Initial Study/Mitigated Negative Declaration for the Camp San Luis Obispo Range Roads Repair Project, San Luis Obispo County, California

JUNE 2024

PREPARED FOR

Camp San Luis Obispo California Army National Guard

PREPARED BY

SWCA Environmental Consultants

INITIAL STUDY/MITIGATED NEGATIVE DECLARATION

FOR THE

CAMP SAN LUIS OBISPO RANGE ROADS REPAIR PROJECT,

SAN LUIS OBISPO COUNTY, CALIFORNIA

Prepared for

Attn: Major Brian D. Woods, PE

Prepared by

Cassidy Bewley, B.S.

SWCA Environmental Consultants 4111 Broad Street, Suite 210 San Luis Obispo, CA 93401

SWCA Project No. 77830

June 2024

Camp San Luis Obispo Range Roads Repair Project Initial Study/Mitigated Negative Declaration i

CONTENTS

1 Introduction

1.1 Project Location

1.2 Environmental Setting

1.3 Project Description

1.3.1 Camp SLO Background

1.3.2 Existing Built Conditions

1.3.3 Roadway and Culvert Improvements

1.3.4 Construction

1.4 Required Discretionary Approvals

2 Environmental Checklist and Environmental Evaluation

I. Aesthetics II. Agriculture and Forestry Resources III. Air Quality IV. Biological Resources V. Cultural Resources VI. Energy VII. Geology and Soils VIII. Greenhouse Gas Emissions IX. Hazards and Hazardous Materials X. Hydrology and Water Quality XI. Land Use and Planning XII. Mineral Resources XIII. Noise XIV. Population and Housing XV. Public Services XVI. Recreation XVII. Transportation XVIII. Tribal Cultural Resources XIX. Utilities and Service Systems XX. Wildfire XXI. Mandatory Findings of Significance

3 References

Appendices Appendix A. Project Plan Sets Appendix B. CalEEMod Reports Appendix C. Biological Resources Assessment Appendix D. NEPA Categorical Exclusion

1 INTRODUCTION

Project Title: Camp San Luis Obispo Range Roads Repair Project

Lead Agency: California Army National Guard 9800 Goethe Road Sacramento, CA 95827

Lead Agency Staff Contact: Major Brian Woods, PE Camp San Luis Obispo 10 Sonoma Avenue San Luis Obispo, CA 93405

Project Applicant: California Army National Guard

1.1 Project Location

The Camp San Luis Obispo Range Roads Repair Project (project) would be located within Camp San Luis Obispo California Army National Guard Base (Camp SLO) north of California State Route 1 (SR 1), approximately 2.25 miles northwest of the city of San Luis Obispo, San Luis Obispo County, California (Figure 1). The project includes roadway and culvert improvements along approximately 13,967 linear feet (2.65 miles) of roadway along San Benito Road and Range Road, located on an approximately 160-acre property (Assessor Parcel Numbers [APNs] 073-231-003, 073-231-004, and 073-231-006). The total proposed project disturbance area is estimated to be approximately 779,000 square feet (17.88 acres).

The proposed disturbance area and immediately surrounding areas constitute the 57.65-acre project site (see Figure 2). The project site is approximately 3.6 miles west of the intersection of SR 1 and Highland Drive. Surrounding land uses include El Chorro Regional Park and Dairy Creek Golf Course to the west, the Los Padres National Forest to the north, Cuesta Conservation Camp #24 and California Men’s Colony to the east, and SR 1 and Camp SLO facilities to the south.

1.2 Environmental Setting

Topography within the project site ranges between nearly flat to moderately sloping. Elevations within the project area range from approximately 345 to 886 feet (105–270 meters). The project property generally supports a range of habitats including oak woodland, chaparral, scrub, grassland, and riparian/wetland with a mix of military base developments. According to USGS topographic maps and other available resources, twelve drainages run through the project site, as well as three ponds, and eleven swales. The hydrological features flow in a southerly direction towards Chorro Creek.

Figure 1. Project Vicinity Map

Figure 2. Project Location Map

1.3 Project Description

The California Army National Guard is proposing roadway improvements and replacement and/or extension of existing roadway culverts along approximately 2.65 miles of roadway along San Benito and Range Roads within the Camp SLO property.

The purpose of the project is to improve the degraded roadways so that they can continue to safely provide access for regular transport of heavy machinery and other vehicles as needed to support current and near future Camp SLO operations over the estimated 25-year lifespan of the improvements, as well as to improve existing drainage through the area through improvements and replacements of culverts in the roadways. Improvements along San Benito Road would generally occur between the San Benito Road/Santa Clara Avenue intersection to the San Benito Road/Range Road intersection (approximately 5,873 linear feet). Improvements along Range Road would generally occur from 4,865 feet west of the San Benito Road/Range Road intersection to 3,230 feet east of the San Benito Road/Range Road intersection (approximately 8,094 linear feet).

1.3.1 Camp SLO Background

Established in 1928, Camp SLO was dedicated as a training site for the California National Guard. In 1934, the camp was named in honor of Governor Frank Merriam and became known as “Camp Merriam.”

