05_Appendix B_Environmental Report_Hwy 9 Sidewalk Improvements_25946.pdf

Biological and Aquatic Resources Memorandum for the Highway 9 Retaining Wall and Sidewalk Project in Frisco, Summit County, Colorado

NOVEMBER 2023

PREPARED FOR

Town of Frisco

PREPARED BY

SWCA Environmental Consultants

BIOLOGICAL AND AQUATIC RESOURCES MEMORANDUM

FOR THE HIGHWAY 9 RETAINING WALL AND SIDEWALK

PROJECT IN FRISCO, SUMMIT COUNTY, COLORADO

Prepared for

Town of Frisco 102 School Road

Frisco, Colorado 80443

Prepared by

SWCA Environmental Consultants 295 Interlocken Boulevard, Suite 300

Broomfield, Colorado 80021

(303) 487-1183 www.swca.com

November 2023

Biological and Aquatic Resources Memorandum for the Highway 9 Retaining Wall and Sidewalk Project in Frisco, Summit County, Colorado i

EXECUTIVE SUMMARY

The Town of Frisco, contracted SWCA Environmental Consultants (SWCA) to complete a due diligence biological and aquatic resources desktop analysis and field survey for the Highway 9 Retaining Wall and

Sidewalks Project (Project). The Project involves the construction of approximately 0.33 mile of new sidewalk and retaining wall replacement in Frisco, Summit County, Colorado. The Project is located within an existing right-of-way and is in an urban setting consisting of residential and commercial retail development. The Project area is bordered by Highway 9 to the east, commercial and residential development to the west, and sits between 10 Mile Drive and School Road (Project area). Current land use consists of developed and undeveloped land.

SWCA performed a desktop analysis of readily available data, and a biologist conducted a pedestrian field survey on September 15, 2023, to assess the natural conditions of the Project area and to document general habitat, aquatic resources, including wetlands and non-wetland waters, wildlife, and habitat for special-status species within the Project area. SWCA also surveyed a 0.5-mile buffer for raptor nests.

Based on the results of the field survey, one drainage ditch with no ordinary high-water mark was located adjacent to the Walmart parking lot. There was no upstream connection, and the ditch flowed downstream to culverts running under Highway 9 to the east and 10 Mile Drive to the north. One drainage basin feature was identified immediately west of the southern terminus of the Project and was entirely outside of the Project area. One active bald eagle (Haliaeetus leucocephalus) nest was observed approximately

2,150 feet (0.41 mile) southeast of the Project area. Additionally, multiple raptor nests were observed near the Project area but were well outside of the 0.5-mile raptor buffer. No other nests were observed on or near the Project area. Additional threatened or endangered species that were evaluated are also unlikely to occur, as the Project area falls outside these species’ geographical ranges and/or lacks suitable habitat.

Biological and Aquatic Resources Memorandum for the Highway 9 Retaining Wall and Sidewalk Project in Frisco, ii

CONTENTS

1 Introduction

2 Methods

2.1 Desktop Analysis

2.2 Field Survey

2.2.1 Aquatic Resources

2.2.2 Wildlife Habitat and Listed Species

3 Results

3.1 Land Use and General Wildlife Habitat

3.2 Aquatic Resources

3.3 Threatened and Endangered Species

3.4 Raptors and Migratory Birds

4 Summary of Findings

5 Literature Cited

Appendices

Appendix A. Maps

Appendix B. Photolog

Tables

Table 1. Dominant Plant Species Identified in the Project Area Table 2. Federally Listed and State-Listed Threatened and Endangered Species and State-Listed

Species of Special Concern and Their Potential to Occur in the Project Area

Biological and Aquatic Resources Memorandum for the Highway 9 Retaining Wall and Sidewalk Project in Frisco, 1 INTRODUCTION

The Town of Frisco is proposing to construct new sidewalk and replace an existing retaining wall within an existing right-of-way for the Highway 9 Retaining Wall and Sidewalks Project (Project) that extends west along Highway 9 between 10 Mile Drive and School Road (Project area) in Summit County, Frisco, Colorado. On behalf of the Town of Frisco, SWCA Environmental Consultants (SWCA) completed a due diligence biological and aquatic resources desktop analysis and field survey to evaluate potential impacts to sensitive biological resources, including aquatic resources and sensitive species; potential impacts to sensitive and protected resources; and compliance with Section 404 of the Clean Water Act (CWA), Endangered Species Act, Migratory Bird Treaty Act, and Bald and Golden Eagle Protection Act.

