HomeMy WebLinkAbout1.11 Application Part12
AES DE Holy Cross PV + BESS: Davis Site Phase I Environmental Site Assessment | Photo Log
Silt, Garfield County, Colorado
8
Photo 15. Debris on top of ravine, ~ 150 feet off-site to the south, viewing south
Photo 16. View of adjacent land to the south, viewing south
AES DE Holy Cross PV + BESS: Davis Site Phase I Environmental Site Assessment | Photo Log
Silt, Garfield County, Colorado
9
Photo 17. View of site from the south to the northwest
Photo 18. View of north jeep trail access road, northeast portion of site, viewing north
AES DE Holy Cross PV + BESS: Davis Site Phase I Environmental Site Assessment | Photo Log
Silt, Garfield County, Colorado
10
Photo 19. View of north jeep trail access road, northeast portion of site, viewing northeast
AES Peace Bear Ranch Solar – Land Use Change – Major Impact permit application (11/5/2021)
AES Peace Bear Ranch Solar – Garfield County 49
Please see the following pages for the Cultural Resources Class I Memo – AES Peace Bear Ranch Solar,
LLC published in February, 2021.
CULTURAL RESOURCES CLASS I MEMO
Appendix C4
1
Date: February 10, 2021
Project: AES Peace Bear Ranch Solar, LLC
To: AES Peace Bear Ranch Solar, LLC
From: Kevin Gilmore, PhD, RPA, Archaeology Program Manager
Subject: AES Peace Bear Ranch Solar, LLC Cultural Resources Class I Memo
AES Peace Bear Ranch Solar, LLC (AES) contracted HDR to conduct a Class I cultural resource
review for their proposed Holy Cross Photovoltaic and Battery Energy Storage Systems Portfolio
(Project). This Class I review will be used as part of a Phase I Environmental Site Assessment
(Phase I ESA) to determine the Project’s suitability for a planned greenfield solar project on the
Peace Bear Ranch Solar, LLC parcel. The privately owned parcel is approximately 3 miles south of
Silt, Colorado.
HDR requested a file search and literature review from the Colorado Office of Archaeology and
Historic Preservation (OAHP) on January 15, 2021. The file search identified 21 previous cultural
resources surveys within 1 mile of the proposed Project area (see Table 1). None of the previous
surveys intersect the proposed Project area.
Table 1. Previous cultural resource surveys within a mile of the proposed Project area.
Report No. Year Report Name Author(s) Type
GF.E.NR10 2004 Fiber Optic Cable Installation from Rifle Sub to
Rifle Microwave Site Garfield County, Colorado
(WAPA # C-04-08)
Giliberti, Joseph Class III
GF.E.R14 2015 A Cultural Resource Inventory of a Portion of
the North Fork-Rifle 230-kV Transmission Line
and Access Roads: Garfield County, Colorado
Bright, Martha Class III
GF.LM.NR1001 2013 Class III Cultural Resources Inventory for the
Proposed Louthan SESE Well Location in
Garfield County, Colorado for Bill Barrett
Corporation (CRVFO#1112-31) (GRI# 2012-99)
Hannah Mills Class III
GF.LM.NR620 2001 Access Road to Gas Well, # Porter Federal 16-
29 (GSFO #1001-43)(GSFO 2001-45EA)
Sokal, Dan Class III
GF.LM.R157 2000 Class III Cultural Resource Inventory Report for
the Proposed Porter Fed. #11-28 & Porter Fed.
#13-28 Well Locations & Related Short Access
in Garfield County, Colorado for Calpine Natural
Gas Company (GRI No. 2052)
Conner, Carl E.
and Barbara J.
Davenport
Class III
GF.LM.R161 2001 Class III Cultural Resource Inventory Report of
Two Proposed Well Pads for Three Wells
(Porter #12-28, #9-29 and #16-29) and Related
Short Access in Garfield County, Colorado for
Calpine Natural Gas Company (GRI 2110)
Conner, Carl E.
and Barbara J.
Davenport
Class III
2
Table 1. Previous cultural resource surveys within a mile of the proposed Project area.
Report No. Year Report Name Author(s) Type
GF.LM.R306 2005 Class III Cultural Resource Inventory Report for
Eleven Proposed Well Locations and Related
New Access Road and Pipeline Routes in
Garfield County, Colorado for Bill Barrett
Corporation (GRI No. 2543)(BLM 1105-15)
Martin, Curtis,
Carl E. Conner
and Nicole
Darnell
Class III
GF.LM.R317 2006 Class III Cultural Resource Inventory Report for
a Proposed Water Line for the Shildeler Fed.
43D-29-692 in Garfield County, Colorado for Bill
Barrett Corporation (GRI No. 2630) (BLM
GSFO# 1106-8)
Conner, Carl E.,
Barbara
Davenport and
Nicole Darnell
Class III
GF.LM.R376 2007 Antero Dixon B Well Pad, Access Road and
Pipeline: A Class III Cultural Resource
Inventory, Garfield County, Colorado (BLM
GSFO# 5407-12 NEPA CO140-2007-102EA)
Mcdonald, Kae Class III
GF.LM.R378 2006 Class III Cultural Resource Inventory for the
Proposed Platzer 33B-27-692 Well Location and
Related Short New Access in Garfield County,
Colorado for Bill Barrett Corporation (GRI No.
