway, school, residential, and light industrial uses. Accordingly, the background ambient noise levels within the vicinity of the Project site are dominated by transportation‐related noise associated with the operation of school buses on the site and the surrounding roadway network, which includes noise from automobile and light/heavy truck activities along SR 60, which is immediately adjacent to the Project improvement area.
Existing Groundborne Vibration
Based on the operational characteristics of the uses on the site under current conditions, there are no sources of substantial groundborne vibration generated on the Project site. With the exception of groundborne vibration generated by school bus operation on the site and roadway vehicle traffic along SR 60 and adjacent roadways, no sources of substantial groundborne vibration occur in the Project site’s vicinity.
Airport Noise and Vibration
The nearest airport to the Project site is the Brackett Field Airport which is located approximately 7.6 miles northeast of the Project site. According to the General Plan EIR, the City is not located within the area of influence of any of the nearby airports.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 87
a) Generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies?
Less Than Significant Impact.
Construction-Related Noise Impacts
According to Development Code Section 22.28.120, construction activities are limited to the hours of 7:00 a.m. to 7:00 p.m., Monday to Saturday. No numerical noise threshold is established by the Development Code pertaining to construction noise levels within the I zoning district. Therefore, the Project’s mandatory compliance with the permitted construction hours established by the City’s Municipal Code would ensure that noise generated by the installation of the electronic billboard would not exceed applicable standards. Construction noise would be primarily related to operation of the drill rig to dig the hole for installation of the steel superstructure, and the crane which would lift the superstructure into place. These activities would take place on an intermittent basis over the course of five to seven days.
Furthermore, the nearest noise sensitive uses (school and residential uses) would be over 500 feet away.
Noise associated with the use of a drill rig and crane were calculated using the Federal Highway Administration’s Roadway Construction Noise Model would result in noise exposure levels of 59 dBA Leq at the nearest noise sensitive use. Noise levels associated with the construction of the Project would result in noise levels of less than the 80 dBA Leq noise threshold recommended by the Federal Transit Administration. Refer to Appendix F for detail. Since the Project’s construction-related noise would be below the FTA’s noise threshold, Project related construction is not substantial and impacts related to noise generated from construction/installation of the Project would be less than significant. The construction noise modeling is shown in Appendix F, Noise Modeling, of this MND.
Operation-Related Noise Impacts
Operation of the Project would not result in any noise, as the proposed electronic billboard does not include any components which would create noise. The billboard is silent and does not have any speakers or sound generating activities.
Regarding Project-related operational activities, noise level standards applicable to the Project include those provided in the Noise Element of the City of Diamond Bar General Plan and the Diamond Bar Development Code, as described below.
City of Diamond Bar General Plan Public Safety Element
The City of Diamond Bar General Plan Public Safety Element identifies noise-sensitive land uses and noise sources and defines areas of noise impact for the purpose of developing policies to ensure that Diamond Bar residents are protected from excessive noise intrusion. Noise sensitive receptors are defined as land uses associated with indoor and/or outdoor activities where the presence of unwanted sound could adversely affect the use of the land. Examples of noise-sensitive receptors include residential areas, senior and childcare facilities, schools, hospitals, religious facilities, parks, libraries, wildlife habitat, and open space. Sensitive receptors located near the Project site include Walnut Elementary School to the north of the Project site, single-family residences located to the east across Glenwick Avenue and to the south across SR 60. Operation of the Project is not anticipated to emit any audible noise except for very minor noise from periodic maintenance activity that would be overshadowed by vehicular noise on adjacent the
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 88
SR 60 freeway. Accordingly, the Project would result in less-than-significant impacts with respect to the noise standards established by the City of Diamond Bar General Plan Public Safety Element.
Development Code
The City of Diamond Bar Development Code Section 22.28.080, Exterior Noise Standards, establishes noise limits that apply to all zones within the City. Table 4.13-1, Municipal Code Exterior Noise Standards, provides base exterior noise standards applicable to the Project site and properties surrounding the Project site.
Table 4.13-1
Exterior Noise Standards
Noise Zone Designated Noise Zone Land
Use (Receptor Property) Time Interval Exterior Noise Levels (dBA) I Noise-sensitive area Anytime 45
II Residential properties 10:00 p.m. to 7:00 a.m. (nighttime) 45 7:00 a.m. to 10:00 p.m. (daytime) 50
III Commercial properties 10:00 p.m. to 7:00 a.m. (nighttime) 55 7:00 am. to 10:00 p.m. (daytime) 60
IV Industrial properties Anytime 70
Source: City of Diamond Bar Development Code Section 22.28.080, Table 3-9.
The operational activities associated with the proposed electronic billboard would not emit any audible noise except for very minor noise from periodic maintenance activity that would be overshadowed by vehicular noise on the adjacent SR 60 freeway. The operational activities associated with the proposed electronic billboard would not be anticipated to generate any substantial increases in noise levels to the area that would result in exceedance of the base exterior noise level standards shown in Table 4.13-1.
Accordingly, the Project would result in less than significant impacts with respect to Municipal Code standards applicable to operational noise, and no mitigation is required.
The only potential sources of substantial temporary or periodic increases in noise levels are temporary and intermittent noise associated with the installation of the Project from the operation of heavy equipment for a period of five to seven days. Construction activity would be restricted to the permissible daytime hours permitted by the City’s Development Code (7:00 a.m. to 7:00 p.m., Monday through Saturday) over the course of the Project’s construction schedule (less than a week). Compliance with the City’s Municipal Code noise standards would ensure that Project construction activities would be less than significant. Further, construction noise would likely be overshadowed by vehicular noise levels from the adjacent SR 60 freeway. Operation of the proposed electronic billboard would not generate increases in ambient noise levels in the Project vicinity.
Based on the foregoing analysis, the Project would not result in the exposure of persons to or generation of noise levels in excess of standards established in the City’s General Plan, the Municipal Code noise ordinance, or the applicable standards of other agencies. As such, impacts would be less than significant.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 89
b) Generation of excessive groundborne vibration or groundborne noise levels? Less Than Significant Impact. Groundborne vibration is an oscillatory motion which can be described in terms of displacement, velocity, or acceleration. It is expected that groundborne vibration from Project installation activities would cause intermittent, localized intrusion through the operation of heavy construction equipment and trucks. Potential vibration from construction equipment would only occur during permissible construction hours as permitted by the City’s Development Code. Any exposure by nearby sensitive receptorsto nominal vibration would be temporary, if it would be perceptible at all. Truck vibration levels are dependent on vehicle characteristics, load, speed, and pavement conditions.
Construction-related vibration dissipates substantially with distance and distances beyond 50 feet are imperceptible to offsite uses. Since the nearest building is approximately 200 feet away, vibration levels at the nearest building is estimated to be 0.004 peak particle velocity (ppv), which is below the annoyance threshold of 0.1 ppv and the building damage threshold of 0.3 ppv for concrete buildings. Refer to Appendix F, Noise Modeling, for detail. Additionally, truck deliveries (if necessary) to the Project site may nominally increase vibration levels in the area; however, truck deliveries would only occur during permissible construction hours as permitted by the City’s Development Code and would be most indiscernible from vehicles traveling on the adjacent SR 60 freeway. Furthermore, there would be no sources of perceptible vibration associated with Project’s operation. Based on this analysis, vibration levels associated with installation and operation of the Project would be less than significant. Vibration calculations are shown in Appendix F, Noise Modeling, of this MND.
Mitigation Measures: No mitigation measures are required. c) For a project located within the vicinity of a private airstrip or an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels?
No Impact. The nearest airport to the Project site is the Brackett Field Airport which is located approximately 7.6 miles northeast of the Project site. According to the General Plan EIR, the City is not located within the area of influence of any of the nearby airports. Accordingly, the Project would not expose people residing or working in the Project area to excessive noise levels in relation to airports.
Furthermore, there are no private airstrips within the Project vicinity. Accordingly, the proposed Project would not expose people residing or working in the Project area to excessive noise levels related to airports. No impact would occur.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 90
4.14 Population and Housing
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Induce substantial unplanned population
growth in an area, either directly (for
example, by proposing new homes and
businesses) or indirectly (for example,
through extension of roads or other
infrastructure)?
X
b. Displace substantial numbers of existing
people or housing, necessitating the
construction of replacement housing
elsewhere?
X
a) Induce substantial unplanned population growth in an area, either directly (for example, by proposing new homes and businesses) or indirectly (for example, through extension of roads or other infrastructure)?
No Impact. The proposed Project consists of the installation and operation of an electronic billboard.
Generally, residential uses or larger commercial uses have the potential to generate population growth; however, the proposed Project does not include any such uses. Electronic billboards are typical of and complementary to commercial freeway uses and have no potential to induce substantial population growth in the area, either directly or indirectly. Electric utility improvements required by the Project would solely serve the digital billboard’s energy demand and would not directly or indirectly induce population growth to the area. No impact would occur.
Mitigation Measures: No mitigation measures are required. b) Displace substantial numbers of existing people or housing, necessitating the construction of replacement housing elsewhere?
No Impact. Under existing conditions, the Project site does not contain any residential structures. The Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway, school, residential, and light industrial uses. Therefore, there is no potential for the Project to displace substantial numbers of people. No impact would occur.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 91
4.15 Public Services
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Result in substantial adverse physical
impacts associated with the provision of
new or physically altered governmental
facilities, need for new or physically altered
governmental facilities, the construction of
which could cause significant
environmental impacts, in order to
maintain acceptable service ratios,
response times or other performance
objectives for any of the public services:
1) Fire protection? X
2) Police protection? X
3) Schools? X
4) Parks? X
5) Other public facilities? X
a) Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered governmental facilities, need for new or physically altered governmental facilities, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios, response times or other performance objectives for any of the public services:
1) Fire protection?
No Impact. Generally, residential uses or larger commercial uses have the potential to generate population growth, which would result in an increase in demand on public services, such as fire protection or emergency services. There are no such uses associated with the proposed Project. Therefore, the proposed Project would not generate additional demand for fire protection or emergency services and would not require the construction or expansion of fire protection services. The proposed Project consists of the installation and operation of an electronic billboard. Fire prevention and access requirements (e.g., plan review for electrical and structural work) would be addressed through standard building and fire code compliance. The Project would be required to comply with City Code Title 16, Fire Safety, which adopts by reference Los Angeles County Fire Code (Title 32), and incorporates the California Fire Code.
Los Angeles County Fire Code Section 503 establishes the requirements for fire apparatus access roads and hydrant locations and distribution. The Project would also be required to comply with the requirements of City Code Title 15, Building and Construction Safety, which adopts by reference the California Building Code, including Division 6, Electrical Code, which adopts the California Electrical Code and its requirements. The Project would also be required to comply with the requirements of City Code
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 92
Title 22.48, Development Review, which specifies the City’s application and approval process for development projects. The City’s development review process would ensure that the Project’s site design, configuration, access and egress, and public health and safety considerations are taken into account prior to Project approval. No new or expanded fire facilities would be required. No impact would occur.
Mitigation Measures: No mitigation measures are required. 2) Police Protection?
No Impact. The Project does not introduce residents or high-intensity commercial activity that would increase calls for police protection services. Routine operation of the proposed Project involves static digital display and occasional maintenance only. No new or expanded police facilities would be needed.
No impact would occur.
Mitigation Measures: No mitigation measures are required. 3) Schools?
No Impact. The Project does not include any residential uses and would not generate student population.
The proposed Project consists of the installation and operation of an electronic billboard. No new or expanded school facilities would be required. No impact would occur.
Mitigation Measures: No mitigation measures are required. 4) Parks?
No Impact. The Project would not induce population growth that could result in increased or new park demand. No new or expanded park facilities would be required. No impact would occur.
Mitigation Measures: No mitigation measures are required. 5) Other public facilities
No Impact. The Project would not increase demand on libraries, community centers, or other public facilities. Occasional maintenance would generate negligible service needs that existing City services can accommodate. No impact would occur.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 93
4.16 Recreation
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Would the project increase the use of
existing neighborhood and regional parks
or other recreational facilities such that
substantial physical deterioration of the
facility would occur or be accelerated?
X
b. Does the project include recreational
facilities or require the construction or
expansion of recreational facilities which
might have an adverse physical effect on
the environment?
X
a) Would the project increase the use of existing neighborhood and regional parks or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated?
No Impact. Refer to Response 4.15(a)(4). The Project would not increase the use of existing neighborhood regional parks or recreational facilities, as no population generating uses are proposed as part of the Project, and, as such, there would be no impact.
Mitigation Measures: No mitigation measures are required. b) Does the project include recreational facilities or require the construction or expansion of recreational facilities which might have an adverse physical effect on the environment? No Impact. Refer to Response 4.15(a)(4). The development of recreational facilities is not proposed as part of the Project, and, as such, there would be no impact.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 94
4.17 Transportation
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Conflict with a program plan, ordinance or
policy addressing the circulation system,
including transit, roadway, bicycle and
pedestrian facilities?
X
b. Would the project conflict or be
inconsistent with CEQA Guidelines section
15064.3, subdivision (b)?
X
c. Substantially increase hazards due to a
geometric design feature (e.g., sharp curves
or dangerous intersections) or
incompatible uses (e.g., farm equipment)?
X
d. Result in inadequate emergency access? X
a) Conflict with a program plan, ordinance or policy addressing the circulation system, including transit, roadway, bicycle and pedestrian facilities?
No Impact. Temporary traffic impacts would be restricted within the window of the Project’s construction schedule (less than a week) and between the permissible construction activity hours (7:00 a.m. to 7:00 p.m., Monday through Saturday) permitted by City of Diamond Bar Development Code Section 22.28.120.
Due to the small scale of the proposed Project, primarily consisting of the installation of an electronic billboard over a period of several days, a substantial quantity of car trips and truck hauls to the site would not occur. There would be a total of four truckloads of dirt associated with installation of the billboard.
Additionally, the Project Applicant estimates a small number of construction crew members would be required at the site each day throughout for Project installation, which would not generate a substantial quantity of trips during construction hours.
Project operation is not anticipated to generate any additional trips to the Project site, with the exception of six to eight trips per year in order to perform on-site maintenance of the electronic billboard. The proposed electronic billboard would be installed within a private parking lot on property owned by WVUSD at 880 S. Lemon Avenue (APN 8760-015-901). The City’s General Plan Circulation Element classifies S. Lemon Avenue as a major arterial, and the closest designated bicycle lanes are the Class II Bicycles Lanes along Golden Springs Drive and Brea Canyon Road, south of SR 60. The portion of S. Lemon Avenue fronting the Project site is identified as a proposed future Class IV separated bikeway. Following the construction activities described above, including limited tree removal and landscaping, ongoing operation would occur entirely within private property and would not modify, encroach upon, or require closures of the public roadway, sidewalks, or bicycle facilities; therefore, operation of the Project would not conflict with an applicable plan, ordinance or policy related to the circulation system, and no impact would occur.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 95
b) Would the project conflict or be inconsistent with CEQA Guidelines section 15064.3, subdivision (b)?