The name was changed to “Camp San Luis Obispo” when it was occupied by the Army in 1940 (California State Military History and Museums Program 2020).

Currently, Camp SLO provides operational, training, and logistical support to a wide variety of civilian and military agencies at the federal, state, and local levels. Camp SLO also supports Grizzly Youth Academy, which is a highly structured educational facility established in 1998 managed by a partnership between the California National Guard and the Grizzly Challenge Charter School for youth between the ages of 15 and 18 who have dropped out of high school or are at risk of dropping out (Grizzly Youth Academy 2023).

As required by the Sikes Act of 1960 and the Sikes Act Improvement Act of 1997, the California Army National Guard (CA ARNG) has prepared an Integrated Natural Resources Management Plan (INRMP) Update to provide Camp SLO with a long-term viable framework for managing natural resources on its lands. The INRMP establishes planning and management strategies and guidelines, identifies natural resources constraints and opportunities, supports the resolution of land use conflicts, provides baseline descriptions of natural resources necessary for the development of conservation strategies and environmental assessment, service as the principal information source for the preparation of future environmental documents for proposed Camp SLO actions, and provides guidance for annual natural resources management reviews (CA ARNG 2022).

1.3.2 Existing Built Conditions

San Benito Road is a north-south running roadway with a vehicle lane in each direction. Range Road is an east-west running roadway with a vehicle lane in each direction that is bisected by San Benito Road.

San Benito Road currently provides vehicle access from the Camp SLO facilities located north of US 101 to Range Road, and Range Road provides vehicle access to each of the base’s six shooting ranges and the Urban Training Complex.

The roadways are both currently paved with asphalt and have a width varying between 18 and 23 feet.

The roadways are assumed to have been paved in the 1940’s, and it is not known whether they have been improved since that time.

1.3.3 Roadway and Culvert Improvements

RANGE ROAD IMPROVEMENTS

The applicant proposes to widen and improve Range Road, which provides access to all six shooting ranges on Camp SLO, including the Alpha, Bravo, Charlie, Delta, Echo, and Foxtrot Ranges, as well as the Urban Training Complex. The project would include improvements to eight existing corrugated metal pipe (CMP) culverts within Range Road. Proposed improvements to existing culverts are summarized in Table 1 and generally would include replacement of CMP culverts with high-density polyethylene (HDPE) pipe culverts, installation of rip-rap materials,1 and/or retaining or replacing existing concrete headwalls (see Table 1).

Table 1. Proposed Culvert Improvements

Culvert Existing Conditions Proposed Improvement(s)

Range Road Culvert A 18-inch-diameter CMP culvert; north side is silted over with no surface evidence

Protect in place.

Expose currently buried end of culvert and install rip rap on north end.

Retain existing concrete headwall and install rip rap on southern end.

Range Road Culvert B 36-inch-diameter CMP culvert Replace existing culvert with 36-inch-diameter HDPE pipe culvert.

Install rip rap on both ends of culvert.

Remove existing concrete headwall and install new pre-cast concrete headwall on north end.

Range Road Culvert C 36-inch-diameter CMP culvert Replace existing culvert with 36-inch-diameter HDPE pipe culvert.

Install rip rap on both ends of culvert.

Remove existing concrete headwall and install new pre-cast concrete headwall on north end.

Range Road Culvert D 48-inch-diameter CMP culvert Replace existing culvert with 48-inch-diameter HDPE pipe culvert.

Install rip rap on both ends of culvert.

Remove existing concrete headwall and install new pre-cast concrete headwall on north end.

Range Road Culvert E 36- to 42-inch-diameter CMP culvert Protect existing culvert in place.

Trim brush and trees at culvert inlet.

Range Road Culvert F 18-inch-diameter CMP culvert Replace existing culvert with 18-inch-diameter HDPE pipe culvert.

Protect existing concrete headwall in place.

Range Road Culvert G 18-inch-diameter CMP culvert Replace existing culvert with 18-inch-diameter HDPE pipe culvert.

Replace concrete headwall with pre-cast concrete headwall on north side*

San Benito Road Culvert H 36-inch-diameter reinforced concrete pipe (RCP) that transitions into 48-inch-diameter CMP culvert

Replace existing 48-inch-diameter culvert with 48-inch-diameter HDPE pipe culvert.

Overlap HDPE pipe with approximately 12 to 24 inches of the remaining RCP.

Fill in upper void space between the two overlapping pipes with concrete.

Protect existing concrete headwall in place.

Install riprap at outlet.

1 Rip-rap describes a range of rocky material used to protect structures from scour and erosion.

San Benito Road Culvert I 84-inch diameter CMP culvert Protect existing culvert in place.

Protect existing concrete headwall in place.

Install riprap at outlet.

Range Road Culvert J 36-inch diameter CMP culvert Replace existing culvert with 36-inch-diameter HDPE pipe culvert with flared-end sections at both ends.

Install riprap on both ends of culvert.

*The existing concrete headwall will be protected in place if possible. For the purposes of this analysis, the assumption is that the headwall will be replaced in order to evaluate a reasonable worst-case scenario.