2645)(BLM GSFO# 1106-10)
Conner, Carl E. Class III
GF.LM.R391 2007 Class III Cultural Resource Inventory Report for
a 100-Acre Block Area in Garfield County,
Colorado for Bill Barrett Corporation (BLM
GSFO# 1107-22) (GRI No. 2740)
Conner, Carl E. Class III
GF.LM.R500 2010 Bill Barrett Corporation's Dixon S23T6SR92W
Two Pad Project: A Class III Cultural Resource
Inventory, Garfield County, Colorado (Original
and Addendum) (BLM # 5411-5)
Elkins, Melissa Class III
GF.LM.R520 2011 Class III Cultural Resources Survey for the
Proposed Carlson SESW and NESE Well
Locations and Short Accesses in Garfield
County, Colorado for Bill Barrett Corporation
(BLM # CRVFO 1112-9)
Conner, Carl E.,
Barbara
Davenport, and
Hannah Mills
Class III
GF.LM.R521 2011 Class III Cultural Resources Inventory Report
for the Proposed CBS Federal NENE-28 Well
Location in Garfield County, Colorado for Barrett
Corporation (BLM # CRVFO 1112-10)
Conner, Carl E.,
Nicole Darnell,
Dakota Kramer,
and Barbara
Davenport
Class III
GF.LM.R524 2011 Class III Cultural Resources Inventory for the
Proposed Federal NE NW 692 Well Location in
Garfield County, Colorado the Bill Barrett
Corporation (BLM # 1111-35) (GRI # 2011-63)
Davenport,
Barbara
Class III
GF.LM.R60 1993 A Class III Cultural Resources Inventory of
Portions of Nassau Resources' Proposed Rifle
Pipelines 1 & 2 in Garfield County, Colorado
(S#1234)
Shields, Wm.
Lane
Class III
3
Table 1. Previous cultural resource surveys within a mile of the proposed Project area.
Report No. Year Report Name Author(s) Type
GF.LM.R94 1996 Intensive Cultural Resource Survey of Porter
Federal 14-28-6-92 and Mamm Creek Federal
12-33-6-92 Well Locations, Access Roads &
Pipelines Garfield County, Colorado (and
Addendum)(S#8296-1A & S#8296-2B)
Brechtel, James
M.
Class III
GF.SC.NR69 2012 Garfield County Limited Results Cultural
Resource Survey Report on Private Lands
(Eagle Springs Organics)
Wyle, D. Class III
MC.CH.R96 1999 A Cultural Resource Survey of Interstates 25,
70, 225, and 270, U.S. Highways 34 and 160,
and State Highways 13 and 470, for the
Proposed Adesta Communications Fiber Optic
System, Colorado (C SW00-102)
Sherman,
Stephen A.,
Tania R. Metcalf,
Mary W. Painter,
D. Chadwick
Jones, and
Christian J. Zier
Class III
MC.E.R59 1982 Volumes I and Ii; Class III Cultural Resource
Investigations, Craig-Rifle 230 to 345-kV
Transmission Line Uprate, Northwest Colorado
(R-2407)
Newkirk, Judith
and Patricia Treat
Class III
MC.LM.R16 1989 A Cultural Resource Inventory of Northern
Geophysical Seismic Explorations Near
Battlement Mesa, Mesa and Garfield Counties,
Colorado (S#1092)
Metcalf, Michael
D.
Class III
GF.E.NR10 2004 Fiber Optic Cable Installation from Rifle Sub to
Rifle Microwave Site Garfield County, Colorado
(WAPA # C-04-08)
Giliberti, Joseph Class III
GF.E.R14 2015 A Cultural Resource Inventory of a Portion of
the North Fork-Rifle 230-kV Transmission Line
and Access Roads: Garfield County, Colorado
Bright, Martha Class III
The previous surveys documented 34 cultural resources within 1 mile of the proposed Project area
(see Table 2). There are no previously recorded sites within the proposed Project area; however,
there are two historic ditch segments adjacent to the southern boundary. These ditches are the
Multa Trina ditch (5GF2308.3) and an unnamed ditch (5GF4618.1). Both continue into the proposed
Project area. Although it is has been determined that the previously recorded segments adjacent to
the proposed Project area are not eligible for inclusion in the National Register of Historic Places
(NRHP), the unrecorded portions may have historical significance and enough integrity to support
the overall significance.
4
Table 2. Previously recorded cultural resources within a mile of the proposed Project area.