No Impact. As discussed under Threshold a), trips generated by construction and operation of the Project would be nominal, and implementation of the Project would not generate trips that would conflict or be inconsistent with CEQA Guidelines section 15064.3, subdivision (b). Therefore, no impact would occur.
Mitigation Measures: No mitigation measures are required. c) Substantially increase hazards due to a geometric design feature (e.g., sharp curves or dangerous intersections) or incompatible uses (e.g., farm equipment)? Less than Significant Impact. Installation and operation of the proposed Project would not require the construction of new roadways, and the existing configuration of the roadways within the vicinity of the Project site would remain unchanged; therefore, impacts related to sharp curves, or dangerous intersections would not occur. Implementation of the Project would not change the existing ingress/egress into the existing WVUSD site and would not affect existing driveways or access paths to the Project improvement area.
Implementation of the Project would be required to comply with the State Outdoor Advertising Act (2014) and the Federal Highway Beautification Act (1965). The Outdoor Advertising Act contains a number of provisions related to the construction and operation of digital and static signs adjacent to roadways which are intended to prevent the creation of unsafe driving conditions along the adjacent roadways as a result of the presence of such signs. These provisions include, but are not limited to, the following:
• The placing of any light source “...of any color of such brilliance as to impair the vision of drivers upon the highway” is prohibited (Caltrans, 2014, § 21466.5); • The sign must be constructed to withstand a wind pressure of 20 pounds per square feet of exposed surface;
• No sign shall display any statements or words of an obscene, indecent, or immoral character; • No sign shall display flashing, intermittent, or moving light or lights; and • Message center signs may not include any illumination or message change that is in motion or appears to be in motion or that change or expose a message for less than four seconds. No message center sign may be located within 500 feet of an existing billboard or 1,000 feet of another message center display, on the same side of the highway. (Caltrans, 2014, § 5401 - § 5405).
The proposed electronic billboard would operate in compliance with the requirements of the Outdoor Advertising Act, as it would not be installed in a manner that could impair the vision of drivers upon the highway. The electronic billboard’s luminance would be automatically controlled with light-sensing technology to adjust brightness in response to ambient lighting conditions. Messaging would not include any prohibited characteristics and would not display any moving messages, and transitions between images would be instantaneous, without any motion, animation, flashing, or other visual effects. The message would appear on the billboard for a duration of at least eight seconds. The proposed billboard would not be located within 800 feet if any existing static billboard or within 2,000 feet of any existing digital billboard.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 96
The Federal Highway Beautification Act governs advertising signage located along the interstate highway system, such as SR 60. The Federal Highway Beautification Act requires advertising signage be erected only in commercial or industrial zones and adhere to the following restrictions:
• No signs shall imitate or resemble any official traffic sign, signal or device, nor shall signs obstruct or interfere with official signs;
• Signs located on the same side of the freeway must be separated by at least 500 feet; and, • Signs shall not include flashing, intermittent or moving lights, and shall not emit light that may obstruct or impair the vision of any driver.
As discussed above, the proposed electronic billboard would be designed in a manner that would comply with the requirements of the Federal Highway Beautification Act. Mandatory compliance with federal and State regulations would ensure that the Project would not increase hazards due to a design feature.
Additionally, the Project site is designated as “School” by the City’s General Plan, and it is zoned as Light Industry (I). The installation of an electronic billboard adjacent to a freeway (SR 60) is a use that is typically seen within urbanized areas adjacent to freeways and would not conflict with future or existing largescale development. Considering the foregoing analysis and regulatory requirements, Project impacts would be less than significant, and no mitigation is required.
Mitigation Measures: No mitigation measures are required. d) Result in inadequate emergency access?
No Impact. Under existing conditions, adequate emergency access is provided within the vicinity of the Project site. Project-related installation and operation would not obstruct existing roadways and would not alter the existing roadway system. No component of the Project would require the temporary or permanent closure of a roadway. Accordingly, the Project would not result in inadequate emergency access, and there would be no impact.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 97
4.18 Tribal Cultural Resources
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Cause a substantial adverse change in the
significance of a tribal cultural resource,
defined in Public Resources Code section
21074 as either a site, feature, place,
cultural landscape that is geographically
defined in terms of the size and scope of the
landscape, sacred place, or object with
cultural value to a California Native
American tribe, and that is:
1) Listed or eligible for listing in the
California Register of Historical
Resources, or in a local register of
historical resources as defined in Public
Resources Code section 5020.1(k), or
X
2) A resource determined by the lead
agency, in its discretion and supported
by substantial evidence, to be significant
pursuant to criteria set forth in
subdivision (c) of Public Resources Code
Section 5024.1. In applying the criteria
set forth in subdivision (c) of Public
Resource Code Section 5024.1, the lead
agency shall consider the significance of
the resource to a California Native
American tribe.
X
The analysis in this section is based, in part, on the Cultural Resources Technical Report, Walnut Valley Unified School District Electronic Billboard Project, City of Diamond Bar, Los Angeles County, California, prepared in July 2025, by South Environmental. It is included as Appendix C, Cultural Resources Report.
As discussed above in Section 4.5, Cultural Resources, a cultural resources technical report was prepared for the proposed Project, which included the results of a CHRIS records search of the Project site and a
0.5-mile radius, a NAHC SLF search, and archival research. This study was completed in compliance with CEQA and all applicable City of Diamond Bar codes, ordinances, and plans. No pedestrian survey was performed due to complete site paving, which precluded ground surface visibility. There are no historical structures or resources in the larger Project improvement area or billboard installation area. No archaeological resources were identified within the Project site through the CHRIS records search, background research, or NAHC SLF search. Furthermore, according to the General Plan Resource Conservation Element, there are no registered historic resources in the City, including the Project site.
The NAHC and the City of Diamond Bar identified Native American Individuals or tribal organizations that may have knowledge of tribal cultural resources within or near the Project site. On June 13, 2025, the City
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 98
of Diamond Bar conducted outreach to the following Native American tribal organizations and respective representatives to engage in consultation, in accordance with AB 52:
• Andrew Salas, Chairperson – Gabrieleño Band of Mission Indians – Kizh Nation • Christine Swindall Martinez, Secretary – Gabrieleño Band of Mission Indians – Kizh Nation • Anthony Morales, Chairperson – Gabrieleño Tongva San Gabriel Band of Mission Indians • Joseph Ontiveros, Tribal Historic Preservation Officer – Soboba Band of Luiseño Indians • Jessica Valdez, Cultural Resource Specialist – Soboba Band of Luiseño Indians On July 13, 2025, the Gabrieleño Band of Mission Indians – Kizh Nation (Kizh Nation) requested formal consultation in writing and within the required timeframe, in accordance with AB 52. Correspondence conducted pursuant to AB 52 is included as Appendix E, AB 52 Correspondence. a) Would the project cause a substantial adverse change in the significance of a tribal cultural resource, defined in Public Resources Code section 21074 as either a site, feature, place, cultural landscape that is geographically defined in terms of the size and scope of the landscape, sacred place, or object with cultural value to a California Native American tribe, and that is:
1) Listed or eligible for listing in the California Register of Historical Resources, or in a local register of historical resources as defined in Public Resources Code section 5020.1(k)? Less Than Significant Impact with Mitigation Incorporated. The Project site is located within a region historically used for agriculture and lies adjacent to the former course of a stream that has been heavily altered by development including SR 60, directly adjacent to the south. Historical aerial photographs and maps confirm the presence of cultivated fields and proximity to San Jose Creek and Diamond Bar Creek.
Environments like this near creeks are preferred for prehistoric habitation due to access to fresh water, plant and animal resources, and transportation routes.
No cultural resources were identified within the Project site through the CHRIS records search, background research, or NAHC SLF search. While the environmental setting indicates inherent moderate archaeological potential, the documented disturbance history and absence of recorded cultural resources within the immediate Project vicinity support a determination of low sensitivity for buried archaeological deposits. The shallow depth of documented fill materials, as well as the immediate proximity of the significant earthen embankment associated with SR-60, suggests that any near-surface archaeological deposits would likely have been disturbed by historical land use activities. The construction of such a major roadway project in the immediate vicinity of the Project site would have likely already disturbed the area beneath the Project site. The cultural resources records search found no records related to resources within the Project site, and the Project site is not considered sensitive for cultural resources.
Nevertheless, there is the potential for accidental discovery of buried resources during ground-disturbing activities. The Project would be required to comply with City of Diamond Bar General Plan Resource Conservation Cultural and Historic Resources Policies, including Policy RC-P-42, Archaeological Resources, which provides procedures for the management of archaeological materials on-site during development projects. Policy RC-P-43 seeks to preserve discovered archaeological resources in place to maintain the relationship between the artifacts and their archaeological context, where feasible. Policy RC-P-44 provides that preservation can be achieved through measures such as avoidance and other protections.
Should ground disturbing activities during Project construction encounter undiscovered buried resources, incorporation of Mitigation Measures CUL-1, which identifies procedures for the unanticipated discovery
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 99
of archaeological resources if it occurs during the Project’s ground disturbing activities. Should ground disturbing activities during Project construction inadvertently encounter buried human remains, incorporation of Mitigation Measure CUL-2, which provides procedures related to the treatment of the unanticipated discovery of human remains, ensures that the Project’s potential impacts to buried remains would be reduced to levels that are less than significant. Through compliance with the General Plan Resource Conservation policies and implementation of Mitigation Measures CUL-1 and CUL-2, the Project’s potential impacts to historical resources, as defined by Public Resources Code section 5020.1(k), would be reduced to levels that are less than significant.
Mitigation Measures: Refer to Mitigation Measures CUL-1 and CUL-2. 2) A resource determined by the lead agency, in its discretion and supported by substantial evidence, to be significant pursuant to criteria set forth in subdivision (c) of Public Resources Code Section 5024.1. In applying the criteria set forth in subdivision (c) of Public Resource Code Section 5024.1, the lead agency shall consider the significance of the resource to a California Native American tribe.
Less Than Significant Impact with Mitigation Incorporated. AB 52 requires that lead agencies evaluate a project’s potential impact on “tribal cultural resources,” which include “sites, features, places, cultural landscapes, sacred places, and objects with cultural value to a California Native American tribe that are eligible for inclusion in the California Register of Historical Resources or included in a local register of historical resources.” AB 52 also gives lead agencies the discretion to determine, based on substantial evidence, whether a resource qualifies as a “tribal cultural resource.” AB 52 applies whenever a lead agency adopts an environmental impact report, mitigated negative declaration, or negative declaration.
AB 52 also establishes a formal consultation process for California tribes regarding tribal cultural resources. Under AB 52 the lead agencies are required to “begin consultation with a California Native American tribe that is traditionally and culturally affiliated with the geographic area of the proposed project.” Native American tribes to be included in the process are those that have requested notice of projects proposed within the jurisdiction of the lead agency.
As part of the AB 52 process, letters were sent by the City of Diamond Bar inviting tribes to consult on the Project, as described above. On June 24, 2025, the Kizh Nation requested consultation and engaged in correspondence with the City. On August 12, the Kizh Nation provided the City of Diamond Bar with substantial evidence of their cultural and ancestral affiliation to the Project area. As such, the Kizh Nation provided specific mitigation measures to ensure the protection and preservation of any tribal cultural resources that may be discovered during ground disturbing activities related to the proposed Project. As the City accepted the mitigation measures required by the Kizh Nation to reduce potential impacts to tribal cultural resources, consultation under AB 52 was successfully concluded on August 20, 2025.
Mitigation Measure TCR-1 would require the retention of a Native American monitor prior to the commencement of ground-disturbing activities. Mitigation Measure TCR-2 is related to the unanticipated discovery of tribal cultural resource objects (non-funerary/non-ceremonial), consisting of protocols related to cessation of construction activities in the immediate Project vicinity in the event of discovery of a tribal cultural resource. Mitigation Measure TCR-3 is related to the unanticipated discovery of human remains and associated funerary or ceremonial objects, including protocols related to the disposition of these resources upon discovery. Additionally, in the unlikely event where tribal cultural resources are found, the resources would require proper treatment in accordance with applicable laws, State CEQA Guidelines Section 15064.5. State CEQA Guidelines Section 15064.5 protects historical resources, archeological sites, human remains, and dedicated cemeteries. With implementation of Mitigation
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 100
Measures TCR-1, TCR-2, and TCR-3, the Project’s potential impacts related to tribal cultural resources would be reduced to levels that are less than significant.
Mitigation Measures:
TCR-1: Retain a Native American Monitor Prior to Commencement of Ground-Disturbing Activities A. The project applicant/lead agency shall retain a Native American Monitor from or approved by the Gabrieleño Band of Mission Indians – Kizh Nation. The monitor shall be retained prior to the commencement of any “ground-disturbing activity” for the subject project at all project locations (i.e., both on-site and any off-site locations that are included in the project description/definition and/or required in connection with the project, such as public improvement work). “Grounddisturbing activity” shall include, but is not limited to, demolition, pavement removal, potholing, auguring, grubbing, tree removal, boring, grading, excavation, drilling, and trenching.
B. A copy of the executed monitoring agreement shall be submitted to the lead agency prior to the earlier of the commencement of any ground-disturbing activity, or the issuance of any permit necessary to commence a ground-disturbing activity.
C. The monitor will complete daily monitoring logs that will provide descriptions of the relevant ground-disturbing activities, the type of construction activities performed, locations of grounddisturbing activities, soil types, cultural-related materials, and any other facts, conditions, materials, or discoveries of significance to the Tribe. Monitor logs will identify and describe any discovered TCRs, including but not limited to, Native American cultural and historical artifacts, remains, places of significance, etc., (collectively, tribal cultural resources, or “TCR”), as well as any discovered Native American (ancestral) human remains and burial goods. Copies of monitor logs will be provided to the project applicant/lead agency upon written request to the Tribe.
D. On-site tribal monitoring shall conclude upon the latter of the following (1) written confirmation to the Kizh from a designated point of contact for the project applicant/lead agency that all ground-disturbing activities and phases that may involve ground-disturbing activities on the project site or in connection with the project are complete; or (2) a determination and written notification by the Kizh to the project applicant/lead agency that no future, planned construction activity and/or development/construction phase at the project site possesses the potential to impact Kizh TCRs.