The project would include the reconstruction and widening of Range Road to include one 11-foot-wide vehicle travel lane in each direction with 1- to 2-foot-wide shoulders on each side of the roadway. Existing barbed-wire fencing along the edge of the roadway would be reconstructed outside of the new roadway edge following completion of roadway improvements. An existing cattle guard located within the roadway would be removed and reconstructed to match the new road width near the same location. Existing utility poles located within the project site would be protected in place during construction activities. The project would also include burial of empty conduit underneath Range Road at the entrances to each shooting range to accommodate potential future utility connections.

SAN BENITO ROAD IMPROVEMENTS

The project would include reconstruction and widening of San Benito Road to include one 11-foot-wide vehicle travel lane in each direction with 1- to 2-foot-wide shoulders on each side of the roadway. This would include improvements to two existing CMP culverts within San Benito Road, as summarized in Table 1. In addition, the roadway centerline would be offset by 1 to 2 feet at certain locations in order to avoid impacting existing utility poles and to minimize grading within the creek adjacent to the roadway, existing barbed-wire fence located along the sides of the existing roadway would be either protected in place or rebuilt following construction activities, and existing overhead utility poles located in close proximity to the existing roadway would be protected in place. The existing State of California 8-inch underground water pipeline that bisects the San Benito Road alignment would also be protected in place and would not be affected by project activities.

1.3.4 Construction

The project would result in 463,600 square feet (10.64 acres) of permanent site disturbance (including previously paved/disturbed areas) and 315,400 square feet (7.24 acres) of temporary site disturbance (e.g., graded areas to be revegetated, equipment staging areas, etc.), resulting in a total site disturbance area of 779,000 square feet (17.88 acres). Equipment staging areas and a designated material stockpile area have been identified near the project site and are shown on Figure 2. Project construction activities would result in approximately 4,998 cubic yards of cut materials and approximately 8,674 cubic yards of fill materials. Material import will be limited to that needed to fortify the road subgrade and the paving material, including approximately 174 tons of lime, 393 tons of cement, and 12,922 tons of asphalt.

Project grading and excavation activities would have a maximum depth of 6 feet. The removal of herbaceous vegetation will be required, and approximately 14 coast live oak and 25 arroyo willow trees would be removed and/or impacted during roadway construction and to facilitate equipment access and grading, as summarized in Table 2, below.

Table 2. Estimated Tree Removals

Location Number of Trees to be Removed Species Diameter at Breast Height

(DBH)

Culvert D 8 Coast live oak 9 to 45 inches

20 Arroyo willow 6 to 35 inches

Culvert H 3 Coast live oak 16 to 25 inches

1 Arryo willow 12 inches

Culvert I 3 Coast live oak 20 to 40 inches

4 Arryo willow 8 to 25 inches

Proposed improvements to San Benito and Range Roads are anticipated to take approximately 4.5 months to complete each, for a total combined construction period of approximately 9 months.

Construction is planned to occur in two phases, with improvements to one roadway occurring between mid-June and early November 2024 and the second roadway being improved between mid-June and early November 2025. Construction activities would generally occur between 6:30 a.m. and 5:00 p.m. on weekdays and are anticipated to require an average of 12 to 15 construction workers to be on-site per day, with a maximum of 20 during paving activities. Following construction, the roadway improvements are anticipated to have a lifespan of 25 years.

1.4 Required Discretionary Approvals

The potential authorizations, permits, reviews, and approvals from federal, state, and local agencies that would be required for the project are listed in Table 3.

Table 3. Potential Authorizations, Permits, Reviews, and Approvals

Permit / Approval / Consultation Authorizing Agency

Federal

Clean Water Act Section 404 Compliance U.S. Army Corps of Engineers

National Environmental Policy Act Compliance California Army National Guard

State

CEQA Environmental Compliance California Army National Guard

Lake and Streambed Alteration Agreement California Department of Fish and Wildlife

National Pollutant Discharge System Storm Water Permit for Construction Activities

Regional Water Quality Control Board

California Endangered Species Act Compliance California Department of Fish and Wildlife

Regional

Authority to Construct/Permit to Operate San Luis Obispo County Air Pollution Control District

1.4.1 National Environmental Policy Act Requirements

The project is will require a permit from the U.S. Army Corps of Engineers and would therefore be subject to environmental review under the National Environmental Policy Act (NEPA). The California Army National Guard is the federal lead agency and has determined the project qualifies for a NEPA Categorical Exclusion. The Camp SLO Environmental Office has prepared NEPA documentation for the proposed project, see Appendix D.

2 ENVIRONMENTAL CHECKLIST AND ENVIRONMENTAL

EVALUATION

ENVIRONMENTAL FACTORS POTENTIALLY AFFECTED

The proposed project could have a "Potentially Significant Impact" for environmental factors checked below. Please refer to the attached pages for discussion on mitigation measures or project revisions to either reduce these impacts to less than significant levels or require further study.

