HomeMy WebLinkAbout1.07 General Application Materials_Part8
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REPORT TOPICS
INTRODUCTION ............................................................................................................. 1
SITE CONDITIONS ......................................................................................................... 1
PROJECT DESCRIPTION .............................................................................................. 2
GEOTECHNICAL CHARACT ERIZATION ...................................................................... 3
Site Geology ............................................................................................................................... 3
Typical Profile ............................................................................................................................. 4
Laboratory Test Results .............................................................................................................. 4
Consolidation/Expansive Bedrock Test Results............................................................... 5
Corrosion Potential Test Results ..................................................................................... 5
Laboratory Thermal Resistivity Test Results ................................................................... 5
Groundwater Conditions .............................................................................................................. 6
SEISMIC CONSIDERATIONS ........................................................................................ 6
GEOTECHNICAL OVERVIEW ....................................................................................... 7
Foundations ................................................................................................................................ 7
Shallow Bedrock ......................................................................................................................... 8
SOLAR PANEL RACKING SYSTEM FOUNDATIONS .................................................. 8
Axial Capacity Design Recommendations ................................................................................... 9
Lateral Capacity Design Recommendations ................................................................................ 9
Frost Heave Considerations ...................................................................................................... 10
Construction Considerations ..................................................................................................... 10
SHALLOW FOUNDATIONS ......................................................................................... 10
Shallow Mat Foundation Design Parameters – Compressive Loads........................................... 11
Shallow Mat Foundation Construction Considerations ............................................................... 12
EARTHWORK............................................................................................................... 13
Site Preparation ........................................................................................................................ 13
Fill Material Types ..................................................................................................................... 13
Fill Compaction Requirements................................................................................................... 14
Excavation ................................................................................................................................ 15
Grading and Drainage ............................................................................................................... 15
Slopes ...................................................................................................................................... 16
Earthwork Construction Considerations ..................................................................................... 16
UNPAVED ACCESS ROADS ....................................................................................... 17
Access Road Recommendations ............................................................................................... 17
Access Road Construction Recommendations .......................................................................... 18
GENERAL COMMENTS ............................................................................................... 19
Note: This report was originally delivered in a web-based format. For more interactive features, please view your project
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DRAFT - Geotechnical Engineering Report
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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FIGURES
GEOMODEL
ATTACHMENTS
EXPLORATION AND TESTING PROCEDURES
SITE LOCATION AND EXPLORATION PLANS
EXPLORATION RESULTS
Note: Refer to each individual Attachment for a listing of contents.
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INTRODUC TION DRAFT - Geotechnical Engineering Report
Holy Cross Solar Project – High Mesa Site
1691 County Road 300
Parachute, Colorado
Terracon Project No. 25205263B
February 19, 2021
INTRODUCTION
This report presents the results of our subsurface exploration and geotechnical engineering
services performed for the proposed future High Mesa photovoltaic solar power facility to be
located at 1691 County Road 300 in Parachute, Colorado. The purpose of these services is to
provide information and geotechnical engineering recommendations relative to:
■ Subsurface soil and bedrock
conditions
■ Foundation design and construction
■ Groundwater conditions ■ Seismic site classification per IBC
■ Site preparation and earthwork ■ Lateral earth pressures
■ Frost considerations ■ Aggregate-surfaced pavement design
and construction ■ Excavation considerations
The geotechnical engineering Scope of Services for this project included the advancement of ten
test borings to depths of about 15 to 20 feet below existing site grades.
Maps showing the site and boring locations are shown in the Site Location and Exploration
Plan sections, respectively. The results of the laboratory testing performed on soil and bedrock
samples obtained from the site during the field explora tion are included on the boring logs and as
separate graphs in the Exploration Results section.
SITE CONDITIONS
The following description of site conditions is derived from our site visit in association with the
field exploration and our review of publicly available geologic and topographic maps.
Item Description
Parcel Information
The project is approximately 84 acres in size and located at 1691 County Road
300 in Parachute, Colorado. Garfield County Parcel No. 240935100136.
Approximate Coordinates: 39.3957° N, 108.0732° W
See Site Location
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Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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Item Description
Existing
Improvements
The subject site is approximately 184 acres in size and generally consists of
agricultural and vacant land. The northern portion of the site consists of a
pivot irrigated agricultural field. Two single-story buildings located to the
northwest of the site and oil and gas equipment located to the northeast and
central portion of the site. Aggregate surfaced and unimproved access drives
are located to the north and east sides of the site.
Current Ground
Cover
The ground cover on the subject site consists of crops, grass, weeds, juniper
trees and sage.
Existing Topography The site topography slopes down to the north with an elevation difference of
about 170 feet across the site.
PROJECT DESCRIPTION
Our initial understanding of the project was provided in our proposal and was discussed during
project planning. A period of collaboration has transpired since the project was initiated, and our
final understanding of the project conditions is as follows:
Item Description
Project Description
We understand that the approximate 184-acre site will be developed as a 5 to
10 MWac photovoltaic (PV) solar power facility. We assume the power facility
will also include pads for electrical equipment such as switchgear,
transformers, and inverters; and buried and/or overhead power lines.
We assume the solar array field grade will follow the existing site grade with
minimum grading required to bring the site to finished grade.
The PV array field is assumed to be comprised of PV modules attached to a
racking system that is supported on driven steel piles (W6x9 or similar).
We understand that no substation is planned for this facility.
Anticipated
Foundation Systems
■ Solar Array: Driven piles
■ Equipment Pads: Mat foundations
Maximum Loads
(assumed)
Structural loads were not provided, but have been estimated based on our
experience on similar solar projects:
Arrays (axis tracking rack systems):
■ Downward: 1 to 7 kips
■ Lateral 1 to 2 kips
■ Uplift: 0.5 to 3 kips
■ Moments: 0.1 to 30 kip-ft
Equipment Pads:
■ Mat foundation: 1,200 pounds per square foot (psf)
Grading/Slopes Less than 3 feet (+/-) max
DRAFT - Geotechnical Engineering Report
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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Item Description
Access Roadways
We understand that access road cross sections used for construction of the
project will be the responsibility of the EPC, and that only post construction
traffic with an allowable rut depth of 2 to 3 inches is what we are to design for
in this report. We anticipate low-volume, aggregate-surfaced and native soil
access roads will have a maximum vehicle load of 30,000 lbs. and will trav el
over the access roads only once per week.
Underground Utilities We anticipate installation of underground utilities within about 5 to 8 feet of
finished grade.
GEOTECHNICAL CHARACTERIZATION
Site Geology
The majority of the site surficial geology is mapped as alluvial terrace and fan gravel deposits
(Qla) with nearby outcrops of the Shire Member of the Wasatch Formation (TWS) adjacent to the
site (Donnell, 1989 1). A geologic map of the area is presented in the Exploration Plan section
of this report.
Based on the geologic data we reviewed for the area, the bedrock units of the Shire Member form
the southern arm of a synclinal fold. This folding event is believed to have formed the Piceance
basin, in which the subject site sits, and is thought to be one of the final tectonic events associated
with the Laramide Orogeny (Donnell, 1969 2). In this location, the Shire Member of the Wasatch
Formation is stratigraphically above the Arkosic ledge -forming sandstone of the Molina Member
of the Wasatch Formation a nd stratigraphically below interbedded sandstone, siltstone, marlstone
and limestone of the Anvil Points Member of the Green River Formation.
In this location, alluvial terrace and gravel deposits consisting of gravel and cobbles derived from
the Wasatch and Green River Formations are mapped at the surface. The terrace deposits have
been cut by recent channel erosion and now form a cap over the top of existing mesas in this
area.
A detailed description of the geologic units mapped in the area of the proj ect site are provided
below:
1 Donnell, J.R., Yeend, W.E., and Smith, M.C., 1986, Geologic Map of the Grand Valley Quadrangle, Garfield County,
Colorado, USGS Miscellaneous Field Studies Map MF-1883, Scale 1:24,000
2 Donnel, J.R., 1969, Paleocene and Lower Eocene Units in the Southern Part of the Piceance Creek Basin Colorado,
Geological Survey Bulletin 1274-M
DRAFT - Geotechnical Engineering Report
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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■ Qla : Alluvial terrace and fan gravel deposits (Pleistocene): Grayish brown sandy gravel of
basaltic origin and locally derived slabby siltstone, marlstone, and sandstone.
■ Tga: Green River Formation – Anvil Points Member (Eocene): fine to coarse grained, gray
and brown sandstone, gray siltstone, marlstone, and oolitic, ostracodal, and algal
limestone, with few tan low-grade oil-shale beds.
■ Tws: Wasatch Formation – Shire Member (Eocene): The Wasatch formation is generally
consists of fine-grained mudstones and siltstones with sparse sandstone and rare
conglomerate (Shoba, 2001). The Shite member is the uppermost member of the Wasatch
Formation, and its principle rock type is claystone with lesser amounts of thick lenticular
beds of arkosic sandstone (Donnell, 1969). Claystone beds of the Shire member are
thought to be volcanically derived sediments rich in iron and magnesium, and have
potential to exhibit very high swell potential when wetted.
Typical Profile
We have developed a general characterization of the subsurface conditions based upon our
review of the subsurface exploration, laboratory data, geologic setting and our understanding of
the project. This characterization, termed GeoModel, forms the basis of our geotechnical
calculations and evaluation of site preparation and foundation options. Conditions encountered at
each exploration point are indicated on the individual logs. The individual logs can be found in the
Exploration Results section and the GeoModel can be found in the Figures section of this report.
As part of our analyses, we identified the following model layers within the subsurface profile. For
a more detailed view of the model layer depths at each boring location, refer to the GeoModel.
Model Layer Layer Name General Description
1 Native Clay Lean clay; with various amounts of silt and sand; very stiff to
hard
2 Green River
Formation
Interbedded siltstone, marlstone, limestone, and sandstone
bedrock; soft to very hard
3 Wasatch Formation Interbedded claystone, shale, and sandstone bedrock;
medium hard to very hard
1. Practical auger refusal was encountered at a depth of 13 feet on marlstone bedrock in Boring No. 1
Laboratory Test Results
The following sections present the results of the laboratory testing performed on selected soil and
bedrock samples collected during our subsurface exploration. A summary of laboratory test
results is included in the Exploration Results.
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Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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Consolidation/Expansive Bedrock Test Results
Consolidation/expansion testing was performed on samples obtained at various depths and from
various borings across the site. Laboratory test results indicate that the near surface silty
claystone samples tested exhibit low compression at in -situ water contents. When exposed to
increases in moisture content, the near surface silty claystone samples tested exhibited low swell
potential.
Corrosion Potential Test Results
The table below lists the results of the water-soluble sulfate, chloride, electrical resistivity, pH, and
redox potential; tests. These values may be used to estimate potential corrosive characteristics
of the on-site soils with respect to contact with the various underground materials that will be used
for project construction, including co ncrete, pile foundations, and underground utilities, and should
be considered during design and construction of underground materials.
Corrosivity Test Results Summary
Boring
No.
Sample
Depth
(feet)
Soil
Description
Soluble
Sulfate
(%) 1
Soluble
Chloride
(%) 1
Electrical
Resistivity
(Ω-cm)
pH
Redox
Potential
(mv)
2 0 to 5 Lean clay (CL) 0.003 0.0004 1,744 7.7 391.3
8 0 to 5 Lean clay (CL) 0.002 0.0006 2,238 7.9 374.0
1. Percent by weight
Results of soluble sulfate testing indicate samples of the on -site soils tested possess negligible
sulfate concentrations when classified in accordance with Table 19.3.1.1 of the ACI Design
Manual. No minimum Portland Cement type is recommended for soils with negligible sulfate
concentrations. Concrete should be designed in accordance with the exposure class S0
provisions of the ACI Design Manual, Section 318, Chapter 19 .
Terracon recommends that an experienced corrosion engineer be retained to design a suitable
corrosion protection system for underground structures and components for EPCs to consider at this
site.
Laboratory Thermal Resistivity Test Results
A bulk sample of near-surface subsurface material obtained from Boring No. 6 was sent to
Geotherm USA for thermal resistivity testing. The testing was performed on specimens remolded
DRAFT - Geotechnical Engineering Report
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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to about 80 and 90 percent of the maximum dry unit weight as determined by ASTM D1557
(Modified Proctor). Thermal dry-out curves were generated for each sample from optimum
moisture down to zero moisture content. Testing was conducted in general accordance with the
IEEE standard 442-2017 and ASTM D5334.14. The results are summarized in the table below
and the Geotherm USA report is presented in the Exploration Results.
Boring No.
(Depth, feet)
Compaction
Effort
(%, ASTM
D1557)
Dry Density
(pcf)
Optimum
Moisture
Content (%)
Thermal Resistivity
(oC-cm/W)
Optimum1 Dry
6 (0 – 5) 80 97 12 83 190
6 (0 – 5) 90 109 12 72 172
1. Sample prepared at optimum moisture content.
Groundwater Conditions
The borings were observed while drilling for the presence and level of groundwater. Groundwater
was not observed during drilling or immediately after drilling in the ten boreholes completed at
this site.
These observations represent groundwater conditions at the time of the field exploration and may
not be indicative of other times or at other locations. Groundwater levels can be expected to
fluctuate with varying seasonal and weather conditions.
Zones of perched and/or trapped groundwater may also occur at times in the subsurface soils
overlying less permeable soils and/or bedrock, on top of the bedrock surface or within permeable
fractures in the bedrock materials. The location and amount of perched water is dependent upon
several factors, including hyd rologic conditions, type of site development, irrigation demands on
or adjacent to the site, fluctuations in water features, seasonal and weather conditions.
SEISMIC CONSIDERATIONS
Based on our subsurface exploration and laboratory testing, it is our opini on that the soils have a
low risk of liquefaction. The following table presents the seismic site classification based on the
2015 International Building Code (IBC), and the subsurface conditions encountered within the
borings:
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Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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Code Used Site Classification
2015 International Building Code (IBC) 1,2 C
1. In general accordance with the 2015 International Building Code, Section 1613.3.2.
2. The 2015 International Building Code (IBC) requires a site subsurface profile determination extending a
depth of 100 feet for seismic site classification. The current scope requested does not include the required
100-foot subsurface profile determination. The deepest borings of this exploration extended to a
maximum depth of about 20 feet and this seismic site class definition considers that similar subsurface
conditions exist below the maximum depth of the subsurface exploration.
GEOTECHNICAL OVERVIEW
Based on the results of our field investigation, laboratory testing program and geotechnical
analyses, development of the site is considered feasible from a geotechnical viewpoint provided
that the conclusions and considerations provided herein are incorporated into the project.
Foundations
A final site development plan was not provided at the time of this report. We have provided
recommendations for shallow mat foundations for support of the proposed equipment pads and
ancillary structures at the site and recommendations for driven piles to support the proposed solar
arrays.
Final driven pile design parameters for support of the panel arrays should be based on full-scale
pile load test results. The most effective means of verifying pile drivability and capacities for either
tension or lateral loads is through pile load tests. A full-scale pile load testing program was not
completed as part of our geotechnical investigation at this site. Based upon calculated capacities
utilizing soil strength criteria determined from the field and laboratory testing conducted during
exploration, we have provided preliminary recommendations for driven pile foundations for
support of the proposed solar panels in the Solar Panel Racking System Foundations section
of this report.
The on-site clay soils are susceptible to becoming unstable when exposed to increased moisture
conditions. These soils are highly susceptible to pumping, even during fill placement, when
subjected to dynamic loading, such as construction equipment and vehicle traffic. A contractor
experienced with these soils should be retained for construction.
W e recommend new shallo w mat foundations be supported on a 1 foot zone of new engineered
fill. On-site soils meeting the material properties in Earthwork are considered suitable for reuse
as engineered fill beneath foundations.
DRAFT - Geotechnical Engineering Report
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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Shallow Bedrock
Bedrock consisting of claystone, sandstone, marlstone, and limestone was encountered as
shallow as 1 foot during our exploration at this site. It is our opinion that steel piles may not be
drivable through bedrock materials encountered within the upper 10 feet across the site. Pre-
drilling will most likely be required to break the cementation in shallow bedrock materials for the
installation of drilled piles for the majority of the subject site.
It is anticipated that excavations for the proposed improvements can be accomplished with
conventional earthmoving equipment; however, specialized heavy -duty equipment capable of
ripping or jack hammering may be required for bedrock excavation to facilitate rock breakup and
removal. Consideration should be given to obtaining a unit price for diffi cult excavation in the
contract documents for the project.
SOLAR PANEL RACKING SYSTEM FOUNDATIONS
We understand that driven pile foundations are the preferred foundation type for support of the
panel racking system. In our opinion, traditional driven pile foundations could be used for the
panel racking system but may be difficult to construct due to the shallow bedrock at the site.