As part of the field survey, the Project area and vicinity were evaluated for wetlands and non-wetland waters that may be considered waters of the United States (WOTUS) as defined by the U.S. Army Corps of Engineers (USACE). Concurrently, SWCA evaluated the Project area and vicinity for the presence of suitable habitat for sensitive and federally listed species. This evaluation included an assessment of migratory bird and raptor nesting habitats and the likelihood of Project impacts on migratory birds and raptors.

This study has been prepared in support of Colorado Department of Transportation Wildlife Resources

Clearance, CWA Section 404 Permit Review, Colorado Department of Transportation Form 128 for

National Environmental Policy Act Determination, and environmental clearance for aquatic resources subject to Senate Bill 40 certification from the Colorado Department of Natural Resources.

2 METHODS

2.1 Desktop Analysis

Prior to the field survey, SWCA conducted a desktop analysis to review environmental resources in the general vicinity of the Project area. This included review of aerial imagery, historical and current aerial photographs of the Project area (Google Earth 2023), U.S. Fish and Wildlife Service (USFWS) National

Wetlands Inventory (NWI) maps (USFWS 2023a), the National Hydrography Dataset (NHD) (U.S.

Geological Survey 2021), USFWS lists of threatened and endangered species within Summit County

(USFWS 2023b, 2023c), and Colorado Parks and Wildlife (CPW) lists of state-listed species (CPW

2022a) and CPW species profiles (CPW 2022b).

2.2 Field Survey

An SWCA biologist conducted a pedestrian field survey of the Project area on September 15, 2023. The field survey focused on aquatic resources including, but not limited to, wetlands, ditches, and streams, as well as sensitive species and federally protected plants and wildlife and their habitats. The biologist used a handheld tablet computer with Esri ArcGIS Field Maps to record data and a sub-meter accuracy global positioning system (GPS) unit to record location information. The tablet was loaded with the Project area boundaries and survey buffers, as well as NHD and NWI features, to ensure accurate survey and mapping of the Project area. The Project area is illustrated in Figure A-1 and on the maps provided in Appendix A.

Overview photographs are presented as a photolog in Appendix B.

Biological and Aquatic Resources Memorandum for the Highway 9 Retaining Wall and Sidewalk Project in Frisco,

2.2.1 Aquatic Resources

The biologist conducted an aquatic resources inventory that included identifying and recording wetlands and non-wetland waters that may be determined to be WOTUS by the USACE. WOTUS can include aquatic resources, such as rivers, creeks, streams, arroyos, lakes, and associated wetlands that have the requisite connectivity to downstream navigable waters.

Under Section 404 of the CWA, wetlands are aquatic resources that are inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support, and under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions (USACE

1987). Non-wetland waters are generally identified and delineated by the presence of an ordinary high-water mark (OHWM). An OHWM is the line on a shore established by fluctuations of water and is typically identified by physical characteristics, such as a clear, natural line impressed on the bank;

shelving; changes in the character of soil; destruction of terrestrial vegetation; the presence of litter and debris; or other appropriate means that consider the characteristics of the surrounding areas.

2.2.1.1 WETLANDS

The presence or absence of wetlands is determined in the field using delineation methods provided in the

Corps of Engineers Wetlands Delineation Manual (USACE 1987) and the Regional Supplement to the

Corps of Engineers Wetlands Delineation Manual: Western Mountains, Valleys, and Coast Regions

(Regional Supplement) (USACE 2010). Data at each potential wetland are recorded on the Regional

Supplement wetland determination data forms. Wetland boundaries are delineated where hydrophytic vegetation, hydric soils, and hydrology are present.

2.2.1.2 NON-WETLAND WATERS

The presence and extent of non-wetland waters (e.g., creeks, rivers, arroyos, ponds, and constructed ditches) is determined in the field using the guidance and methods provided in USACE Regulatory

Guidance Letter 05-05 (USACE 2005) and the USACE technical guidance, A Field Guide to the

Identification of the Ordinary High Water Mark (OHWM) in the Arid West Region of the Western United

States (USACE 2008). Although the Project area is not located within the Arid West Region, the USACE has not published a Western Mountains, Valleys, and Coast Regions–specific field guide to the identification of OHWMs, and several indicators of OHWMs in the Arid West Region are applicable to the Western Mountains, Valleys, and Coast Regions.

