“Here in Colorado, we are preserving and protecting our world-class outdoors, supporting our thriving agriculture industry, and expanding opportunities for outdoor recreation, and legislation to protect our treasured land in the Lower Dolores River canyon is a great step towards achieving these goals.” —Governor Jared Polis, July 15, 2022[1]
This chapter provides a baseline information on the resource in the Project area and the anticipated consequences from Project implementation. The baseline information on each resource topic describes the existing conditions and allows for a comparative “before-and-after” analysis between pre-Project conditions and the anticipated effects associated with Project implementation.
Field investigations of the proposed Project area were conducted on October 3 and 4, and January 6, 2024. The proposed Section 1 east array area was surveyed via pedestrian surveys throughout the area. Access to the SLB tract was granted by the current agricultural lease holder (pers. comm. Mont Snyder, October 2, 2023). The proposed west array area, or Section 2, is privately owned. Observations of this area were made from outside the fenced area, along Lone Cone Road and from the property to the north (with landowner’s permission).
Wright’s Mesa General Description
Wright’s Mesa is an approximate 27-square-mile area delineated roughly by Naturita Creek and canyon to the west and the San Miguel River canyon and Beaver Creek to the north and east. Wright’s Mesa is part of the shale deserts and sedimentary basins of the Colorado Plateau ecoregion (Chapman et al. 2006). The proposed Project area would encompass 1,009.4 acres of pinyon-juniper sagebrush scrubland and riparian cottonwood forests within a rural ranching community, and is situated in an otherwise undeveloped area.
3.1 Air Quality
Regulatory
Federal and state regulations to protect air quality are, Clean Air Act of 1972 (42 USC 7401 et seq.) (CAA) and Colorado § 5 CCR 1001. The CAA requires the EPA to set National Ambient Air Quality Standards (Title 40, CFR Part 50) (NAAQS) for six "criteria pollutants" that are common in outdoor air and considered harmful to public health and the environment. (Reviewing National Ambient Air Quality Standards (NAAQS): Scientific and Technical Information | US EPA). The NAAQS specify the maximum ambient (outdoor air) concentration levels of criteria pollutants considered safe for public health and the environment and provide a management guideline by which governing entities such as the Colorado Department of Public Health and Environment (CDPHE) can monitor and regulate pollution. An area where a criteria pollutant concentration exceeds NAAQS levels is categorized as “nonattainment”.
The NAAQS criteria pollutants are: particulate matter (PM2.5 and PM10), ground-level ozone (O3), Sulfur dioxide (SO2), Nitrogen dioxide (NO2), Lead (Pb), and Carbon monoxide (CO). Particulate matter is a mixture of solid particles and liquid droplets found in the air and is classified based on the size of the particles (less than 2.5 microns or between 2.5 and 10 microns).
It is widely accepted that solar photovoltaic array Projects have beneficial long-term effects on air-quality and greenhouse gas (GHG) emissions and the correlated global warming effects, and is the basis for the rationale behind federal and state mandates to hasten the shift from utility-scale fossil fuel-generated electricity to alternative electricity generation such as solar or wind (Executive Order 14082, Millstein et al., 2017). Such effects are generally analyzed on large-scale models, with discussions focused on the regional and global effects of alternative energy sources. Analysis of the proposed Project on regional or global scales is outside the scope of this EA. This EA will present the immediate short-term effects to local air quality and GHG emissions associated with construction and maintenance of solar facilities. The analysis area for this resource topic is the general vicinity of the proposed Project on Wright’s Mesa and the community of Norwood.
Baseline Conditions
San Miguel County
The San Miguel County environmental health department collaborates with the EPA, CDPHE, U.S. Forest Service (USFS) and other public health agencies to protect and improve air quality. San Miguel County Environmental Health Department operates sampling devices for PM2.5 and PM10. San Miguel County is currently in attainment for NAAQS and compliance with all State and Federal standards for air quality. According to the 2022 Regional Air Quality Summary (San Miguel County, 2022), sources of air pollution in San Miguel County include:
- wildfires
- high winds
- oil & gas extraction
- combustion engines
- power plants
- construction
- solid fuel heaters
Western Slope
San Miguel County is one of nine counties in the Western Slope Region of Colorado. A mix of mountains on the east, and mesas, plateaus, valleys and canyons to the west form the landscape of this region. Grand Junction is the largest urban area, and other cities include Telluride, Montrose, Delta, Rifle, Glenwood Springs, Meeker, Rangely and Craig. Primary industries include ranching, agriculture, mining, energy development and tourism. The population of this region is 325,046 (U.S. Census Bureau, 2021).