Predrilling will most likely be required for the installation of driven piles for the majority of the
subject site. The intent of the predrilled holes is to facilitate drivability. Drilling should not disturb
the subsurface soils supporting the proposed piles. Therefore, pre -drilled holes should have
smaller diameter than the proposed depth of the W -sections or diameter of pipe piles.
Alternative foundation systems could be considered to support the proposed PV array, such as
ballast or micropile foundations. Additional recommendations for these foundation options can
be provided upon request.
We have provided geotechnical design parameters for foundation evaluation based on the results
of our subsurface characterization and have used these parameters to perform pile capacity
analyses.
The actual foundation design should be performed in consideration of the preconstruction full-
scale pile load testing (PLT) program. Pile testing will also verify the drivability of the steel piles
to support the proposed solar photovoltaic panels. The results of a PLT program performed in
conjunction with subsurface site characterization are usual ly successful in reducing the design
embedment depth when compared to design based on site characterization and analytical
methods alone.
The recommended PLT program should be performed when more details regarding foundation
type and loads become available . The PLT program should also be performed using the intended
production and installation methods, equipment, and procedures. The final structural design for
DRAFT - Geotechnical Engineering Report
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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pile foundations should consider anticipated steel loss due to corrosion and the design loads
provided by the racking manufacturer.
Axial Capacity Design Recommendations
The axial tensile (pull-out) capacity can be developed from skin friction while axial compressive
capacity can be developed from skin friction of individual piles. Due to negligible tip area, the end
bearing component of the driven steel pile should be neglected.
The below table provides ultimate unit skin friction for design of piles for varied soil depth.
Soil Layer Depth interval below existing
ground surface (ft) Ultimate skin friction (psf) 1, 2
Native Clay Soils 1 to 2 250
Silty Claystone 2 to 8 700
Limestone, Marlstone,
Sandstone, or
Claystone
8 to 20 800
1. Bedrock was encountered as shallow as 1-foot from existing site grade and will be encountered during
pile installations. Driving piles into bedrock will be difficult may require special installation techniques.
2. The skin friction should be ignored in the upper 12 inches due to ground disturbance. If scour analysis
show deeper scour depth than 12 inches, the depth of neglect should extend to the depth of scour.
The above values are to be used in the following equation to obtain the ultimate uplift or compression
load capacity of a pile:
Qult = H x P x fs
Qult = Ultimate uplift or compression capacity of post (lbs.)
H = Depth of embedment of pile (ft)
P = Box perimeter area/ft. of pile. (i.e. W6x9 = 1.64 ft.)
fs = Skin friction per table above (psf)
The skin friction is appropriate for uplift and compressive loading and represents ultimate values.
A factor of safety of 2 should be applied to the skin friction values. If the capacity of the pile cannot
be achieved through skin friction alone, we should be contacted to provide an equation that
incorporates end bearing.
Lateral Capacity Design Recommendations
We understand that the structural engineer may perform p -y based analyses to model the soil
structure interaction for driven pile foundations subjected to lateral load. We developed L-pile
DRAFT - Geotechnical Engineering Report
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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parameters for this use based on the results of our subsurface investigation. These values are
presented in the tables below:
Soil Layer
Depth
(feet
bgs)
p-y model
Total Unit
Weight γ,
(pcf)
Cohesion (psf) Strain, 50 (%)
Native Clay
Soils 0 to 2 Stiff Clay w/o
Free Water 110 400 Default
Silty
Claystone 2 to 8 Stiff Clay w/o
Free Water 115 2,000 Default
Limestone,
Marlstone,
Sandstone,
or
Claystone
8 to 20 Stiff Clay w/o
Free Water 125 2,500 Default
Frost Heave Considerations
The soils on this site are susceptible to frost heave. However, because groundwater was not
encountered in the borings, the potential for development of an ice lens and subsequent frost heave
is considered negligible.
Construction Considerations
Based on the field exploration pile refusal in the bedrock materials is considered very likely for
some of the piles, and therefore, pre-drilling of undersized holes will likely be required to drive
piles to their embedment depths. A pile load test program that incorporates different pre -drilled
hole diameters is recommended for development of ultimate skin friction and lateral design
parameters. A geophysical exploration could be performed to further explore the bedrock depth
and identify areas where refusal on bedrock will likely occur.
SHALLOW FOUNDATIONS
We understand equipment pads and ancillary structures will be constructed as part of site
development. The proposed equipment pads and ancillary structures can be supported on mat
foundations bearing on a zone of compacted engineered fill.
We recommend subgrade be prepared as described in Earthwork and additional subgrade
evaluation at the time of construction. The following sections present our recommendations for
shallow mat foundation design and construction.
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February 19, 2021 ■ Terracon Project No. 25205263B
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Design recommendations for mat foundation systems are presented in the following table.
Shallow Mat Foundation Design Parameters – Compressive Loads
Item Description
Maximum Net Allowable Bearing
Pressure 1, 2
2,500 psf (foundations bearing on a 1 foot zone of new
engineered fill)
Estimated Modulus of Subgrade
Reaction 8
k1 = 90 pounds per square inch per inch (psi/in)
𝐾(𝐵𝑋𝐵)= 𝐾1 (𝐵+1
2𝐵)
2
𝐾(𝐵𝑋𝐿)=
𝐾(𝐵𝑋𝐵)(1 +0.5 ∗ (𝐵
𝐾))
1.5
Where:
k1 = modulus of subgrade reaction of a foundation
measuring 1 ft x 1 ft
K(BXB) = modulus of subgrade reaction for a foundation
having a square dimension B
K(BXL) = modulus of subgrade reaction for a foundation
having dimensions of B by L
Required Bearing Stratum 3 Minimum of 1 foot zone of new engineered fill
Foundation Dimensions Maximum width 12 feet
Ultimate Passive Resistance 4
(equivalent fluid pressures) 210 pcf
Ultimate Coefficient of Sliding Friction 5 0.3
Minimum Embedment below
Finished Grade 6 36 inches
Estimated Total movement from
Structural Loads 2 About 1 inch
Estimated Differential movement 2, 7 About ½ to ¾ of total movement
1. The maximum net allowable bearing pressure is the pressure in excess of the minimum surrounding
overburden pressure at the base foundation elevation. An appropriate factor of safety has been applied.
The allowable bearing pressure may be increased by one-third when considering the alternative load
combinations of Section 1605.3.2 of the 2015 International Building Code, however, it should not be
increased when loads are determined by the basic allowable stress design load combinations of Section
1605.3.1. Values assume that exterior grades are no steeper than 20% within 10 feet of structure.
2. Values provided are for maximum loads noted in Project Description and the use of on-site low plasticity
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Item Description
soils for engineered fill. The foundation movement will depend upon the variations within the subsurface
soil profile, the structural loading conditions, the embedment depth of the foundations, the thickness of
compacted fill, the quality of the earthwork operations, and maintaining uniform soil water content
throughout the life of the structure. The estimated movements are based on maintaining uniform soil water
content during the life of the structure. Additional foundation movements could occur if water from any
source infiltrates the foundation soils; therefore, proper drainage and irrigation practices should be
incorporated into the design and operation of the facility. Failure to maintain soil water content and positive
drainage will nullify the movement estimates provided above.
3. Unsuitable or soft soils should be over -excavated and replaced per the recommendations presented in the
Earthwork.
4. Use of passive earth pressures require the sides of the excavation for the foundation to be nearly vertical
and the concrete placed neat against these vertical faces or that the foundation forms be removed and
compacted engineered fill be placed against the vertical foundation face or backfill is compacted to a
minimum of 90% relative compaction.
5. Can be used to compute sliding resistance where foundations are placed on suitable soil/materials. Should
be neglected for foundations subject to net uplift conditions.
6. Embedment necessary to minimize the effects of frost and/or seasonal water content variations.
Requirement not necessary for structures that can tolerate seasonal water content variations. For sloping
ground, maintain depth below the lowest adjacent exterior grade within 5 horizontal feet of the structure.
7. Differential settlements are as measured over a span of 40 feet.
8. Modulus of subgrade reaction is an estimated value based upon our experience with the subgrade
condition, the requirements noted in Earthwork, and the bearing stratum as noted in this table.
Foundations should be proportioned based on equal total dead load pressure to reduce
differential movement between adjacent fo undations. Additional foundation movements could
occur if water from any source infiltrates the foundation soils; therefore, proper drainage should
be provided in the final design and during construction and throu ghout the life of the structures.
Failure to maintain the proper drainage will nullify the movement estimates provided above.
Shallow Mat Foundation Construction Considerations
As noted in Earthwork, the foundation excavations should be evaluated under the direction of
the Geotechnical Engineer. The base of all foundation excavations should be free of water and
loose soil, prior to placing concrete. Concrete should be placed soon after the placement of new
engineered fill. Care should be taken to prevent wetting or drying of the bearing materials during
construction. Excessively wet or dry material or any loose/disturbed material in the bottom of the
foundation excavations should be removed/reconditioned before foundation concrete is placed.
If unsuitable bearing soils are encountered at the base of the planned over-excavation, additional
measures will need to be taken to stabilize the bearing soils. This could include additional over -
excavation and replacement, stabilization w ith geotextile, or replacement of the unsuitable soils
with lean concrete. Unstable subgrade conditions should be observed by Terracon to assess the
subgrade and provide suitable alternatives for stabilization. Stabilized areas should be proof -
rolled prior to continuing construction to assess the stability of the subgrade.
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The over-excavation should be backfilled up to the foundation base elevation with engi neered fill
placed as recommended in the Earthwork section.
EARTHWORK
The following presents recommendations for site preparation, excavation, subgrade preparation,
and placement of engineered fills on the project. All earthwork on the project should be observed
and evaluated by Terracon.
Site Preparation
Strip and remove existing vegetation, organics, an d other deleterious materials from proposed
mat and shallow foundation areas and aggregate-surfaced roadway areas. Stripping of
vegetation and topsoil may not be necessary at solar array areas where final grades will match
existing grades. Keeping existing topsoil and vegetation within the array could minimize
stormwater erosion during construction and maintain overall ground surface stability for the life
span of the facility.
Foundation and roadway subgrade should be proof -rolled with an adequately loaded vehicle such
as a fully loaded tandem axle dump truck. The proof-rolling should be performed under the
direction of the Geotechnical Engineer. Areas excessively deflecting under the proof -roll should
be delineated and subsequently addressed by the Geotechnical Engineer. Such areas should
either be removed or modified by stabilizing with geotextile . Excessively wet or dry material should
either be removed or moisture conditioned and recompacted.
The stability of subgrade soils may be affected by precipitation, repetitive construction traffic or
other factors. Based on the results of our field exploration, we anticipate unstable soils will likely
be encountered within portions of the site once construction commences. If unstable conditions
are encountered or develop during construction, workability may be improved by over -excavation
of wet zones and mixing these soils with crushed gravel. Use of geotextiles could also be
considered as a stabilization technique. Lightweight excavation equipment may be required to
reduce subgrade pumping. Terracon should be retained to provide observations and
supplemental recommendatio ns during construction.
Fill Material Types
Fill required to achieve design grade should be classified as engineered fill and general fill.
Engineered fill is material used below or within 5 feet of structures. General fill is material used to
achieve grade outside of these areas. Earthen materials used for engineered and general fill
should meet the following material property requirements:
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Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
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Soil Type 1 USCS Classification Acceptable Locations for Placement
On-site lean clay soils CL On-site lean clay soils are considered suitable for re-use
as compacted fill beneath foundations.
On-site siltstone,
sandstone, marlstone,
limestone, and
claystone bedrock
N/A
Properly processed bedrock may be reused as
engineered and/or general fill after processing to a soil
like consistency with a maximum particle size of 3
inches in diameter.
Imported soils Varies
Imported soils meeting the gradation outlined herein
can be considered suitable for use as structural and/or
general fill.
1. Structural and general fill should consist of approved materials free of organic matter and debris. Frozen
material should not be used, and fill should not be placed on a frozen subgrade. A sample of each material
type should be submitted to the Geotechnical Engineer for evaluation prior to use on this site.
Imported soils for use as structural and/or general fill should conform to the following:
Gradation Percent finer by weight (ASTM C136)
3” 100
No. 4 Sieve 50-100
No. 200 Sieve >50
Soil Properties Value
Liquid Limit 30 (max)
Plastic Index 10 (max)
Expansive Potential 1 1.5 percent (max)
1. Measured on a sample compacted to approximately 95 percent of the ASTM D698 maximum dry density
at optimum water content. The sample is confined under a 200 psf surcharge and submerged.
Fill Compaction Requirements
Structural and general fill should meet the following compaction requirements.
Item Structural and General Fill
Maximum lift thickness
8 inches or less in loose thickness when heavy, self-
propelled compaction equipment is used.
4 to 6 inches in loose thickness when hand-guided
equipment (i.e. jumping jack, plate compactor) is used.
Minimum compaction requirements 1, 2, 3 95% of the material’s maximum dry density
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Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
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Item Structural and General Fill
Water content cohesive soils
(clay soils) 2, 4
0 to +3% of the optimum moisture content in pavement
areas
Water content granular soils
(sand soils) 2, 4
-2 to +2% of the optimum moisture content in pavement
areas
1. We recommend that engineered fill be tested for water content and compaction during placement. Should
the results of the in-place density tests indicate the specified water or compaction limits have not been met,
the area represented by the test should be reworked and retested as required until the specified water and
compaction requirements are achieved.
2. Maximum dry density and optimum water content as determined by the Standard Proctor test (D698).
3. If the granular material is a coarse sand or gravel, or of a uniform size, or has a low fines content,
compaction comparison to relative density may be more appropriate. In this case, granular materials should
be compacted to at least 70% relative density (ASTM D4253 and D4254).
4. Moisture conditioned clay soils should not be allowed to dry out. A loss of moisture within these materials
could result in an increase in the materials expansive potential. Subsequent wetting of these materials
could result in undesirable movement.
Excavation
Excavations into the subsurface soils and bedrock will encounter a variety of conditions. The
individual contractor(s) is responsible for designing and constructing stable, temporary
excavations as required to maintain stability of both the excavation sides and bottom. All
excavations should be sloped or shored in the interest of safety following local and federal
regulations, including current Occupational Safety and Health Administration (OSHA) excavation
and trench safety standards.
Soils and bedrock penetrated by the proposed excavations may vary significantly across the site.
The soil and bedrock classifications are based solely on the materials encountered in the
exploratory borings. The contractor should verify that similar conditions exist throughout the
proposed area of excavation. If different subsurface conditions are encountered at the time of
construction, the actual conditions should be evaluated to determine any excavation modifications
necessary to maintain safe conditions.
Grading and Drainage
All grades must provide effective drainage away structures during and after construction and
should be maintained thro ughout the life of the project. Water retained next to structures can
result in soil movements greater than those discussed in this report. As a result, any estimations
of potential movement described in this report cannot be relied upon if positive draina ge is not
obtained and maintained, and water is allowed to infi ltrate to fill and subgrade soils and bedrock.
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Exposed ground should be sloped and maintained at a minimum 5 pe rcent away for at least 10
feet beyond the perimeter of the structures. After construction final grades should be verified to
document effective drainage away from structures has been achieved. Grades around the
structures should also be periodically inspected and adjusted as necessary as part of the
structure’s maintenance program.
Slopes
For permanent slopes in unreinforced compacted fill areas, recommended maximum
configurations are as follows:
Material Maximum Slope (Horizontal: Vertical)
Cohesive soils 3:1
Recommendations are for maximum 10 -foot high slopes. If steeper or higher slopes are required
for site development, stability analyses should be completed to design the grading plan. The face
of all slopes should be compacted to the minimum specification for fill embankments. Fill slopes
should be overbuilt and trimmed to co mpacted material.
Earthwork Construction Considerations
Bedrock consisting of claystone, sandstone, and shale was encountered as shallow as 1 foot
during our exploration at this site. Excavations that encounter bedrock may become more difficult
and necessitate the use of specialized equipment or techniques. Upon completion of filling and
grading, care should be taken to maintain the subgrade water content prior to construction of
foundations and aggregate-surfaced roads. Construction traffic over the completed subgrades
should be avoided. The site should also be graded to prevent ponding of surface water on the
prepared subgrades or in excavations. Water collecting over or adjacent to construction areas
should be removed. If the subgrade freezes, desiccates, saturates, or is disturbed, the affected
material should be removed, or the materials should be scarified, moisture conditioned, and
recompacted, prior to foundation, slab, or aggregate -surfaced roadway construction.
Unstable subgrade conditions could develop during general construction operations, particularly if
the soils are wetted and/or subjected to repetitive construction traffic. Should unstable subgrade
conditions develop, stabilization measures will need to be employed. Options for subgrade
stabilization can include removal of unsuitable material and replacement with approved fill material
or by crowding rock into the unstable subgrade soils. An alternative can also include the use of
Tensar TX -160 geogrid (or approved equivalent) overlain by a granular engineered fill. The depth of
engineered fill will depend on the severity of unstable soils.