☐ Aesthetics ☐ Greenhouse Gas Emissions ☐ Public Services

☐ Agriculture and Forestry Resources

☒ Hazards and Hazardous Materials

☐ Recreation

☒ Air Quality ☒ Hydrology and Water Quality ☐ Transportation

☒ Biological Resources ☒ Land Use and Planning ☒ Tribal Cultural Resources

☒ Cultural Resources ☐ Mineral Resources ☐ Utilities and Service Systems

☐ Energy ☒ Noise ☐ Wildfire

☒ Geology and Soils ☐ Population and Housing ☒ Mandatory Findings of Significance

ENVIRONMENTAL DETERMINATION

On the basis of this initial evaluation:

☐ I find that the proposed project COULD NOT have a significant effect on the environment, and a NEGATIVE DECLARATION will be prepared.

☒ I find that although the proposed project could have a significant effect on the environment, there will not be a significant effect in this case because revisions in the project have been made by or agreed to by the project proponent. A MITIGATED NEGATIVE DECLARATION will be prepared.

☐ I find that the proposed project MAY have a significant effect on the environment, and an ENVIRONMENTAL IMPACT REPORT is required.

☐ I find that the proposed project MAY have a “potentially significant impact” or “potentially significant unless mitigated” impact on the environment, but at least one effect 1) has been adequately analyzed in an earlier document pursuant to applicable legal standards, and 2) has been addressed by mitigation measure based on the earlier analysis as described on attached sheets. An ENVIRONMENTAL IMPACT REPORT is required, but it must analyze only the effects that remain to be addressed.

☐ I find that although the proposed project could have a significant effect on the environment, because all potentially significant effects (a) have been analyzed adequately in an earlier EIR or NEGATIVE DECLARATION pursuant to applicable standards, and (b) have been avoided or mitigated pursuant to that earlier EIR or NEGATIVE DECLARATION, including revisions or mitigation measures that are imposed upon the proposed project, nothing further is required.

Date: Signed:

I. Aesthetics

Environmental Issues

Potentially Significant

Impact

Less Than Significant with Mitigation

Incorporated

Less Than Significant

Impact No Impact

Except as provided in Public Resources Code Section 21099, would the project:

(a) Have a substantial adverse effect on a scenic vista? ☐ ☐ ☐ ☒

(b) Substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, and historic buildings within a state scenic highway?

(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?

(d) Create a new source of substantial light or glare which would adversely affect day or nighttime views in the area?

Setting

Scenic Vista

A scenic vista is defined as a view that provides visual and aesthetic value to the surrounding community.

CEQA outlines that it is California’s duty to “provide the people of this state with clean air and water, enjoyment of aesthetic, natural, scenic, and historic environmental qualities, and freedom form excessive noise” Public Resources Code Section 21001(b)). A project is determined to have a significant impact on aesthetics if the degree to which the public can enjoy a scenic vista is hindered, which largely depends on how well the proposed project blends in with the existing natural setting.

California Scenic Highway Program

The California Scenic Highway Program was created by the State Legislature in 1963 to protect and enhance the natural scenic beauty of California highways and adjacent corridors. A highway may be designated scenic depending upon how much of the natural landscape can be seen by travelers, the scenic quality of the landscape, and the extent to which development intrudes upon the traveler's enjoyment of the view. Scenic Highways within San Luis Obispo County include U.S. Highway 101 (US 101), State Route 46 (SR 46), portions of State Route 41 (SR 41), State Route 1 (SR 1), and Lake Nacimiento Drive. The distance from SR 1 to the nearest part of the project site is approximately 0.5 mile;

SR 1 is designated as a State Scenic Highway at this location (California Department of Transportation [Caltrans] 2018).

Existing Conditions

The project site is located in a rural environment characterized by nearly flat to moderately sloping topography containing various habitats including oak woodland, chaparral, scrub, grassland, and riparian/wetland with a mix of military base developments. Twelve drainages, three ponds, and eleven swales run through the project site, all flowing in a southerly direction towards Chorro Creek.

a) Would the project have a substantial adverse effect on a scenic vista?

The project site is located near the foothills of the Santa Lucia Mountain Range and would be intermittently visible to viewers traveling in vehicles along SR 1 located approximately 0.5 mile south of the project site and viewers hiking the Eagle Rock trail, which is located approximately 0.8 mile southwest of the project site. Views of the project site are well-screened from SR 1 and the Eagle Rock hiking trail by existing topography and vegetation. Public views of the site and surrounding area are not expansive and do not constitute a scenic vista. In addition, the County of San Luis Obispo has not designated the site or surrounding area as having unique or high scenic value in its General Plan. Therefore, the project would not have a substantial adverse effect on a scenic vista and no impacts would occur.

b) Would the project substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, and historic buildings within a state scenic highway?

The project site is located approximately 0.5 miles north of SR 1 which is designated as a State Scenic Highway at this location (California Department of Transportation [Caltrans] 2018). The project site does not support significant scenic resources such as rock outcroppings or historic structures, and tree removals would be limited to those associated with the culvert improvements for culverts D, H, and I as summarized in Table 2. Views of the project site as seen from SR 1 are heavily screened by existing topography and vegetation. During construction, intermittent, temporary views of construction vehicles, equipment, and signage could be visible to viewers traveling along SR 1. However, construction-related views would be heavily screened by existing topography and vegetation that would not be altered by construction. In addition, construction-related views would be limited to the 9-month construction period and following construction, the site would not result in any long-term noticeable visual changes.