Site No. Name/Description Resource Type
NRHP Eligibility
from Previous
Investigation*
NRHP
Eligibility
Date
5GF244 Open Lithic Scatter Prehistoric
Archaeology
Not Eligible (F) 1978
5GF246 Homestead Historical Archaeology Unevaluated 1978
5GF2307 Fire-Cracked Rock,
Hearth and Lithic Scatter
Prehistoric
Archaeology
Not Eligible (O) 2007
5GF2308.1 Multa Trina Ditch -
Segment
Historical, Historical
Archaeology
Not Eligible (O) 1996
5GF2308.3 Multa Trina Ditch -
Segment
Historical, Historical
Archaeology
Not Eligible (O) 2012
5GF2308.6 Multa Trina Ditch -
Segment
Historical, Historical
Archaeology
Non-supporting 2015
5GF2308.7 Multa Trina Ditch -
Segment
Historical, Historical
Archaeology
Non-supporting 2015
5GF2308.8 Multa Trina Ditch -
Segment
Historical, Historical
Archaeology
Non-supporting 2015
5GF2308.9 Multa Trina Ditch -
Segment
Historical, Historical
Archaeology
Non-supporting 2015
5GF2792 IF - Archaic Petroglyph Prehistoric
Archaeology
Eligible (O) 2019
5GF2809 IF - Mano Prehistoric
Archaeology
Not Eligible (F) 2000
5GF2810 IF - Mano Prehistoric
Archaeology
Not Eligible (F) 2000
5GF2811 IF - Mano Prehistoric
Archaeology
Not Eligible (F) 2000
5GF2852 IF - Mano and Fire-
Cracked Rock
Prehistoric
Archaeology
Not Eligible (F) 2011
5GF3837 IF - Mano Prehistoric
Archaeology
Not Eligible (F) 2006
5GF3838 IF - Mano Prehistoric
Archaeology
Not Eligible (F) 2006
5GF4017.1 Dry Hollow Ditch -
Segment
Historical, Historical
Archaeology
Not Eligible (O) 2007
5GF4018.1 McPherson Ditch -
Segment
Historical, Historical
Archaeology
Needs Data (O) 2007
5GF4019.1 Ed Conner Ditch -
Segment
Historical, Historical
Archaeology
Needs Data (O) 2007
5GF4472 IF - Groundstone, Core
and Debitage
Prehistoric
Archaeology
Not Eligible (O) 2011
5GF4473 IF - Amethyst Glass Historical Archaeology Not Eligible (F) 2010
5
Table 2. Previously recorded cultural resources within a mile of the proposed Project area.
Site No. Name/Description Resource Type
NRHP Eligibility
from Previous
Investigation*
NRHP
Eligibility
Date
5GF4476 IF - Core Prehistoric
Archaeology
Not Eligible (F) 2010
5GF4477 IF - Debitage Prehistoric
Archaeology
Not Eligible (F) 2010
5GF4478 Protohistoric Ute
Windbreak and Lithic
Scatter
Prehistoric
Archaeology
Needs Data (O) 2011
5GF4479 IF - Debitage Prehistoric
Archaeology
Not Eligible (F) 2010
5GF4482 Fire-Cracked Rock,
Potential Wickiup and
Lithic Scatter
Prehistoric
Archaeology
Eligible (O) 2011
5GF4484 Fire-Cracked Rock and
Lithic Scatter
Prehistoric
Archaeology
Eligible (O) 2011
5GF4618.1 Unnamed Ditch -
Segment
Historical, Historical
Archaeology
Not Eligible (O) 2012
5GF4619 Trash Scatter Historical Archaeology Not Eligible (O) 2012
5GF4645 IF - Mano Prehistoric
Archaeology
Not Eligible (F) 2011
5GF4646 IF - Mano Prehistoric
Archaeology
Not Eligible (F) 2011
5GF4647 IF - Mano and Debitage Prehistoric
Archaeology
Not Eligible (F) 2011
5GF4648 IF - Debitage Prehistoric
Archaeology
Not Eligible (F) 2011
5GF4649 IF - Tested Cobble Prehistoric
Archaeology
Not Eligible (F) 2011
Note: (O) indicates Official determination, (F) indicates Field recommendation
A review of historical maps and aerial photos of the area was also conducted to identify other
potential unrecorded cultural resources within the proposed Project area. General Land Office (GLO)
maps, United States Geological Survey (USGS) topographic quadrangles, and USGS single frame
aerial images were reviewed. The 1888 GLO map for Sections 21 and 22 of T6S R92W did not show
any historical structures or buildings within the proposed Project area. Available USGS aerial photos
and topographic maps were limited. A 1955 USGS aerial image shows three structures, the Multa
Trina ditch, and the unnamed ditch (see Figure 1). The two eastern structures and the Multa Trina
are shown on the 1962 USGS Silt 1:24,000 topographic map (see Figure 2). The eastern structures
and ditches are still visible on modern aerial images from 2016. The central structure from the 1955
aerial image is not visible on modern aerial images.
6
Figure 1. Clip of 1955 USGS aerial showing ditches and structures. Proposed study area is dashed
box. (USGS 1955)
Figure 2. Clip of 1962 USGS topographic map showing ditch and structures. Proposed study area
is dashed box.
7
Because of the presence of structures within the proposed Project area on modern aerial images,
the Garfield County assessor data was reviewed to help further define the structures’ ages (Garfield
County 2021). The Project area consists of a single parcel and only lists building information for the
residential building on the east side of County Road 331 (see Figure 3). Modern aerial images
indicate there are four buildings within the parcel boundary. The building that has assessor
information is the eastern most structure, which is present on the 1955 aerial image and the 1962
topographic map. The one and a half story wood framed house has a year-built date of 1909. No
further information was found at this time regarding the age and function of the other buildings
present in the historical documents or on modern aerial images.
Figure 3. Assessor photograph of building on east side of County Road 331, date unknown
(Garfield County 2021).