As a minimum, excavations should be performed in accordance with OSHA 29 CFR, Part 1926,
Subpart P, “Excavations” and its appendices, and in accordance with any applicable local, and/or
state regulations.
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Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
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Construction site safety is the sole responsibility of the contractor who controls the means,
methods, and sequencing of construction operations. Under no circumstances shall the
information provided herein be interpreted to mean Terracon is assuming responsibility for
construction site safety, or the contractor's activities; such responsibility shall neither be implied
nor inferred.
UNPAVED ACCESS ROADS
Access roadways for this project are expected to consist of aggregate surfaced roads over
prepared subgrades.
Close evaluation of the roadways should be provided, prior to moving critical equipment,
particularly after a rainfall event. Critical access roads can be constructed with geogrid
reinforcement or chemical stabilization to reduce the risk of instability associated with elevated
water contents.
Access Road Recommendations
Design traffic loads and volumes were not available for our analysis. A sample of near surface
soil was collected from Boring No. 5 which yielded an R-Value of 20. Due to the variability of the
subsurface materials across the site, we used a design R-Value of 10 and an Mr value of 3,000
psi for the design of aggregate surfaced access roads . Roadway subgrades should be prepared
as recommended in the Earthwork section of this report. On-site soils can be re-used as
compacted engineered fill within roadway areas.
Section thickness design of the aggregate surfaced roadways for the project has been based o n
the procedures outlined in the 1993 Guideline for Design of Pavement Structures by the American
Association of State Highway and Transportation Officials (AASHTO) for low volume design . We
have provided two alternatives for construction of aggregate surfaced roadways depending on
the amount of risk the owner is willing to accept with respect to subgrade support, particularly
during extended wet periods.
The following design section does not take into account heavy traffic that may occur during
construction. The following thickness recommendations a ssume approximately 4,000 Equivalent
Single Axial Loads (ESALs) and rut depth of 2 inches is acceptable. These design assumptions
are based on pick-up truck traffic for operations and maintenance af ter construction operations
have been completed.
Based on the subsurface conditions encountered at the borings, the assumed traffic, subgrade
support, and our experience on similar projects, we recommend that the roadway section consist
of a minimum 6-inch thick layer of compacted crushed aggregate base course placed on a minimum
of 12-inches of scarified, moisture conditioned, and recompacted subgrade soils. Prior to placement
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Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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of aggregate base, we recommend the use of a geotextile, such as a Mirafi RS380i (or equivalent),
or a Geogrid, such as a Tensar TX160 (or equivalent) in conjunction with a separation fabric.
We understand it is preferable to construct the roadway section supported on on-site soils, however
there is a higher risk of failure and maintenance based on the results of our field exploration . As
a higher-risk alternative, the roadway section could consist of a minimum 5 -inch thick layer of
compacted crushed aggregate base course placed on scarified, moisture conditioned, and
recompacted on-site soils, with a separation fabric consisting of a Mirafi 140N filter fabric, or
equivalent, placed at roadway subgrade elevation .
Aggregate base course should consist of a blend of sand and gravel which meets Colorado
Department of Transportation (CDOT) Class 5 or 6 specifications. Aggregate base course should
be placed and compacted as recommended in the Earthwork section of this report.
Access Road Construction Recommendations
Site grading is generally accomplished early in the construction phase. However, as construction
proceeds, the subgrade may be disturbed due to construction traffic, desiccation, or rainfall. As
a result, the subgrade construction and corrective action will be required. If subgrade soils
become unstable, we recommend removing the soft or yielding soils and replacing the material
with approved imported fill. As an alternative, consideration can be given to placing geogrid and
additional base course on top of the unstable area.
Positive surface drainage of the roadway and subgrade should be provided and maintained. The
roadway should be sloped to provide surface water drainage at all times. Water should not be
allowed to remain within the roadway section and subgrade soils. In addition, the subgrade soils
should be prepared in accordance with the Earthwork section of this report.
The following recommendations should be considered at minimum:
■ Site grading at a minimum 2% grade away from the roadways
■ The subgrade surfaces have a minimum ¼ inch per foot slope to promote proper surface
drainage
■ Consider appropriate edge drainage and ditches/culverts
■ The roadway subgrade should be slightly above surrounding grades to promote positive
drainage. Aggregate base course should not be placed in a “trough” condition within the
roadway section that is prone to holding water.
We emphasize that gravel surfaced roadways, regardless of the section thickness or subgrade
preparation measures, will require on -going maintenance and repairs to keep them in a
serviceable condition. It is not practical to design a gravel section of sufficient thickness that on -
going maintenance will not be required. This is due to the porous nature of the gravel that will
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Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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allow precipitation and surface water to infiltrate a nd soften the subgrade soils, and the limited
near surface strength of unconfined gravel that makes it susceptible to rutting. When potholes,
ruts, depressions or yielding subgrades develop they must be addressed as soon as possible in
order to avoid major repairs. Failure to make timely repairs will result in more rapid deterioration
of the roadways, making more extensive repairs necessary.
The roadways should be carefully reevaluated at the time of the use by heavy equipment or critical
component delivery for signs of disturbance or excessive rutting. Roadway reevaluation should
include proof rolling immediately prior to use by heavy or critical equipment, particularly after a
rainfall event. If disturbance and/or excessive wetting have occurred, roadw ay areas should be
reworked, moisture conditioned (if necessary), and properly compacted as indicated in this report.
GENERAL COMMENTS
Our analysis and opinions are based upon our understanding of the project, the geotechnical
conditions in the area, and the data obtained from our site exploration. Natural variations will occur
between exploration point locations or due to the modifying effec ts of construction or weather.
The nature and extent of such variations may not become evident unti l during or after construction.
Terracon should be retained as the Geotechnical Engineer, where noted in th is report, to provide
observation and testing services during pertinent construction phases. If variations appear, we
can provide further evaluation and supplemental recommendations. If variations are noted in the
absence of our observation and testing services on -site, we should be immediately notified so
that we can provide evaluation and supplemental recommendations.
Our Scope of Services does not include either specifically or by implication any environmental or
biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of
pollutants, hazardous materials or conditions. If the owner is concerned about the potential for
such contamination or pollution, other studies should be undertaken.
Our services and any correspondence or collaboration through this system are intended for the
sole benefit and exclusive use of our client for specific application to the project discussed and
are accomplished in accordance with generally accepted geotechnical engineering practices with
no third-party beneficiaries intended. Any third-party access to services or correspondence is
solely for information purposes to support the services provided by Ter racon to our client.
Reliance upon the services and any work product is limited to our client, and is not intended for
third parties. Any use or reliance of the provided information by third parties is done solely at their
own risk. No warranties, either express or implied, are intended or made.
Site characteristics as provided are for design purposes and not to estimate excavation cost. Any
use of our report in that regard is done at the sole risk of the excavating cost estimator as there
may be variations on the site that are not apparent in the data that could significantly impact
excavation cost. Any parties charged with estimating excavation costs should seek their own site
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Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
Responsive ■ Resourceful ■ Reliable 20
characterization for specific purposes to obtain the specific level of detail n ecessary for costing.
Site safety, and cost estimating including, excavation support, and dewatering
requirements/design are the responsibility of others. If changes in the nature, design, or location
of the project are planned, our conclusions and recommendations shall not be considered valid
unless we review the changes and either verify or modify our conclusions in writing.
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FIGURES
Contents:
GeoModel
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
ELEVATION (MSL) (feet)Holy Cross Solar Project - High Mesa Site Parachute, Colorado
Terracon Project No. 25205263B
Layering shown on this figure has been developed by the
geotechnical engineer for purposes of modeling the subsurfaceconditions as required for the subsequent geotechnical engineeringfor this project.
Numbers adjacent to soil column indicate depth below ground
surface.
NOTES:
01 02 03 04 05 06 07 08 09 10
GEOMODEL
This is not a cross section. This is intended to display the Geotechnical Model only. See individual logs for more detailed conditions.
Model Layer General DescriptionLayer Name
Lean to silty clay; with varying amounts of silt and sand;variable densities1
Green River Formation; interbedded siltstone, marlstone,limestone, and sandstone bedrock; soft to very hard2
Wasatch Formation; interbedded claystone bedrock: mediumhard to very hard3
LEGEND
Lean Clay
Siltstone
Limestone
Shale
Sandstone
Native Clay
Green River Formation
Wasatch Formation
1
2
1
13
1
2
3
2
12
20
1
2
3
2
13
20
1
2
3
1
12
20
1
2
2
15
1
2
3
2
7
15
1
2
3
2
9
15
1
2
3
1
12
15
1
2
3
1
4
15
1
2
3
2
6
15
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ATTACHMENTS
DRAFT - Geotechnical Engineering Report
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
Responsive ■ Resourceful ■ Reliable EXPLORATION AND TESTING PROCEDURES 1 of 2
EXPLORATION AND TESTING PROCEDURES
Field Exploration
Number of Borings Boring Depth (feet) Planned Location
10 15 to 20 Planned solar array areas
Boring Layout and Elevations: Boring locations were developed by Terracon at the beginning
of the project. Coordinates were obtained with a handheld GPS unit (estimated horizontal
accuracy of about ±10 feet). Ground surface elevations were not determined in the field.
Subsurface Exploration Procedures: We advanced the borings with a truck-mounted CME-45
drill rig using continuous flight solid-stem augers. Four samples were obtained in the upper 10 feet
of each boring and at intervals of 5 feet thereafter. Relatively undisturbed samples were obtained
at selected intervals utilizing a 2½-inch outside diameter modified California barrel sampler. Bulk
samples were obtained from auger cuttings. In the split-barrel sampling procedure, a standard
2½-inch outer diameter split-barrel sampling spoon is driven into the ground by a 140-pound
automatic hammer falling a distance of 30 inches. The number of blows required to advance the
sampling spoon the last 12 inches of a normal 18 -inch penetration is recorded as the Standard
Penetration Test (SPT) resistance value. The SPT resistance values, also referred to as N-values,
are indicated on the boring logs at the test depths. Ring-lined, split-barrel sampling procedures are
similar to standard split spoon sampling procedure; however, blow counts are typically recorded
for 6-inch intervals for a total of 12 inches of penetration. We did not encounter groundwater in
our borings during drilling and sampling. For safety purposes, all borings were backfilled with
auger cuttings after their completion.
The sampling depths, penetration distances, and other sampling information was recorded on the
field boring logs. The samples were placed in appropriate containers and taken to our soil laboratory
for testing and classification by a Geotechnical Engineer. Our exploration team prepared field
boring logs as part of the drilling operations. These field logs include d visual classifications of the
materials encountered during drilling and our interpretation of the subsurface conditions betw een
samples. Final boring logs we re prepared from the field logs. The f inal boring logs represent the
Geotechnical Engineer's interpretation of the field logs and include modification s based on
observations and tests of the samples in our laboratory.
Field Electrical Resistivity Testing: Terracon proposed to perform one electrical resistivity test
at the site. The field electrical resistivity test was conducted following the Wenner Four-Electrode
method (ASTM G57). The test was completed along two mutually perpendicular lines. The
Wenner arrangement (equal electrode spacing) test was performed with the a -spacings of 1, 2,
5, 10, 20, 50 and 80 feet. Results can be found in the Exploration Results section.
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Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 19, 2021 ■ Terracon Project No. 25205263B
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Laboratory Testing
The project engineer reviewed the field data and assigned laboratory tests to understand the
engineering properties of the various soil and rock strata, as necessary, for this project. Testing
included the following:
■ Visual classification
■ Moisture content
■ Dry unit weight
■ Atterberg limits
■ Grain size analysis
■ Swell/consolidation
■ Corrosion suite – water-soluble sulfate, water-soluble chloride, pH, “soil box” resistivity,
and oxidation-reduction potential
■ Modified Proctor test and thermal resistivity (rho) testing
■ Hveem Stabilometer (R-Value) testing
The laboratory testing program often included examination of soil samples by an engineer. B ased
on the material’s texture and p lasticity, we described and classified the soil samples in accordance
with the Unified Soil Classification System.
Rock classification was conducted using locally accepted practices for engineering purposes .
Thermal Resistivity (RHO) Testing: We obtained a sample of the site soils and performed
laboratory thermal resistivity testing on one bulk soil sample (auger cuttings) from a depth
between 0 and 5 feet below existing site grades. Thermal resistivity testing was completed by
GeoTherm in general accordance with ASTM D5334 and IEEE standard 442 on the specimen
remolded to approximately 8 0 and 90 percent of the maximum dry unit weight as determined by
ASTM D1557 (Modified Proctor). Dry-out curves were generated for each sample from optimum
moisture down to zero moisture content with a minimum of three data points.
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SITE LOCATION AND EXPLORATION PLANS
Contents:
Site Location Plan
Exploration Plan with Aerial Image
Electrical Resistivity Location Plan
Exploration Plan with Geologic Map Overlay
Note: All attachments are one page unless noted above.
SITE LOCATION
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 12, 2021 ■ Terracon Project No. 25205263B
TOPOGRAPHIC MAP IMAGE COURTESY OF THE U.S. GEOLOGICAL SURVEY
QUADRANGLES INCLUDE: PARACHUTE, CO (1/1/1962) and HOUSETOP MOUNTAIN,
CO (1/1/1972).
DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS
NOT INTENDED FOR CONSTRUCTION PURPOSES
SITE
EXPLORATION PLAN WITH AERIAL IMAGE
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 12, 2021 ■ Terracon Project No. 25205263B
DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS
NOT INTENDED FOR CONSTRUCTION PURPOSES AERIAL PHOTOGRAPHY PROVIDED
BY MICROSOFT BING MAPS
ELECTRICAL RESISTIVITY LOCATION PLAN
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 12, 2021 ■ Terracon Project No. 25205263B
DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS
NOT INTENDED FOR CONSTRUCTION PURPOSES AERIAL PHOTOGRAPHY PROVIDED
BY MICROSOFT BING MAPS
EXPLORATION PLAN WITH GEOLOGIC MAP OVERLAY
Holy Cross Solar Project – High Mesa Site ■ Parachute, Colorado
February 12, 2021 ■ Terracon Project No. 25205263B
DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS
NOT INTENDED FOR CONSTRUCTION PURPOSES AERIAL PHOTOGRAPHY PROVIDED
BY MICROSOFT BING MAPS
LEGEND
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EXPLORATION RESULTS
Contents:
General Notes
Unified Soil Classification System
Boring Logs (1 through 10)
Consolidation/Swell (2 pages)
Grain Size Distribution (3 pages)
Moisture Density Relationship (2 pages)
Thermal Resistivity (4 pages)
R-Value
Corrosivity
Summary of Lab Results
Field Electrical Resistivity
Note: All attachments are one page unless noted above.
Soft
UNIFIED SOIL CLASSIFICATION SYSTEM
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A
Soil Classification
Group
Symbol Group Name B
Coarse Grained Soils:
More than 50% retained
on No. 200 sieve
Gravels:
More than 50% of
coarse fraction retained
on No. 4 sieve
Clean Gravels:
Less than 5% fines C
Cu 4 and 1 Cc 3 E GW Well-graded gravel F
Cu 4 and/or 1 Cc 3 E GP Poorly graded gravel F
Gravels with Fines:
More than 12% fines C
Fines classify as ML or MH GM Silty gravel F,G,H
Fines classify as CL or CH GC Clayey gravel F,G,H
Sands:
50% or more of coarse
fraction passes No. 4
sieve
Clean Sands:
Less than 5% fines D
Cu 6 and 1 Cc 3 E SW Well-graded sand I
Cu 6 and/or 1 Cc 3 E SP Poorly graded sand I
Sands with Fines:
More than 12% fines D
Fines classify as ML or MH SM Silty sand G,H,I
Fines classify as CL or CH SC Clayey sand G,H,I
Fine-Grained Soils:
50% or more passes the
No. 200 sieve
Silts and Clays:
Liquid limit less than 50
Inorganic: PI 7 and plots on or above “A” line J CL Lean clay K,L,M
PI 4 or plots below “A” line J ML Silt K,L,M
Organic: Liquid limit - oven dried 0.75 OL Organic clay K,L,M,N
Liquid limit - not dried Organic silt K,L,M,O
Silts and Clays:
Liquid limit 50 or more
Inorganic: PI plots on or above “A” line CH Fat clay K,L,M
PI plots below “A” line MH Elastic Silt K,L,M
Organic: Liquid limit - oven dried 0.75 OH Organic clay K,L,M,P
Liquid limit - not dried Organic silt K,L,M,Q
Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat
A Based on the material passing the 3-inch (75-mm) sieve
B If field sample contained cobbles or boulders, or both, add “with cobbles
or boulders, or both” to group name.