2.2.2 Wildlife Habitat and Listed Species

The biologist recorded general wildlife habitat, vegetation communities, and habitat suitable for special-status species within the Project area to identify potential constraints associated with construction of the new sidewalk and replacement of the retaining wall.

The special-status species evaluation included a habitat review for 1) all federally protected (i.e., endangered and threatened) species, 2) additional species listed by the USFWS as candidate and proposed species and species under review, 3) state-protected species, and 4) migratory birds and raptors.

The potential for wildlife species occurrence is based on existing information on distribution and on qualitative comparisons of the habitat requirements of each species with vegetation communities, landscape features, and/or water quality conditions in the Project area. The potential for occurrence is summarized according to the categories listed below.

Biological and Aquatic Resources Memorandum for the Highway 9 Retaining Wall and Sidewalk Project in Frisco,

• Known to occur: The species was documented either during or prior to the field survey by a reliable observer.

• May occur: The Project area is within the species’ currently known range, and vegetation communities, soils, and water quality conditions, etc., resemble those known to be used by the species.

• Unlikely to occur: The Project area is within the species’ currently known range, but vegetation communities, soils, and water quality conditions, etc., do not resemble those known to be used by the species.

• None: The Project area is clearly outside the species’ currently known range, and vegetation communities, soils, and water quality conditions, etc., do not resemble those known to be used by the species.

Possible impacts to these species are evaluated based on reasonably foreseeable Project-related activities and any associated temporary loss of habitat.

3 RESULTS

3.1 Land Use and General Wildlife Habitat

Dominant plant species observed across the Project area are consistent with early seral species and introduced herbaceous species commonly associated with disturbed soils and/or revegetation. Current land use for the Project area consists of an existing sidewalk, retaining wall, and undeveloped land that is maintained via mowing. The Project area lacks any significant native vegetation that may provide adequate habitat for species. The dominant plant species identified in the Project area during the

September 2023 field survey are listed in Table 1.

Table 1. Dominant Plant Species Identified in the Project Area

Common Name Scientific Name

Smooth brome Bromus inermis

Western wheatgrass Pascopyrum smithii

Yellow rabbitbrush Chrysothamnus viscidiflorus

Quaking aspen Populus tremuloides

Engelmann spruce Picea engelmannii

3.2 Aquatic Resources

The Project area is located in the Dillon Reservoir subwatershed (hydrologic unit code 140100020401

[HUC 12]).

3.2.1.1 DESKTOP ANALYSIS

According to the results of the desktop analysis, no NWI or NHD features are mapped within the Project area (Figure A-2A and Figure A-2B). These figures also show representative photo points within the

Project area; a corresponding photolog is provided in Appendix B.

Biological and Aquatic Resources Memorandum for the Highway 9 Retaining Wall and Sidewalk Project in Frisco,

3.2.1.2 FIELD SURVEY

3.2.1.2.1 Wetlands

Wetlands were not observed within the Project area during the September 2023 pedestrian survey;

therefore, no effect to and no permitting for wetland resource impacts is anticipated.

3.2.1.2.2 Non-wetland Resources

Non-wetland resources were observed within the Project area during the September 2023 field survey. A drainage ditch with no OHWM (WB02) was mapped between the western extent of the Project area and the Walmart parking lot (Figure A-2A). Downstream connectivity included two culverts running north under 10 Mile Drive and east under Highway 9, though a connection to navigable waters is unknown.

There was no upstream connection identified. Because there is no discernable downstream connectivity to navigable waters or an identifiable OHWM, this resource is not considered WOTUS and permitting for this resource is likely not anticipated. A second water body (WB01) was identified near the southern terminus of the Project (Figure A-2B). Though this waterbody is outside of the Project area, best management practices for erosion and sediment control should be used to reduce the risk of impacts to this feature.