The proposed Project area has not been surveyed for cultural resources. Review of OAHP data and
historical documents indicate the presence of two ditches, two historical structures, and two
structures of unknown age within the proposed Project area. However, HDR’s field visits to the
proposed Project area for the Phase I ESA indicated that the structures have been demolished
recently. The Phase I ESA noted the presence of debris in one of the ditches and in locations where
the structures once stood (HDR 2021). These debris piles are likely historical archaeological artifact
concentrations associated with the former structures and occupants. If a federal nexus is determined
for the proposed Project, HDR recommends a Class III cultural resource survey for a future defined
area of potential effects (APE). Federal agencies are required to assess the probable impacts of an
undertaking’s APE pursuant to 36 Code of Federal Regulations Part 800 of the National Historic
Preservation Act (NHPA) (1966, as amended in 2000). Section 106 of NHPA (16 United States Code
40f) directs federal agencies to consider the potential effect of an undertaking on “historic
properties,” which refers to cultural resources listed in, or eligible for inclusion in the NRHP.
8
However, in the absence of a federal nexus any cultural resource survey on private property would
be considered due diligence on the part of AES.
If any ground disturbance during the course of the proposed Project exposes artifacts, foundation, or
other indications of past human occupation, HDR strongly encourages AES to notify the State
Historic Preservation Officer and OAHP. If there is a federal nexus, the lead federal agency would
also be notified. In the event that human remains are encountered all construction activities will be
halted immediately and the Garfield County Coroner’s Office will be called to determine if the
remains are prehistoric, historical or modern. If determined to be prehistoric or historical the State
Historic Preservation Officer and the potential federal agency will be notified immediately.
9
References
Garfield County
2021 Assessor record for parcel 217921400130. Electronic document,
https://qpublic.schneidercorp.com/Application.aspx?AppID=1038&LayerID=22381&Page
TypeID=4&PageID=9447&KeyValue=R023416, accessed February 1, 2021.
HDR
2021 Phase I Environmental Site Assessment, Davis, 2714 County Road 331, Silt, Colorado
81652. Draft. Prepared for AES Peace Bear Ranch Solar, LLC. Denver, Colorado.
USGS
1955 Aerial image A001370152081. Electronic document, https://earthexplorer.usgs.gov/,
accessed February 1, 2021.
AES Peace Bear Ranch Solar – Land Use Change – Major Impact permit application (11/5/2021)
AES Peace Bear Ranch Solar – Garfield County 50
Please see the following pages for the Determination of No Hazard to Air Navigation from the Federal
Aviation Administration for AES Peace Bear Ranch Solar, LLC published in February, 2021.
FAA - DETERMINATION OF NO HAZARD TO AIR NAVIGATION
Appendix C5
Mail Processing Center
Federal Aviation Administration
Southwest Regional Office
Obstruction Evaluation Group
10101 Hillwood Parkway
Fort Worth, TX 76177
Aeronautical Study No.
2021-ANM-495-OE
Page 1 of 4
Issued Date: 03/01/2021
Joshua Mayer
AES Peace Bear Ranch Solar, LLC
282 Century Place, Suite 2000
Louisville, CO 80027
** DETERMINATION OF NO HAZARD TO AIR NAVIGATION **
The Federal Aviation Administration has conducted an aeronautical study under the provisions of 49 U.S.C.,
Section 44718 and if applicable Title 14 of the Code of Federal Regulations, part 77, concerning:
Structure:Solar Panel AES Peace Bear Ranch Solar, LLC PV plant
Location:Silt, CO
Latitude:39-30-18.92N NAD 83
Longitude:107-40-01.11W
Heights:5832 feet site elevation (SE)
14 feet above ground level (AGL)
5846 feet above mean sea level (AMSL)
This aeronautical study revealed that the structure does not exceed obstruction standards and would not be a
hazard to air navigation provided the following condition(s), if any, is(are) met:
It is required that FAA Form 7460-2, Notice of Actual Construction or Alteration, be e-filed any time the
project is abandoned or:
_____ At least 10 days prior to start of construction (7460-2, Part 1)
__X__ Within 5 days after the construction reaches its greatest height (7460-2, Part 2)
Based on this evaluation, marking and lighting are not necessary for aviation safety. However, if marking/
lighting are accomplished on a voluntary basis, we recommend it be installed in accordance with FAA Advisory
circular 70/7460-1 M.
This determination expires on 09/01/2022 unless:
(a)the construction is started (not necessarily completed) and FAA Form 7460-2, Notice of Actual
Construction or Alteration, is received by this office.
(b)extended, revised, or terminated by the issuing office.
(c)the construction is subject to the licensing authority of the Federal Communications Commission
(FCC) and an application for a construction permit has been filed, as required by the FCC, within
6 months of the date of this determination. In such case, the determination expires on the date
prescribed by the FCC for completion of construction, or the date the FCC denies the application.
Page 2 of 4
NOTE: REQUEST FOR EXTENSION OF THE EFFECTIVE PERIOD OF THIS DETERMINATION MUST
BE E-FILED AT LEAST 15 DAYS PRIOR TO THE EXPIRATION DATE. AFTER RE-EVALUATION
OF CURRENT OPERATIONS IN THE AREA OF THE STRUCTURE TO DETERMINE THAT NO
SIGNIFICANT AERONAUTICAL CHANGES HAVE OCCURRED, YOUR DETERMINATION MAY BE
ELIGIBLE FOR ONE EXTENSION OF THE EFFECTIVE PERIOD.