C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded
gravel with silt, GW -GC well-graded gravel with clay, GP-GM poorly
graded gravel with silt, GP-GC poorly graded gravel with clay.
D Sands with 5 to 12% fines require dual symbols: SW -SM well-graded
sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded
sand with silt, SP-SC poorly graded sand with clay
E Cu = D60/D10 Cc =
6010
2
30
DxD
)(D
F If soil contains 15% sand, add “with sand” to group name.
G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.
H If fines are organic, add “with organic fines” to group name.
I If soil contains 15% gravel, add “with gravel” to group name.
J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay.
K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,”
whichever is predominant.
L If soil contains 30% plus No. 200 predominantly sand, add “sandy” to
group name.
M If soil contains 30% plus No. 200, predominantly gravel, add
“gravelly” to group name.
N PI 4 and plots on or above “A” line.
O PI 4 or plots below “A” line.
P PI plots on or above “A” line.
Q PI plots below “A” line.
50/10"
8-11
50/6"
50/0"
945.2
8.5
7.4
108
95
94
27-17-10
LEAN CLAY (CL), light brown to gray
SILTY CLAYSTONE, light brown to orange, soft to medium
hard
MARLSTONE, with sand, gravel and calcium carbonatecementation, subangular, light brown, very hard
Auger Refusal at 13 Feet
1.0
7.0
13.0
Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 25205263B - KLEBOLD SITE.GPJ TERRACON_DATATEMPLATE.GDT 2/11/21FIELD TESTRESULTSSWELL (%)WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10 PERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)ATTERBERGLIMITS
LL-PL-PI
LOCATION See Exploration Plan
Latitude: 39.3980° Longitude: -108.0751°GRAPHIC LOGMODEL LAYERDEPTH
Page 1 of 1
Advancement Method:4-inch solid stem power auger
Abandonment Method:Boring backfilled with soil cuttings upon completion.
Notes:
Project No.: 25205263B
Drill Rig: CME-45
BORING LOG NO. 1
CLIENT: HDR Engineering, Inc.
Driller: Unlimited
Boring Completed: 12-03-2020
PROJECT: Holy Cross Solar Project - High Mesa Site
See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).
See Supporting Information for explanation ofsymbols and abbreviations.
1691 County Road 300 Parachute, Colorado
SITE:
Boring Started: 12-03-2020
10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
None encountered while drilling
WATER LEVEL OBSERVATIONS
1
2 SAMPLE TYPE
9-13
9-14
50/9"
15-16
50/3"
92
4.9
12.7
8.2
108
113
131
31-18-13
LEAN CLAY (CL), light brown to gray
SILTY CLAYSTONE, with sand, light brown, soft
MARLSTONE, with sand and gravel, subangular, fine to coarsegrained, white to light gray, hard, moderate cementation
SANDY CLAYSTONE, with gravel and cobbles, subangular, lightbrown, firm to very hard
Boring Terminated at 20 Feet
2.0
8.0
12.0
20.0
Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 25205263B - KLEBOLD SITE.GPJ TERRACON_DATATEMPLATE.GDT 2/11/21FIELD TESTRESULTSSWELL (%)WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15
20 PERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)ATTERBERGLIMITS
LL-PL-PI
LOCATION See Exploration Plan
Latitude: 39.3975° Longitude: -108.0716°GRAPHIC LOGMODEL LAYERDEPTH
Page 1 of 1
Advancement Method:4-inch solid stem power auger
Abandonment Method:Boring backfilled with soil cuttings upon completion.
Notes:
Project No.: 25205263B
Drill Rig: CME-45
BORING LOG NO. 2
CLIENT: HDR Engineering, Inc.
Driller: Unlimited
Boring Completed: 12-03-2020
PROJECT: Holy Cross Solar Project - High Mesa Site
See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).
See Supporting Information for explanation ofsymbols and abbreviations.
1691 County Road 300 Parachute, Colorado
SITE:
Boring Started: 12-03-2020
10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
None encountered while drilling
WATER LEVEL OBSERVATIONS
1
2
3 SAMPLE TYPE
11-13
11-19
9-12
50/4"
20-25
+1.2@500psf
92
5.6
7.6
8.5
106
109
125
30-17-13
LEAN CLAY (CL), brown
SILTY CLAYSTONE, with sand, light brown to orange,
soft to firm
CLAYSTONE, brown to orange, medium hard to very hard
Boring Terminated at 20 Feet
2.0
13.0
20.0
Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 25205263B - KLEBOLD SITE.GPJ TERRACON_DATATEMPLATE.GDT 2/11/21FIELD TESTRESULTSSWELL (%)WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15
20 PERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)ATTERBERGLIMITS
LL-PL-PI
LOCATION See Exploration Plan
Latitude: 39.3960° Longitude: -108.0760°GRAPHIC LOGMODEL LAYERDEPTH
Page 1 of 1
Advancement Method:4-inch solid stem power auger
Abandonment Method:Boring backfilled with soil cuttings upon completion.
Notes:
Project No.: 25205263B
Drill Rig: CME-45
BORING LOG NO. 3
CLIENT: HDR Engineering, Inc.
Driller: Unlimited
Boring Completed: 12-03-2020
PROJECT: Holy Cross Solar Project - High Mesa Site
See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).
See Supporting Information for explanation ofsymbols and abbreviations.
1691 County Road 300 Parachute, Colorado
SITE:
Boring Started: 12-03-2020
10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
None encountered while drilling
WATER LEVEL OBSERVATIONS
1
2
3 SAMPLE TYPE
50/12"
10-12
50/3"
50/6"
50/10"
6.4
5.0
6.9
111
105
LEAN CLAY (CL), brown
SILTY CLAYSTONE, with sand, brown, soft to medium hard
SANDSTONE, cabonaceous, fine to medium grained, light grayishbrown to white, very hard, strong cementation
SANDY CLAYSTONE, with sand and gravel, subangular, brown,hard to very hard
Boring Terminated at 20 Feet
1.0
6.0
12.0
20.0
Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 25205263B - KLEBOLD SITE.GPJ TERRACON_DATATEMPLATE.GDT 2/11/21FIELD TESTRESULTSSWELL (%)WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15
20 PERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)ATTERBERGLIMITS
LL-PL-PI
LOCATION See Exploration Plan
Latitude: 39.3959° Longitude: -108.0730°GRAPHIC LOGMODEL LAYERDEPTH
Page 1 of 1
Advancement Method:4-inch solid stem power auger
Abandonment Method:Boring backfilled with soil cuttings upon completion.
Notes:
Project No.: 25205263B
Drill Rig: CME-45
BORING LOG NO. 4
CLIENT: HDR Engineering, Inc.
Driller: Unlimited
Boring Completed: 12-04-2020
PROJECT: Holy Cross Solar Project - High Mesa Site
See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).
See Supporting Information for explanation ofsymbols and abbreviations.
1691 County Road 300 Parachute, Colorado
SITE:
Boring Started: 12-04-2020
10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
None encountered while drilling
WATER LEVEL OBSERVATIONS
1
2
3 SAMPLE TYPE
18-20
14-21
50/9"
50/2"
926.1
14.3
99 32-17-15
LEAN CLAY (CL), brown
SILTY CLAYSTONE, light brown to pink, firm to medium hard
LIMESTONE, white to gray, hard to very hard
Boring Terminated at 15 Feet
2.0
8.0
15.0
Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 25205263B - KLEBOLD SITE.GPJ TERRACON_DATATEMPLATE.GDT 2/11/21FIELD TESTRESULTSSWELL (%)WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15 PERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)ATTERBERGLIMITS
LL-PL-PI
LOCATION See Exploration Plan
Latitude: 39.3946° Longitude: -108.0705°GRAPHIC LOGMODEL LAYERDEPTH
Page 1 of 1
Advancement Method:4-inch solid stem power auger
Abandonment Method:Boring backfilled with soil cuttings upon completion.
Notes:
Project No.: 25205263B
Drill Rig: CME-45
BORING LOG NO. 5
CLIENT: HDR Engineering, Inc.
Driller: Unlimited
Boring Completed: 12-04-2020
PROJECT: Holy Cross Solar Project - High Mesa Site
See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).
See Supporting Information for explanation ofsymbols and abbreviations.
1691 County Road 300 Parachute, Colorado
SITE:
Boring Started: 12-04-2020
10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
None encountered while drilling
WATER LEVEL OBSERVATIONS
1
2 SAMPLE TYPE
19-19
9-11
18-27
50/6"
828.2
8.6
7.8
95
118
LEAN CLAY (CL), with sand, brown
SILTY CLAYSTONE, carbonaceous, light brown, soft to medium
hard
SANDY CLAYSTONE, with sand and gravel, subangular, brown,medium hard to very hard
Boring Terminated at 15 Feet
2.0
7.0
15.0
Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 25205263B - KLEBOLD SITE.GPJ TERRACON_DATATEMPLATE.GDT 2/11/21FIELD TESTRESULTSSWELL (%)WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15 PERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)ATTERBERGLIMITS
LL-PL-PI
LOCATION See Exploration Plan
Latitude: 39.3947° Longitude: -108.0746°GRAPHIC LOGMODEL LAYERDEPTH
Page 1 of 1
Advancement Method:4-inch solid stem power auger
Abandonment Method:Boring backfilled with soil cuttings upon completion.
Notes:
Project No.: 25205263B
Drill Rig: CME-45
BORING LOG NO. 6
CLIENT: HDR Engineering, Inc.
Driller: Unlimited
Boring Completed: 12-04-2020
PROJECT: Holy Cross Solar Project - High Mesa Site
See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).
See Supporting Information for explanation ofsymbols and abbreviations.
1691 County Road 300 Parachute, Colorado
SITE:
Boring Started: 12-04-2020
10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
None encountered while drilling
WATER LEVEL OBSERVATIONS
1
2
3 SAMPLE TYPE31-18-13
8-15
16-19
50/4"
6-8-9
8414.1
14.3
95
97
LEAN CLAY (CL), with sand, brown
SILTY CLAYSTONE, with sand, carbonaceous, light brown, soft to 31-18-13
SANDY CLAYSTONE, with sand and gravel, interbedded withlimestone, subangular, brown, soft to very hard
Boring Terminated at 15 Feet
2.0
9.0
15.0
Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 25205263B - KLEBOLD SITE.GPJ TERRACON_DATATEMPLATE.GDT 2/11/21FIELD TESTRESULTSSWELL (%)WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15 PERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)ATTERBERGLIMITS
LL-PL-PI
LOCATION See Exploration Plan
Latitude: 39.3931° Longitude: -108.0747°GRAPHIC LOGMODEL LAYERDEPTH
Page 1 of 1
Advancement Method:4-inch solid stem power auger
Abandonment Method:Boring backfilled with soil cuttings upon completion.
Notes:
Project No.: 25205263B
Drill Rig: CME-45
BORING LOG NO. 7
CLIENT: HDR Engineering, Inc.
Driller: Unlimited
Boring Completed: 12-04-2020
PROJECT: Holy Cross Solar Project - High Mesa Site
See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).
See Supporting Information for explanation ofsymbols and abbreviations.
1691 County Road 300 Parachute, Colorado
SITE:
Boring Started: 12-04-2020
10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
None encountered while drilling
WATER LEVEL OBSERVATIONS
1
2
3 SAMPLE TYPE
20-25
7-11
50/9"
21-32-44
-0.2@500psf
904.7
5.0
10.5
105
106
101
26-16-10
LEAN CLAY (CL), brown
SILTY CLAYSTONE, sandy, light brown to orange, soft to
medium hard
MARLSTONE, with sand and gravel, fine to medium grained,subangular, light brown, hard
SANDY CLAYSTONE, with sand and gravel, interbedded withmarlstone, subangular, brown, hard
Boring Terminated at 15 Feet
1.0
8.0
12.0
15.0
Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 25205263B - KLEBOLD SITE.GPJ TERRACON_DATATEMPLATE.GDT 2/11/21FIELD TESTRESULTSSWELL (%)WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15 PERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)ATTERBERGLIMITS
LL-PL-PI
LOCATION See Exploration Plan
Latitude: 39.3920° Longitude: -108.0723°GRAPHIC LOGMODEL LAYERDEPTH
Page 1 of 1
Advancement Method:4-inch solid stem power auger
Abandonment Method:Boring backfilled with soil cuttings upon completion.
Notes:
Project No.: 25205263B
Drill Rig: CME-45
BORING LOG NO. 8
CLIENT: HDR Engineering, Inc.
Driller: Unlimited
Boring Completed: 12-04-2020
PROJECT: Holy Cross Solar Project - High Mesa Site
See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).
See Supporting Information for explanation ofsymbols and abbreviations.
1691 County Road 300 Parachute, Colorado
SITE:
Boring Started: 12-04-2020
10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
None encountered while drilling
WATER LEVEL OBSERVATIONS
1
2
3 SAMPLE TYPE
14-14
50/10"
50/6"
40-50/2"
84
7210.6 108
34-18-16
LEAN CLAY (CL), with sand, brown
SILTY CLAYSTONE, carbonaceous, light brown, firm to medium
hard
SANDY CLAYSTONE, with sand and gravel, interbedded with 41-18-23marlstone, fine to coarse grained, subangular, gray to light brown,medium hard to very hard
Boring Terminated at 15 Feet
1.0
4.0
15.0
Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 25205263B - KLEBOLD SITE.GPJ TERRACON_DATATEMPLATE.GDT 2/11/21FIELD TESTRESULTSSWELL (%)WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15 PERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)ATTERBERGLIMITS
LL-PL-PI
LOCATION See Exploration Plan
Latitude: 39.3925° Longitude: -108.0701°GRAPHIC LOGMODEL LAYERDEPTH
Page 1 of 1
Advancement Method:4-inch solid stem power auger
Abandonment Method:Boring backfilled with soil cuttings upon completion.
Notes:
Project No.: 25205263B
Drill Rig: CME-45
BORING LOG NO. 9
CLIENT: HDR Engineering, Inc.
Driller: Unlimited
Boring Completed: 12-04-2020
PROJECT: Holy Cross Solar Project - High Mesa Site
See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).
See Supporting Information for explanation ofsymbols and abbreviations.
1691 County Road 300 Parachute, Colorado
SITE:
Boring Started: 12-04-2020
10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
None encountered while drilling
WATER LEVEL OBSERVATIONS
1
2
3 SAMPLE TYPE
12-13
10-31
50/6"
40-40-34
7814.3
9.2
73 28-18-10
LEAN CLAY (CL), with sand, fine grained, brown
SILTY CLAYSTONE, carbonaceous, light brown, firm to medium
hard
SANDY CLAYSTONE, with sand and gravel, interbedded withmarlstone, subangular, light brown, hard to very hard
Boring Terminated at 15 Feet
2.0
6.0
15.0
Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 25205263B - KLEBOLD SITE.GPJ TERRACON_DATATEMPLATE.GDT 2/11/21FIELD TESTRESULTSSWELL (%)WATER LEVELOBSERVATIONSDEPTH (Ft.)5
10
15 PERCENT FINESWATERCONTENT (%)DRY UNITWEIGHT (pcf)ATTERBERGLIMITS
LL-PL-PI
LOCATION See Exploration Plan
Latitude: 39.3905° Longitude: -108.0694°GRAPHIC LOGMODEL LAYERDEPTH
Page 1 of 1
Advancement Method:4-inch solid stem power auger
Abandonment Method:Boring backfilled with soil cuttings upon completion.
Notes:
Project No.: 25205263B
Drill Rig: CME-45
BORING LOG NO. 10
HDR Engineering, Inc.CLIENT:
Driller: Unlimited
Boring Completed: 12-04-2020
PROJECT: Holy Cross Solar Project - High Mesa Site
See Exploration and Testing Procedures for adescription of field and laboratory procedures usedand additional data (If any).
See Supporting Information for explanation ofsymbols and abbreviations.
1691 County Road 300 Parachute, Colorado
SITE:
Boring Started: 12-04-2020
10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
None encountered while drilling
WATER LEVEL OBSERVATIONS
1
2
3 SAMPLE TYPE
-8
-6
-4
-2
0
2
4
6
8
100 1,000 10,000AXIAL STRAIN, %PRESSURE, psf
NOTES: Water was added at 500 psf.
SWELL CONSOLIDATION TEST
SITE: 1691 CR 300
Parachute, Colorado
PROJECT: Holy Cross Solar - High Mesa Site PROJECT NUMBER: 25205263B
CLIENT: HDR Engineering, Inc.10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. TC_CONSOL_STRAIN-USCS-NO ASTM 25205263B - KLEBOLD SITE.GPJ 02195238 US 50 AND CHIPMAN.GPJ 1/27/21 3 4 - 5 ft SILTY CLAYSTONE 106 5.6
Specimen Identification Classification , pcf WC, %
-8
-6
-4
-2
0
2
4
6
8
100 1,000 10,000AXIAL STRAIN, %PRESSURE, psf
NOTES: Water was added at 500 psf.