Therefore, impacts would be less than significant.

c) In non-urbanized areas, would the project 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?

The project is located in a rural, non-urbanized area. During construction, intermittent, temporary views of construction vehicles, equipment, and signage could be visible to viewers traveling along SR 1 and viewers hiking the Eagle Rock trail. However, construction-related views would be heavily screened by existing topography and vegetation from both public viewing locations that would not be altered by construction. In addition, construction-related views would be limited to the 9-month construction period and following construction, the site would not result in noticeable visual changes. The project would include widening and re-paving existing roadways, replacement of existing culverts, and minor vegetation removal. No aboveground structures would be built. Therefore, completion of the project would not substantially degrade the existing visual character or quality of public views of the site. Impacts would be less than significant.

d) Would the project create a new source of substantial light or glare which would adversely affect day or nighttime views in the area?

Project construction is planned to occur in two phases, with improvements to one roadway (San Benito Road or Range Road) occurring between mid-June and early November the first year of construction and the second roadway being improved between mid-June and early November of the second year of construction. Construction activities would take place between 6:30 a.m. and 5:00 p.m. on weekdays.

Accordingly, use of temporary artificial light would not be substantial and would be limited to relatively short timeframes throughout each construction phase. Following construction, the project would not establish any permanent sources of light or glare. Therefore, impacts associated with creation of a new source of substantial light or glare would be less than significant.

Conclusion

The project site is not located within a scenic vista. The project would not result in adverse impacts to scenic resources within the viewshed of a state scenic highway or substantially degrade the existing visual character of public views of the site and its surroundings. The project would not create a new source of substantial light or glare that would adversely affect nighttime views in the area. Therefore, impacts associated with aesthetics would be less than significant and no mitigation measures are necessary.

Mitigation Measures

Mitigation is not necessary.

II. Agriculture and Forestry Resources

Environmental Issues

Potentially Significant

Impact

Less Than Significant with Mitigation

Incorporated

Less Than Significant

Impact No Impact

In determining whether impacts to agricultural resources are significant environmental effects, lead agencies may refer to the California Agricultural Land Evaluation and Site Assessment Model (1997) prepared by the California Dept. of Conservation as an optional model to use in assessing impacts on agriculture and farmland. In determining whether impacts to forest resources, including timberland, are significant environmental effects, lead agencies may refer to information compiled by the California Department of Forestry and Fire Protection regarding the state’s inventory of forest land, including the Forest and Range Assessment Project and the Forest Legacy Assessment project; and forest carbon measurement methodology provided in Forest Protocols adopted by the California Air Resources Board. Would the project:

(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?

(b) Conflict with existing zoning for agricultural use, or a Williamson Act contract?

(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))?

(d) Result in the loss of forest land or conversion of forest land to non-forest use?

(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?

Setting

The California Department of Conservation (DOC) Farmland Mapping and Monitoring Program (FMMP) produces maps and statistical data used for analyzing impacts on California’s agricultural resources.

Agricultural land is rated according to soil quality and current land use. According to the FMMP, the project site is located on land designated as Grazing Land and Farmland of Local Potential (California Department of Conservation [CDOC] 2022).

The Land Conservation Act of 1965, also known as the Williamson Act, enables local governments to form contracts with private landowners in order to restrict specific parcels of land to agriculture or related open space use. Landowners then receive lower property tax assessments because they are based upon farming and open space uses instead of full market value. The project site is not within lands subject to a Williamson Act contract.

According to the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Soil Survey of San Luis Obispo County, California and the NRCS Web Soil Survey, the project site is underlain by a number of soil types as shown in Figure 3 and described below (NRCS 2023):

• Soil Unit 109: Briones-Pismo loamy sands, 9 to 30 percent slopes

This soil unit consists of Briones and Pismo soils at 40 and 30 percent, respectively. The drainage class of this soil type is somewhat excessively drained, and it is composed primarily of loamy sand and weathered bedrock. This soil type occurs on mountains and hills at elevations between 300 and 2,000 feet (90 and 600 meters). This soil type is not considered prime farmland.

• Soil Unit 127: Cropley clay, 0 to 2 percent slopes, MRLA 14

This soil unit consists of Cropley soils at 85 percent. The drainage class of this soil type is moderately well drained, and it is composed primarily of clay and sandy clay loam. This soil type occurs on terraces and alluvial fans at elevations between 20 and 2,040 feet (5 and 620 meters). This soil type is considered prime farmland if irrigated.

• Soil Unit 129: Diablo clay, 5 to 9 percent slopes, MRLA 15

This soil unit consists of Diablo soils at 90 percent. The drainage class of this soil type is well drained, and it is composed primarily of clay. This soil type occurs on mountains and hills at elevations between 30 and 1,130 feet (10 and 350 meters). This soil type is considered prime farmland if irrigated.