This determination is based, in part, on the foregoing description which includes specific coordinates, heights,
frequency(ies) and power. Any changes in coordinates, heights, and frequencies or use of greater power, except
those frequencies specified in the Colo Void Clause Coalition; Antenna System Co-Location; Voluntary Best
Practices, effective 21 Nov 2007, will void this determination. Any future construction or alteration, including
increase to heights, power, or the addition of other transmitters, requires separate notice to the FAA.This
determination includes all previously filed frequencies and power for this structure.
If construction or alteration is dismantled or destroyed, you must submit notice to the FAA within 5 days after
the construction or alteration is dismantled or destroyed.
This determination does include temporary construction equipment such as cranes, derricks, etc., which may be
used during actual construction of the structure. However, this equipment shall not exceed the overall heights as
indicated above. Equipment which has a height greater than the studied structure requires separate notice to the
FAA.
This determination concerns the effect of this structure on the safe and efficient use of navigable airspace
by aircraft and does not relieve the sponsor of compliance responsibilities relating to any law, ordinance, or
regulation of any Federal, State, or local government body.
If we can be of further assistance, please contact our office at (206) 231-2990, or paul.holmquist@faa.gov. On
any future correspondence concerning this matter, please refer to Aeronautical Study Number 2021-ANM-495-
OE.
Signature Control No: 466817878-470991951 ( DNE )
Paul Holmquist
Specialist
Attachment(s)
Map(s)
Page 3 of 4
TOPO Map for ASN 2021-ANM-495-OE
Page 4 of 4
Sectional Map for ASN 2021-ANM-495-OE
Mail Processing Center
Federal Aviation Administration
Southwest Regional Office
Obstruction Evaluation Group
10101 Hillwood Parkway
Fort Worth, TX 76177
Aeronautical Study No.
2021-ANM-496-OE
Page 1 of 4
Issued Date: 03/01/2021
Joshua Mayer
AES Peace Bear Ranch Solar, LLC
282 Century Place, Suite 2000
Louisville, CO 80027
** DETERMINATION OF NO HAZARD TO AIR NAVIGATION **
The Federal Aviation Administration has conducted an aeronautical study under the provisions of 49 U.S.C.,
Section 44718 and if applicable Title 14 of the Code of Federal Regulations, part 77, concerning:
Structure:Solar Panel AES Peace Bear Ranch Solar, LLC PV plant
Location:Silt, CO
Latitude:39-30-37.98N NAD 83
Longitude:107-39-44.75W
Heights:5832 feet site elevation (SE)
14 feet above ground level (AGL)
5846 feet above mean sea level (AMSL)
This aeronautical study revealed that the structure does not exceed obstruction standards and would not be a
hazard to air navigation provided the following condition(s), if any, is(are) met:
It is required that FAA Form 7460-2, Notice of Actual Construction or Alteration, be e-filed any time the
project is abandoned or:
_____ At least 10 days prior to start of construction (7460-2, Part 1)
__X__ Within 5 days after the construction reaches its greatest height (7460-2, Part 2)
Based on this evaluation, marking and lighting are not necessary for aviation safety. However, if marking/
lighting are accomplished on a voluntary basis, we recommend it be installed in accordance with FAA Advisory
circular 70/7460-1 M.
This determination expires on 09/01/2022 unless:
(a)the construction is started (not necessarily completed) and FAA Form 7460-2, Notice of Actual
Construction or Alteration, is received by this office.
(b)extended, revised, or terminated by the issuing office.
(c)the construction is subject to the licensing authority of the Federal Communications Commission
(FCC) and an application for a construction permit has been filed, as required by the FCC, within
6 months of the date of this determination. In such case, the determination expires on the date
prescribed by the FCC for completion of construction, or the date the FCC denies the application.
Page 2 of 4
NOTE: REQUEST FOR EXTENSION OF THE EFFECTIVE PERIOD OF THIS DETERMINATION MUST
BE E-FILED AT LEAST 15 DAYS PRIOR TO THE EXPIRATION DATE. AFTER RE-EVALUATION
OF CURRENT OPERATIONS IN THE AREA OF THE STRUCTURE TO DETERMINE THAT NO
SIGNIFICANT AERONAUTICAL CHANGES HAVE OCCURRED, YOUR DETERMINATION MAY BE
ELIGIBLE FOR ONE EXTENSION OF THE EFFECTIVE PERIOD.
This determination is based, in part, on the foregoing description which includes specific coordinates, heights,
frequency(ies) and power. Any changes in coordinates, heights, and frequencies or use of greater power, except
those frequencies specified in the Colo Void Clause Coalition; Antenna System Co-Location; Voluntary Best
Practices, effective 21 Nov 2007, will void this determination. Any future construction or alteration, including
increase to heights, power, or the addition of other transmitters, requires separate notice to the FAA.This
determination includes all previously filed frequencies and power for this structure.
If construction or alteration is dismantled or destroyed, you must submit notice to the FAA within 5 days after
the construction or alteration is dismantled or destroyed.