SWELL CONSOLIDATION TEST
SITE: 1691 CR 300
Parachute, Colorado
PROJECT: Holy Cross Solar - High Mesa Site PROJECT NUMBER: 25205263B
CLIENT: HDR Engineering, Inc.10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. TC_CONSOL_STRAIN-USCS-NO ASTM 25205263B - KLEBOLD SITE.GPJ 02195238 US 50 AND CHIPMAN.GPJ 1/27/21 8 4 - 5 ft SILTY CLAYSTONE 106 5.0
Specimen Identification Classification , pcf WC, %
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
0.0010.010.1110100
2006810142
GRAIN SIZE IN MILLIMETERSPERCENT FINER BY WEIGHTASTM D422 / ASTM C136
46 16 20 30 40
GRAIN SIZE DISTRIBUTION
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS
4 1 3/4 1/2 60
HYDROMETER
3/8 3 100 1403501.5
A-4 (8)
A-6 (11)
A-6 (11)
A-6 (13)
LEAN CLAY (CL)
LEAN CLAY (CL)
LEAN CLAY (CL)
LEAN CLAY (CL)
1
2
3
5
1
2
3
5
Boring ID Depth D100 D60 D30 D10
Boring ID Depth USCS Classification AASHTO Classification LL PL PI
%Gravel %Sand
%Silt
mediumcoarsecoarsefine fineCOBBLESGRAVELSAND SILT OR CLAY
%Fines %Clay
WC (%)
1.18
1.18
1.18
4.75
93.7
91.9
91.8
92.0
0.0
0.0
0.0
0.0
6.3
8.1
8.2
8.0
0 - 5
0 - 5
0 - 5
0 - 5
0 - 5
0 - 5
0 - 5
0 - 5
10
13
13
15
17
18
17
17
27
31
30
32
SITE: 1691 CR 300
Parachute, Colorado
PROJECT: Holy Cross Solar - High Mesa Site PROJECT NUMBER: 25205263B
10625 W
W
I7
h
0
e
a
F
t
r
R
on
id
ta
g
g
e
e
, C
R
O
d N Ste 3 CLIENT: HDR Engineering, Inc.LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS & AASHTO DESC COMBINED 25205263B - KLEBOLD SITE.GPJ 02195238 US 50 AND CHIPMAN.GPJ 1/29/21Cc Cu
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
0.0010.010.1110100
2006810142
GRAIN SIZE IN MILLIMETERSPERCENT FINER BY WEIGHTASTM D422 / ASTM C136
46 16 20 30 40
GRAIN SIZE DISTRIBUTION
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS
4 1 3/4 1/2 60
HYDROMETER
3/8 3 100 1403501.5
A-6 (9)
A-6 (10)
A-4 (7)
A-6 (12)
LEAN CLAY with SAND (CL)
LEAN CLAY with SAND (CL)
LEAN CLAY (CL)
LEAN CLAY with SAND (CL)
6
7
8
9
6
7
8
9
Boring ID Depth D100 D60 D30 D10
Boring ID Depth USCS Classification AASHTO Classification LL PL PI
%Gravel %Sand
%Silt
mediumcoarsecoarsefine fineCOBBLESGRAVELSAND SILT OR CLAY
%Fines %Clay
WC (%)
12.5
9.5
4.75
9.5
81.8
84.4
90.0
84.1
3.5
0.4
0.0
1.2
14.7
15.1
10.0
14.7
0 - 5
0 - 5
0 - 5
0 - 5
0 - 5
0 - 5
0 - 5
0 - 5
13
13
10
16
18
18
16
18
31
31
26
34
SITE: 1691 CR 300
Parachute, Colorado
PROJECT: Holy Cross Solar - High Mesa Site PROJECT NUMBER: 25205263B
CLIENT: HDR Engineering, Inc.10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS & AASHTO DESC COMBINED 25205263B - KLEBOLD SITE.GPJ 02195238 US 50 AND CHIPMAN.GPJ 1/29/21Cc Cu
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
0.0010.010.1110100
2006810142
GRAIN SIZE IN MILLIMETERSPERCENT FINER BY WEIGHTASTM D422 / ASTM C136
46 16 20 30 40
GRAIN SIZE DISTRIBUTION
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS
4 1 3/4 1/2 60
HYDROMETER
3/8 3 100 1403501.5
A-7-6 (15)
A-4 (6)
LEAN CLAY with SAND (CL)
LEAN CLAY with SAND (CL)
9
10
9
10
Boring ID Depth D100 D60 D30 D10
Boring ID Depth USCS Classification AASHTO Classification LL PL PI
%Gravel %Sand
%Silt
mediumcoarsecoarsefine fineCOBBLESGRAVELSAND SILT OR CLAY
%Fines %Clay
WC (%)
12.5
9.5
72.4
77.7
5.0
0.9
22.6
21.4
4 - 5
0 - 5
4 - 5
0 - 5
23
10
18
18
10.6 41
28
SITE: 1691 CR 300
Parachute, Colorado
PROJECT: Holy Cross Solar - High Mesa Site PROJECT NUMBER: 25205263B
CLIENT: HDR Engineering, Inc.10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS & AASHTO DESC COMBINED 25205263B - KLEBOLD SITE.GPJ 02195238 US 50 AND CHIPMAN.GPJ 1/29/21Cc Cu
75
80
85
90
95
100
105
110
115
120
125
130
135
0 5 10 15 20 25 30 35 40 45DRY DENSITY, pcfWATER CONTENT, %
Z
A
V
f
o
r
G
s =
2
.
8
Z
A
V
f
o
r
G
s =
2
.
7
Z
A
V
f
o
r
G
s =
2
.
6
MOISTURE-DENSITY RELATIONSHIP
ASTM D698/D1557
SITE: 1691 CR 300
Parachute, Colorado
PROJECT: Holy Cross Solar - High Mesa Site PROJECT NUMBER: 25205263B
CLIENT: HDR Engineering, Inc.10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. COMPACTION - V2 25205263B - KLEBOLD SITE.GPJ 02195238 US 50 AND CHIPMAN.GPJ 1/27/21ASTM D1557 Method B
Source of Material 6 @ 0 - 5 feet
Description of Material
Remarks:
Test Method
PCF
%
TEST RESULTS
LEAN CLAY with SAND(CL)
Maximum Dry Density
%
31LL
121.6
81.8
Optimum Water Content
PIPL18 13
ATTERBERG LIMITS
12.0
Percent Fines
75
80
85
90
95
100
105
110
115
120
125
130
135
0 5 10 15 20 25 30 35 40 45DRY DENSITY, pcfWATER CONTENT, %
Z
A
V
f
o
r
G
s =
2
.
8
Z
A
V
f
o
r
G
s =
2
.
7
Z
A
V
f
o
r
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6
MOISTURE-DENSITY RELATIONSHIP
ASTM D698/D1557
SITE: 1691 CR 300
Parachute, Colorado
PROJECT: Holy Cross Solar - High Mesa Site PROJECT NUMBER: 25205263B
CLIENT: HDR Engineering, Inc.10625 W I70 Frontage Rd N Ste 3Wheat Ridge, CO
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. COMPACTION - V2 25205263B - KLEBOLD SITE.GPJ 02195238 US 50 AND CHIPMAN.GPJ 1/27/21ASTM D698 Method A
Source of Material 10 @ 0 - 5 feet
Description of Material
Remarks:
Test Method
PCF
%
TEST RESULTS
LEAN CLAY with SAND(CL)
Maximum Dry Density
%
28LL
110.9
77.7
Optimum Water Content
PIPL18 10
ATTERBERG LIMITS
15.5
Percent Fines
COOL SOLUTIONS FOR UNDERGROUND POWER CABLES
THERMAL SURVEYS, CORRECTIVE BACKFILLS & INSTRUMENTATION
Serving the electric power industry since 1978
21239 FM529 Rd., Bldg. F
Cypre ss, T X 77433
Tel: 281-985-9344
Fax: 832 -427-1752
i nfo@geothermusa.com
http://www.geothermusa.com
January 21, 2021
Terracon Consultants , Inc
10625 W. I -70 Frontage Rd N, Ste 3
Wheat Ridge, CO 80033
Attn: John T. Taylor
Re: Thermal Analysis of Native Soil Sample
Holy Cross Solar - High Mesa Site – Parachute, CO (Project No. 25205263B)
The followin g is the repo rt of thermal dryou t char a cterization tests conducted on one (1)
bulk sample of native soil from the referenced project sent to our laboratory .
Thermal Resistivity Tests: The sample w as test ed at the ‘optimum ’ moisture content
and at 80% of the maximum d ry den sit y p rovided by Terraco n. The tests were
conducted in accordance with the IEEE standard 442 -2017 . The results are tabulated
below and the thermal dryout curve is presented in Figure 1.
Sample ID, Description, Thermal Resistivity, Mo isture Conte nt a nd Densi ty
Sample
I D
Effort
(%)
Depth
(ft)
Description
(Terracon )
Thermal Resistivity
(°C-cm/W) Moisture
Content
(%)
Dry
Density
(lb/ft 3 ) Wet Dry
B -6 80 0 ’-5 ' L ean Clay w/
Sand (CL) 8 3 1 90 12 97
Plea se contact us if you have an y questi ons or if we can be o f furt h e r a ss is ta n ce.
Geotherm USA
Deepak Parmar
2
COOL SOLUTIONS FOR UNDERGROUND POWER CABLES
THERMAL SURVEYS, CORRECTIVE BACKFILLS & INSTRUMENTATION
Serving the electric power industry since 1978
21239 FM529 Rd., Bldg. F
Cypre ss, T X 77433
Tel: 281-985-9344
Fax: 832 -427-1752
i nfo@geothermusa.com
http://www.geothermusa.com
January 25, 2021
Terracon Consultants , Inc
10625 W. I -70 Frontage Rd N, Ste 3
Wheat Ridge, CO 80033
Attn: John T. Taylor
Re: Thermal Analysis o f Native Soil Sample
Holy Cross Solar - High Mesa Site – Parachute, CO (Project No. 25205263B)
The followi ng is the repo rt of thermal dryou t char a cterization tests conducted on one (1)
bulk sample of native soil from the referenced project sent to our laboratory .
Thermal Resistivity Tests: The sample w as test ed at the ‘optimum ’ moisture content
and at 90% of the maximum d ry den sit y p rovided by Terraco n. The tests were
conducted in accordance with the IEEE standard 442 -2017 . The results are tabulated
below and the thermal dryout curve is presented in Figure 1.
Sample ID, Description, Thermal Resistivity, Moisture Conte nt a nd Densi ty
Sample
I D
Effort
(%)
Depth
(ft)
Description
(Terracon )
Thermal Resistivity
(°C-cm/W) Moisture
Content
(%)
Dry
Density
(lb/ft 3 ) Wet Dry
B -6 90 0 ’-5 ' L ean Clay w/
Sand (CL) 72 172 12 109
Plea se contact us if you ha v e an y questi ons or if we can be o f furt h e r a ss is ta n ce.
Geotherm USA
Deepak Parmar
2
##
Client:
Project:
Site:
Project No.:25205263 (B)
Specimen Identification Compaction
Pressure (psi)
R-Value at 300
psi
148.3 20
R-Value Test
HDR Engineering, Inc.
BORING 5 @ 0-5'
Holy Cross Solar
High Mesa
0
10
20
30
40
50
60
70
80
90
100
0100200300400500600700800R-ValueExudation Pressure, psi
201218052TASK NO:
Analytical Results
Terr acon, Inc. - W heat Ridge
John Taylor
Company:
Report To:
Company:
Bill To:
10625 W . I-70 Frontage Road
Wheat Ridge CO 80033
Accounts Payable
Terracon,Inc.-Accounts Payable
18001 W.106th St
Suite 300
Olathe KS 66061
25205263 Date Reported:12/28/20
Task No.:201218052
Matrix:Soil - Geotech
Date Received:12/18/20
Client Project:
Client PO:
2 at 0-5 ACustomer Sample ID
Test Method
201218052-01Lab Number:
Result
Chloride - Water Soluble AASHTO T291-91/ ASTM D43270.0040 %
pH AASHTO T289-918.0 units
Redox Potential ASTM D1498428.6 mv
Resistivity AASHTO T288-911598 ohm.cm
Sulfate - Water Soluble AASHTO T290-91/ ASTM D43270.008 %
8 at 0-5 ACustomer Sample ID
Test Method
201218052-02Lab Number:
Result
Chloride - Water Soluble AASHTO T291-91/ ASTM D43270.0008 %
pH AASHTO T289-917.8 units
Redox Potential ASTM D1498388.7 mv
Resistivity AASHTO T288-912450 ohm.cm
Sulfate - Water Soluble AASHTO T290-91/ ASTM D43270.003 %
2 at 0-5 BCustomer Sample ID
Test Method
201218052-03Lab Number:
Result
Chloride - Water Soluble AASHTO T291-91/ ASTM D43270.0004 %
pH AASHTO T289-917.7 units
Redox Potential ASTM D1498391.3 mv
Resistivity AASHTO T288-911744 ohm.cm
Sulfate - Water Soluble AASHTO T290-91/ ASTM D43270.003 %
10411 Heinz Way / Commerce City, CO 80640 / 303-659-2313
Mailing Address: P.O. Box 507 / Brighton, CO 80601-0507
DATA APPROVED FOR RELEASE BY
Abbreviations/ References:
201218052
AASHTO - American Association of State Highway and Transportation Officials.
ASTM - American Society for Testing and Materials.
ASA - American Society of Agronomy.
DIPRA - Ductile Iron Pipe Research Association Handbook of Ductile Iron Pipe.
Surcharge
(ksf)
Swell
(%)
Maximum
Dry Density
(pcf)
Optimum
Water
Content (%)
Test
Method 3/4"#4 #10 #40 #200 LL PI
1 0 - 5 CL 100 100 100 100 94 27 10
1 2 5.2 108 4
1 4 8.5 95 4
1 9 7.4 94 4
2 0 - 5 CL 100 100 100 100 92 31 13 0.003 0.0004 7.7 391.3 1744
2 4 4.9 108 4
2 9 12.7 113 4
2 14 8.2 131 4
3 0 - 5 CL 100 100 100 99 92 30 13
3 4 5.6 106 0.5 +1.2 3,4
3 9 7.6 109 4
3 14 8.5 125 4
4 2 6.4 111 4
4 4 5.0 105 4
4 9 6.9 4
5 0 - 5 CL 20 100 100 100 99 92 32 15
5 2 6.1 99 4
5 9 14.3 4
6 0 - 5 CL 121.6 12.0 D1557B 100 96 95 93 82 31 13 6
6 2 8.2 95 4
6 4 8.6 4
6 9 7.8 118 4
7 0 - 5 CL 100 100 99 97 84 31 13
7 2 14.1 95 4
7 4 14.3 97 4
8 0 - 5 CL 100 100 100 99 90 26 10 0.002 0.0006 7.9 374.0 2238
8 2 4.7 105 4
8 4 5.0 106 0.5 -0.2 3,4
8 9 10.5 101 4
9 0 - 5 CL 100 99 98 95 84 34 16
9 4 10.6 108 100 95 92 84 72 41 23 4
10 0 - 5 CL 110.9 15.5 D698A 100 99 98 93 78 28 10 5
10 2 14.3 73 4
10 4 9.2 4
Moisture-Density Relationship
Water
Soluble
Chlorides
(%)
pH Redox Resistivity
Particle Size Distribution, Percent Passing by Weight
SUMMARY OF LABORATORY TEST RESULTS
Holy Cross Solar - High Mesa Site - Parachute, Colorado
Terracon Project No. 25205263B
Boring No. Depth (ft)USCS
Class.
Initial
Water
Content
(%)
Atterberg Limits
Initial Dry
Density
(pcf)
Remarks
Water
Soluble
Sulfates
(%)
Swell/Consolidation
R-Value
Page 1 of 1
FIELD ELECTRICAL RESISTIVITY TEST DATA
Holy Cross Solar Project - High Mesa Site ■ Parachute, Colorado
December 15, 2020 ■ Terracon Project No. 25205263B
Array Loc.
Instrument Weather
Serial #Ground Cond.