3.3 Threatened and Endangered Species

SWCA performed a desktop analysis to review and analyze the likelihood for federally listed and state-listed species to occur in the Project area. Federally listed (USFWS 2023b, 2023c) and state-listed species

(CPW 2022a) for Summit County are listed in Table 2, as well as their potential to occur in the Project area. Seven federally listed species, gray wolf (Canis lupus), Canada lynx (Lynx canadensis), Mexican spotted owl (Strix occidentalis lucida), bonytail (Gila elegans), Colorado pikeminnow (Ptychocheilus

Lucius), humpback chub, (Gila cypha), razorback sucker (Xyrauchen texanus) are listed for Summit

County, along with one candidate species, monarch butterfly (Danaus plexippus). Based on the desktop review and pedestrian survey conducted by the SWCA biologist, threatened and endangered species are not expected to occur in the Project area based on the lack of suitable habitat in the Project area and the known ranges of these species.

Additionally, SWCA has reviewed and analyzed the likelihood for CPW-designated species of special concern, bald eagle and golden eagle, to occur in the Project area; however, it should be noted that this designation is not a statutory category.

Table 2. Federally Listed and State-Listed Threatened and Endangered Species and State-Listed Species of Special Concern and Their Potential to Occur in the Project Area

Common Name (scientific name)

Status* Potential to Occur

Mammals

Gray wolf (Canis lupus)

FE, SE None. In Colorado, isolated sightings of a pack and scattered individuals have occurred in the northwestern part of the state (CPW 2022b). This species is typically associated with montane woodlands of oaks (Quercus spp.), pinyon pine (Pinus edulis), or juniper (Juniperus spp.) to higher elevation pine (Pinus spp.) or mixed conifer forests and adjacent grasslands at elevations between 4,000 and 5,000 feet above mean sea level (USFWS 2023c). The Project area is outside this species’ typical habitat.

Biological and Aquatic Resources Memorandum for the Highway 9 Retaining Wall and Sidewalk Project in Frisco, Common Name (scientific name)

Status* Potential to Occur

Canada lynx (Lynx canadensis)

FT, SE None. This species persists in areas characterized by deep snow and dense horizontal forests (USFWS 2023c). This habitat type supports dense populations of snowshoe hares, which are the species primary food source. The Project area lacks suitable habitat for this species and its prey base.

Birds

Golden eagle (Aquila chrysaetos)

SC May occur. Though this species prefers hills, cliffs, and bluffs for foraging and roosting, this species is sensitive to human activity and is known to avoid developed areas (USFWS 2023c).

Bald eagle (Haliaeetus leucocephalus)

SC Known to occur. This species is typically found in association with water and tall trees for nesting, perching, and roosting, as well as in association with prairie dog colonies (CPW 2022b). The Project area does not contain any prairie dog colonies; however, a tree supporting an active nest was observed approximately 2,150 feet southeast of the Project area.

Mexican spotted owl (Strix occidentalis lucida)

FT, ST Unlikely to occur. Though land adjacent to the Project area is lightly forested, the Project area is outside of the designated critical habitat for the species.

Fish

Bonytail (Gila elegans)

FE, SE None. There is no potential for this species to occur due to lack of suitable habitat.

Colorado pikeminnow (Ptychocheilus Lucius)

FE, ST None. There is no potential for this species to occur due to lack of suitable habitat.

Humpback chub (Gila cypha)

FE, ST None. There is no potential for this species to occur due to lack of suitable habitat.

Razorback sucker (Xyrauchen texanus)

FE, SE None. There is no potential for this species to occur due to lack of suitable habitat.

Insects

Monarch butterfly (Danaus plexippus)

FC Unlikely to occur. This species is directly associated with the milkweed plant (Asclepias spp.). Due to a lack of suitable habitat in the Project area, it is unlikely this species will occur in the Project area.

* FC = federal candidate; FE = federally endangered; FT = federally threatened; SC = state species of special concern; SE = state endangered;

ST = state threatened.

3.4 Raptors and Migratory Birds

The Migratory Bird Treaty Act prohibits the take, possession, import, export, transport, sale, purchase, barter, or offer for sale of any migratory bird or the parts, nests, or eggs of such a bird, except under the terms of a valid permit issued by the USFWS.

An active bald eagle nest was observed approximately 2,150 feet southeast of the Project area near Dillon reservoir (Figure A-4), which is within the 0.5-mile buffer that the CPW recommends with regard to active raptor nests (CPW 2020). Two peregrine falcon (Falco peregrinus) nests were observed southwest of the Project area but are well outside of the 0.5-mile raptor buffer. Based on the distance to the Project area and high intensity land use between the nests and Project area, timing restrictions and consultation with the USFWS and CPW may be required but is unlikely.