This determination does include temporary construction equipment such as cranes, derricks, etc., which may be
used during actual construction of the structure. However, this equipment shall not exceed the overall heights as
indicated above. Equipment which has a height greater than the studied structure requires separate notice to the
FAA.
This determination concerns the effect of this structure on the safe and efficient use of navigable airspace
by aircraft and does not relieve the sponsor of compliance responsibilities relating to any law, ordinance, or
regulation of any Federal, State, or local government body.
If we can be of further assistance, please contact our office at (206) 231-2990, or paul.holmquist@faa.gov. On
any future correspondence concerning this matter, please refer to Aeronautical Study Number 2021-ANM-496-
OE.
Signature Control No: 466817879-470991952 ( DNE )
Paul Holmquist
Specialist
Attachment(s)
Map(s)
Page 3 of 4
TOPO Map for ASN 2021-ANM-496-OE
Page 4 of 4
Sectional Map for ASN 2021-ANM-496-OE
Mail Processing Center
Federal Aviation Administration
Southwest Regional Office
Obstruction Evaluation Group
10101 Hillwood Parkway
Fort Worth, TX 76177
Aeronautical Study No.
2021-ANM-497-OE
Page 1 of 4
Issued Date: 03/01/2021
Joshua Mayer
AES Peace Bear Ranch Solar, LLC
282 Century Place, Suite 2000
Louisville, CO 80027
** DETERMINATION OF NO HAZARD TO AIR NAVIGATION **
The Federal Aviation Administration has conducted an aeronautical study under the provisions of 49 U.S.C.,
Section 44718 and if applicable Title 14 of the Code of Federal Regulations, part 77, concerning:
Structure:Solar Panel AES Peace Bear Ranch Solar, LLC PV plant
Location:Silt, CO
Latitude:39-30-22.38N NAD 83
Longitude:107-39-44.88W
Heights:5832 feet site elevation (SE)
14 feet above ground level (AGL)
5846 feet above mean sea level (AMSL)
This aeronautical study revealed that the structure does not exceed obstruction standards and would not be a
hazard to air navigation provided the following condition(s), if any, is(are) met:
It is required that FAA Form 7460-2, Notice of Actual Construction or Alteration, be e-filed any time the
project is abandoned or:
_____ At least 10 days prior to start of construction (7460-2, Part 1)
__X__ Within 5 days after the construction reaches its greatest height (7460-2, Part 2)
Based on this evaluation, marking and lighting are not necessary for aviation safety. However, if marking/
lighting are accomplished on a voluntary basis, we recommend it be installed in accordance with FAA Advisory
circular 70/7460-1 M.
This determination expires on 09/01/2022 unless:
(a)the construction is started (not necessarily completed) and FAA Form 7460-2, Notice of Actual
Construction or Alteration, is received by this office.
(b)extended, revised, or terminated by the issuing office.
(c)the construction is subject to the licensing authority of the Federal Communications Commission
(FCC) and an application for a construction permit has been filed, as required by the FCC, within
6 months of the date of this determination. In such case, the determination expires on the date
prescribed by the FCC for completion of construction, or the date the FCC denies the application.
Page 2 of 4
NOTE: REQUEST FOR EXTENSION OF THE EFFECTIVE PERIOD OF THIS DETERMINATION MUST
BE E-FILED AT LEAST 15 DAYS PRIOR TO THE EXPIRATION DATE. AFTER RE-EVALUATION
OF CURRENT OPERATIONS IN THE AREA OF THE STRUCTURE TO DETERMINE THAT NO
SIGNIFICANT AERONAUTICAL CHANGES HAVE OCCURRED, YOUR DETERMINATION MAY BE
ELIGIBLE FOR ONE EXTENSION OF THE EFFECTIVE PERIOD.
This determination is based, in part, on the foregoing description which includes specific coordinates, heights,
frequency(ies) and power. Any changes in coordinates, heights, and frequencies or use of greater power, except
those frequencies specified in the Colo Void Clause Coalition; Antenna System Co-Location; Voluntary Best
Practices, effective 21 Nov 2007, will void this determination. Any future construction or alteration, including
increase to heights, power, or the addition of other transmitters, requires separate notice to the FAA.This
determination includes all previously filed frequencies and power for this structure.
If construction or alteration is dismantled or destroyed, you must submit notice to the FAA within 5 days after
the construction or alteration is dismantled or destroyed.
This determination does include temporary construction equipment such as cranes, derricks, etc., which may be
used during actual construction of the structure. However, this equipment shall not exceed the overall heights as
indicated above. Equipment which has a height greater than the studied structure requires separate notice to the
FAA.
This determination concerns the effect of this structure on the safe and efficient use of navigable airspace
by aircraft and does not relieve the sponsor of compliance responsibilities relating to any law, ordinance, or
regulation of any Federal, State, or local government body.
If we can be of further assistance, please contact our office at (206) 231-2990, or paul.holmquist@faa.gov. On
any future correspondence concerning this matter, please refer to Aeronautical Study Number 2021-ANM-497-
OE.