Cal. Check Tested By
Test Date Method
Notes &
Conflicts
Apparent resistivity ρ is calculated as :
Measured
Resistance R
Apparent
Resistivity ρ
Measured
Resistance R
Apparent
Resistivity ρ
Ω (Ω-cm)Ω (Ω-cm)
1 30 6 15 198.70 49290 186.30 46210
2 61 6 15 56.90 23920 46.20 19420
5 152 6 15 10.347 10050 12.112 11760
10 305 6 15 3.224 6200 3.797 7310
20 610 12 30 1.828 7040 1.539 5920
50 1524 12 30 0.669 6410 0.704 6740
80 2438 12 30 0.381 5840 0.401 6150
N-S Test E-W Test
Approximate Center of Array (39.39158,-108.07122)
Mini-Res
N/A
N/A
December 15, 2020
35 F, Sunny
1"-2" of snow, grass, brush
Kyle T. Johnson
Wenner 4-pin (ASTM G57-06 (2012); IEEE 81-2012)
(feet)(centimeters)(inches)(centimeters)
Electrode Spacing a Electrode Depth b
1.0
10.0
100.0
1,000.0
10,000.0
100,000.0
1 10 100 1000 10000Apparent Resistivity R(Ω-cm)Electrode Spacing a (cm)
Apparent resistivity vs a spacing
N-S Array
E-W Array
𝜋=4𝜋𝑎𝑅
1 +2𝑎
𝑎2 +4𝑎2 −𝑎
𝑎2 +𝑎2
AES High Mesa Solar – Land Use Change – Major Impact permit application (10/22/2021)
AES High Mesa Solar – Garfield County 60
Please see the following pages for the AES’ planned Operations and Maintenance Schedule for AES High
Mesa Solar, LLC.
OPERATIONS AND MAINTENANCE SCHEDULE
Appendix C12
SCHEDULE 1
SCHEDULE 1
1. System-Wide Maintenance
System-wide maintenance includes but is not limited to the following:
Item Service Description Frequency
1 Complete and submit Maintenance Reports. As Needed
SCHEDULE 1
2 Inspect the mechanical functionality of the Project – including but not limited to
randomly inspecting a reasonable quantity of the fastening/mounting elements,
equipment connection and coupling cases, visual inspection of overhead poles
and lines, verifying that the threaded connections are tight, visual inspection of
all parts of the equipment and checking the cabling. Quantity inspected shall be
not less than 10% and is acknowledged as sufficient to make informed
recommendation if follow-up or additional remediation is required.
1x per year
3 Inspect all electrical boxes, combiner boxes and electrical equipment for water
damage or signs of significant water accumulation in underground conduit.
1x per year
4 Scan combiner boxes with Infrared camera to identify loose of broken connections. 1x per year
5 Visually Inspect the medium-voltage components and conduct grounding
measurements and verification.
1x per year
6 Visually inspect each AMPT DC/DC String Optimizer 1x per year
7 Inspect accessible cabling for signs of cracks, defects, pulling out of connections,
overheating, arcing, short or open circuits, and ground faults.
1x per year
8 Check for abnormal corrosion on parts of the Project and perform minor service on
any parts with the potential for corrosion to remove long-term risks.
1x per year
9 Check the mechanical functionality of the built-in components and interrupters
(ground fault circuit interrupters and circuit breakers).
1x per year
10 Check the functionality of the meters. For avoidance of doubt, functionality of the
meters means that meters are operating, communicating reliably and measuring
coherent values as compared to the backup meters.
1x per year
11 Maintain pyranometers on a regular basis according to the manufacturer's
recommendations, including but not limited to: calibration, cleaning, checking
electrical connections and mechanical supports, verifying installation tilt and
azimuth, checking desiccant and filters.
As Needed
12 Maintenance of the structure that will support the Panels shall be by various means
including visual inspection, searching for impacts, corrosion and condition of the
protective paint, and absence of water deposits.
1x per year
13 Thermal camera testing of electrical current connections and circuit breakers. 1x per year
SCHEDULE 1
14 Carryout maintenance of Project transformer(s) in accordance with manufacturer’s
recommendation.
As Needed
2. Panel Maintenance
Ongoing panel maintenance includes but is not limited to the following operations:
Item Service Description Frequency
1 Check for possible glass breakage, normally caused by external actions, and
rarely by thermal fatigue arising from assembly errors.
1x per year
2 Visually check for oxidation in the circuits and welding of the photovoltaic cells,
normally due to the entrance of dampness into the panel because of a fault or breakage of the sealing layers.
1x per year
3 Check for change of color to yellow or brown (known as yellowing and browning)
of the sealant or encapsulant.
1x per year
4 Check for issues with the panel backsheet, as inflammations in this area could be a
symptom of a hot point in the module.
1x per year
5 Check for deformations in the junction boxes of the module due to overheating of
the bypass diodes and/or high contact resistance because of bad tightness of an
electrical terminal.
1x per year
6 Check the tightness and condition on not less than 10% of the module series
connections.
1x per year
7 Where feasible, visually check the watertight integrity of the terminal boxes or the
condition of the protective hoods of the terminals, depending on the type of Panel.
1x per year
8 In the event that faults are detected in the watertight integrity, either 1) make minor
repairs that do not compromise the panel warranty or 2) process a panel warranty
claim.
1x per year
9 Undertake comparative measurement of string DC currents and/or conduct aerial
thermal imaging of the solar array.
1x per year
SCHEDULE 1
3. Inverter Maintenance
Ongoing inverter maintenance includes but is not limited to the following:
Item Service Description Frequency
1 Annual maintenance performed by O&M Contractor as required to meet the
manufacturer’s warranty requirements. O&M Contractor will provide a detailed
report of findings.
As required
2 General visual observation of the condition and functioning of the inverter. 1x per year
3 Check wiring and the connection tightness of the parts. 1x per year
4 Verify that the site of the inverter is clean, dry and well ventilated and insulated. 1x per year
5 Check that the inverter works properly and that unusual noises are not coming from
inside it.
1x per year
6 Check that where the inverter is placed maintains suitable temperatures so that this
equipment can always work within the temperature range specified by the inverter
manufacturer such that it does not derate.
1x per year
7 Check the equipment protection and alarms. 1x per year
8 Inspect air filters annually. Replace or clean as necessary. 1x per year
4. Component Testing
Component tests required include:
Item Service Description Frequency
1 Test all DC source circuits and input circuits, VOC and ISC 1x per year
2 Test all OCPDs and disconnects 1x per year
3 Test equipment grounding/continuity 1x per year
4 Verify accuracy of all meters, sensors, monitoring devices, communications equipment, weather station.
1x per year
5. Ground-Mount Project Maintenance
Ongoing general Project maintenance includes but is not limited to the following:
Item Service Description Frequency
1 Visual inspection of the general Project conditions, vegetation, animal damage,
and erosion.
As needed when
at Project
SCHEDULE 1
2 Maintain weeds, grasses and ground cover to prevent shading and risk of fire. This
includes: mowing, and reseeding grass when necessary to mitigate erosion.
2x per year,
plus as
needed
following a
quoted price
3 Monitor trees and larger vegetation to prevent shading. If shading is present or
imminent, O&M Contractor will assist Owner in identifying a third-party service to
conduct the needed trimming. O&M Contractor will provide direction to that third
As needed
4 Remove all rubbish, excessive vegetation, animal nests, dead animals, and other
obstructions from underneath array, electrical equipment servicing zones and other
key access areas.
As needed
6. Racking Maintenance
Ongoing tracking and non-tracking racking maintenance includes but is not limited to the following:
Item Service Description Frequency
1 Visually inspect all racking hardware and components for abnormal wear or
excessive corrosion.
1x per year
2 Verify torque of bolted connections at the racking and/or tracking systems. At least 1x per
year
3 Inspect all ground mounts, visually inspect structural footings and check for
abnormal wear and physical damage from vehicles.
1x per year
7. Cleaning Requirements
Ongoing cleaning requirements include but is not limited to the following:
Item Service Description Frequency
1 Clean PV modules with pressurized plain water. Do not use brushes, any types of
solvents, abrasives, or harsh detergents. The timing of cleanings are at the
discretion of the O&M Contractor but preferably before summer, and after a period
of no rainfall or when there is an event that affects the production of the Project.
As Requested
for Additional
Fee
2 Clean weather station as necessary to provide accurate data readings. As Needed
8. Battery Plant
SCHEDULE 1
For all equipment in the Battery Plant, inclusive containers and support systems, complete the full
visual/mechanical/electrical inspections and tests as recommended by ANSI/NETA and the OEM owner manuals per
the respective intervals.
SCHEDULE 1
Item Service Description Frequency
1 Battery Plant – 10MW/20MWh, Samsung batteries, integrated via DC/DC converters behind four (4) 2.8MW Inverter Skid (derated to 2.5MW). Per Above
2 Battery Energy Storage Systems – One (1) system, comprised of (8) CEN container containing Samsung batteries and associated Auxiliary Power, HVAC and Fore
Suppression systems.
Per Above
3 DC/DC Converter Modules – eight (8) units serving the BESS Per Above
4 All associated Disconnect Switches and BESS Recombiners Per Above
5 Inspect all fire extinguishers in accordance with regulations; monthly, annually, As Applicable
Operator Rates for Non-Covered Services
All expenses for Non-Covered Services, including labor, materials and equipment related thereto, will be billed to
Owner at Operator’s cost on a time and materials, cost plus 10% basis at Operator’s reasonable, documented rates. Such
services include, but are not limited to, additional panel washings and additional vegetation management beyond the frequencies
or intervals listed in the Maintenance Services Scope.
Should the Customer, the utility or the transmission provider require reporting and operating services materially
different in scope than those required in any operating agreements for the System as of the effective date of this agreement,
these additional services will also be billed at Operator’s reasonable and documented rates.
Operator Rates
Field Technician $75/hr Supervisor/Manager
$100/hr
Overtime 150% Standard Billing Rate Holiday Time 200%
Standard Billing Rate Travel Time 50% Standard Billing Rate Parts &
Materials Cost plus 10%
3rd Party Services Cost plus 10%
Vegetation Management services will be provided according to negotiated and approved fee. Module Washing services will
be provided according to negotiated and approved fee.
Gurfield County
PAYMENT AGREEMENT FORM
GARFIELD COUNW ("COUNTY") and Property Owner ("APPLICANT")
AES Hioh Mesa Solar. LLC agree as follows:
7. The Applicant has
AES Hioh Mes a Solar,
submitted to the County an application for the following Project:
lmpact permitLLC for Land Use Chanqe - Maior
2. The Applicant understands and agrees that Garfield County Resolution No. 201.4-60, as
amended, establishes a fee schedule for each type application, and the guidelines for the
administration of the fee structure.
3. The Applicant and the County agree that because of the size, nature or scope of the
proposed project, it is not possible at this time to ascertain the full extent of the costs
involved in processing the application. The Applicant agrees to make payment of the Base
Fee, established for the Project, and to thereafter permit additional costs to be billed to the
Applicant. The Applicant agrees to make additional payments upon notification by the
County, when they are necessary, as costs are incurred.
4. The Base Fee shall be in addition to and exclusive of any cost for publication or cost of
consulting service determined necessary by the Board of County Commissioners for the
consideration of an application or additional County staff time or expense not covered by
the Base Fee. lf actual recorded costs exceed the initial Base Fee, the Applicant shall pay
additional billings to the County to reimburse the County for the processing of the Project.
The Applicant acknowledges that all billing shall be paid prior to the final consideration by
the County of any Land Use Change or Division of Land.
I hereby agree to pay all fees related to this application
Billing Contact Person Joshua Mayer Phone: (720 )
514-2957
Billi ng Contact Address:282 Century Place, Suite 2000
City Louisville state: CO Zip code 80027
Billing Contact Email D EAccou nts@aes. com (cc: josh ua. mayer@aes. com )
Printed Name of Person Authorized to Sign Rob Cooper
,€"é &teoo
(Signature
5t13t2021
(Date)
04/18/22
C01-0104/19/22MMLRDBISSUED FOR GARFIELD COUNTY REVIEW0-------------------------1691 300 COUNTY ROAD, PARACHUTE, CO1" = 200'
3704.002 PV CIVILCOVER SHEETHIGH MESAPRELIMINARY
NOT FOR CONSTRUCTION
FOR REVIEW & APPROVAL ONLY JOB NO.
SCALEDATEREVISIONSNO.DATEDWN.CHK.ELECTRIC POWER ENGINEERING, INC.12600 W. COLFAX AVE, STE. C500LAKEWOOD, CO 80215(303) 431-7895 www.neieng.comCIVIL PROJECT DRAWING LIST
SHEET NUMBER SHEET TITLE
C01-01 COVER SHEET
C01-02 CIVIL GENERAL NOTES
C01-03 EXISTING CONDITIONS
C01-04 EXISTING CONDITIONS - SLOPE ANALYSIS
C01-05 SITE PLAN - OVERALL
C01-06 SITE PLAN (SHEET 1 OF 2)
C01-07 SITE PLAN (SHEET 2 OF 2)
C01-08 GRADING AND EROSION CONTROL PLAN - OVERALL
C01-09 GRADING AND EROSION CONTROL PLAN - (SHEET 1 OF 2)
C01-10 GRADING AND EROSION CONTROL PLAN - (SHEET 2 OF 2)
C01-11 RESTORATION PLAN
C01-12 SITE DETAILS
C01-13 SITE DETAILS
C01-14 SITE DETAILS
C01-15 SITE DETAILS
PROJECT
LOCATION
VICINITY MAP
N.T.S.INTERSTATE 70STONE
Q
U
A
R
R
Y
R
D
SITE DATA TABLE
PROJECT LOCATION 39° 23' 45.63" N, 108° 04' 25.49" W
PROPERTY AREA 82 ACRES
COVERAGE RATIO 1.59%COLORADO RIVERN
HIGH MESA SOLAR
PARACHUTE COUNTY, COLORADO
90% CIVIL PLANS
04/19/2022
04/18/2204/19/22MMLRDBISSUED FOR GARFIELD COUNTY REVIEW0-------------------------1691 300 COUNTY ROAD, PARACHUTE, CO1" = 200'
3704.002HIGH MESAC01-02PV CIVILGENERAL NOTESGENERAL NOTES
1.OBTAIN ALL APPLICATION PERMITS PRIOR TO CONSTRUCTION.
2.THE FOLLOWING MUST BE KEPT ON SITE UNTIL THE E.S.C. PLAN HAS BEEN CLOSED OUT BY COLORADO DEPARTMENT OF
PUBLIC HEALTH AND ENVIRONMENT (CDPHE): 12 MONTHS OF SELF INSPECTION RECORDS, RAIN GAUGE, APPROVAL
CERTIFICATE/LETTER, APPROVED PLAN AND NPDES PERMIT. THESE ITEMS SHOULD BE LOCATED NEAR THE MAIN
CONSTRUCTION ENTRANCE. FAILURE TO MAINTAIN THESE ITEMS ON SITE VIOLATES THE NPDES PERMIT.
3.ELECTRICAL EQUIPMENT SHOWN IN THIS DRAWING ARE PROPOSED AND FOR ILLUSTRATIVE PURPOSES ONLY.
4.ANY STOCKPILE SHALL HAVE A SURROUNDING SILT FENCE EXCEPT FOR THE INGRESS/EGRESS. (3 SIDES)
5.ADD ADDITIONAL SILT FENCING AND SILT FENCE OUTLETS AS NEEDED INSIDE THE DISTURBANCE LIMIT FOR
EROSION CONTROL AND SILT FENCE INTEGRITY.
6.CONTRACTOR SHALL ENSURE THAT THERE IS PROPER COVER AND PROTECTION OVER ALL CULVERTS.
7.CONTRACTOR SHOULD MINIMIZE SUBGRADE DISTURBANCE BY USING LIGHT TRACKED EQUIPMENT.
8.PERMANENT GROUND COVER WILL BE PROVIDED FOR ALL DISTURBED AREAS WITHIN 14 WORKING DAYS OR PER
NPDES REQUIREMENTS, WHICHEVER IS SHORTER.
9.ADDITIONAL PERTINENT EROSION CONTROL MEASURES TO BE DETAILED IN OVERALL SITE GRADING AND EROSION
CONTROL PLAN.
10.ALL SUBGRADE, FILL, AND STONE SHALL BE COMPACTED AS SPECIFIED IN THE GRADING SPECIFICATIONS.
11.SURVEY AND WETLAND DATA TAKEN FROM "HIGH MESA-ALTA SURVEY - ACQUISITION-ISSUED_04-20-2021" BY SGM
INC.; DATED APRIL 20, 2021.
12.8' TALL CHAIN LINK FENCE (AS SEEN IN C01-21) TO BE DESIGNED AND INSTALLED BY FENCING CONTRACTOR. THE
PROPOSED ACCESS GATE WILL BE LOCKED WITH STANDARD KEYED OR COMBINATION LOCK. EMERGENCY
PERSONNEL WILL BE PROVIDED A KEY OR COMBINATION FOR ACCESS.
13.NO STRUCTURE SHALL EXCEED A HEIGHT GREATER THAN TWENTY-FIVE (25) FEET, EXCEPT FOR ELECTRICAL
TRANSMISSION LINES AND UTILITY POLES.
14.NO LIGHTING IS PROPOSED FOR THIS SITE.