According to the 2022 Regional Air Quality Summary, all of the Western Slope Region was in compliance with federal air quality standards. However, elevated ozone levels were recorded in the Rangely area during the winters of 2010-2011 and 2012-2013, which resulted in violations of the 2008 ozone standard. The area has not experienced such elevated ozone concentrations since that time. The 3-year average (2015-2017) ozone concentration is below the 2008 NAAQS, so a “nonattainment designation” was not appropriate for Rangely. The Grand Junction area experiences elevated wintertime PM2.5 concentrations due to inversions, though the area has not violated the federal NAAQS (San Miguel County, 2022).
Sources of air pollution on the Western Slope:
- motor vehicles
- oil and gas development
- Craig coal-fired power plant
- coal mines (Delta, Rio Blanco and Moffat counties)
- sand and gravel operations
- windblown dust
- wildfires and prescribed fire
Climatology
Air quality in a given area is directly affected by local climatology and regional topography. Prevailing winds, forested versus open range, mountain ranges and canyon topography all play into the how air masses move and impact concentrations of pollutants. Wright’s Mesa sits at approximately 7,500 ft in elevation. The San Miguel River and Canyon border the Mesa to the north. Distant mountain ranges surround the area to the east and west, and Lone Cone Mountain is to the south.
Prevailing surface winds on Wright’s Mesa are bimodal: after sunset, winds are mainly SE thru NE directions with speeds below 5 meters per second (mps); after sunrise wind direction shifts to S-WSW with speeds between 7-25mps. These winds are close to the surface and within the boundary layer. Above the boundary layer winds are subject to non-local forcing and may have a different direction and speed; even in calm conditions. A stable boundary layer will trap pollutants and any wind will move them downwind. Calm conditions are infrequent but not rare. Occasionally, waves that form on the nighttime inversion will break and flush out the boundary layer. There is also a daytime inversion, though not as intense as the nighttime one. During the day, convective currents can disperse pollutants throughout the boundary layer. Generally, local topography doesn’t support the formation of eddy circulation that could “trap” pollutants in the local area. (pers. comm. Dr. Robert Grossman, meteorologist University of Colorado, retired)
Consequences
Construction
The proposed Project would add to the air quality issues (combustion engines, motor vehicles and windblown dust) in the county as identified in the San Miguel County (2022) Regional Air Quality Summary. Construction of a solar facility has many phases and requires numerous passes of vehicles and heavy industrial equipment throughout the Project site. The general elements of constructing a PV array include surveying, site preparation (clearing and grading where necessary), tracker row installation and PV module assembly, inverter installation, burying MV cable. Table 2-2 provides a list of typical equipment used during construction.
Workforce traffic would increase emissions in the Project area and regionally. Vehicle and equipment operation during construction would emit diesel particulate matter and other criteria air pollutants. Construction activities associated with the Project would significantly increase PM levels from fugitive dust. Clearing and grading would expose soils. Soil disturbance from clearing, grading, excavations and vehicle/equipment traffic can destroy soil structure that would otherwise maintain soil integrity preventing wind erosion. Removal of vegetation will further increase the soils susceptibility to erosion.
Air quality impacts would be most intense during active equipment use and subside after activities cease. It is likely that the maximum ambient concentrations of PM10, PM2.5, and NO2 would exceed the NAAQS within close proximity to operating machinery, and would be expected to decrease in proportion to distance from emissions source(s). The determination of effects from the Gemini Project indicates that maximum ambient concentrations at the fence lines around the development areas would exceed NAAQS for PM10 and PM2.5 (BLM, 2019). The residences within 0.5 mile of the Project site would likely experience significant adverse effects from fugitive dust emissions (both PM10 and PM2.5).