Signature Control No: 466817880-470991953 ( DNE )
Paul Holmquist
Specialist
Attachment(s)
Map(s)
Page 3 of 4
TOPO Map for ASN 2021-ANM-497-OE
Page 4 of 4
Sectional Map for ASN 2021-ANM-497-OE
Mail Processing Center
Federal Aviation Administration
Southwest Regional Office
Obstruction Evaluation Group
10101 Hillwood Parkway
Fort Worth, TX 76177
Aeronautical Study No.
2021-ANM-494-OE
Page 1 of 4
Issued Date: 03/01/2021
Joshua Mayer
AES Peace Bear Ranch Solar, LLC
282 Century Place, Suite 2000
Louisville, CO 80027
** DETERMINATION OF NO HAZARD TO AIR NAVIGATION **
The Federal Aviation Administration has conducted an aeronautical study under the provisions of 49 U.S.C.,
Section 44718 and if applicable Title 14 of the Code of Federal Regulations, part 77, concerning:
Structure:Solar Panel AES Peace Bear Ranch Solar, LLC PV plant
Location:Silt, CO
Latitude:39-30-44.21N NAD 83
Longitude:107-40-17.85W
Heights:5832 feet site elevation (SE)
14 feet above ground level (AGL)
5846 feet above mean sea level (AMSL)
This aeronautical study revealed that the structure does not exceed obstruction standards and would not be a
hazard to air navigation provided the following condition(s), if any, is(are) met:
It is required that FAA Form 7460-2, Notice of Actual Construction or Alteration, be e-filed any time the
project is abandoned or:
_____ At least 10 days prior to start of construction (7460-2, Part 1)
__X__ Within 5 days after the construction reaches its greatest height (7460-2, Part 2)
Based on this evaluation, marking and lighting are not necessary for aviation safety. However, if marking/
lighting are accomplished on a voluntary basis, we recommend it be installed in accordance with FAA Advisory
circular 70/7460-1 M.
This determination expires on 09/01/2022 unless:
(a)the construction is started (not necessarily completed) and FAA Form 7460-2, Notice of Actual
Construction or Alteration, is received by this office.
(b)extended, revised, or terminated by the issuing office.
(c)the construction is subject to the licensing authority of the Federal Communications Commission
(FCC) and an application for a construction permit has been filed, as required by the FCC, within
6 months of the date of this determination. In such case, the determination expires on the date
prescribed by the FCC for completion of construction, or the date the FCC denies the application.
Page 2 of 4
NOTE: REQUEST FOR EXTENSION OF THE EFFECTIVE PERIOD OF THIS DETERMINATION MUST
BE E-FILED AT LEAST 15 DAYS PRIOR TO THE EXPIRATION DATE. AFTER RE-EVALUATION
OF CURRENT OPERATIONS IN THE AREA OF THE STRUCTURE TO DETERMINE THAT NO
SIGNIFICANT AERONAUTICAL CHANGES HAVE OCCURRED, YOUR DETERMINATION MAY BE
ELIGIBLE FOR ONE EXTENSION OF THE EFFECTIVE PERIOD.
This determination is based, in part, on the foregoing description which includes specific coordinates, heights,
frequency(ies) and power. Any changes in coordinates, heights, and frequencies or use of greater power, except
those frequencies specified in the Colo Void Clause Coalition; Antenna System Co-Location; Voluntary Best
Practices, effective 21 Nov 2007, will void this determination. Any future construction or alteration, including
increase to heights, power, or the addition of other transmitters, requires separate notice to the FAA.This
determination includes all previously filed frequencies and power for this structure.
If construction or alteration is dismantled or destroyed, you must submit notice to the FAA within 5 days after
the construction or alteration is dismantled or destroyed.
This determination does include temporary construction equipment such as cranes, derricks, etc., which may be
used during actual construction of the structure. However, this equipment shall not exceed the overall heights as
indicated above. Equipment which has a height greater than the studied structure requires separate notice to the
FAA.
This determination concerns the effect of this structure on the safe and efficient use of navigable airspace
by aircraft and does not relieve the sponsor of compliance responsibilities relating to any law, ordinance, or
regulation of any Federal, State, or local government body.
If we can be of further assistance, please contact our office at (206) 231-2990, or paul.holmquist@faa.gov. On
any future correspondence concerning this matter, please refer to Aeronautical Study Number 2021-ANM-494-
OE.
Signature Control No: 466817877-470991954 ( DNE )
Paul Holmquist
Specialist
Attachment(s)
Map(s)
Page 3 of 4
TOPO Map for ASN 2021-ANM-494-OE
Page 4 of 4
Sectional Map for ASN 2021-ANM-494-OE
AES Peace Bear Ranch Solar – Land Use Change – Major Impact permit application (11/5/2021)
AES Peace Bear Ranch Solar – Garfield County 51
Please see the following pages for the Stormwater Memo prepared by NEI Engineering for AES Peace
Bear Ranch LLC published in October 2021.
STORMWATER MEMO
Appendix C6
neiengineering.com + 303-431-7895
12600 W Colfax Avenue, Suite C500, Lakewood, CO 80215
To: Joshua Mayer
AES Clean Energy
The AES Corporation
282 Century Place, Suite 2000
Louisville, CO 80027
From: NEI Electric Power Engineering, Inc.