• Soil Unit 130: Diablo and Cibo clays, 9 to 15 percent slopes

This soil unit consists of Diablo and Cibo soils at 50 and 45 percent, respectively. The drainage class of this soil type is well drained, and it is composed primarily of clay. This soil type occurs on hills at elevations between 200 and 600 feet (60 and 180 meters). This soil type is considered farmland of statewide importance.

• Soil Unit 131: Diablo and Cibo clays, 15 to 30 percent slopes

This soil unit consists of Diablo and Cibo soils at 50 and 45 percent, respectively. The drainage class of this soil type is well drained, and it is composed primarily of clay. This soil type occurs on mountains hills at elevations between 200 and 3,000 feet (60 and 920 meters). This soil type is not considered prime farmland.

• Soil Unit 147: Lodo clay loam, 5 to 15 percent slopes

This soil unit consists of Lodo soils at 85 percent. The drainage class of this soil type is somewhat excessively drained, and it is composed primarily of clay loam. This soil type occurs on mountains and hills at elevations between 300 and 3,000 feet (90 and 920 meters). This soil type is not considered prime farmland.

• Soil Unit 148: Lodo clay loam, 15 to 30 percent slopes

This soil unit consists of Lodo soils at 85 percent. The drainage class of this soil type is somewhat excessively drained, and it is composed primarily of clay loam. This soil type occurs on mountains and hills at elevations between 300 and 3,000 feet (90 and 920 meters). This soil type is not considered prime farmland.

• Soil Unit 149: Lodo clay loam, 30 to 50 percent slopes, MRLA 15

This soil unit consists of Lodo soils at 85 percent. The drainage class of this soil type is somewhat excessively drained, and it is composed primarily of clay loam. This soil type occurs on mountains and hills at elevations between 10 and 2,760 feet (5 and 850 meters). This soil type is not considered prime farmland.

• Soil Unit 158: Los Osos loam, 5 to 9 percent slopes

This soil unit consists of Los Osos soils at 85 percent. The drainage class of this soil type is well drained, and it is composed primarily of loam, clay, and sandy loam. This soil type occurs on hills and ridges at elevations between 100 and 2,000 feet (30 and 610 meters). This soil type is considered farmland of statewide importance.

• Soil Unit 159: Los Osos loam, 9 to 15 percent slopes

This soil unit consists of Los Osos soils at 85 percent. The drainage class of this soil type is well drained, and it is composed primarily of loam, clay, and sandy loam. This soil type occurs on hills and ridges at elevations between 100 and 2,000 feet (30 and 610 meters). This soil type is not considered prime farmland.

• Soil Unit 160: Los Osos loam, 15 to 30 percent slopes

This soil unit consists of Los Osos soils at 85 percent. The drainage class of this soil type is well drained, and it is composed primarily of loam, clay, and sandy loam. This soil type occurs on hills and ridges at elevations between 140 and 910 feet (40 and 280 meters). This soil type is not considered prime farmland.

• Soils Unit 162: Los Osos – Diablo complex, 5 to 9 percent slopes

This soil unit consists of Los Osos and Diablo soils at 35 and 30 percent, respectively. The drainage class of this soil type is well drained, and it is composed primarily of loam, clay, and sandy loam. This soil type occurs on hills and ridges at elevations between 200 and 1,500 feet (60 and 460 meters).

This soil type is considered farmland of statewide importance.

• Soil Unit 168: Los Osos variant clay loam, 15 to 50 percent slopes

This soil unit consists of Los Osos soils at 85 percent. The drainage class of this soil type is well drained, and it is composed primarily of clay and clay loam. This soil type occurs on mountains and hills at elevations between 300 and 1,500 feet (90 and 460 meters). This soil type is not considered prime farmland.

• Soil Unit 195: Rock outcrop – Lithic Haploxerolls complex, 30 to 75 percent slopes

This soil unit consists of Rock outcrop and Lithic haploxerolls soils at 55 and 25 percent, respectively.

The drainage class of this soil type is excessively drained, and it is composed primarily of unweathered bedrock. This soil type occurs on mountains at elevations between 20 and 4,000 feet (5 and 1220 meters). This soil type is not considered prime farmland.

• Soil Unit 197: Salinas silty clay loam, 0 to 2 percent slopes, MRLA 14

This soil unit consists of Salinas soils at 85 percent, respectively. The drainage class of this soil type is well drained, and it is composed primarily of very fine sandy loam and silty clay loam. This soil type occurs on flood plains, alluvial flats, and alluvial fans at elevations between 0 and 1,180 feet (0 and 360 meters). This soil type is considered prime farmland if irrigated.

• Soil Unit 198: Salinas silty clay loam, 2 to 9 percent slopes, MRLA 14

This soil unit consists of Salinas soils at 85 percent, respectively. The drainage class of this soil type is well drained, and it is composed primarily of silty clay loam. This soil type occurs on flood plains, terraces, and alluvial fans at elevations between 0 and 1,480 feet (0 and 450 meters). This soil type is considered prime farmland if irrigated.

• Soil Unit 221: Xererts – Xerolls – Urban land complex, 0 to 15 percent slopes

This soil unit consists of Xererts, Xerolls, and Urban soils at 40, 35, and 20 percent, respectively. The drainage class of this soil type is well drained, and it is composed primarily of variable soils and weathered bedrock. This soil type occurs on mountains and hills at elevations between 0 and 2,500 feet (0 and 760 meters). This soil type is not considered prime farmland.