Until construction is complete and site stabilization efforts have been implemented, exposed soils will be susceptible to wind erosion, thereby having a direct adverse effect on air quality in the project area and surrounding areas. Impacts to air quality in the town of Norwood are expected to be adversely affected, with intensity of effects dependent on weather patterns. Southeasterly winds would carry dust and emissions towards Norwood.
Operations
Workforce vehicles traveling to and from the site and those conducting maintenance activities would emit some pollutants. Some emissions from the testing and use of generators could occur but would be minimal. Operation of the Project would involve the disturbance of approximately 580 acres of land. Some areas of the Project site would be paved with concrete or gravel (i.e., substation access roads, inverter skids); however, the majority of the Project site would be disturbed soil. Until site stabilization has been achieved, wind events could disturb soils on the Project site, resulting in erosion and fugitive dust. Dust can dramatically affect the energy output of solar cells as much as 23 percent, depending on the type of dust and angle of solar panel (Maghami, et al. 2016). Panel cleaning and dust controls (such as watering and applying regulation-compliant palliatives) are commonly used in solar fields to minimize output losses. Permitting requirements would include a Dust Control and Air Quality Plan, which would minimize emissions. Provided a dust control plan is implemented, it is anticipated that impacts to air quality during operations would not be significant.
No Action Alternative
The No Action Alternative would result in no impacts to air quality. Conditions would continue unchanged.
3.2 Greenhouse Gas Emissions
Regulatory
Executive Order 14082 Implementation of the Energy and Infrastructure Provisions of the Inflation Reduction Act of 2022 and Executive Order 14072 Strengthening the Nation’s Forests, Communities, and Local Economies, include mandates to manage GHG in an effort to thwart effects of climate change.
Greenhouse gases are natural and human-caused emissions that cumulatively create an atmospheric barrier that traps and holds heat within Earth’s atmosphere that would otherwise be radiated into space. The net effect causes changes in the radiative balance of the Earth altering climate and weather patterns at global and regional scales. Human activities are the primary cause of the global warming since the start of the 20th century (Intergovernmental Panel on Climate Change (IPCC), 2021). Anthropogenic sources result from energy-related activities (e.g., combustion of fossil fuels in the electric utility and transportation sectors), agriculture, land-use change, waste management and treatment, and various industrial processes.
Major GHG include CO2, CH4, N2O, and various synthetic chemicals. Many GHG are extremely long-lived in the atmosphere, remaining airborne for tens to hundreds of years. GHG concentrations in the atmosphere reflect past and recent contributions from emissions sources worldwide. GHGs become globally mixed, meaning that the amount in the atmosphere is roughly the same all over the world, regardless of the source of the emissions (IPCC, 2021).
Baseline Conditions
No specific GHG reporting documents are available for the town of Norwood. However, EcoAction Partners, a 501(c)3 non-profit organization funded by the Town of Telluride and San Miguel County, tracks the region’s GHG emissions and develops programs to accomplish GHG reduction. Their 2020 GHG Emissions Inventory (GHG Inventory — EcoAction Partners) indicates that GHG emissions in Ouray and San Miguel counties come from: residential buildings (28%), gasoline vehicles (19%), commercial buildings (17%), food purchase (11%), fuel production (8%), air travel (6%), diesel vehicles (4%), waste MSW (4%), water/waste water treatment/irrigation (1.6%), cement (1.6%), and government energy use (1.2%) (EcoAction Partners, 2020).
Carbon sequestration
Carbon sequestration is the process by which atmospheric carbon dioxide is taken up by plants and stored via photosynthesis, as carbon in biomass and soils. Unlike other land use sectors, forests and trees not only emit GHGs, they also remove CO2 from the atmosphere. This sink of carbon or sequestration in forests helps offset emissions from other sources (i.e., fossil fuel emissions) and is recognized as an important element in the effort to meet state and federal mandates to reduce GHG emissions (San Miguel County, 2022). Intrinsic within Executive Order 14082 are directives to “harness nature-based solutions” that “benefit rural communities, Tribes, farmers, ranchers, and forest landowners; reduce climate pollution; increase resilience to climate change; conserve our lands and biodiversity”, citing carbon sequestration by forests among the nature-based solutions.