12600 W Colfax Avenue, Suite C500
Lakewood, CO 80215
Date: October 8, 2021
Project Name: Peace Bear Solar
Project No.: 3704.001
Subject: Stormwater Memo
Peace Bear Solar is a proposed solar facility located at 2714 331 County Road, Garfield
County approximately 3 miles south of Silt, Colorado. Construction of this project will be limited
to approximately 81.3 acres of the 200-acre lot. The project is expected to change
approximately 46,596 (1.07 ac; 1.32% lot coverage) of pervious area into impervious area. The
impervious area will consist of four (4) concrete equipment pads, a gravel access road, and
foundations for solar arrays. Onsite drainage patterns will be maintained with exception to
minor grading related to proposed gravel roads; therefore a Drainage Report is not required per
county Land Use Code. The access road will also require the implementation of six (6) culverts
to maintain drainage of upstream areas.
This memo is intended to provide Garfield County with drainage and land disturbance
information with respect to this project as well as provide the culvert sizing methodology and
results.
Existing Conditions
The project site is undeveloped with the exception of irrigated agricultural fields throughout the
property. Land cover consists of native vegetation, sparse weeds and grasses. The topography
consists of rolling hills, plains and mesas. The site generally drains from west to east mesas
AES Clean Energy Peace Bear Solar
STORMWATER MANAGEMENT PLAN p. ii
with a topographic relief of approximately 120 ft. Stormwater runoff collects in an existing
channel, which has several berms along the invert, creating impoundments. The channel
conveys flow east and discharges to Dry Hollow Creek approximately 600 ft east of the project
site.
Proposed Conditions
Construction activities associated with the proposed solar facility will affect approximately 81.3
acres onsite. However, much of the disturbed area will involve construction of support structures
for solar panel arrays, leaving the surface beneath the panels undeveloped and pervious. These
solar arrays are not expected to result in a significant creation of impervious area. The project
also proposes four (4) concrete equipment pads, an O&M pad, a switchgear pad, and gravel
access roads. In total, the project will result in the generation of 46,516 sf of impervious area,
which covers 1.32% of the project site. Grading activities will be localized around the gravel
access road and existing drainage patterns will be maintained.
Impervious Area Calculations
Quantity Area Impervious factor Impervious area Units
Equipment Pads 4 2,660 1.0 10,640 sf
O&M Pad 1 800 1.0 800 sf
Switchgear Pad 1 24 1.0 24 sf
Gravel Access Road 1 87,631 0.4 35,052 sf
Total Area 46,516 sf
Total LOD 3,540,916 sf
Coverage Ratio 1.32%
The gravel access road will cross existing stormwater conveyances; therefore, the project also
proposes six (6) culverts, which will be discussed below.
Stormwater Management Strategy
Stormwater Management (treatment & detention) are not required because the proposed
impervious area is not expected to significantly alter stormwater quality and quantity and
existing drainage patterns are maintained. Using a grass seed mix to restore all areas of
disturbance, stormwater quality will be improved through a native seed mix. The mix will also
decrease the quantity of stormwater runoff previously experienced on site.
Flood Zone
This site is located with Zone X (un-shaded) per Flood Insurance Rate Map (FIRM) community
panel number 0802051093C. Per FEMA, this zone is “An area of minimal flood hazard, usually
depicted on FIRMs as above the 500-yr flood level (0.2% chance).”
Culvert Design
This project proposes an access road which intersects six (6) stormwater conveyances: a
drainage ditch at four (4) locations, two (2) natural ditches. These crossings require a culvert to
maintain drainage through the site.
AES Clean Energy Peace Bear Solar
STORMWATER MANAGEMENT PLAN p. iii
The culverts are designed to convey the 25-yr peak flow from their contributing drainage basin.
The 25-yr storm event (4% annual exceedance probability) is the typical design storm for
stormwater conveyances per the County’s Land Use & Development Code (2013).
The UDFCD’s modified rational method, an allowable reference per CDOT’s Drainage Design
Manual (DDM, 2019), was used to quantify the 25-yr peak flow for each culvert’s contributing
drainage basin. The following equation is referenced:
Q25 =C25 ∙ I25 ∙ A
Where Q25 is the 25-yr peak flow (cfs), A is the contributing drainage area (acres), I 25 is the
rainfall intensity in inches per hour for a duration equal to the time of concentration, and C 25 is
the runoff coefficient from equations based on NRCS soil groups and storm return period. For
soil groups C/D, the runoff coefficient was determined to from the equation:
CC/D = 0.64i + 0.31
The runoff coefficient, C, used was 0.33 and the rainfall intensity, I, used was 3.46 inches per
hour. Rainfall depth was derived from “NOAA ATLAS 14 POINT PRECIPITATION
FREQUENCY ESTIMATES”.
Culverts are assumed to be HDPE, with the exception of Culvert E being RCP, which both have
a roughness coefficient (n) of 0.012 per the DDM. The results of the hydraulics calculations are
shown in Table 1 below.
Table 1 – Culvert Sizing Results
Summary
The project proposes 1.07 ac of impervious area, which consists of concrete equipment pads, a
gravel access road, and foundations for solar arrays. This impervious area constitutes of 1.32%
of the solar development area. The project will not alter existing drainage patterns, thus does
not require a drainage report.
The proposed access road will require the installation of culverts. Initial sizing has been
provided and will be refined as the site design develops.
Attachments
• Basin Exhibit