15.THE PROPERTY SHOWN HEREON LIES IN AN AREA OF UNDETERMINED, BUT POSSIBLE FLOOD HAZARD, ZONE D PER
FEMA FIRM MAP PANEL 0802051700B, DATED DECEMBER 15, 1977.
16.UTILITY LINES AND SERVICES SHOWN HEREON ARE APPROXIMATE PER AERIAL PHOTOGRAPHY OR AS REPORTED BY
VARIOUS RESPONSIBLE PARTIES. LOCATION OF UNDERGROUND UTILITIES ARE APPROXIMATE AND MUST BE FIELD
VERIFIED.
17.CLARIFICATIONS CAN BE ADDRESSED BY CONTACTING RYAN BRICK P.E email: RBRICK@NEIENG.COM / PHONE: (303)
468-3055
MAINTENANCE NOTES:
1.INSPECT SILT FENCE OUTLETS WEEKLY AND AFTER EACH SIGNIFICANT RAINFALL EVENT (ONE-HALF INCH OR
GREATER WITHIN TWENTY-FOUR HOURS) CLEAR MESH WIRE OF DEBRIS OR OTHER OBJECTS TO PROVIDE
ADEQUATE FLOW FOR SUBSEQUENT RAINS. TAKE CARE NOT TO DAMAGE OR UNDERCUT THE WIRE MESH DURING
SEDIMENT REMOVAL. REPLACE STONE AS NEEDED.
2.ADD ADDITIONAL SILT FENCE SECTIONS AND SILT FENCE OUTLETS AS NEEDED IN ORDER TO ENSURE ADEQUATE
EROSION PROTECTION AND SILT FENCE INTEGRITY.
3.ADD TEMPORARY SEED AND SINGLE-NET STRAW ROLLED EROSION CONTROL PRODUCT TO ANY DISTURBED
SLOPES AS NEEDED.
4.ADD COIR WATTLES THROUGHOUT SITE AS NEEDED AS SLOPE BREAKS.
5.ALL DISTURBED AREAS FLATTER THAN 3:1 TO BE STABILIZED WITHIN 14 DAYS. SLOPES STEEPER THAN 3:1 AND ALL
DIVERSION DITCHES TO BE STABILIZED WITHIN 7 DAYS.
6.PERMANENT GROUNDCOVER TO BE INSTALLED FOR ALL DISTURBED AREAS WITHIN 14 WORKING DAYS OR PER
NPDES REQUIREMENTS (WHICHEVER IS SHORTER) FOLLOWING COMPLETION OF CONSTRUCTION.
CONSTRUCTION SEQUENCE:
1.CONTRACTOR SHALL VERIFY LOCATION OF BURIED UTILITIES PRIOR TO START OF CONSTRUCTION. UNDERGROUND
UTILITIES NOT SHOWN ON DRAWINGS MAY EXIST.
2.OBTAIN APPROVED SET OF CONSTRUCTION DRAWINGS. AN APPROVED EROSION CONTROL PLAN SHALL BE
REQUIRED BEFORE THE ONSET OF ANY GRADING ACTIVITY. KEEP A COPY OF BOTH ITEMS ONSITE THROUGHOUT
CONSTRUCTION.
3.INSTALL STORM WATER INSPECTION BOX WITH STORM WATER INSPECTION REPORTS, A COPY OF THE PERMITS,
AND THE APPROVED E&SC PLANS. THE INSPECTION BOX WILL BE PLACED IN A PROMINENT LOCATION BY THE MAIN
ROAD AND DRIVEWAY. THE INSPECTION RECORDS FOR LAND DISTURBING ACTIVITIES MUST BE COMPLETED
WEEKLY AND AFTER EACH SIGNIFICANT RAINFALL EVENT OF ONE-HALF INCH (1/2”) OR GREATER WITHIN
TWENTY-FOUR (24) HOURS. EXTRA COPIES OF THE INSPECTION REPORT FORMS SHOULD BE PLACED IN THE
INSPECTION BOX. ALL INSPECTION RECORDS MUST BE RETAINED AND SIGNED BY THE QUALIFIED INSPECTOR
IDENTIFIED IN PART II.J.2 OF THE CONSTRUCTION GENERAL PERMIT.
4.INSTALL CONSTRUCTION ENTRANCES PRIOR TO ANY LAND DISTURBING ACTIVITIES.
5.FLAG CONSTRUCTION LIMITS AND CLEAR ONLY WHAT IS NECESSARY TO INSTALL SILT FENCING, SILT FENCE
OUTLETS, AND THE TEMPORARY TOPSOIL BERM. IMMEDIATELY STABILIZE THE EMBANKMENTS WITH ROLLED
EROSION CONTROL PRODUCT, MULCH AND SEED.
6.INSTALL ALL PERIMETER CONTROLS INCLUDING SILT FENCE AND SILT FENCE OUTLETS.
7.BEGIN ROUGH GRADING THE CONSTRUCTION ACCESS ROAD TO REQUIRED SUBGRADE.
8.INSTALL THE GRAVEL CONSTRUCTION ACCESS ROAD.
9.BEGIN CLEARING AND GRUBBING OF THE VEGETATION AND DEMOLITION OF OTHER SITE ITEMS AS SHOWN ON
THESE PLANS.
10.ONCE THE TEMPORARY SEDIMENT CONTROL BMPS ARE STABILIZED AND OPERATIONAL, COMPLETE THE
REMAINDER OF THE SITE CLEARING WITHIN THE CONSTRUCTION LIMITS.
11.TOPSOIL TO BE REUSED IN AREAS TO BE LANDSCAPED OR SEEDED MAY BE STOCKPILED WITHIN THE DESIGNATED
STOCKPILE LOCATIONS AS INDICATED ON THE DRAWINGS. THE STOCKPILE LOCATIONS SHALL BE SURROUNDED ON
THREE (3) SIDES BY SILT FENCE WITH ONE (1) SIDE OPEN TO EARTH MOVING EQUIPMENT. ALL TOPSOIL,
VEGETATION, DEBRIS, AND OTHER UNSUITABLE MATERIAL SHOULD BE REMOVED FROM THE SITE TO AN APPROVED
AND PERMITTED LOCATION.
12.BEGIN ROUGH GRADING EQUIPMENT PADS TO GRADING PLAN TO REQUIRED SUBGRADES.
13.USE TEMPORARY SEED AS CONDITIONS WARRANT IN AREAS WITH NO CURRENT WORK.
14.FINALIZE THE INSTALLATION OF THE ACCESS DRIVES (INCLUDING STONE), COMPLETE GRADING, AND STABILIZE ALL
DISTURBED AREAS BY SEEDING AND MULCHING.
15.HAUL AWAY OR DISPOSE OF ANY EXCESS SPOILS NOT NEEDED TO BALANCE SITE. IF ANY TOPSOIL IS TO REMAIN
STOCKPILED, PROTECT WITH SILT FENCING AROUND PERIMETER.
16.SOIL STABILIZATION MEASURES SHALL BE INITIATED AS SOON AS PRACTICABLE IN PORTIONS OF THE SITE WHERE
CONSTRUCTION ACTIVITIES HAVE TEMPORARILY OR PERMANENTLY CEASED, BUT IN NO CASE MORE THAN SEVEN
(7) OR FOURTEEN (14) DAYS (DEPENDING ON SLOPE) AFTER WORK HAS CEASED.
17.SEED GRADED SLOPES AND DENUDED AREAS FOLLOWING INITIAL SOIL DISTURBANCE. AFTER FINAL USE, THE
SPOILS AREA SHALL BE RESTORED AND SEEDED.
18.INSTALL AND REPAIR PERMANENT VEGETATION ACROSS THE ENTIRETY OF THE SITE ONCE ACCESS ROADS HAVE
BEEN COMPLETED. USE LIGHT, TRACKED EQUIPMENT FOR MINIMUM GROUND DISTURBANCE DURING STEEL PILE
AND SOLAR PANEL MOUNTING STRUCTURE INSTALLATION.
19.IMMEDIATELY RE-SEED AREAS DISTURBED DURING PANEL INSTALLATION AND TRENCHING OF UNDERGROUND
ELECTRICAL UTILITIES.
20.REMOVE ALL STOCKPILES OF SOIL, CONSTRUCTION MATERIAL/DEBRIS, CONSTRUCTION EQUIPMENT, ETC. FROM
THE CONSTRUCTION SITE.
21.ENSURE THE SITE HAS UNIFORM VEGETATIVE COVER OF AT LEAST 70% COMPARED TO THE ORIGINAL
UNDISTURBED SITE.
22.PROVIDE ALL ON-SITE REPORTS AND DOCUMENTS TO AES; ATTN: MICHAEL JENKINSON.
GRADING PLAN NOTES
1.PROJECT LOCATION IS IN GARFIELD COUNTY, COLORADO. APPROXIMATE SITE LOCATION IS AT 39° 23' 45.63" N, 108°
04' 25.49" W.
2.COORDINATES ARE IN NSRS2011 COLORADO STATE PLANE CENTRAL ZONE, US FT.
3.CONTRACTOR SHALL FIELD VERIFY ALL LOCAL BENCHMARKS/MONUMENTS PRIOR TO CONSTRUCTION.
4.EG IS DENOTED AS EXISTING GRADE.
5.IE IS DENOTED AS INVERT ELEVATION OF CULVERT OR SWALE.
6.ALL MEASUREMENTS ARE IN FEET, UNLESS SPECIFIED OTHERWISE.
7.CUT AND FILL SLOPES SHALL BE 3:1 OR FLATTER UNLESS NOTED OTHERWISE ON THE PLAN SHEET. ALL DISTURBED
GROUND NOT COVERED WITH GRAVEL SHALL BE TEMPORARILY STABILIZED PER THE REQUIREMENTS OF THE
STORMWATER POLLUTION PREVENTION PLAN.
8.FINAL STABILIZATION REQUIREMENTS SHALL BE BASED ON THE REQUIREMENTS OF THE STORM WATER
MANAGEMENT PLAN.
9.DIRECTION OF TRAFFIC SHALL BE CONFIRMED BY THE CONTRACTOR PRIOR TO CONSTRUCTION
10.THE CONTRACTOR SHALL VERIFY ALL EXISTING CONDITIONS, UTILITIES AND CULVERTS PRIOR TO CONSTRUCTION.
THE CONTRACTOR SHALL INFORM THE ENGINEER OF ANY DISCREPANCIES BETWEEN THE EXISTING CONDITIONS AND
THE PLANS.
11.CONTRACTOR TO PROTECT EXISTING UTILITIES AND MAINTAIN EXISTING DRAINAGE PATTERNS AT ALL TIMES.
12.CONTRACTOR TO VERIFY RIGHT OF WAY LIMITS PRIOR TO CONSTRUCTION.
13.AGGREGATE AND EMBANKMENT COMPACTION AND TESTING SHALL BE DONE PER THE CONSTRUCTION NOTES AND
THE ROAD CONSTRUCTION STANDARDS FROM THE GEOTECHNICAL REPORT.
14.EXISTING FEATURES (FENCE, MAILBOX, SIGN, ETC.) THAT ARE DISTURBED AS PART OF THE TEMPORARY
IMPROVEMENT SHALL BE REINSTALLED OR REPLACED IN A CONDITION EQUAL TO OR BETTER THAN THE
PRECONSTRUCTION CONDITION.
15.CULVERT END SECTIONS MUST HAVE 6:1 OR SHALLOWER SLOPE.
16.THE CONTRACTOR SHALL BE RESPONSIBLE FOR ALL TRAFFIC CONTROL. TRAFFIC CONTROL SHALL MEET THE
REQUIREMENTS OF THE COUNTY AND THE STATE DEPARTMENT OF TRANSPORTATION AND ALL RECOMMENDATIONS
IN THE MANUAL ON UNIFORM TRAFFIC CONTROL DEVICES (MUTCD).
17.CONTRACTOR SHALL CALL 811, ONE CALL ENTITIES PRIOR TO CONSTRUCTION. ALL HAZARDS SHALL BE ASSESSED
PRIOR TO CONSTRUCTION.
18.FINAL GRADE TO MAINTAIN POSITIVE (I.E. OFFSET) DRAINAGE ACROSS THE ENTIRE PROJECT SITE UNLESS
SPECIFICALLY INDICATED OTHERWISE IN THIS DRAWING PACKAGE.
19.CONSTRUCTION OF EROSION AND SEDIMENT CONTROL DEVICES IS TO BE CARRIED OUT AND THEIR LOCATION IS TO
BE AS DESCRIBED IN THE CONSTRUCTION SEQUENCE. CERTAIN DEVICES ARE TO BE CONSTRUCTED BEFORE
GRADING OPERATIONS BEGIN. ALL DEVICES ARE TO BE MAINTAINED DURING CONSTRUCTION AND TEMPORARY ONES
REMOVED AFTERWARD.
20.ALL VEGETATION AND DEBRIS SHOULD BE REMOVED FROM THE SITE. ALL SUBGRADE SOILS SHALL BE FREE OF
ORGANIC MATERIAL, COMPACTED, AND INSPECTED BY AN APPROVED GEOTECHNICAL ENGINEER PRIOR TO THE
PLACEMENT OF FILL MATERIAL. ANY MATERIAL TO BE STOCKPILED ON SITE SHALL BE STOCKPILED WITHIN THE
CONSTRUCTION LIMITS AND IN DESIGNATED AREAS.
STABILIZATION REQUIREMENTS
1.TEMPORARY STABILIZATION MUST BE IMPLEMENTED FOR EARTH DISTURBING ACTIVITIES ON ANY PORTION OF THE
SITE WHERE GROUND DISTURBING CONSTRUCTION ACTIVITY HAS PERMANENTLY CEASED, OR TEMPORARILY
CEASED FOR MORE THAN 14 CALENDAR DAYS. TEMPORARY STABILIZATION METHODS MAY INCLUDE, BUT ARE NOT
LIMITED TO, TARPS, SOIL TACKIFIER, AND HYDROSEED.
2.FINAL STABILIZATION IS REACHED WHEN ALL GROUND SURFACE DISTURBING ACTIVITIES AT THE CONSTRUCTION
SITE ARE COMPLETE; AND, FOR ALL AREAS OF GROUND SURFACE DISTURBING ACTIVITIES, EITHER A UNIFORM
VEGETATIVE COVER WITH AN INDIVIDUAL PLANT DENSITY OF AT LEAST 70 PERCENT OF PRE-DISTURBANCE LEVELS
IS ESTABLISHED, OR EQUIVALENT PERMANENT ALTERNATIVE STABILIZATION METHODS ARE IMPLEMENTED.
3.ALL TEMPORARY CONTROL MEASURES MUST BE REMOVED FROM THE CONSTRUCTION SITE ONCE FINAL
STABILIZATION IS ACHIEVED, EXCEPT WHEN THE CONTROL MEASURE SPECIFICATION ALLOW THE CONTROL
MEASURE TO BE LEFT IN PLACE.
EROSION AND SEDIMENTATION CONTROL NOTES
1.CONSTRUCTION OF EROSION AND SEDIMENT CONTROL DEVICES IS TO BE CARRIED OUT AS DESCRIBED IN THE
CONSTRUCTION SEQUENCE AND THEIR LOCATION IS TO BE AS SHOWN ON THE DRAWINGS. CERTAIN DEVICES ARE
TO BE CONSTRUCTED BEFORE GRADING OPERATIONS BEGIN. ALL DEVICES ARE TO BE MAINTAINED DURING
CONSTRUCTION AND TEMPORARY ONES REMOVED AFTERWARD.
2.THE CONTRACTOR SHALL PROVIDE EROSION CONTROL MEASURES AS PLANNED AND SPECIFIED FOLLOWING BEST
MANAGEMENT PRACTICES AS OUTLINED BY THE COLORADO DEPARTMENT OF HEALTH AND ENVIRONMENT (CDPHE)
AND BEING IN CONFORMANCE WITH THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) GENERAL
STORMWATER PERMIT. SEE THE PROJECT SITE PLANS AND ASSOCIATED STORMWATER MANAGEMENT PLAN (SWMP)
FOR EROSION CONTROL AND RESTORATION LOCATIONS AND SPECIFICATIONS. UNLESS OTHERWISE NOTED OR
MODIFIED IN THE SWMP/HEREIN, ALL SECTIONS OF THE GENERAL CONDITIONS SHALL APPLY.
3.THE CONTRACTOR SHALL BE RESPONSIBLE FOR MAINTAINING THE SWMP'S AVAILABILITY.
4.ALL FIBER ROLLS AND OTHER EROSION CONTROL FEATURES SHALL BE IN-PLACE PRIOR TO ANY
EXCAVATION/CONSTRUCTION AND SHALL BE MAINTAINED UNTIL VIABLE TURF OR GROUND COVER HAS BEEN
ESTABLISHED.