TCR-2: Unanticipated Discovery of Tribal Cultural Resource Objects (Non-Funerary/Non-Ceremonial) A. Upon discovery of any TCRs, all construction activities in the immediate vicinity of the discovery shall cease (i.e., not less than the surrounding 50 feet) and shall not resume until the discovered TCR has been fully assessed by the Kizh monitor and/or Kizh archaeologist. The Kizh will recover and retain all discovered TCRs in the form and/or manner the Tribe deems appropriate, in the Tribe’s sole discretion, and for any purpose the Tribe deems appropriate, including for educational, cultural and/or historic purposes.
TCR-3: Unanticipated Discovery of Human Remains and Associated Funerary or Ceremonial Objects A. Native American human remains are defined in PRC 5097.98 (d)(1) as an inhumation or cremation, and in any state of decomposition or skeletal completeness. Funerary objects, called associated
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 101
grave goods in Public Resources Code Section 5097.98, are also to be treated according to this statute.
B. If Native American human remains and/or grave goods are discovered or recognized on the project site, then Public Resource Code 5097.9 as well as Health and Safety Code Section 7050.5 shall be followed.
C. Human remains and grave/burial goods shall be treated alike per California Public Resources Code section 5097.98(d)(1) and (2).
D. Preservation in place (i.e., avoidance) is the preferred manner of treatment for discovered human remains and/or burial goods.
E. Any discovery of human remains/burial goods shall be kept confidential to prevent further disturbance.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 102
4.19 Utilities and Service Systems
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Require or result in the relocation or
construction of new or expanded water, or
wastewater treatment or storm water
drainage, electric power, natural gas, or
telecommunications facilities, the
construction or relocation of which could
cause significant environmental effects?
X
b. Have sufficient water supplies available to
serve the project and reasonably
foreseeable future development during
normal, dry and multiple dry years?
X
c. Result in a determination by the
wastewater treatment provider which
serves or may serve the project that it has
adequate capacity to serve the project’s
projected demand in addition to the
provider’s existing commitments?
X
d. Generate solid waste in excess of State or
local standards, or in excess of the capacity
of local infrastructure, or otherwise impair
the attainment of solid waste reduction
goals?
X
e. Comply with federal, state, and local
management and reduction statutes and
regulations related to solid waste?
X
a) Require or result in the relocation or construction of new or expanded water, or wastewater treatment or storm water drainage, electric power, natural gas, or telecommunications facilities, the construction or relocation of which could cause significant environmental effects? Less Than Significant Impact. Implementation of the Project would result in the installation and operation of an electronic billboard. The Project improvement area consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway, school, residential, and light industrial uses. Due to the nature of the Project, it would not result in demand for water, wastewater, stormwater, or natural gas. Additionally, the Project would not substantially alter the Project site’s existing hydrological characteristics. With installation of the proposed Project, there would be no significant alteration of the site’s existing drainage pattern and there would not be any significant increases in the rate or quantity of surface runoff that could affect storm drains. The Project would utilize electric power, but not in a manner that would require or result in the relocation or construction of new facilities. If needed, the Project would connect to existing electric
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 103
infrastructure already in place and provided by Southern California Edison, and as such, no relocation or construction of new electrical facilities would be required. No other utility connections would be required.
Therefore, impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. b) Have sufficient water supplies available to serve the project and reasonably foreseeable future development during normal, dry and multiple dry years?
No Impact. The installation and operation of the proposed electronic billboard would not require the use of water; nor would it create a demand for domestic water. Therefore, no impact would occur.
Mitigation Measures: No mitigation measures are required. c) Result in a determination by the wastewater treatment provider which serves or may serve the project that it has adequate capacity to serve the project’s projected demand in addition to the provider’s existing commitments?
No Impact. The installation and operation of the proposed electronic billboard would not generate wastewater or cause an increased demand for wastewater treatment. Therefore, no impact would occur.
Mitigation Measures: No mitigation measures are required. d) Generate solid waste in excess of State or local standards, or in excess of the capacity of local infrastructure, or otherwise impair the attainment of solid waste reduction goals? Less than Significant Impact. As of September 1, 2025, the City of Diamond Bar has contracted with Waste Management to provide commercial waste hauling services. Construction waste generated within the proposed Project would be transported to an authorized facility. In this case, Sunshine Canyon Landfill is authorized to receive construction waste from the City and the County of Los Angeles. As of 2024, Sunshine Canyon Landfill is permitted to receive no more than 12,000 tons per day and currently receives approximately 9,000 tons of municipal solid waste per day. It has a maximum permitted capacity of 140,900,000 cubic yards and has a remaining capacity of 66,200,000 cubic yards. Sunshine Canyon Landfill has a cease operation date of October 31, 2037.
18 El Sobrante Landfill was calculated to have a remaining capacity of 121,083,583 cubic yards as of May 1, 2023, with a cease operation date of January 1, 2051.19 Olinda Alpha Landfill was calculated to have a remaining capacity of 17,500,000 cubic yards as of October 1, 2020, with a cease operated date of December 31, 2036. 20 Cumulatively, these solid waste facilities
would have sufficient capacity to accommodate the Project’s 32 cubic yards of soil and other nominal construction-related waste. Lastly, Project operation would generate negligible, if any, demand for solid 18 CalRecycle, SWIS Facility/Site Activity Details, Sunshine Canyon Landfill, 2025a. Available at:
https://www2.calrecycle.ca.gov/SolidWaste/SiteActivity/Details/259?siteID=4702. Accessed May 14, 2025. 19 CalRecycle, SWIS Facility/Site Activity Details, El Sobrante Landfill, 2025b. Available at:
https://www2.calrecycle.ca.gov/SolidWaste/SiteActivity/Details/2280?siteID-2402. Accessed May 14, 2025. 20 CalRecycle, SWIS Facility/Site Activity Details, Olinda Alpha Landfill, 2025c. Available at:
https://www2.calrecycle.ca.gov/SolidWaste/SiteActivity/Details/2757?siteID=2093. Accessed May 14, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 104
waste disposal. Therefore, the Project would not adversely affect the physical capacity of any landfills, and impacts would be less than significant.
Mitigation Measures: No mitigation measures are required. e) Comply with federal, state, and local management and reduction statutes and regulations related to solid waste?
Less Than Significant Impact. The construction and operation of an electronic billboard is not anticipated to generate a substantial demand for solid waste disposal. Project-related construction activities would generate nominal quantities of solid waste during the Project’s construction schedule (less than a week).
The Project would be required to comply with all applicable solid waste statutes and regulations; as such, impacts related to solid waste statutes and regulations would be less than significant. Accordingly, the Project would not foreseeably conflict with any federal, State, and local statutes and regulations related to solid waste, resulting in a less than significant impact.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 105
4.20 Wildfire
If located in or near state responsibility areas
or lands classified as very high fire hazard
severity zones, would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Substantially impair an adopted emergency
response plan or emergency evacuation
plan?
X
b. Due to slope, prevailing winds, and other
factors, exacerbate wildfire risks, and
thereby expose project occupants to,
pollutant concentrations from a wildfire or
the uncontrolled spread of a wildfire?
X
c. Require the installation or maintenance of
associated infrastructure (such as roads,
fuel breaks, emergency water sources,
power lines or other utilities) that may
exacerbate fire risk or that may result in
temporary or ongoing impacts to the
environment?
X
d. Expose people or structures to significant
risks, including downslope or downstream
flooding or landslides, as a result of runoff,
post-fire slope instability, or drainage
changes?
X
a) Substantially impair an adopted emergency response plan or emergency evacuation plan? No Impact. As discussed above, the Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway, school, residential, and light industrial uses. According to the CAL FIRE Fire Hazard Severity Zone Map, the Project site is not located within a VHFHSZ, nor is the site within or near a State Responsibility Area.21 The Project would be required to comply with all City and Los Angeles County Fire requirements for fire prevention and safety measures, including site access. Therefore, there would be no impact related to impairment an adopted emergency response plan or emergency evacuation plan.
Mitigation Measures: No mitigation measures are required. 21 California Department of Forestry and Fire Protection (CalFire), FHSZ Viewer, https://osfm.fire.ca.gov/what-wedo/community-wildfire-preparedness-and-mitigation/fire-hazard-severity-zones, accessed June 5, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 106
b) Due to slope, prevailing winds, and other factors, exacerbate wildfire risks, and thereby expose project occupants to, pollutant concentrations from a wildfire or the uncontrolled spread of a wildfire?
As discussed above, the Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway, school, residential, and light industrial uses. Furthermore, according to the CAL FIRE Fire Hazard Severity Zone Map, the Project site is not located within a VHFHSZ, nor is the site within or near a State Responsibility Area. In addition, the Project site and its characteristics would not exacerbate wildfire risks, and there are no Project occupants that could be exposed to pollutant concentrations from a wildfire or the uncontrolled spread of wildfire. Therefore, there would be no impact in this regard.
Mitigation Measures: No mitigation measures are required. c) Require the installation or maintenance of associated infrastructure (such as roads, fuel breaks, emergency water sources, power lines or other utilities) that may exacerbate fire risk or that may result in temporary or ongoing impacts to the environment? As discussed above, the Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway, school, residential, and light industrial uses. Furthermore, according to the CAL FIRE Fire Hazard Severity Zone Map, the Project site is not located within a VHFHSZ, nor is the site within or near a State Responsibility Area. In addition, due to its characteristics, the Project would not require the installation or maintenance of associated infrastructure that could exacerbate fire risk or result environmental impacts. Therefore, there would be no impact in this regard.
Mitigation Measures: No mitigation measures are required. d) Expose people or structures to significant risks, including downslope or downstream flooding or landslides, as a result of runoff, post-fire slope instability, or drainage changes? Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 107
4.21 Mandatory Findings of Significance
Would the project:
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a. Does the project have the potential to
substantially degrade the quality of the
environment, substantially reduce the
habitat of a fish or wildlife species, cause a
fish or wildlife population to drop below
self-sustaining levels, threaten to eliminate
a plant or animal community, substantially
reduce the number or restrict the range of
a rare or endangered plant or animal or
eliminate important examples of the major
periods of California history or prehistory?
X
b. Does the project have impacts that are
individually limited, but cumulatively
considerable?
(“Cumulatively considerable” means that
the incremental effects of a project are
considerable when viewed in connection
with the effects of past projects, the effects
of other current projects, and the effects of
probable future projects)?
X
c. Does the project have environmental
effects which will cause substantial adverse
effects on human beings, either directly or
indirectly?
X
a) Does the project have the potential to substantially degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, substantially reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory? Less Than Significant Impact with Mitigation Incorporated. All impacts to the environment, including impacts to habitat for fish and wildlife species, fish and wildlife populations, plant and animal communities, rare and endangered plants and animals, and historical and pre-historical resources were evaluated as part of this IS/MND. Implementation of the Project would result in the installation and operation of an electronic billboard. The Project site consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the area surrounding the Project site is urbanized and developed with freeway,school, residential, and light industrial uses. The proposed Project would not impact biological resources. As indicated in the discussion and analysis of Cultural Resources, none of the existing buildings on the Project site are included on the National Register of Historic Places, California Register of Historical Resources, or a local register of historical resources, nor are they eligible for listing;
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 108
accordingly, there would be no impact to historical resources resulting from Project implementation. The Project site is fully developed under existing conditions; therefore, no significant archaeological, paleontological, or tribal cultural resources are likely to be discovered during excavation activities.
Additionally, the limited and focused amount of excavation that would be required to install the proposed billboard column and associated utility connections would not result in impacts to significant archaeological, paleontological, or tribal cultural resources. Nonetheless, Mitigation Measures CUL-1 and CUL-2 would be implemented to reduce impacts in the event of inadvertent discovery of potential archaeological resources or human remains, and Mitigation Measure GEO-1 would be implemented to reduce potential impacts to paleontological resources to a less than significant level. Mitigation Measures TCR-1, TCR-2, and TCR-3 would reduce potential impacts to tribal cultural resources be requiring the retention of a Native American monitor prior to commencement of ground-disturbing activities, the unanticipated discovery of tribal cultural resource objects, and the unanticipated discovery of human remains and associated funerary or ceremonial objects. Accordingly, the Project would not degrade the quality of the environment and impacts would be less than significant with implementation of Mitigation Measures CUL-1, CUL-2, GEO-1, TCR-1, TCR-2, and TCR-3.
Mitigation Measures: Refer to Mitigation Measures CUL-1, CUL-2, GEO-1, TCR-1, TCR-2, and TCR-3. b) Does the project have impacts that are individually limited, but cumulatively considerable? (“Cumulatively considerable” means that the incremental effects of a project are considerable when viewed in connection with the effects of past projects, the effects of other current projects, and the effects of probable future projects)?
Less Than Significant Impact. Based on the analysis contained in this Initial Study, the proposed Project would result in less than significant impacts with implementation of Project mitigation measures.
Furthermore, there are no other electronic billboards proposed or permitted in the City of Diamond Bar, and there are no other related projects within the area with the potential to combine with the proposed Project, resulting in a significant impact. Implementation of standard conditions and mitigation measures at the project-level would reduce the potential for the incremental effects of the proposed Project to be considerable when viewed in connection with the effects of past projects, current projects, or probable future projects.
Mitigation Measures: No mitigation measures are required. c) Does the project have environmental effects which will cause substantial adverse effects on human beings, either directly or indirectly?
Less Than Significant Impact. Previous sections of this Initial Study reviewed the proposed Project’s potential impacts to human beings related to several environmental topical areas. As determined throughout this Initial Study, the proposed Project would not result in any potentially significant impacts that cannot be mitigated or reduced below the level of significance with implementation of mitigation measures and/or standard conditions imposed by the City. The Project would not cause any substantial adverse effect on human beings, either directly or indirectly, and impacts would be less than significant.
Mitigation Measures: No mitigation measures are required.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 109
5.0 REFERENCES
California Department of Conservation, California Important Farmland Finder. Available at:
https://maps.conservation.ca.gov/DLRP/CIFF/. Accessed May 13, 2025.
California Department of Conservation, California Geological Survey (CGS), Earthquake Zones of Required Investigation. Available at: https://maps.conservation.ca.gov/cgs/EQZApp/. Accessed June 10, 2025.
California Department of Conservation, Geologic Hazards Data Viewer. Available at:
https://maps.conservation.ca.gov/geologichazards/. Accessed June 10, 2025.