4 SUMMARY OF FINDINGS

This assessment was conducted to evaluate the potential for the Project to impact sensitive and protected natural resources, including wetlands and non-wetland waters regulated under Section 404 of the CWA, federally listed species protected under the Endangered Species Act, state-listed sensitive species, and

Biological and Aquatic Resources Memorandum for the Highway 9 Retaining Wall and Sidewalk Project in Frisco, raptor and migratory bird nesting habitat. WOTUS were not identified within the Project area; therefore, permitting is not anticipated to be necessary. Federally listed threatened and endangered species or their habitat were not observed in or in the vicinity of the Project area. An active bald eagle nest was observed approximately 2,150 feet southeast of the Project area; however, based on the nature of the Project and the distance and high-intensity land use between the nest and Project area, consultation with regulatory agencies may be required but is not anticipated to impact the Project.

Based on the results of the desktop analysis and field survey and the nature of the Project activities, additional permitting or studies are not anticipated to be necessary.

Biological and Aquatic Resources Memorandum for the Highway 9 Retaining Wall and Sidewalk Project in Frisco, 5 LITERATURE CITED

Colorado Parks and Wildlife (CPW). 2020. Recommended Buffer Zones and Seasonal Restrictions for

Colorado Raptors. Available at: https://cpw.state.co.us/Documents/WildlifeSpecies/

LivingWithWildlife/Raptor-Buffer-Guidelines.pdf. Accessed September 28, 2023.

———. 2022a. Threatened and Endangered List. Available at: http://cpw.state.co.us/learn/Pages/SOC-

ThreatenedEndangeredList.aspx. Accessed September 28, 2023.

———. 2022b. Species Profiles. Available at: http://cpw.state.co.us/learn/Pages/SpeciesProfiles.aspx.

Accessed September 28, 2023.

Google Earth. 2023. Available at: https://www.google.com/earth/. Accessed September 28, 2023.

U.S. Army Corps of Engineers (USACE). 1987. Corps of Engineers Wetland Delineation Manual.

Technical Report Y-87-1. Vicksburg, Mississippi: U.S. Army Engineers Waterways Experiment

Station.

———. 2005. Regulatory Guidance Letter No. 05-05, Subject: Ordinary High Water Mark Identification.

Signed by Major General Don T. Riley, Director of Civil Works.

———. 2008. A Field Guide to the Identification of the Ordinary High Water Mark (OHWM) in the Arid

West Region of the Western United States, edited by R.W. Lichvar and S.M. McColley.

ERDC/CRREL TR-08-12. Hanover, New Hampshire: U.S. Army Engineer Research and

Development Center.

———. 2010. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Great

Plains Region (Version 2.0), edited by J.S. Wakeley, R.W. Lichvar, and C.V. Noble. ERDC/EL

TR-08-12. Vicksburg, Mississippi: U.S. Army Engineer Research and Development Center.

U.S. Fish and Wildlife Service (USFWS). 2023a. National Wetlands Inventory Data. Available at:

http://www.fws.gov/wetlands/data/Data-Download.html. Accessed September 10, 2023.

———. 2023b. USFWS Endangered Species Program. Environmental Conservation Online System, Species by County Report. Available at: http://www.fws.gov/endangered. Accessed September

28, 2023.

———. 2023c. IPaC - Information for Planning and Consultation System. Available at:

http://ecos.fws.gov/ipac/. Accessed September 28, 2023.

U.S. Geological Survey. 2021. Hydrography – Get NHD Data. Available at:

http://nhd.usgs.gov/data.html. Accessed September 10, 2023.

APPENDIX A

Maps

A-1

Figure A-1. Project area overview.

Broomfield

Zoning: PUD

A-2

Figure A-2A. Aquatic resources identified during the pedestrian survey (northern portion). Also includes photo point locations to support Appendix B.

A-3

Figure A-2B. Aquatic resources identified during the pedestrian survey (southern portion). Also includes photo point locations to support Appendix B.

A-4

Figure A-3. National Wetlands Inventory and National Hydrography Dataset features depicted in or near the Project area.

A-5

Figure A-4. Raptor survey area.

A-6

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APPENDIX B

Site Photographs

B-1

Photo Point 1-A. North. Photo Point 1-B. East.

Photo Point 1-C. South. Photo Point 1-D. West.

B-2

Photo Point 2-A. Buried Cable Line. Facing Southwest. Photo Point 2-B. Buried Cable Line. Facing Southwest

Photo Point 3-A. Electrical Boxes. Facing West.