5.ALL DRAINAGE SWALES DISTURBED DURING CONSTRUCTION ACTIVITIES AND NOT COVERED BY ROAD SURFACING
MATERIALS, SHALL BE STABILIZED IN ACCORDANCE WITH THE SWMP PLAN.
6.INSPECT SILT FENCE OUTLETS WEEKLY AND AFTER EACH SIGNIFICANT RAINFALL EVENT OF HALF INCH (1/2") OR
GREATER WITHIN TWENTY-FOUR (24) HOURS. CLEAR MESH WIRE OF DEBRIS OR OTHER OBJECTS TO PROVIDE
ADEQUATE FLOW FOR SUBSEQUENT RAINS. TAKE CARE NOT TO DAMAGE OR UNDERCUT THE WIRE MESH DURING
SEDIMENT REMOVAL. REPLACE STONE AS NEEDED.
7.ADD ADDITIONAL SILT FENCE SECTIONS AND SILT FENCE OUTLETS AS NEEDED IN ORDER TO ENSURE ADEQUATE
EROSION PROTECTION AND SILT FENCE INTEGRITY.
8.ADD TEMPORARY SEED AND SINGLE-NET STRAW ROLLED EROSION CONTROL PRODUCT TO ANY DISTURBED SLOPES
AS NEEDED.
9.ADD COIR WATTLE SEDIMENT TUBES THROUGHOUT SITE AS NEEDED AS SLOPE BREAKS.
10.ALL BARE SOILS ARE TO BE STABILIZED UNDER CONDITIONS OUTLINED IN THE CURRENT NPDES PERMIT, OR, IF IN A
CRITICAL AREA, BY THE END OF THE DAY.
11.STABILIZATION WILL BE PROVIDED FOR ALL DISTURBED AREAS WITHIN 14 DAYS AFTER CONSTRUCTION ACTIVITY IS
COMPLETE UNLESS CONSTRUCTION ACTIVITY IS GOING TO RESUME WITHIN 21 DAYS, EXCEPT SLOPES STEEPER
THAN 3H:1V TO BE STABILIZED WITHIN 7 DAYS.
12.SEDIMENT CONTAINMENT DEVICES ARE TO REMAIN IN OPERATING CONDITION UNTIL PERMANENT VEGETATION IS
ESTABLISHED.
EQUIPMENT AND VEHICLE MAINTENANCE
1.MAINTAIN VEHICLES AND EQUIPMENT TO PREVENT DISCHARGE OF FLUIDS.
2.PROVIDE DRIP PANS UNDER ANY STORED EQUIPMENT.
3.IDENTIFY LEAKS AND REPAIR AS SOON AS FEASIBLE, OR REMOVE LEAKING EQUIPMENT FROM THE PROJECT.
4.COLLECT ALL SPENT FLUIDS, STORE IN SEPARATE CONTAINERS AND PROPERLY DISPOSE AS HAZARDOUS
WASTE (RECYCLE WHEN POSSIBLE).
5.REMOVE LEAKING VEHICLES AND CONSTRUCTION EQUIPMENT FROM SERVICE UNTIL THE PROBLEM HAS
BEEN CORRECTED.
6.BRING USED FUELS, LUBRICANTS, COOLANTS, HYDRAULIC FLUIDS AND OTHER PETROLEUM PRODUCTS TO A
RECYCLING OR DISPOSAL CENTER THAT HANDLES THESE MATERIALS.
LITTER, BUILDING MATERIAL AND LAND CLEARING WASTE
1.NEVER BURN OR BURY NON-ORGANIC WASTE. PLACE LITTER AND DEBRIS IN APPROVED WASTE
CONTAINERS.
2.PROVIDE A SUFFICIENT NUMBER AND SIZE OF WASTE CONTAINERS (E.G DUMPSTER, TRASH RECEPTACLE)
ON SITE TO CONTAIN CONSTRUCTION AND DOMESTIC WASTES.
3.LOCATE WASTE CONTAINERS AT LEAST 50 FEET AWAY FROM STORM DRAIN INLETS AND SURFACE WATERS
UNLESS NO OTHER ALTERNATIVES ARE REASONABLY AVAILABLE.
4.LOCATE WASTE CONTAINERS ON AREAS THAT DO NOT RECEIVE SUBSTANTIAL AMOUNTS OF RUNOFF FROM
UPLAND AREAS AND DOES NOT DRAIN DIRECTLY TO A STORM DRAIN, STREAM OR WETLAND.
5.COVER WASTE CONTAINERS AT THE END OF EACH WORKDAY AND BEFORE STORM EVENTS OR PROVIDE
SECONDARY CONTAINMENT. REPAIR OR REPLACE DAMAGED WASTE CONTAINERS.
6.ANCHOR ALL LIGHTWEIGHT ITEMS IN WASTE CONTAINERS DURING TIMES OF HIGH WINDS.
7.EMPTY WASTE CONTAINERS AS NEEDED TO PREVENT OVERFLOW. CLEAN UP IMMEDIATELY IF CONTAINERS
OVERFLOW.
8.DISPOSE WASTE OFF-SITE AT AN APPROVED DISPOSAL FACILITY.
9.ON BUSINESS DAYS, CLEAN UP AND DISPOSE OF WASTE IN DESIGNATED WASTE CONTAINERS.
EARTHEN STOCKPILE MANAGEMENT
1.LOCATE EARTHEN-MATERIAL STOCKPILE AREAS AT LEAST 50 FEET AWAY FROM PERIMETER SEDIMENT
CONTROLS AND SURFACE WATERS UNLESS IT CAN BE SHOWN NO OTHER ALTERNATIVES ARE REASONABLY
AVAILABLE.
2.PROTECT STOCKPILE WITH SILT FENCE INSTALLED ALONG TOE OF SLOPE WITH A MINIMUM OFFSET OF FIVE
FEET FROM THE TOE OF STOCKPILE.
3.PROVIDE STABLE STONE ACCESS POINT WHEN FEASIBLE.
4.STABILIZE STOCKPILE WITHIN THE TIMEFRAMES PROVIDED ON THE EROSION AND SEDIMENT CONTROL PLAN
AND ANY ADDITIONAL REQUIREMENTS. SOIL STABILIZATION IS DEFINED AS VEGETATIVE, PHYSICAL OR
CHEMICAL COVERAGE TECHNIQUES THAT WILL RESTRAIN ACCELERATED EROSION ON DISTURBED SOILS
FOR TEMPORARY OR PERMANENT CONTROL NEEDS.
CONCRETE WASHOUTS
1.DO NOT DISCHARGE CONCRETE OR CEMENT SLURRY FROM THE SITE.
2.DISPOSE OF, OR RECYCLE SETTLED, HARDENED CONCRETE RESIDUE IN ACCORDANCE WITH LOCAL AND
STATE SOLID WASTE REGULATIONS AND AT AN APPROVED FACILITY.
3.MANAGE WASHOUT FROM MORTAR MIXERS IN ACCORDANCE WITH THE ABOVE ITEM AND IN ADDITION PLACE
THE MIXER AND ASSOCIATED MATERIALS ON IMPERVIOUS BARRIER AND WITHIN LOT PERIMETER SILT FENCE.
4.INSTALL TEMPORARY CONCRETE WASHOUTS PER LOCAL REQUIREMENTS, WHERE APPLICABLE. IF AN
ALTERNATE METHOD OR PRODUCT IS TO BE USED, CONTACT YOUR APPROVAL AUTHORITY FOR REVIEW AND
APPROVAL. IF LOCAL STANDARD DETAILS ARE NOT AVAILABLE, USE ONE OF THE TWO TYPES OF
TEMPORARY CONCRETE WASHOUTS PROVIDED ON THIS DETAIL.
5.DO NOT USE CONCRETE WASHOUTS FOR DEWATERING OR STORING DEFECTIVE CURB OR SIDEWALK
SECTIONS. STORMWATER ACCUMULATED WITHIN THE WASHOUT MAY NOT BE PUMPED INTO OR
DISCHARGED TO THE STORM DRAIN SYSTEM OR RECEIVING SURFACE WATERS. LIQUID WASTE MUST BE
PUMPED OUT AND REMOVED FROM PROJECT.
6.LOCATE WASHOUTS AT LEAST 50 FEET FROM SURFACE WATERS UNLESS IT CAN BE SHOWN THAT NO OTHER
ALTERNATIVES ARE REASONABLY AVAILABLE.
7.LOCATE WASHOUTS IN AN EASILY ACCESSIBLE AREA, ON LEVEL GROUND AND INSTALL A STONE ENTRANCE
PAD IN FRONT OF THE WASHOUT. ADDITIONAL CONTROLS MAY BE REQUIRED BY THE APPROVING
AUTHORITY.
8.INSTALL AT LEAST ONE SIGN DIRECTING CONCRETE TRUCKS TO THE WASHOUT WITHIN THE PROJECT LIMITS.
POST SIGNAGE ON THE WASHOUT ITSELF TO IDENTIFY THIS LOCATION.
9.REMOVE LEAVINGS FROM THE WASHOUT WHEN AT APPROXIMATELY 75% CAPACITY TO LIMIT OVERFLOW
EVENTS. REPLACE THE TARP, SAND BAGS OR OTHER TEMPORARY STRUCTURAL COMPONENTS WHEN NO
LONGER FUNCTIONAL. WHEN UTILIZING ALTERNATIVE OR PROPRIETARY PRODUCTS, FOLLOW
MANUFACTURER'S INSTRUCTIONS.
10.AT THE COMPLETION OF THE CONCRETE WORK, REMOVE REMAINING LEAVINGS AND DISPOSE OF IN AN
APPROVED DISPOSAL FACILITY. FILL PIT, IF APPLICABLE, AND STABILIZE ANY DISTURBANCE CAUSED BY
REMOVAL OF WASHOUT.
GARFIELD COUNTY LAND USE CODES
1.CURRENT ZONING IS INDUSTRIAL USE AND A 100' SETBACK IS REQUIRED FOR ELECTRICAL EQUIPMENT. PER
GARFIELD COUNTY LAND USE CODE ZONING 7-1001 SECTION B
2.FENCES MAY BE LOCATED WITHIN THE 100' SETBACK AS PER GARFIELD COUNTY LAND USE CODE 7-1201
SECTION B
PROPOSED CONTOUR MINOR
PROPOSED CONTOUR MAJOR
PROPOSED LIMIT OF DISTURBANCE
LEGEND:
PROPOSED ACCESS ROAD
PROPOSED SILT FENCE
PROPOSED CULVERT
PROPOSED SECURITY FENCE
EXISTING FEATURES
PROPOSED FEATURES
PROPOSED LAYDOWN AREA
EROSION CONTROL
TEMPORARY SEEDING
PERMANENT SEEDING
CONSTRUCTION ENTRANCE
PROPOSED INVERTER/ BESS PAD
PROPOSED SWITCHGEAR PAD
SEDIMENT CONTROL LOG
JOB NO.
SCALEDATEREVISIONSNO.DATEDWN.CHK.ELECTRIC POWER ENGINEERING, INC.12600 W. COLFAX AVE, STE. C500LAKEWOOD, CO 80215(303) 431-7895 www.neieng.comEXISTING FENCE
EXISTING CONTOUR MINOR
EXISTING CONTOUR MAJOR
EXISTING ROAD EASEMENT
EXISTING FENCE
EXISTING UTILITY POLE
EXISTING OVERHEAD ELECTRIC
EXISTING LIMITS OF GAS PIPELINE
EXISTING PROPERTY LINE
EXISTING WETLANDS
EXISTING DITCH
EXISTING PROPERTY LINE
EXISTING WETLANDS
EXISTING DITCH
EXISTING DITCH SETBACK
EXISTING WETLANDS SETBACK
PROPOSED UNDERGROUND MV CABLE
GENERAL NOTES - COR400000 PERMIT
1.HIGH MESA COR400000 PERMIT #: COR414792
2.PRIOR TO CONSTRUCTION, THE FOLLOWING CONDITIONS MUST BE MET TO ATTAIN AUTOMATIC
COVERAGE UNDERNEATH THIS PERMIT :
2.1.A COMPLETED NOTICE OF COVERAGE (NOC) MUST BE POSTED.
2.2.A STORMWATER MANAGEMENT PLAN (SWMP) MUST BE PREPARED AND A COPY MAINTAINED
AT THE CONSTRUCTION SITE.
2.3.ALL PERMIT CONDITIONS SET FORTH IN THE GENERAL PERMIT MUST BE FOLLOWED.
2.4.APPROVED PLAN AND NPDES PERMIT.
THESE ITEMS SHOULD BE LOCATED NEAR THE MAIN CONSTRUCTION ENTRANCE. FAILURE TO
MAINTAIN THESE ITEMS ON SITE VIOLATES THE NPDES PERMIT.
3.ANY STOCKPILES SHALL BE SURROUNDED BY SILT FENCE ON ALL SIDES EXCEPT FOR THE
INGRESS/EGRESS. (3 SIDES)
4.CONTRACTOR IS RESPONSIBLE FOR REVIEWING GEOTECHNICAL REPORTS ACCOMPANYING ANY
GRADING SPECIFICATIONS FOR PERTINENT SITE SOILS INFORMATION.
5.ADDITIONAL PERTINENT EROSION CONTROL MEASURES TO BE DETAILED IN OVERALL SITE
GRADING AND EROSION CONTROL PLAN.
6.ALL SUBGRADE, FILL, AND STONE SHALL BE COMPACTED AS SPECIFIED IN THE GRADING
SPECIFICATIONS.
7.FOLLOW PHASES 1, 2, AND 3 OF THE CONSTRUCTION SEQUENCE FOR GENERAL PROCESS AND
PROJECT PHASING.
8.ALL DISTANCES SHOWN ARE NAD83 COLORADO STATE PLANE, CENTRAL ZONE. ZONE GRID
DISTANCES IN U.S. FEET UNLESS OTHERWISE SPECIFIED.
9.CLARIFICATIONS MAY BE ADDRESSED BY
9.1.CONTACTING MR. RYAN BRICK, P.E.; Email: RBRICK@NEIENG.COM / PHONE: (303) 468-3055
9.2.CONSULTING THE COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT (CDPHE)
WEBSITE.
RIPRAP
PROPOSED UNDERGROUND
WATER LINE
PROPOSED VISUAL SCREENING BERM
EXISTING UNDERGROUND
WATER LINE
04/19/2022
FYRWALD EXEMPTION PLAT LOT 3LAND SURVEY PLAT DEPOSIT NO. 312FRANK W & YONEKO McNEILPARCEL NO. 240935300128
FYRWALD EXEMPTION PLAT LOT 4LAND SURVEY PLAT DEPOSIT NO. 312GERALD GRUNKSA ET ALPARCEL NO. 240935300129
FYRWALD EXEMPTION PLAT LOT 3LAND SURVEY PLAT DEPOSIT NO. 312FRANK W & YONEKO McNEILPARCEL NO. 240935300128
FYRWALD EXEMPTION PLAT LOT 4LAND SURVEY PLAT DEPOSIT NO. 312GERALD GRUNKSA ET ALPARCEL NO. 240935300129
04/18/22
C01-0304/19/22MMLRDBISSUED FOR GARFIELD COUNTY REVIEW0-------------------------JOB NO.
SCALEDATEREVISIONSNO.DATEDWN.CHK.ELECTRIC POWER ENGINEERING, INC.12600 W. COLFAX AVE, STE. C500LAKEWOOD, CO 80215(303) 431-7895 www.neieng.com1691 300 COUNTY ROAD, PARACHUTE, CO1" = 200'
3704.002 PV CIVILEXISTING CONDITIONSHIGH MESAPRELIMINARY
NOT FOR CONSTRUCTION
FOR REVIEW & APPROVAL ONLY
SCALE:
200'100'0 200'400'600'
1"=200'
N
NOTES
1.SURVEY AND TOPOGRAPHY DATA TAKEN FROM "HIGH MESA-ALTA SURVEY -
ACQUISITION-ISSUED_04-20-2021" BY SGM INC.; DATED APRIL 20, 2021.
2.WETLANDS SHOWN AS PROVIDED IN THE ALTA SURVEY.
LEGEND:
EXISTING FEATURES
EXISTING FENCE
EXISTING CONTOUR MINOR
EXISTING CONTOUR MAJOR
EXISTING ROAD EASEMENT
EXISTING FENCE
EXISTING UTILITY POLE
EXISTING OVERHEAD ELECTRIC
EXISTING LIMITS OF GAS PIPELINE
EXISTING UNDERGROUND
WATER LINE
EXISTING PROPERTY LINE
EXISTING WETLANDS
EXISTING DITCH
EXISTING PROPERTY LINE
EXISTING WETLANDS
EXISTING DITCH
EXISTING DITCH SETBACK
EXISTING WETLANDS SETBACK
04/19/2022