California Department of Conservation, California Tsunami Maps and Data, Available at:
https://www.conservation.ca.gov/cgs/tsunami/maps. Accessed June 11, 2025.
California Department of Fish and Wildlife, 2023. California Regional Conservation Plans Map. Available at: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=68626&inline. Accessed May 13, 2025.
California Department of Forestry and Fire Protection (CalFire), FHSZ Viewer. Available at:
https://osfm.fire.ca.gov/what-we-do/community-wildfire-preparedness-and-mitigation/firehazard-severity-zones. Accessed June 5, 2025.
California Department of Transportation (Caltrans), California State Scenic Highway System Map.
Available at:
https://caltrans.maps.arcgis.com/apps/webappviewer/index.html?id=465dfd3d807c46cc8e805 7116f1aacaa. Accessed June 11, 2025.
CalRecycle, SWIS Facility/Site Activity Details, Sunshine Canyon Landfill, 2025a. Available at:
https://www2.calrecycle.ca.gov/SolidWaste/SiteActivity/Details/259?siteID=4702. Accessed May 14, 2025
CalRecycle, SWIS Facility/Site Activity Details, El Sobrante Landfill, 2025b. Available at:
https://www2.calrecycle.ca.gov/SolidWaste/SiteActivity/Details/2280?siteID=2402. Accessed May 14, 2025.
CalRecycle, SWIS Facility/Site Activity Details, Olinda Alpha Landfill, 2025c. Available at:
https://www2.calrecycle.ca.gov/SolidWaste/SiteActivity/Details/2757?siteID=2093. Accessed May 14, 2025.
City of Diamond Bar, September 2019. Diamond Bar EIR 2040 Public Review Draft City of Diamond Bar, 2019. Diamond Bar Climate Action Plan 2040. Available at:
https://www.diamondbarca.gov/DocumentCenter/View/7071/Diamond-Bar-Climate-ActionPlan-2040pdf?bidId=. Accessed June 10, 2025.
City of Diamond Bar, n.d. Utilities. Available at:
https://www.diamondbarca.gov/BusinessDirectoryII.aspx?lngBusinessCategoryID=23. Accessed June 9, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 110
Federal Emergency Management Agency (FEMA), Flood Map Service Center: Search by Address. Available at: https://msc.fema.gov/portal/search?AddressQuery. Accessed June 11, 2025.
State Water Resources Control Board, GeoTracker. Available at:
https://geotracker.waterboards.ca.gov/map/?CMD=runreport&myaddress=880+s+lemon+ave% 2C+diamond+bar. Accessed August 2025.
Walnut Vally Water District, 2021. Urban Water Management Plan, Figure 4- Puente Basin Location.
Available at: https://walnutvalleywater.gov/wp-content/uploads/2023/03/FINAL-Walnut-ValleyWater-District-2020-UWMP.pdf. Accessed August 1, 2025.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 111
6.0 REPORT PREPARATION PERSONNEL
City of Diamond Bar (Lead Agency)
Planning Division
21810 Copley Dr,
Diamond Bar, CA 91765
Greg Gubman, Community Development Director
Grace Lee, Planning Manager
Rudy Lopez, Assistant Planner
De Novo Planning Group (Environmental Consultant)
180 E Main Street, Suite 108
Tustin, CA 92780
Starla Barker, Principal Planner
Christine Abraham, Principal Planner
Tin Cheung, Principal Scientist
Josh Smith, Senior Planner
Megan Thorne, Senior Planner - Designer
Jennifer DeMartino, GIS Manager
Abdul Jama, Assistant Planner
Natasha Victa, Assistant Planner
Technical Specialists
Ryback Geotechnical (Foundation Engineering Investigation) 16022 Arminta Street, Suite 7
Van Nuys, CA 91406
Watchfire (Lighting Study)
1850 M Street, N.W., Suite 1040
Washington, D.C. 20036
South Environmental (Cultural Resources Technical Report) 2061 N. Los Robles Avenue, Suite 205
Pasadena, CA 91104
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration
September 2025 Page 112
This page intentionally left blank.
WALNUT VALLEY UNIFIED SCHOOL DISTRICT
ELECTRONIC BILLBOARD PROJECT
FINAL
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
NOVEMBER 2025
Prepared for:
City of Diamond Bar
21810 Copley Drive
Diamond Bar, CA 91765
Prepared by:
De Novo Planning Group
180 E. Main Street, Suite 108
Tustin, CA 92780
D e N o v o P l a n n i n g G r o u p
A L a n d U s e P l a n n i n g , D e s i g n , a n d E n v i r o n m e n t a l F i r m
WALNUT VALLEY UNIFIED SCHOOL DISTRICT
ELECTRONIC BILLBOARD PROJECT
Final
Initial Study/Mitigated Negative Declaration
LEAD AGENCY: CITY OF DIAMOND BAR
21810 Copley Drive
Diamond Bar, California 91765
Contact: Rudy Lopez, Assistant Planner
[email protected]
PREPARED BY: DE NOVO PLANNING GROUP
180 E. Main Street, Suite 108
Tustin, California 92780
Contact: Starla Barker, AICP
[email protected]
November 2025
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 1
Table of Contents
1.0 INTRODUCTION................................................................................................................................. 2
2.0 RESPONSES TO COMMENTS ............................................................................................................. 3
3.0 ERRATA............................................................................................................................................ 17
4.0 MITIGATION MONITORING AND REPORTING PROGRAM .............................................................. 18 Mitigation Monitoring and Reporting Program Checklist....................................................................... 21
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 2
1.0 INTRODUCTION
The Walnut Valley Unified School District Electronic Billboard (Planning Case No. PL2024-40) Project (referenced herein as “Project”) site is located in the City of Diamond Bar within the County of Los Angeles.
The applicants are requesting approval to install and operate a dual-faced digital LED billboard on the Walnut Valley Unified School District (WVUSD) property at 880 South Lemon Avenue, Diamond Bar, immediately north of SR-60. The sign would be placed within an approximately 100-square-foot base area at the southwest corner of the 6.08-acre parcel, occupying roughly 1,500 square feet of airspace above the base. The proposed structure would be approximately 97 feet in total height, consisting of a 90-foot sign with up to 7 feet of decorative architectural features. Each sign face would measure 14 feet high by 48 feet wide and display static images that change every eight seconds. Project work includes foundation excavation, installation of the monopole and superstructure, underground electrical trenching to connect to WVUSD or SCE service, removal of two pine trees along South Lemon Avenue with replacement planting of two 24-inch box crape myrtles, and minor landscape enhancements along the SR-60 frontage. The Project site’s General Plan designation is School (S) and the zoning is Light Industry (I).
In accordance with the California Environmental Quality Act (CEQA) Guidelines, an Initial Study/Mitigated Negative Declaration (IS/MND) has been prepared for the proposed Project.
The Draft IS/MND was made available for public review and comment pursuant to CEQA Guidelines Section 15073 and 15105. The public review period commenced on September 22, 2025, and concluded on October 21, 2025. The Draft IS/MND and supporting attachments were available for review by the general public at:
• Diamond Bar City Hall, 21810 Copley Drive, Diamond Bar, CA 91765 • City of Diamond Bar Website: www.diamondbarca.gov/wvusdbillboard The Draft IS/MND identifies the potential environmental impacts associated with development of the Project. The Responses to Comments, together with the Public Review Draft IS/MND, constitutes the Final IS/MND for the proposed Walnut Valley Unified School District Electronic Billboard (Planning Case No.
PL2024-40) Project.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 3
2.0 RESPONSES TO COMMENTS
During the public review period, comments were received on the IS/MND. The following is a list of the public agencies, organizations, and individuals that submitted comments on the IS/MND during the public review period:
Comment Letter Agency, Organization or Individual Letter Dated A
State of California
Department of Toxic Substances Control (DTSC)
Tamara Purvis
Associate Environmental Planner
September 26, 2025
B
State of California
Department of Transportation (Caltrans)
Miya Edmonson
LDR/CEQA Branch Chief
October 15, 2025
C William Moore
Resident September 26, 2025
Although the CEQA Guidelines do not require a Lead Agency to prepare written responses to comments received on an IS/MND, the City of Diamond Bar has elected to prepare the following written responses with the intent of conducting a comprehensive and meaningful evaluation of the proposed Project. The comment letter and responses follow. Each comment letter is lettered (i.e., Letter A), each comment within each letter is numbered (i.e., A-1, A-2, etc.), and each response is numbered correspondingly (i.e., A-1, A-2, etc.).
dtsc.ca.gov
SENT VIA ELECTRONIC MAIL
September 26, 2025
Rudy Lopez
Assistant Planner
City of Diamond Bar
21810 Copley Drive
Diamond Bar, CA 91765
[email protected]
RE: MITIGATED NEGATIVE DECLARATION FOR THE WALNUT VALLEY UNIFIED SCHOOL DISTRICT ELECTRONIC BILLBOARD PROJECT DATED SEPTEMBER 19, 2025, STATE CLEARINGHOUSE NUMBER 2025090910
Dear Rudy Lopez,
The Department of Toxic Substances Control (DTSC) reviewed the Mitigated Negative Declaration (MND) for the Walnut Valley Unified School District Electronic Billboard Project (Project). The applicants request approval to install and operate a dual-faced digital LED billboard on the Walnut Valley Unified School District (WVUSD) property at 880 South Lemon Avenue, Diamond Bar, immediately north of SR-60. The sign would be placed within an approximately 100-square-foot base area at the southwest corner of the 6.08-acre parcel, occupying roughly 1,500 square feet of airspace above the base.
The proposed structure would be approximately 97 feet in total height, consisting of a 90-foot sign with up to 7 feet of decorative architectural features. Each sign face would measure 14 feet high by 48 feet wide and display static images that change every eight seconds. Project work includes foundation excavation, installation of the monopole and superstructure, underground electrical trenching to connect to WVUSD or Southern California Edison service, removal of two pine trees along South Lemon Avenue with replacement planting of two 24-inch box crape myrtles, and minor landscape
COMMENT LETTER A
A-1
Rudy Lopez
September 26, 2025
enhancements along the SR-60 frontage. DTSC recommends and requests consideration of the following comments:
1. If the district plans to use California Department of Education (CDE) State funds for the Project, then the district shall comply with the requirements of Education Code (EDC), §17210, §17213.1, and §17213.2, unless otherwise specifically exempted under section §17268. If the district is not using CDE State funds for the Project, or is otherwise specifically exempt under section §17268, DTSC recommends the district continue to investigate, clean up the Site under the oversight of Los Angeles County and in concurrence with all applicable DTSC guidance documents, if necessary. For more information on the CDE State funding, please visit the Office of Public-School Construction webpage. A local education agency may also voluntarily request the CDE site/plan approval for locally funded site acquisitions and new construction projects. In these cases, CDE will require DTSC to review and approve prior to its final approval, except when exempt under section 17268.
2. If buildings or other structures are to be demolished on any Project sites included in the proposed Project, surveys should be conducted for the presence of lead-based paints or products, mercury, asbestos containing materials, and polychlorinated biphenyl caulk. Removal, demolition, and disposal of any of the above-mentioned chemicals should be conducted in compliance with California environmental regulations and policies. In addition, sampling near current and/or former buildings should be conducted in accordance with DTSC’s Preliminary Endangerment Assessment (PEA) Guidance Manual.
3. All imported soil/fill material should be tested to assess any contaminants of concern meet screening levels as outlined in DTSC's PEA Guidance Manual.
Additionally, DTSC advises referencing the DTSC Information Advisory Clean Imported Fill Material Fact Sheet if importing fill is necessary. To minimize the possibility of introducing contaminated soil/fill material, there should be
COMMENT LETTER A
A-1
con't
A-2
A-3
A-4
Rudy Lopez
September 26, 2025
documentation of the origins of the soil/fill material and, if applicable, sampling be conducted to ensure that the imported soil/fill material are suitable for the intended land use. The soil sampling should include analysis based on the source of the soil/fill and knowledge of prior land use.
DTSC appreciates the opportunity to comment on the MND for the Walnut Valley Unified School District Electronic Billboard Project. If you would like to proceed with DTSC’s school environmental review process, please visit DTSC's Evaluating & Clean-up School 3-Step Process to begin a Phase I Environmental Site Assessment. If you have any questions or would like clarification on DTSC’s comments, please respond to this letter or via our CEQA Review email for additional guidance.
Sincerely,
Tamara Purvis
Associate Environmental Planner
HWMP - Permitting Division – CEQA Unit
Department of Toxic Substances Control
[email protected]
COMMENT LETTER A
A-4
con't
A-5
Rudy Lopez
September 26, 2025
cc: (via email)
Governor’s Office of Land Use and Climate Innovation
State Clearinghouse
[email protected]
Christine Abraham
Principal Planner
De Novo Planning Group / Consulting Firm
[email protected]
Matthew Torres
Assistant Superintendent
Walnut Valley Unified School District / Project Applicant [email protected]
Andy Goodman
President
Evergreen Media, LLC. / Project Applicant
[email protected]
Dave Kereazis
Associate Environmental Planner
HWMP-Permitting Division – CEQA Unit
Department of Toxic Substances Control
[email protected]
Scott Wiley
Associate Governmental Program Analyst
HWMP - Permitting Division – CEQA Unit
Department of Toxic Substances Control
[email protected]
COMMENT LETTER A
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 8
Response to Commenter Letter A
Tamara Purvis, Associate Environmental Planner
State of California
Department of Toxic Substances Control (DTSC)
September 26, 2025
A-1 The comment is introductory in nature. The comment does not contain any information requiring changes to the Public Review Draft IS/MND. No further response is warranted.
A-2 The proposed Project will not use California Department of Education (CDE) State funds, and the WVUSD is not seeking CDE site or plan approval. Therefore, Education Code §§17210, 17213.1, and 17213.2 do not apply. Consistent with DTSC’s recommendation for locally funded projects, WVUSD will continue to implement appropriate due diligence and manage any unanticipated contamination under Los Angeles County oversight and applicable DTSC guidance, if necessary.
The Project involves limited asphalt removal, drilling a single hole approximately five feet in diameter to a depth of approximately 31 feet, and a shallow electrical conduit trench. All existing on-site buildings would remain in place. If stained or odorous soils are encountered during ground disturbance, would be paused and soils will be handled, profiled, and, if off-hauled, disposed at an appropriately permitted facility in compliance with federal, State, and local requirements. The comment does not contain any information requiring changes to the Draft IS/MND. No further response is warranted.