Figure 3. Project Site Soils Map

Project Site Boundary

Forestland is defined in California Public Resources Code (PRC) Section 12220(g) as land that can support 10% native tree cover of any species, including hardwoods, under natural conditions, and that allows for management of one or more forest resources, including timber, aesthetics, fish and wildlife, biodiversity, water quality, recreation, and other public benefits. Timberland is defined in PRC Section 4526 as land, other than land owned by the federal government and land designated by the State Board of Forestry and Fire Protection as experimental forest land, which is available for, and capable of, growing a crop of trees of any commercial species used to produce lumber and other forest products, including Christmas trees.

Environmental Evaluation

a) Would the project 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?

According to the Farmland Mapping and Monitoring Program of the California Resources Agency, the project site is located on Grazing Land and Farmland of Local Potential. The project site consists primarily of existing paved roadways and adjacent road shoulders, which have little to no potential to be used for agricultural purposes in the future due to the very limited square footage and thin shape of the area.

Further, roadways are not mapped within the FMMP land designations, but if they were, these areas would be designated as Urban and Built-Up Land. The project would not convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance to non-agricultural use. Therefore, no impacts would occur.

b) Would the project conflict with existing zoning for agricultural use, or a Williamson Act contract?

This project site is not located within a Williamson Act contract (CDOC 2022). The project site is located within the Agriculture land use category designated by the County of San Luis Obispo. The project consists of minor widening and improvements to existing roadways and replacement of existing culverts and would not preclude the surrounding areas from future agricultural uses. Therefore, the project would not conflict with existing zoning for agricultural use or a Williamson Act contract, and no impacts would occur.

c) Would the project 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))?

The project site and surrounding area is not within forest land, timberland, or timberland production land use or zoning designations; therefore, the project would not conflict with the existing zoning for, or cause rezoning of, forest land, timberland, or Timberland Production. No impacts would occur.

d) Would the project result in the loss of forest land or conversion of forest land to non-forest use?

Neither the project site nor the immediately surrounding area supports forest land uses or meets the definition of forest land established in PRC Section 12220(g). Implementation of the project would result in removal of approximately 14 coast live oak and 25 arroyo willow trees located within or directly adjacent to culvert improvement areas. Based on the location of these trees adjacent to existing roadways, and their scattered distribution across multiple areas of the project site, removal of these trees would not constitute loss or conversion of forestland. The project would not result in the loss of forest land or conversion of forest land to non-forest use; therefore, no impacts would occur.

e) Would the project 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?

The project includes improvements of existing roadways and culverts and does not include additional development of surrounding land. Surrounding land that Range Road and San Benito Road provide access to does not currently support any active agricultural activities or forest land. The project would not involve other changes in the existing environment that could result in conversion of Farmland to non-agricultural use or conversion of forest land to non-forest use; therefore, no impact would occur.

Conclusion

The project would not directly or indirectly result in the conversion of farmland, forest land, or timber land to non-agricultural uses or non-forest uses and would not conflict with agricultural zoning or otherwise adversely affect agricultural resources or uses. Potential impacts to agricultural resources would be less than significant and no mitigation measures are necessary.

Mitigation Measures

Mitigation is not necessary.

III. Air Quality

Environmental Issues

Potentially Significant

Impact

Less Than Significant with Mitigation

Incorporated

Less Than Significant

Impact No Impact

Where available, the significance criteria established by the applicable air quality management district or air pollution control district may be relied upon to make the following determinations. Would the project:

(a) Conflict with or obstruct implementation of the applicable air quality plan?

(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?

(c) Expose sensitive receptors to substantial pollutant concentrations?

(d) Result in other emissions (such as those leading to odors) adversely affecting a substantial number of people?

Setting

Federal and State Air Quality Standards

San Luis Obispo County is part of the South Central Coast Air Basin (SCCAB), which also includes Santa Barbara and Ventura Counties. Air quality within the SCCAB is regulated by several jurisdictions, including the U.S. Environmental Protection Agency (U.S. EPA), California Air Resources Board (CARB), and San Luis Obispo County Air Pollution Control District (SLOAPCD). Each of these jurisdictions develops rules, regulations, and policies to attain the goals or directives imposed upon them through legislation.

The CARB is the agency responsible for coordination and oversight of state and local air pollution control programs in California and for implementing the California Clean Air Act (CCAA) of 1988. The California Department of Public Health established California Ambient Air Quality Standards (CAAQS) in 1962 to define the maximum amount of a pollutant (averaged over a specified period of time) that can be present without any harmful effects on people or the environment. The CARB adopted the CAAQS developed by the California Department of Public Health in 1969, which had established CAAQS for 10 criteria pollutants: particulate matter (less than 10 microns in diameter [PM10] and less than 2.5 microns in diameter [PM2.5]), ozone (O3), nitrogen dioxide (NO2), sulfate, carbon monoxide (CO), sulfur dioxide (SO2), visibility-reducing particles, lead (Pb), hydrogen sulfide (H2S), and vinyl chloride.