The U.S. Geological Survey (USGS) is congressionally mandated (2007 Energy Independence and Security Act) to conduct a comprehensive national assessment of storage and flux (flow) of carbon and the fluxes of other GHG (including CO2) in ecosystems. According to USGS Professional Paper 1797, (Zhu and Reed, 2012), terrestrial and aquatic ecosystems in the U.S. take up approximately a quarter of the nation’s CO2 emissions. Ecosystems of the Western U.S. serve as a GHG sink for CO2, N2O, and CH4; accumulating GHGs at an estimated −599.1 to −51.3 TgCO2-eq/yr (teragrams of CO2 equivalent per year). (Negative values denote a carbon sink.) Forests are the largest carbon sink (62% of the average), followed by grasslands/shrublands (30%), and agricultural lands (7%). That report also noted that land use and land cover changes directly affect carbon fluxes and carbon stocks in ecosystems. Decline in forest clearcutting led to an increased per-unit-of area net flux of carbon; changes in species composition that lead to a reduced amount of aboveground biomass, accelerated soil decomposition and a loss of soil organic carbon stock to the atmosphere (Zhu and Reed, 2012).
The San Miguel County, Summary Report: GHG Inventory for Forests and Trees Outside Forests, 2004 to 2019 San Miguel County, Colorado (GHG Summary Report), provides information on how local changes in land use and tree canopy contribute to the county’s net GHG profile. The GHG Summary Report indicates that of 333,667 hectares (824,507 acres) of the county’s land base, 54% is forest.
Key findings from that report are:
- Emissions from forests and trees were 13,872 t CO2e per year.
- Annual CO2 removals from forests and trees were -234,786 t CO2e per year.
- Net GHG balance of forests and trees was -220,913 t CO2e per year
The report states that conversion of forests to other land cover uses increases GHG emissions and that total GHG emissions for San Miguel County across all sectors could be reduced if additional forests/trees were added to its land base, and/or if losses of trees were reduced further. The importance of forest carbon stocks is well recognized in the scientific literature, with regrowth, reforestation, avoiding conversion of forests to other land uses, minimizing forest disturbance, and increasing sequestration through enhanced forest growth among recognized strategies for capitalizing on the carbon sequestration potential of forests systems (Gutrich and Howarth, 2007).
Consequences
Though the ultimate purpose of alternative energy generating projects is to have an overall positive effect on GHG emissions regionally and globally, the Project as proposed would directly and adversely impact GHG emissions. Land use conversion from forest to industrial will remove 580 acres of forests and scrublands currently providing the ecosystem service of carbon sequestration in San Miguel County. As indicated by Gutrich and Howarth, 2007, avoiding conversion of forests to other land uses is among the recognized strategies for capitalizing on the carbon sequestration potential of forest systems. The San Miguel County GHG Summary Report supports that assertion stating that conversion of forests to other land cover uses increases GHG emissions and that total GHG emissions could be reduced if additional forests/trees were added to its land base, and/or if losses of trees were reduced further.
The San Miguel County GHG Summary Report indicates that Annual CO2 removals from forests and trees were -234,786 t CO2e per year. Though the types of forests used in calculations for that report were not identified, using the base figure to calculate carbon sequestration for the forests on the Project site provides a rough estimate of the sequestration value of forests in the Project area. Based on that 824,507 acres sequester -234,786 t CO2e per year, gives a factor of -0.29 t CO2e per acre X 580 acres = -165.16 t CO2e per year and -4,954.8 t CO2e over the 30-year life of the Project. Implementation of the Project would result in the loss of 580 acres of carbon sink and the sequestration potential of up to -4,954.8 t CO2e over the 30-year life of the Project.
Operation of the Project would generate minimal GHG emissions. Indeed, the premise behind federal mandates to increase alternative energy generation is to offset a GHG emissions generated by non-renewable energy generating plants. Thus, operation of the Project is expected to be beneficial overall with respect to GHG emissions. However, the proposed site holds resource value and GHG sequestration value that would be lost for the life of the project and until time the site could be adequately reclaimed, if at all. The proposed Project would yield indefinite and long-term to permanent adverse impacts on natural forests in San Miguel County to sequester CO2.
[1] Bennet, Hickenlooper Unveil Legislation to Protect the Dolores River Canyon | Press Releases | U.S. Senator Michael Bennet (senate.gov)