A-3 The proposed Project does not include the demolition of buildings or other structures. All construction is limited to minor asphalt removal, auger drilling for the monopole foundation, and shallow utility trenching within an existing paved yard; all existing on-site buildings and the remaining areas of the property would remain unchanged. DTSC’s recommendation for sampling near current and/or former buildings under its Preliminary Endangerment Assessment (PEA) Guidance Manual would not be required, because no additional demolition or subsurface work adjacent to building footprints is anticipated. Because the current Project scope does not include building demolition or subsurface disturbance at building pads, this comment does not require changes to the IS/MND. No further response is warranted.
A-4 Implementation of the proposed Project would result in the installation and operation of an electronic billboard. The Project improvement area consists of an existing asphalt-covered parking lot used for WVUSD school buses and other vehicles, and the surrounding area is urbanized and developed with freeway, school, residential, and light industrial uses. The Project does not propose the demolition of buildings or other structures. Construction will be limited to minor asphalt removal, auger drilling for the monopole foundation, and shallow utility trenching within an existing paved yard. All existing on-site buildings will remain in place and unchanged. DTSC’s recommendation for sampling near current and former buildings under its PEA Guidance Manual would not be required, because no additional demolition or subsurface work adjacent to building footprintsis anticipated. Thus, importing soils is not required for the Project. However, should the import of soil become necessary, the applicant would comply with applicable clean-fill testing and documentation requirements. Because the current Project scope does not include building
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 9
demolition or subsurface disturbance at building pads, this comment does not require changes to the IS/MND. No further response is warranted.
A-5 The comment does not contain any information requiring changes to the Draft IS/MND. No further response is warranted.
“Provide a safe and reliable transportation network that serves all people and respects the environment” STATE OF CALIFORNIA-------CALIFORNIA STATE TRANSPORTATION AGENCY GAVIN NEWSOM, Governor
DEPARTMENT OF TRANSPORTATION
DISTRICT 7
100 S. MAIN STREET, MS 16
LOS ANGELES, CA 90012
PHONE (213) 269-1124
FAX (213) 897-1337
TTY 711
www.dot.ca.gov
Making Conservation
a California Way of Life
October 15, 2025
Rudy Lopez, Assistant Planner
Planning Division
City of Diamond Bar
21810 Copley Drive
Diamond Bar, CA 91765
RE: Walnut Valley Unified School District
(WVUSD) Electronic Billboard Project
(Planning Case No. PL2024-40)
SCH #2025090910
Vic. LA-60/PM R22.397
GTS # LA-2025-04913-MND
Dear Rudy Lopez:
Thank you for including the California Department of Transportation (Caltrans) in the environmental review process for the above-referenced environmental document. The applicants request approval to install and operate a dual-faced digital LED billboard on the Walnut Valley Unified School District (WVUSD) property at 880 South Lemon Avenue, Diamond Bar, immediately north of SR-60. The sign would be placed within an approximately 100-square-foot base area at the southwest corner of the 6.08-acre parcel, occupying roughly 1,500 square feet of airspace above the base. The proposed structure would be approximately 97 feet in total height, consisting of a 90-foot sign with up to 7 feet of decorative architectural features. Each sign face would measure 14 feet high by 48 feet wide and display static images that change every eight seconds. Project work includes foundation excavation, installation of the monopole and superstructure, underground electrical trenching to connect to WVUSD or SCE service, removal of two pine trees along South Lemon Avenue with replacement planting of two 24-inch box crape myrtles, and minor landscape enhancements along the SR-60 frontage.
Any proposed off-premises commercial advertising display visible from the State Highway System (SHS) must obtain an Outdoor Advertising (ODA) Permit from Caltrans prior to placement, you may visit our website at
COMMENT LETTER B
B-2
B-1
Rudy Lopez, Assistant Planner
October 15, 2025
“Provide a safe and reliable transportation network that serves all people and respects the environment” https://dot.ca.gov/programs/traffic-operations/oda
for our permit application forms and permitting requirements. Also, please note that this freeway segment may be classified as a Landscaped Freeway and pursuant to the California Outdoor Advertising Act new outdoor advertising displays are prohibited from being placed adjacent to a Landscaped Freeway segment.
Please be reminded that any work performed within the State Right-of-way will require an Encroachment Permit from Caltrans. Any modifications to State facilities must meet all mandatory design standard and specifications.
Any transportation of heavy construction equipment and/or materials which require use of oversized transport vehicles on State highways will need a Caltrans transportation permit. We recommend large-size truck trips be limited to off-peak commute periods. Truck drivers should cover construction trucks with tarpaulin to avoid debris spillage onto the State Highway.
If you have any questions, please feel free to contact the Caltrans ODA Program at (916) 654-6473 or at [email protected].
Sincerely,
MIYA EDMONSON
LDR/CEQA Branch Chief
email: State Clearinghouse
COMMENT LETTER B
B-2
con't
B-3
B-4
B-5
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 12
Response to Commenter Letter B
Miya Edmonson, LDR/CEQA Branch Chief
State of California
Department of Transportation (Caltrans)
October 15, 2025
B-1 The comment is introductory in nature. The comment does not contain any information requiring changes to the Public Review Draft IS/MND. No further response is warranted.
B-2 The proposed Project is required to obtain an Outdoor Advertising Display (ODA) Permit from Caltrans before installation. Further, the Project will remain outside the State right of way and will comply with ODA location and design criteria. The City will condition approvals on proof of an issued ODA permit. This comment is related to permitting and compliance, rather than the evaluation of an environmental impact in the Draft IS/MND. As such, this comment does not contain any information requiring changes to the Draft IS/MND. No further response is warranted.
B-3 The proposed Project would install and operate an electronic billboard within the WVUSD parking lot on the southwestern portion of the site, outside the State right of way, and thus no encroachment would occur. Further, the Project will not involve any modifications to State facilities. The comment does not contain any information requiring changes to the Draft IS/MND.
No further response is warranted.
B-4 Project construction activities will not take place within a Caltrans right of way. Construction activities related to installation of the electronic billboard will, instead, take place on the WVUSD parking lot. A Caltrans transportation permit will be obtained if the Project necessitates the transportation of heavy construction equipment and/or materials requiring the use of oversized transport vehicles on State highways. This comment is related to permitting and compliance, rather than the evaluation of an environmental impact in the Draft IS/MND. Thus, the comment does not contain any information requiring changes to the Draft IS/MND. No further response is warranted.
B-5 The comment does not contain any information requiring changes to the Draft IS/MND. No further response is warranted.
COMMENT LETTER C
C-1
COMMENT LETTER C
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 15
Response to Commenter Letter C
William Moore, Resident
September 26, 2025
C-1 Advertising content and advertiser selection are controlled by the sign owner or operator, subject to City regulations, State and federal laws, and any lease or operating agreement with WVUSD.
The City does not pre-approve individual ads but enforces content-neutral sign rules and conditions of approval, and residents may participate through public hearings and may report alleged violations for City enforcement. This comment does not alter the Draft IS/MND analysis or conclusions, and no further response is warranted.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 16
This page intentionally left blank.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 17
3.0 ERRATA
This chapter is intended to include minor edits, or errata, to the IS/MND that are warranted based on responses to comments received during the Draft IS/MND public review period or other minor modifications and clarifications to the text of the IS/MND which are more editorial in nature. The comments received did not require any changes to the Draft IS/MND. The revisions herein do not result in new significant environmental impacts, do not constitute significant new information, and do not alter the conclusions of the environmental analysis that would warrant recirculation of the Draft IS/MND pursuant to State CEQA Guidelines Section 15073.5. Minor editorial revisions are limited to the text of Mitigation Measures CUL-1 and CUL-2, as indicated below. Changes are provided in revision marks with underline for new text and strikeout for deleted text. There are no other errata changes warranted.
Revisions to the Draft IS/MND
4.5 Cultural Resources
The following edits are made to page 56 in Section 4.5 of the Draft IS/MND.
Mitigation Measures:
CUL-1: Should archaeological resources (sites, features, or artifacts) be exposed during construction activities for the proposed Project, all construction work shall immediately stop until the Project applicant engages a qualified archaeologist, meeting the Secretary of the Interior’s Professional Qualification Standards, that can evaluate the significance of the find and determine whether or not additional study is warranted. Depending upon the significance of the find, the archaeologist may simply record the find and allow work to continue. If the discovery proves significant under CEQA, additional work such as preparation of an archaeological treatment plan, testing, or data recovery may be warranted.
The following edits are made to page 57 in Section 4.5 of the Draft IS/MND.
Mitigation Measures:
CUL-2: In accordance with Section 7050.5 of the California Health and Safety Code, if human remains are found, the Project applicant shall notify the County Coroner shall be notified within 24 hours of the discovery. No further excavation or disturbance of the site or any nearby area reasonably suspected to overlie adjacent remains shall occur until the County Coroner has determined, within two working days of notification of the discovery, the appropriate treatment and disposition of the human remains. If the remains are determined to be Native American, the Coroner shall notify the NAHC in Sacramento within 24 hours. In accordance with California PRC, Section 5097.98, the NAHC must immediately notify those persons it believes to be the Most Likely Descendant (MLD) from the deceased Native American. The MLD shall complete their inspection within 48 hours of being granted access to the site. The MLD would then determine, in consultation with the property owner, the disposition of the human remains.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 18
4.0 MITIGATION MONITORING AND REPORTING PROGRAM
The California Environmental Quality Act (CEQA) requires that when a public agency completes an environmental document which includes measures to mitigate or avoid significant environmental effects, the public agency must adopt a reporting or monitoring program. This requirement ensures that environmental impacts found to be significant will be mitigated. The reporting or monitoring program must be designed to ensure compliance during project implementation (Public Resources Code Section 21081.6). Specifically, Public Resources Code Section 21081.6 states:
(a) When making findings required by paragraph (1) of subdivision (a) of Section 21081 or when adopting a mitigated negative declaration pursuant to paragraph (2) of subdivision (c) of Section 21080, the following requirements shall apply:
(1) The public agency shall adopt a reporting or monitoring program for the changes made to the project or conditions of project approval, adopted in order to mitigate or avoid significant effects on the environment. The reporting or monitoring program shall be designed to ensure compliance during project implementation.
For those changes which have been required or incorporated into the project at the request of a responsible agency or a public agency having jurisdiction by law over natural resources affected by the project, that agency shall, if so requested by the lead or responsible agency, prepare and submit a proposed reporting or monitoring program.
(2) The lead agency shall specify the location and custodian of the documents or other material which constitute the record of proceedings upon which its decision is based.
This Mitigation Monitoring and Reporting Program (MMRP) has been developed to provide the mechanism by which to monitor mitigation measures outlined in Walnut Valley Unified School District Electronic Billboard Project Draft IS/MND. The MMRP has been prepared in conformance with Public Resources Code Section 21081.6 and City of Diamond Bar’s (City) monitoring requirements.
State CEQA Guidelines Section 15097 provides clarification of mitigation monitoring and reporting requirements and guidance to local lead agencies on implementing strategies. The reporting or monitoring program must be designed to ensure compliance during project implementation. The City of Diamond Bar is the Lead Agency for the Walnut Valley Unified School District Electronic Billboard Project and is therefore responsible for ensuring MMRP implementation. This MMRP has been drafted to meet Public Resources Code Section 21081.6 requirements as a fully enforceable monitoring program.
The MMRP Checklist is intended to provide verification that all applicable mitigation measures relative to significant environmental impacts are monitored and reported. Monitoring will include: 1) verification that each mitigation measure has been implemented; 2) recordation of the actions taken to implement each mitigation; and 3) retention of records in the Walnut Valley Unified School District Electronic Billboard Project file.
This MMRP delineates responsibilities for monitoring the Project, but also allows the City flexibility and discretion in determining how best to monitor implementation. Monitoring procedures will vary according to the type of mitigation measure. Adequate monitoring consists of demonstrating that monitoring
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 19
procedures took place and that mitigation measures were implemented. This includes the review of all monitoring reports, enforcement actions, and document disposition, unless otherwise noted in the MMRP Checklist. If an adopted mitigation measure is not being properly implemented, the designated monitoring personnel shall require corrective actions to ensure adequate implementation.
The numbering system in the following table corresponds with the IS/MND’s numbering system. The MMRP table “Verification” column will be used by the parties responsible for documenting when the mitigation measure has been completed. The City of Diamond Bar will complete ongoing documentation and mitigation compliance monitoring. The completed MMRP and supplemental documents will be kept on file at the City of Diamond Bar Community Development Department.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 20
This page intentionally left blank.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 21
Mitigation Monitoring and Reporting Program Checklist
Mitigation Measures Implementation
Timing
Monitoring/
Reporting
Methods
Responsible
for Approval/
Monitoring
Verification
Initials Date Remarks
CULTURAL RESOURCES
Mitigation Measures
CUL-1: Should archaeological resources (sites, features, or artifacts) be exposed during construction activities for the proposed Project, all construction work shall
immediately stop until the Project applicant engages a
qualified archaeologist, meeting the Secretary of the
Interior’s Professional Qualification Standards, that can evaluate the significance of the find and determine
whether or not additional study is warranted. Depending upon the significance of the find, the archaeologist may simply record the find and allow work to continue. If the discovery proves significant under CEQA, additional work such as preparation of an archaeological treatment plan, testing, or data recovery may be warranted.
During grounddisturbing
activities
Notification of
Native
American
Heritage
Commission, if
identified
remains are
Native
American in
origin
Community
Development
Department
Director, or
designee
CUL-2: In accordance with Section 7050.5 of the California Health and Safety Code, if human remains are found, the Project applicant shall notify the County Coroner within 24 hours of the discovery. No further excavation or
disturbance of the site or any nearby area reasonably
suspected to overlie adjacent remains shall occur until the County Coroner has determined, within two working
days of notification of the discovery, the appropriate
treatment and disposition of the human remains. If the
remains are determined to be Native American, the
Coroner shall notify the NAHC in Sacramento within 24
hours. In accordance with California PRC, Section
5097.98, the NAHC must immediately notify those
persons it believes to be the Most Likely Descendant
During grounddisturbing
activities
Notification of
Los Angeles
County
Coroner/
Notification of
Native
American
Heritage
Commission, if
identified
remains are
Native
Community
Development
Department
Director, or
designee
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 22
Mitigation Measures Implementation
Timing
Monitoring/
Reporting
Methods
Responsible
for Approval/
Monitoring
Verification
Initials Date Remarks
(MLD) from the deceased Native American. The MLD
shall complete their inspection within 48 hours of being granted access to the site. The MLD would then
determine, in consultation with the property owner, the disposition of the human remains.