The Federal Clean Air Act (FCAA) later required the U.S. EPA to establish National Ambient Air Quality Standards (NAAQS) for pollutants considered harmful to public health and the environment, and also set deadlines for their attainment. The U.S. EPA has established NAAQS for six criteria pollutants (all of which are also regulated by CAAQS): CO, lead, NO2, ozone, PM10 and PM2.5, and SO2.

California law continues to mandate compliance with the CAAQS, which are often more stringent than national standards. However, California law does not require that CAAQS be met by specified dates as is the case with NAAQS. Rather, it requires incremental progress toward attainment. The SLOAPCD is the agency primarily responsible for ensuring that NAAQS and CAAQS are not exceeded and that air quality conditions within the county are maintained.

San Luis Obispo County Clean Air Plan

The San Luis Obispo County Air Pollution Control District (SLOAPCD) San Luis Obispo County 2001 Clean Air Plan (2001 CAP) is a comprehensive planning document intended to evaluate long-term air pollutant emissions and cumulative effects and provide guidance to the SLOAPCD and other local agencies on how to attain and maintain the state standards for ozone and particulate matter 10 micrometers or less in diameter (PM10) (SLOAPCD 2001). The 2001 CAP presents a detailed description of the sources and pollutants that impact the jurisdiction’s attainment of state standards, future air quality impacts to be expected under current growth trends, and an appropriate control strategy for reducing ozone precursor emissions, thereby improving air quality. In order to be considered consistent with the 2001 CAP, a project must be consistent with the land use planning and transportation control measures and strategies outlined in the 2001 CAP.

Sensitive Receptors

Sensitive receptors are people that have an increased sensitivity to air pollution or environmental contaminants, such as the elderly, children, people with asthma or other respiratory illnesses, and others who are at a heightened risk of negative health outcomes due to exposure to air pollution. Some land uses are considered more sensitive to changes in air quality than others due to the population that occupies the uses and the activities involved. Sensitive receptor locations include schools, parks and playgrounds, daycare centers, nursing homes, hospitals, and residences. The nearest off-site sensitive receptor location is El Chorro Regional Park, located approximately 100 feet west of the project site.

Emissions Sources and Local Air District Emissions Thresholds

The SLOAPCD has developed and updated their CEQA Air Quality Handbook (most recently updated via a 2023 Administrative Update Version) to help local agencies evaluate project-specific impacts and determine if air quality mitigation measures are needed, or if potentially significant impacts could result.

This handbook includes established thresholds for both short-term construction emissions and long-term operational emissions.

Use of heavy equipment and earth-moving operations during project construction can generate fugitive dust and engine combustion emissions that may have substantial temporary impacts on local air quality and climate change. Combustion emissions, such as nitrogen oxides (NOx), reactive organic gases (ROG), greenhouse gases (GHGs), and diesel particulate matter (DPM), are most significant when using large, diesel-fueled scrapers, loaders, bulldozers, haul trucks, compressors, generators, and other heavy equipment. The SLOAPCD has established thresholds of significance for each of these contaminants.

Operational impacts are focused primarily on the indirect emissions (i.e., motor vehicles) associated with residential, commercial, and industrial development. Certain types of projects can also include components that generate direct emissions, such as power plants, gasoline stations, dry cleaners, and refineries (referred to as stationary source emissions). Operational impacts associated with residential development consist primarily of indirect emissions (i.e., motor vehicles). Certain other types of projects can also include components that generate direct emissions, such as power plants, gasoline stations, dry cleaners, and refineries (referred to as stationary source emissions).

Naturally Occurring Asbestos

Naturally occurring asbestos (NOA) is identified as a toxic air contaminant by the California Air Resources Board (CARB). Serpentine and other ultramafic rocks are fairly common throughout San Luis Obispo County and may contain NOA. If these areas are disturbed during construction, NOA-containing particles can be released into the air and have an adverse impact on local air quality and human health. Based on the SLOAPCD NOA Screening map, the project site is located in an area identified as having known potential for NOA (San Luis Obispo County Air Pollution Control District [SLOAPCD] 2024).

Environmental Evaluation

a) Would the project conflict with or obstruct implementation of the applicable air quality plan?

In order to be considered consistent with the 2001 CAP, a project must be consistent with the land use planning and transportation control measures and strategies that are outlined in the 2001 CAP. If the project is consistent with these measures, the project is considered consistent with the CAP (SLOAPCD 2023).

The project consists of improvements to existing roadways and culverts. The project would not result in a change in land uses or facilitate future changes in land uses; therefore, the land use planning measures of the CAP, such as planning compact communities and balancing jobs and housing, would not be applicable to the project. The proposed roadway improvements would not increase vehicle capacity on either roadway and would not result in a significant increase in vehicle trips following construction activities. The project would not be inconsistent with the land use planning or transportation control measures of the CAP or otherwise obstruct the implementation of the CAP or other applicable air quality plans. Therefore, potential impacts would be less than significant.

b) Would the project 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?

San Luis Obispo County is currently designated as non-attainment for ozone and PM10 under state…