American in
origin
GEOLOGY AND SOILS
Mitigation Measures
GEO-1: If evidence of subsurface paleontological resources is found during construction, excavation and other
construction activity in that area shall cease and the
construction contractor shall contact the City of Diamond Bar Community Development Director or designee. With
direction from the Community Development Director, a
paleontologist certified by the County of Los Angeles shall evaluate the find prior to resuming grading in the
immediate vicinity of the find. If warranted, the
paleontologist shall prepare and complete a standard
Paleontological Resources Mitigation Program for the
salvage and curation of the identified resources.
During grounddisturbing
activities
Assessment of
resources by a
professional
vertebrate
paleontologist.
If significant
under CEQA,
verify
additional
work, such as
data recovery
excavation, has
been
implemented.
Community
Development
Department
Director, or
designee
TRIBAL CULTURAL RESOURCES
Mitigation Measures
TCR-1: Retain a Native American Monitor Prior to
Commencement of Ground-Disturbing Activities.
a) The project applicant/lead agency shall retain a Native American Monitor from or approved by the Gabrieleño
Band of Mission Indians – Kizh Nation. The monitor shall be retained prior to the commencement of any “groundDuring grounddisturbing activities
Grading Plan:
Prior to grading
or ground
disturbing
activities
Community
Development
Department
Director, or
designee
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 23
Mitigation Measures Implementation
Timing
Monitoring/
Reporting
Methods
Responsible
for Approval/
Monitoring
Verification
Initials Date Remarks
disturbing activity” for the subject project at all project locations (i.e., both on-site and any off-site locations that are included in the project description/definition and/or required in connection with the project, such as public improvement work). “Ground-disturbing activity” shall
include, but is not limited to, demolition, pavement
removal, potholing, auguring, grubbing, tree removal,
boring, grading, excavation, drilling, and trenching.
b) A copy of the executed monitoring agreement shall be submitted to the lead agency prior to the earlier of the commencement of any ground-disturbing activity, or the
issuance of any permit necessary to commence a
ground-disturbing activity.
c) The monitor will complete daily monitoring logs that will provide descriptions of the relevant ground-disturbing
activities, the type of construction activities performed, locations of ground-disturbing activities, soil types,
cultural-related materials, and any other facts,
conditions, materials, or discoveries of significance to the Tribe. Monitor logs will identify and describe any
discovered TCRs, including but not limited to, Native
American cultural and historical artifacts, remains, places of significance, etc., (collectively, tribal cultural
resources, or “TCR”), as well as any discovered Native
American (ancestral) human remains and burial goods.
Copies of monitor logs will be provided to the project
applicant/lead agency upon written request to the Tribe. d) On-site tribal monitoring shall conclude upon the latter of the following: (1) written confirmation to the Kizh
from a designated point of contact for the project
applicant/lead agency that all ground-disturbing
Prior to
issuance of any
grading permit
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 24
Mitigation Measures Implementation
Timing
Monitoring/
Reporting
Methods
Responsible
for Approval/
Monitoring
Verification
Initials Date Remarks
activities and phases that may involve ground-disturbing activities on the project site or in connection with the project are complete; or (2) a determination and written notification by the Kizh to the project applicant/lead
agency that no future, planned construction activity
and/or development/construction phase at the project
site possesses the potential to impact Kizh TCRs.
TCR-2: Unanticipated Discovery of Tribal Cultural Resource Objects (Non-Funerary/Non-Ceremonial).
a) Upon discovery of any TCRs, all construction activities in the immediate vicinity of the discovery shall cease (i.e., not less than the surrounding 50 feet) and shall not
resume until the discovered TCR has been fully assessed by the Kizh monitor and/or Kizh archaeologist. The Kizh will recover and retain all discovered TCRs in the form and/or manner the Tribe deems appropriate, in the
Tribe’s sole discretion, and for any purpose the Tribe
deems appropriate, including for educational, cultural
and/or historic purposes.
During grounddisturbing
activities
Grading Plan:
Prior to grading
or ground
disturbing
activities.
Prior to
issuance of any
grading
permits
Community
Development
Department
Director, or
designee
TCR-3: Unanticipated Discovery of Human Remains and
Associated Funerary or Ceremonial Objects.
a) Native American human remains are defined in PRC
5097.98 (d)(1) as an inhumation or cremation, and in any state of decomposition or skeletal completeness.
Funerary objects, called associated grave goods in Public Resources Code Section 5097.98, are also to be treated
according to this statute.
b) If Native American human remains and/or grave goods
are discovered or recognized on the project site, then
During grounddisturbing
activities
Grading Plan:
Prior to grading
or ground
disturbing
activities
Prior to
issuance of any
grading
permits
Community
Development
Department
Director, or
designee
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 25
Mitigation Measures Implementation
Timing
Monitoring/
Reporting
Methods
Responsible
for Approval/
Monitoring
Verification
Initials Date Remarks
Public Resource Code 5097.9 as well as Health and Safety Code Section 7050.5 shall be followed.
c) Human remains and grave/burial goods shall be treated alike per California Public Resources Code section
5097.98(d)(1) and (2).
d) Preservation in place (i.e., avoidance) is the preferred manner of treatment for discovered human remains
and/or burial goods.
e) Any discovery of human remains/burial goods shall be kept confidential to prevent further disturbance.
Walnut Valley Unified School District Electronic Billboard Project Initial Study/Mitigated Negative Declaration Final
November 2025 Page 26
This page intentionally left blank.
ORDINANCE NO. 01 (2026)
AN ORDINANCE OF THE CITY OF DIAMOND BAR AMENDING
SECTIONS 22.10.030, 22.36.080, 22.36.120, AND 22.80.020 OF THE
DIAMOND BAR CITY CODE PERTAINING TO THE REGULATION
OF BILLBOARDS.
WHEREAS, WVUSD and Evergreen have submitted an application with the City for approval of: the Development Agreement governing the operation and community benefits for the electronic billboard; a Development Code Amendment to allow billboards in the I (Light Industry) zone by Conditional Use Permit, and to establish development standards for billboards; a Conditional Use Permit to authorize the billboard on the property; and Development Review for sign architecture, materials, and placement of the billboard on the property; and
WHEREAS, on November 25, 2025, the Planning Commission held a duly noticed public hearing regarding proposed amendments to Title 22 (“Development Code”) of the Diamond Bar City Code pertaining to billboards, Planning Case No. PL 2024-40, and adopted Resolution No. 2025-19 recommending City Council approval of said Development Code Amendment; and
WHEREAS, on December 5, 2025, notification of the City Council public hearing for this project was published in the San Gabriel Valley Tribune. Public hearing notices were mailed to property owners within a 1000-foot radius of the project site and notices were posted at the City’s designated community posting sites; and WHEREAS, on December 16, 2025, the City Council held a duly noticed public hearing regarding the proposed Development Code Amendment; and WHEREAS, the City Council finds that this Ordinance is subject to the California Environmental Quality Act (“CEQA”) because it can be seen with certainty that the proposed Development Code Amendment will result in a project that has the potential for causing a significant effect on the environment (Section 15061(b)(3) of the CEQA Guidelines). Environmental review for the proposed project has been conducted pursuant to CEQA, and a Mitigated Negative Declaration (MND) has been prepared, circulated, and reviewed in accordance with CEQA Section 15070 and the CEQA Guidelines Section 15105. The MND determined that, with implementation of the identified mitigation measures, the project will not have a significant effect on the environment. Therefore, the City Council finds that adoption of this Ordinance is consistent with the conclusions of the MND; and
WHEREAS, the documents and materials constituting the administrative record of the proceedings upon which the City's decision is based are located at the City of Diamond Bar, Community Development Department, Planning Division, 21810 Copley Drive, Diamond Bar, CA 91765; and
WHEREAS, the City Council hereby adopts the facts and reasons stated in
Ordinance No. 01 (2026)
2 Planning Commission Resolution No. 2025-19 recommending City Council approval of said Development Code Amendments, a copy of which is on file with the City Clerk and which is incorporated herein by reference with the same force and effect as if set forth in full.
NOW, THEREFORE, the City Council of the City of Diamond Bar does hereby find, determine and ordains as follows:
SECTION 1: Table 2-6 of Section 22.10.030 (Commercial/Industrial district land uses and permit requirements) of Title 22, Chapter 22.10 of the Diamond Bar City Code is amended as follows (deletions in strikethrough text and additions shown in double underline):
TABLE 2-6
ALLOWED USES AND PERMIT REQUIREMENTS FOR
COMMERCIAL/INDUSTRIAL ZONING DISTRICTS
Permit Requirement by District
LAND USE (1) C-1 C-2 C-3 I
See Standards in
Section:
. . . . . . . . . . . . . . . . . .
TRANSPORTATION & COMMUNICATION USES
Billboards CUP 22.36.120
. . . . . . . . . . . . . . . . . .
SECTION 2: Subsection (11) of Section 22.36.080 (Prohibited Signs) of Title 22, Chapter 22.36 of the Diamond Bar City Code is amended as follows (deletions in strikethrough text and additions shown in double underline):
(11) Off-site signs not specifically allowed by the provisions of this chapter, including billboards and outdoor advertising;
SECTION 3: Subsection (b) of Section 22.36.120 (Standards for Specific Types of Signs) of Title 22, Chapter 22.36 of the Diamond Bar City Code is amended as follows to add a new subsection that provides development standards for billboards (deletions in strikethrough text and additions shown in double underline):
(b) Billboards. Billboards may be permitted by conditional use permit and a development agreement on properties located within the I zone, subject to the following limitations:
Ordinance No. 01 (2026)
3 (1) No billboard shall be located more than 400 feet from the edge of a freeway right-of-way, measured from the nearest point of the sign structure to the nearest point of the right-of-way boundary. (2) No billboard shall be located within 800 feet of any existing static billboard, regardless of whether the proposed billboard is static or digital. In addition, no digital billboard shall be located within 2,000 feet of any existing digital billboard. Distance shall be measured in a straight line between the bases of the respective billboard structures. (3) No billboard shall be located within 400 feet of any parcel that is zoned or used for residential purposes. Distance shall be measured in a straight line from the closest point of the residentially-zoned or residentially-used parcel boundary to the base of the proposed billboard.
(4) The maximum height of a billboard shall not exceed 75 feet, measured as the vertical distance from the highest point of the sign structure to the finished surface elevation at the edge of the nearest freeway travel lane. This measurement shall be taken along a line drawn perpendicularly from the base of the sign structure to the tangent of the nearest freeway lane. A decorative or architectural element may extend up to 10 feet above the maximum height, provided it does not contain any additional display area or advertising content.
(5) The maximum area of any individual sign face shall not exceed 672 square feet. Each sign face shall be limited to a maximum length of 48 feet and a maximum height of 14 feet. No billboard shall contain more than one sign face per direction of travel, and vertical stacking of sign faces on the same side of a structure is prohibited.
(6) Architectural features such as framing, decorative borders, or structural shrouds that do not contain any advertising content shall be permitted above, below, or around the sign face and shall not count toward the maximum allowable sign area, provided they are designed as integral components of the sign structure and do not function as additional sign faces.
(7) No billboard shall contain more than two sign faces. Where two sign faces are configured in a V-shaped or angled arrangement, the angle between the faces shall not exceed 45 degrees as measured between the planes of the two sign faces.
(8) All illuminated billboards shall be equipped with automatic light-sensing technology to adjust brightness in response to ambient lighting conditions. Maximum luminance shall not exceed 0.3 foot-candles above ambient levels, measured at a distance of 250 feet perpendicular
Ordinance No. 01 (2026)
4 to the center of the sign face.
All luminance measurements shall be verified at a horizontal distance of 250 feet perpendicular to the sign face. A photometric analysis shall be submitted with the permit application and shall include certification by a qualified lighting professional or electrical engineer confirming compliance with these standards.
All illumination shall be directed to avoid light spillover onto adjacent properties, roadways, or into the night sky. Sign lighting shall not cause glare or impair visibility for motorists, and shall remain static, without flashing, strobing, or rapidly changing brightness.
(9) Digital billboards shall display static images only. Each image shall remain on the screen for a minimum duration of eight (8) seconds.
Transitions between images shall be instantaneous, without any motion, animation, flashing, or other visual effects
The Section 22.36.120 standards for specific signs beginning with freestanding monument signs and ending with window signs are consecutively renumbered beginning at subsection (c) and ending at subsection (i).
SECTION 4: Subsection (b) and Subsection (s) of Section 22.80.020 (Definitions of specialized terms and phrases) of Title 22, Chapter 22.80 of the Diamond Bar City Code is amended as follows to add a new definition for “billboard” as well as a definition for the subcategories “digital billboard” and “static billboard” (deletions in strikethrough text and additions shown in double underline):
(a) Definitions, “B.” The following definitions are in alphabetical order:
. . .
Billboard. See Sign/Billboard
. . .
(e) Definitions, “S.” The following definitions are in alphabetical order:
. . .
(8) Billboard. A freestanding sign structure designed and used to display offsite advertising copy, including commercial or non-commercial messages that direct attention to a business, product, service, activity, event, or location not located on the same premises as the sign. A billboard may be either a static billboard or a digital billboard as defined below. Billboards do not include on-site business identification signs, civic information signs, or temporary political signs;
a. Digital Billboard. A billboard that displays off-site advertising copy using electronic changeable copy technology, such as light-emitting diodes
Ordinance No. 01 (2026)
5 (LEDs) or similar digital display methods. The content may change remotely and at programmed intervals but shall comply with limitations on message duration and visual effects as set forth in this Title. b. Static Billboard. A billboard that displays a fixed image or message, typically through printed or painted panels. The copy does not change electronically and remains static until physically replaced . . .
The subsection (s) definitions beginning with Business identification sign and ending with Window sign are consecutively renumbered beginning at subsection (9) and ending at subsection (47).
SECTION 5: If any section, subdivision, paragraph, sentence, clause or phrase of this Ordinance is for any reason held to be invalid or unconstitutional, such decision shall not affect the validity of the remaining portions of this Ordinance. The City Council hereby declares that it would have passed this Ordinance, and each section, subdivision, paragraph, sentence, clause and phrase thereof, irrespective of the fact that any one (or more) section, subdivision, paragraph, sentence, clause or phrase had been declared invalid or unconstitutional.
SECTION 6: The City Clerk shall certify to the passage and adoption of this Ordinance and shall cause a certified copy of this Ordinance to be posted within fifteen (15) days after this Ordinance is passed and adopted, in the Office of the City Clerk and two additional public places, together with the vote for and against the same, and forthwith transmit a certified copy of this Ordinance, by certified mail, to: Walnut Valley Unified School District, 880 South Lemon Avenue, Walnut, CA 91789.
APPROVED AND ADOPTED this 20th day of January, 2026, by the City Council of the City of Diamond Bar.
CITY OF DIAMOND BAR
Steve Tye, Mayor
Ordinance No. 01 (2026)
6 ATTEST:
I, Kristina Santana, City Clerk of the City of Diamond Bar, do hereby certify that the foregoing Ordinance was duly introduced at a regular meeting of the City Council of the City of Diamond Bar held on the 16th day of December, 2025, and was finally passed at a regular meeting of the City Council of the City of Diamond Bar held on the 20th day of January, 2026, by the following vote:
AYES: Councilmembers:
NOES: Councilmembers:
ABSENT: Councilmembers:
ABSTAIN: Councilmembers:
Kristina Santana, City Clerk
ORDINANCE NO. 02 (2026)
AN ORDINANCE OF THE CITY OF DIAMOND BAR APPROVING
DEVELOPMENT AGREEMENT NO. 2026-01, FOR PROPERTY
COMPRISED OF APPROXIMATELY 6.08 ACRES LOCATED AT 880
SOUTH LEMON AVENUE, WALNUT, CALIFORNIA WITHIN THE
JURISDICTIONAL BOUNDARIES OF THE CITY OF DIAMOND BAR
(ASSESSOR'S PARCEL NUMBER 8760-015-901).
WHEREAS, the property owner/co-applicant, Walnut Valley School District (“WVUSD”), and its lessee /co-applicant, Evergreen Media, LLC, (“Evergreen”) entered into an Outdoor Advertising Lease Agreement dated February 15, 2023, to construct and operate a new double sided electronic billboard on a portion of the property located at 880 S. Lemon Street, ground leased to Evergreen; and
WHEREAS, WVUSD and Evergreen have submitted an application with the City for approval of: the Development Agreement governing the operation and community benefits for the electronic billboard; a Development Code Amendment to allow billboards in the I (Light Industry) zone by Conditional Use Permit, and to establish development standards for billboards; a Conditional Use Permit to authorize the billboard on the property; and Development Review for sign architecture, materials, and placement of the billboard on the property; and
WHEREAS, the billboard would be placed within an approximately 100-squarefoot base area at the southwest corner of the 6.08-acre parcel, occupying roughly 1,500 square feet of airspace above the base. The proposed structure would be approximately 97 feet in total height, consisting of a 90-foot sign with up to 7 feet of decorative architectural features. Each sign face would measure 14 feet high by 48 feet wide and display static images that change every eight seconds. Project work includes foundation excavation, installation of the monopole and superstructure, underground electrical trenching to connect to WVUSD or SCE service, removal of two pine trees along South Lemon Avenue with replacement planting of two 24-inch box crape myrtles, and minor landscape enhancements along the SR-60 frontage. The Project site’s General Plan designation is School (S) and the zoning is Light Industry (I); and WHEREAS, on November 25, 2025, the Planning Commission held a duly noticed public hearing regarding proposed amendments to Title 22 (“Development Code”) of the Diamond Bar City Code pertaining to billboards, Planning Case No. PL 2024-40, and adopted Resolution No. 2025-20, recommending City Council approval of said Development Agreement; and
WHEREAS, on December 5, 2025, notification of the City Council public hearing for this project was published in the San Gabriel Valley Tribune. Public hearing notices were mailed to property owners within a 1000-foot radius of the project site and notices were posted at the City’s designated community posting sites; and
Ordinance No. 02 (2026)
2 WHEREAS, on December 16, 2025, the City Council held a duly noticed public hearing regarding Development Agreement No. 2026-01; and WHEREAS, pursuant to Government Code Section 65864, et seq., the City is authorized to enter into development agreements with persons having legal or equitable interests in real property located within the City; and WHEREAS, pursuant to Development Code Section 22.62 and Government Code Section 65865, the City has adopted rules and regulations for consideration of development agreements; and
WHEREAS, the City is entering into a Development Agreement with the WVUSD for the purpose of establishing an agreement between the City and WVUSD setting forth obligations and benefits to the respective parties; and WHEREAS, the City Council finds that this Ordinance is subject to the California Environmental Quality Act (“CEQA”) because it can be seen with certainty that the proposed Development Code Amendment will result in a project that has the potential for causing a significant effect on the environment (Section 15061(b)(3) of the CEQA Guidelines). Environmental review for the proposed project has been conducted pursuant to CEQA, and a Mitigated Negative Declaration (MND) has been prepared, circulated, and reviewed in accordance with CEQA Section 15070 and the CEQA Guidelines Section 15105. The MND determined that, with implementation of the identified mitigation measures, the project will not have a significant effect on the environment. Therefore, the City Council finds that adoption of this Ordinance is consistent with the conclusions of the MND; and
WHEREAS, the documents and materials constituting the administrative record of the proceedings upon which the City's decision is based are located at the City of Diamond Bar, Community Development Department, Planning Division, 21810 Copley Drive, Diamond Bar, CA 91765; and
WHEREAS, the City Council hereby adopts the facts and reasons stated in Planning Commission Resolution No. 2025-20 recommending City Council approval of said Development Agreement, a copy of which is on file with the City Clerk and which is incorporated herein by reference with the same force and effect as if set forth in full.
NOW, THEREFORE, the City Council of the City of Diamond Bar does hereby find, determine and ordains as follows:
SECTION 1: The City Council hereby finds that the facts set forth in the Recitals of this Ordinance are true and correct.
SECTION 2: In compliance with CEQA, the City Council approved the initial study and Mitigated Negative Declaration and mitigation reporting and monitoring program for the project.
Ordinance No. 02 (2026)
3 SECTION 3: In accordance with the Development Code, Section
22.62.030(e) of the Diamond Bar City Code, the City Council makes the following findings of fact regarding Development Agreement 2026-01:
(a) The Development Agreement, attached hereto as Exhibit 1, would be in the best interests of the City; is consistent with the General Plan, and the Development Code; and would promote the public interest and welfare of the city;
(b) The Development Agreement is in compliance with the conditions, requirements, restrictions, and terms of Development Code Sections
22.62.030(d) and 22.62.040, because the agreement contains all the mandatory provisions and permissive content required by Government Code Section 65865.2;
SECTION 4: The City Manager is hereby authorized to execute the Development Agreement;
SECTION 5: The City Clerk shall certify to the passage and adoption of this Ordinance and shall cause a certified copy of this Ordinance to be posted within fifteen (15) days after this Ordinance is passed and adopted, in the Office of the City Clerk and two additional public places, together with the vote for and against the same, and forthwith transmit a certified copy of this Ordinance, by certified mail, to: Walnut Valley Unified School District, 880 South Lemon Avenue, Walnut, CA 91789.
APPROVED AND ADOPTED at a regular meeting of the City Council of the City of Diamond Bar on the 20th day of January, 2026.
CITY OF DIAMOND BAR
__________________________
Steve Tye, Mayor
ATTEST:
I, Kristina Santana, City Clerk of the City of Diamond Bar, do hereby certify that the foregoing Ordinance was duly introduced at a regular meeting of the City Council of the City of Diamond Bar held on the 16th day of December, 2025, and was finally passed at a regular meeting of the City Council of the City of Diamond Bar held on the 20th day of January, 2026, by the following vote:
AYES: Councilmembers:
NOES: Councilmembers:
ABSENT: Councilmembers:
ABSTAIN: Councilmembers:
Kristina Santana, City Clerk
Ordinance No. 02 (2026)
5 Exhibit A
Development Agreement No. 2026-01
[Attached]
RECORDING REQUESTED BY )
AND WHEN RECORDED MAIL TO: )
City Clerk’s Office )
City of Diamond Bar )
21810 Copley Drive )
Diamond Bar, CA 91765 )
)
___________________________________________________________________ (Space above for Recorder)
APN: Portion of 8760-015-901
This document is exempt from payment of a recording fee pursuant to Govt. Code §§ 6103 & 21383.
By: _______________________
Dated:_____________________
DEVELOPMENT AGREEMENT
880 S. Lemon Billboard Project
THIS DEVELOPMENT AGREEMENT (“AGREEMENT”) is made this 16th day of December, 2025, by the CITY OF DIAMOND BAR, a municipal corporation ("CITY"), and Walnut Valley Unified School District (“DISTRICT"). DISTRICT and CITY are hereinafter referred to as the “PARTIES” or individually as a “PARTY”.
RECITALS
The following recitals are a substantive part of this Development Agreement:
1. DISTRICT is the owner of property located at 880 S. Lemon Street, Walnut, California and having assessor’s parcel number (“APN”) 8760-015-901 (the “PROPERTY”).
2. The DISTRICT and Evergreen Media LLC (“EVERGREEN” or “DEVELOPER”), a Delaware Limited Liability Company, entered into an Outdoor Advertising Lease Agreement dated February 15, 2023, attached hereto and incorporated herein as Exhibit “A” (“LEASE AGREEMENT”), to construct and operate a new double sided digital light-emitting diode (“LED”) billboard (“BILLBOARD”) on a portion of the Property (“PROJECT”) ground leased to EVERGREEN. The billboard location is depicted in Exhibit A of the LEASE AGREEMENT.
3. Pursuant to the LEASE AGREEMENT in Exhibit “A”, EVERGREEN is the applicant for any and all entitlement applications, and any requirements for the District to obtain entitlements pursuant to this AGREEMENT, shall be passed on to EVERGREEN, at EVERGREEN’S sole cost and expense.
4. The CITY and DISTRICT desire to enter into this Agreement in order to outline the CITY and DISTRCT’s obligations.
5. The CITY’s City Council approved a Development Code Amendment, Conditional Use Permit, and Development Review on December 16, 2025 in conjunction with this AGREEMENT.
6. The PROJECT is a development requiring the foregoing legislative and discretionary approvals by the CITY before it may be constructed.
7. Per the LEASE AGREEMENT, the DISTRICT receives lease revenue from EVERGREEN. In consideration for entitling the PROJECT, the CITY seeks to receive a Community Benefit Fee (further defined below) that is a percentage of the lease revenue received by the DISTRICT. The CITY also seeks advertising time on the digital LED BILLBOARD at no cost to the CITY.
8. Government Code Section 65864 et seq. provides the authority for CITY to enter into binding development agreements with the DISTRICT having a legal and equitable interest in real property.
AGREEMENT
THE PARTIES MUTUALLY AGREE AS FOLLOWS:
1. Duration. This AGREEMENT, the CUP to install and maintain the BILLBOARD, and any and all discretionary land use entitlements granted to EVERGREEN for the PROPERTY shall expire twenty (20) years from its effective date, unless any duty specified remains executory, in which case this Agreement may be renewed for a successive ten (10) year term upon notice from the DISTRICT, pursuant to law, until all duties are performed. This renewal shall not be unreasonably withheld by the CITY.
2. Exclusive Rights to Develop. Subject to the terms of this AGREEMENT, DISTRICT shall have an exclusive vested right to develop the Property in accordance with, and to the extent of, the LEASE AGREEMENT and EVERGREEN’s entitlement applications.
3. Permitted Uses. The following use is permitted at the PROJECT: erecting, constructing, installing, placing, operating, maintaining, and servicing, a doublesided digital LED BILLBOARD for advertising, including supporting structures, illumination facilities and connections, back-up panels, service ladders, telecommunication devices and other appurtenances and ancillary equipment subject to a CUP.
4. Maximum Height and Building Size. The maximum height and building size are as follows: A fourteen feet (14) x forty-eight feet (48) (Height x Width) double sided digital LED Billboard with an overall height including the supports plus sign of ninety feet (90).
5. Resolution/Material Terms. All conditions of approval as per City Council Resolution No. 2025-XX, attached hereto and incorporated herein as Exhibit “B”,
are material terms of this AGREEMENT. Breach of any condition of approval shall be deemed to be a breach of this Development Agreement.
6. Reimbursement. DISTRICT shall pay CITY as follows:
a. Community Benefit Fee. The CITY shall receive twenty- five percent (25%) of all revenue the DISTRICT receives pursuant to Section 4.2(c) of the LEASE AGREEMENT or any amendment to the LEASE AGREEMENT or other agreement pertaining to the installation of a Billboard or other advertising display with EVERGREEN or any other party. (“Community Benefit Fee”).
The DISTRICT shall remit payment of the Community Benefit Fee to the CITY within thirty (30) days after the DISTRICT receives payment from EVERGREEN pursuant to the LEASE AGREEMENT.
b. Public Safety Messages. Pursuant and subject to Section 2.5 of the LEASE AGREEMENT, Amber Alerts and other emergency and public safety announcements shall be posted on the billboard at no cost to the DISTRICT and the CITY. DISTRICT and CITY agree on shared needs for future installation of telecommunications equipment on the billboard, as necessary for public safety.
c. Public Service Messages. DISTRICT shall receive approximately 12% of the available time from EVERGREEN (or any other advertising display party), equally spread throughout a 24-hour day for public service messages on the sign, on a space available basis. DISTRICT and CITY shall split that time on a 50/50 basis. The Party wishing to post public service messages shall be responsible for producing all camera-ready artwork ready to post at their cost. d. Except with respect to the display of CITY public service announcements and emergency broadcasts, District shall have sole and exclusive control over and responsibility for the content of any messages, announcements or advertisements displayed on the BILLBOARD or any other advertising display, and the CITY shall have no responsibility or authority with respect to such displays.
7. Records of Revenue. CITY shall have the right to audit the calculations, accounting, and payments to the DISTRICT, and to receive a copy of the “Annual Report” or similar report provided by EVERGREEN (or any other adverting display party) to the DISTRICT. These records will be made available at reasonable times to CITY with prior written request from the CITY.
8. Payment Due Date. The amounts due to CITY under this Agreement shall be due and payable within thirty (30) days after the DISTRICT receives payment from EVERGREEN (or any other advertising display party) pursuant to the LEASE AGREEMENT (or any amendment or other advertising display agreement).
9. Termination Provisions. This Agreement may be terminated upon the happening of any of the following events:
a. Failure of DISTRICT to perform any of the provisions of this Agreement, or b. Mutual agreement of the Parties or,
c. Failure of DISTRICT to cure any default under the terms and conditions of this Development Agreement or,
d. DISTRICT retains the right to terminate this Agreement upon thirty (30) days’ written notice to CITY in the event that the Lease Agreement is terminated or expired.
e. In any event of termination, DISTRICT shall remove, or cause to be removed, the BILLBOARD or any other advertising display installed on the PROPERTY.
10. Periodic Review. CITY shall review DISTRICT’S performance every twelve (12) months at the anniversary of the adoption of this Agreement. DISTRICT shall demonstrate good faith compliance with the terms of this Agreement. If as a result of the review, CITY finds and determines, based upon substantial evidence, that DISTRICT has not taken good faith efforts to comply with terms or conditions of this Agreement, CITY may terminate or modify the Agreement. This review shall be conducted by the Director of Community Development.
11. CITY Discretion. CITY retains its right and discretion, under all applicable Codes, to approve or disapprove any item related to this PROJECT which it has not specifically agreed to via this Agreement, however such approval shall not be unreasonably withheld. DISTRICT acknowledges that it shall comply with all CITY requirements for applications and permits of any nature and that this Agreement does not relieve DISTRICT of the necessity of filing appropriate applications and obtaining appropriate permits.
12. DISTRICT Breach. Failure by DISTRICT to pay amounts specified as required by this AGREEMENT, shall result in the withholding of building permits or any other permit until the breach is remedied.
13. Non-Liability of Officials and Employees of the CITY. No official, employee or agent of CITY shall be personally liable to DISTRICT in the event of any default or breach by CITY, or for any amount that will become due to DISTRICT, or for any obligation under the terms of this Agreement.
14. Notices. All notices shall be personally delivered or mailed to the below listed address, or to such other address as may be designated by written notice and shall be deemed sufficiently given and served for all purposes when delivered personally, by generally recognized overnight courier service (provided that sender retains a receipt evidencing the date and time of delivery), or three (3) days after deposit in the United States mail, certified or registered, return receipt requested, with postage prepaid. These addresses shall be used for delivery or service of process.
a. Address of DISTRICT is as follows:
Walnut Unified School District
Attention: Matt Torres Ed.D
Assistant Superintendent, Business Services
[email protected]
880 S. Lemon Ave.
Walnut, CA 91789
With a copy to:
Orbach Huff & Henderson LLP
Attn: Sarine Abrahamian
[email protected]
1901 Avenue of the Stars, Suite 575
Los Angeles, CA 90067
b. Address of CITY is as follows:
City of Diamond Bar
Attention: City Clerk
21810 Copley Drive
Diamond Bar, CA 91765
15. Developer Proposal. The PROJECT shall include EVERGREEN’s proposal, as modified by the City Council, including all conditions of approval contained in Planning Commission/City Council Resolution No. 2025-XX, which is incorporated herein by this reference. In the event of any inconsistency between terms of the proposal and this Agreement, this Agreement shall govern.
16. Licenses, Permits, Fees, and Assessments. At its sole expense, EVERGREEN shall obtain all licenses, permits, and approvals as may be required by this Agreement, or by the nature of the PROJECT.
17. Time of Essence. Time is of the essence in the performance of this Agreement.
18. Successor's Interest. The provisions of this Agreement shall be binding upon and inure to successors in interest of the parties and shall be specifically binding upon any future lessees or other owners of an interest in the PROPERTY.
19. Authority to Execute. The persons executing this Agreement on behalf of the parties warrant that they are duly authorized to execute this Agreement and that by executing this Agreement, the parties are formally bound.
20. Indemnification. DISTRICT agrees to protect, defend, and hold harmless CITY and their elective or appointive boards, officers, agents, and employees from any and all claims, liabilities, expenses or damages of any nature, including attorneys' fees, for bodily injury or death of any person, or damage to property, or interference with use of property, or otherwise arising out of negligent acts or omissions, or willful misconduct in the performance of the Agreement by DISTRICT, DISTRICT’S agents, officers or employees, contractors and
subcontractors hired by DISTRICT. DISTRICT shall have the right to select counsel to perform the defense, subject to such counsel being reasonably acceptable to CITY. DISTRICT shall also have the ability to control strategy and resolution of such actions, provided that DISTRICT must obtain CITY’s consent for any strategy or resolution that would impose an obligation on CITY (financial or otherwise) that would not be borne by DISTRICT or that would amount to a representation concerning, or an admission by, CITY.
21. Modification. This Agreement constitutes the entire agreement between the parties and supersedes any previous agreements, oral or written. This Agreement may be modified only by subsequent mutual written agreement executed by CITY and DISTRICT.
22. Remedies. The occurrence of any Event of Default shall give the nondefaulting party the right to proceed with any and all remedies set forth in this Agreement, including an action for damages, an action or proceeding at law or in equity to require the defaulting party to perform its obligations and covenants under this Agreement or to enjoin acts or things which may be unlawful or in violation of the provisions of this Agreement, and the right to terminate this Agreement.
23. Force Majeure. Subject to the party’s compliance with the notice requirements as set forth below, performance by either party hereunder shall be deemed not to be in default, and all performance and other dates specified in this Agreement shall be extended, where delays or default are due to causes beyond the control and without the fault of the party claiming an extension of time to perform, which may include, without limitation, the following: war, insurrection, strikes, lockouts, riots, floods, earthquakes, fires, assaults, acts of God, acts of the public enemy, epidemics, quarantine restrictions, freight embargoes, lack of transportation, governmental restrictions or priority, litigation, unusually severe weather, inability to secure necessary labor, material or tools, acts or omissions of the other party, or acts or failures to act of any public or governmental entity (except that the City’s acts or failure to act shall not excuse performance of the City hereunder). An extension of the time for any such cause shall be for the period of the enforced delay and shall commence to run from the time of the commencement of the cause, if notice by the party claiming such extension is sent to the other party within thirty (30) days of the commencement of the cause.
24. Attorney’s Fees. In addition to any other remedies provided hereunder or available pursuant to law, if either party brings an action or proceeding to enforce, protect or establish any right or remedy hereunder, the prevailing party shall be entitled to recover from the other party its costs of suit and reasonable attorney’s fees.
25. Remedies Cumulative. No right, power, or remedy given by the terms of this Agreement is intended to be exclusive of any other right, power, or remedy; and each other and every such right, power, remedy shall be cumulative and in addition to every other right, power, or remedy given by the terms of any such instrument, or by any statute or otherwise.
26. Waiver of Terms and Conditions. The failure of a PARTY to insist upon the strict performance of any of the provisions of this Agreement by the other PARTY, or the failure by a PARTY to exercise its rights upon the default of the other PARTY, shall not constitute a waiver of such PARTY’s right to insist and demand strict compliance by the other PARTY with the terms of this Agreement thereafter.
27. Recitals. The Recitals above are hereby incorporated into this section as though fully set forth herein and each party acknowledges and agrees that such Party is bound, for purposes of this Agreement, by the same.
[SIGNATURE PAGE FOLLOWS]
IN WITNESS WHEREOF, these parties have executed this Agreement on the day and year shown below.
"CITY"
CITY OF DIAMOND BAR,
a municipal corporation
BY:___________________
Mayor
Date:_____________
ATTEST:
_______________________
City Clerk
Date:______________
APPROVED AS TO FORM:
_______________________________
City Attorney
Date: ___________
"DISTRICT"
Walnut Valley Unified School
District
By: ___
Name:______________________
Title:_______________________
Date:______________
ATTEST:
_______________________
Secretary
Date:______________
APPROVED AS TO FORM:
_______________________________
General Counsel
Date: ___________
Exhibit A
EXHIBIT A
LEASE AGREEMENT BETWEEN DISTRICT AND EVERGREEN
Exhibit B
EXHIBIT B
CITY COUNCIL RESOLUTION NO. 2025-37
A notary public or other officer completing this certificate verifies only the identity of the individual who signed the document to which this certificate is attached, and not the truthfulness, accuracy, or validity of that document.
STATE OF CALIFORNIA )
)
COUNTY OF LOS ANGELES )
On _________, 2025, before me, _________________________________, Notary Public, personally appeared _________________________, who proved to me on the basis of satisfactory evidence to be the person(s) whose name is subscribed to the within instrument and acknowledged to me that he/she/they executed the same in his/her/their authorized capacity, and that by his/her/their signature on the instrument the person, or the entity upon behalf of which the person acted, executed the instrument.
I certify UNDER PENALTY OF PERJURY under the laws of the State of California that the foregoing paragraph is true and correct.
WITNESS my hand and official seal.
Signature ________________________________
(seal)
RESOLUTION NO. 2025-37
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF DIAMOND BAR,
CALIFORNIA, APPROVING THE WALNUT VALLEY UNIFIED SCHOOL
DISTRICT (WVUSD) ELECTRONIC BILLBOARD PROJECT NO. PL 2024-40
CONSISTING OF A CONDITIONAL USE PERMIT AND DEVELOPMENT
REVIEW LOCATED AT 880 SOUTH LEMON AVENUE, DIAMOND BAR, CA 91789 (ASSESSORS PARCEL NO. 8760-015-901).
A. RECITALS
1. The applicant, Evergreen Media LLC, and property owner, Walnut Valley Unified School District (WVUSD), filed an application requesting approval of specific entitlements necessary for the installation and operation of a 97-foot high, dualfaced digital LED billboard on a 6.08-acre lot located at 880 South Lemon Avenue, Diamond Bar, CA 91789.
2. The following approvals (collectively, the “Project”) are requested of the City Council:
(a) Development Code Amendment (DCA) to Title 22 (“Development Code”) of the Diamond Bar City Code to allow billboards and regulate billboards in the Light Industry (I) zone, subject to the approval of a Conditional Use Permit, Development Review, and a Development Agreement. The Development Code sections to be amended are as follows: 22.10.030,
22.36.080, 22.36.120, and 22.80.020.
(b) Conditional Use Permit (CUP) to authorize a billboard on the subject property, consistent with the Development Code Amendment. (c) Development Review (DR) to assess the visual design elements of the proposed billboard.
(d) Development Agreement (DA) between the City and WVUSD guaranteeing specified community benefits to be derived from the construction and operation of the proposed billboard.
3. The subject property consists of one parcel totaling 6.08-acres, located in the Light Industry (I) zone with an underlying General Plan land use designation of School (S).
4. The legal description of the subject property is Southwest Quarter of the Northwest Quarter of Section 17, Township 2 South, Range 9 West of Tract No. 10122. The Assessor’s Parcel Number (APN) is 8760-015-901.
5. In accordance to the provisions of the California Environmental Quality Act (CEQA), Section 15070, the City prepared and filed an Initial Study/Environmental Checklist and Notice of Intent to Adopt Mitigated Negative Declaration for the Project on September 19, 2025 and with the Los Angeles
Resolution No. 2025-37
2 County Clerk on September 19, 2025. The notice was published in the San Gabriel Valley Tribune newspaper. The notice was also mailed to property owners within a 700-foot radius of the project site. The public review period for the MND began on September 22, 2025, and ended on October 21, 2025, for a total of 30 days pursuant to CEQA Guidelines Section 15105.
6. In accordance with CEQA Guidelines Section 15074, a Resolution approving the Mitigated Negative Declaration and adopting the Mitigation Monitoring and Reporting Program for the project was reviewed by the City Council concurrently with this Resolution.
7. Notification of the public hearing for this project was published in the San Gabriel Valley Tribune newspaper on November 5, 2025. Public hearing notices were mailed to property owners within a 700-foot radius of the project site. In addition to the published and mailed notices, the project site was posted with a display board and public notices were posted at the City’s designated community posting sites.
8. On November 25, 2025, the Planning Commission of the City of Diamond Bar conducted a duly noticed public hearing, solicited testimony from all interested individuals, and concluded said hearing on that date.
9. Notification of the public hearing for this project was published in the San Gabriel Valley Tribune newspaper on December 5, 2025. Public hearing notices were mailed to property owners within a 700-foot radius of the project site. In addition to the published and mailed notices, the project site was posted with a display board and public notices were posted at the City’s designated community posting sites.
10. On December 16, 2025, the City Council of the City of Diamond Bar conducted a duly noticed public hearing, solicited testimony from all interested individuals, and concluded said hearing on that date.
11. The documents and materials constituting the administrative record of the proceedings upon which the City’s decision is based are located at the City of Diamond Bar, Community Development Department, Planning Division, 21810 Copley Drive, Diamond Bar, CA 91765.
B. RESOLUTION
NOW, THEREFORE, it is found, determined and resolved by the City Council of the City of Diamond Bar as follows:
1. This City Council hereby specifically finds that all of the facts set forth in the Recitals, Part A, of this Resolution are true and correct;
2. The City Council hereby finds that the project identified above in this Resolution required a Mitigated Negative Declaration (MND). The MND has been prepared according to the requirements of the California Environmental Quality Act (CEQA) and guidelines promulgated thereunder. The minimum 30-day public review
Resolution No. 2025-37
3 period for the MND began on September 22, 2025, and ended on October 21, 2025. Furthermore, the City Council has reviewed the MND and related documents in reference to the Project.
C. FINDINGS OF FACT
Based on the findings and conclusions set forth herein and as prescribed under Diamond Bar City Code (DBCC) Sections 22.58 and 22.48, this City Council hereby finds and approves as follows:
Conditional Use Permit Findings (DBCC Section 22.58)
1. The Proposed Use is allowed within the subject zoning district with the approval of a conditional use permit and complies with all other applicable provisions of this Development Code and the Municipal Code.
Pursuant to the Development Code Amendment and DBCC Section 22.10.030 Table 2-6, billboards, as defined by DBCC Section 22.80.020 once amended, will be a permitted use in the I zoning district with approval of a conditional use permit.
Through compliance with the conditions of approval stipulating the manner in which the use must be conducted, the proposed digital billboard will be compatible with neighboring uses and surrounding neighborhood.
Staff has evaluated the proposed digital billboard and determined that it is compatible with the surrounding industrial and commercial setting. The billboard’s location adjacent to the SR-60 freeway, its placement, and orientation are designed to minimize visibility from nearby residential areas and will not obstruct views, impede access, or conflict with existing site operations. Operational characteristics, including brightness, display transitions, and content, will be regulated through project conditions to prevent visual distractions or light spillover.
The project will not generate additional parking demand, as the structure is selfcontained and does not involve on-site employees or land use intensification.
Installation and maintenance activities will occur periodically without affecting existing site circulation or parking.
The project is consistent with the intent of the proposed DCA, which regulates the location, design, and permitting of digital billboards to ensure visual compatibility and minimize potential visual, operational, and aesthetic impacts
2. The Proposed Use is consistent with the general plan and any applicable specific plan.
The Proposed Use is consistent with General Plan Goal PF-G-4: (“Continue to provide residents of all ages and abilities with access to high quality local educational facilities in cooperation with the Walnut Valley and Pomona Unified School District (WVUSD and PUSD, respectively), the Los Angeles County library system, and community organizations”) in that the Proposed Use will be located on an existing developed site owned by WVUSD. The project utilizes an already