B-3

Photo Point 4-A. North. Photo Point 4-B. East.

Photo Point 4-C. South. Photo Point 4-D. Adjacent property Valvoline: 800 N Summit Blvd, Frisco, CO 80443. Facing West.

B-4

Photo Point 5-A. North. Photo Point 5-B. East.

Photo Point 5-C. South. Photo Point 5-D. Adjacent property Big O Tires: 820 N Summit Blvd, Frisco, CO 80443. Facing West.

B-5

Photo Point 6-A. Junction Box. Facing Northeast.

B-6

Photo Point 7-A. North. Photo Point 7-B. East.

Photo Point 7-C. South. Photo Point 7-D. West.

B-7

Photo Point 8-A. North. Photo Point 8-B. East.

Photo Point 8-C. South. Photo Point 8-D. West.

B-8

Photo Point 9-A. Telecommunications Box. Facing West. Photo Point 9-B. Drainage Ditch (WB02). Facing South

Photo Point 10. Culvert under 10 Mile Drive. Facing North. Photo Point 11. Culvert under Highway 9. Facing Southeast.

B-9

Photo Point 12. Buried access box to water control valves. Facing West.

Photo Point 13. Electrical box. Facing South.

Photo Point 14. Culvert under Hawn Drive. Facing North.

Photo Point 15. Stormwater Drain. Facing South

B-10

Photo Point 16-A. North. Photo Point 16-B. East.

Photo Point 16-C. South. Photo Point 16-D. West.

B-11

Photo Point 17-A. North. Photo Point 17-B. East.

Photo Point 17-C. South. Photo Point 17-D. West.

B-12

Photo Point 18. Telecommunications Box. Facing West. Photo Point 19-A. Electrical Box. Facing West.

Photo Point 19-B. Electrical Box. Facing North. Photo Point 20. Stormwater drainage pond (WB01). Facing West.

B-13

Photo Point 21-A. North. Photo Point 21-B. East.

Photo Point 21-C. South. Photo Point 21-D. West.

B-14

Photo Point 22. Stormwater drain and manhole cover.

Facing West.

Photo Point 23. Traffic signal box. Facing West.

Photo Point 24-A. Stormwater drain. Facing Northwest. Photo Point 24-B. Sewer manhole cover. Facing Northwest

TECHNICAL MEMORANDUM

To: Jason Huddle, Region 3 Environmental Manager Colorado Department of Transportation 222 S. 6th Street, Room 317 Grand Junction, CO, 81501

From: Matthew Fisher, B.A., SWCA Cultural Resources Specialist Melanie Medeiros, M.A., RPA, SWCA Cultural Resources Principal Investigator

Date: October 26, 2023

Re: Cultural Resource Review for the JR Engineering Frisco Highway 9 Sidewalk Project SWCA Project No. 83689-001

JR Engineering (JR) is proposing to construct a retaining wall and sidewalk (project) on the west side of Colorado Highway 9 between 10 Mile Drive and School Road in Frisco (Town), Summit County, Colorado (project area). SWCA understands that project activities will take place within the existing right-of-way (ROW) and will be funded by Federal Highway Administration funds, which will require project compliance with the National Environmental Policy Act (NEPA). On behalf of the Town and JR, SWCA Environmental Consultants (SWCA) completed this analysis of existing data, which provides baseline cultural resource data to support the project environmental clearances required by the Colorado Department of Transportation.

PROJECT AREA AND LAND USE

The project area is lies within public rights-of-way in the southeast quarter of Section 26, Township (T) 5 South (S), Range (R) 78 West (W) (Figure 1). The proposed development area covers approximately 1.54 acres of land along State Highway 9 in the town of Frisco, Summit County, Colorado. Land use in the area consists of commercial, municipal, and residential development. There are numerous apartment complexes and residential homes located to the west, southwest, and northeast of the project area, whereas the northern portion of the project area is dominated by commercial development in all directions, with some residential development to the northeast.

Cultural Resource Review for the JR Engineering Frisco Highway 9 Sidewalk Project

Figure 1. Project area overview.

At an average elevation of 9,097 feet above mean sea level, the project area is within the Rocky Mountain physiographic province (National Park Service 2023) and within the larger Level III Southern Rockies ecoregion and the smaller Sedimentary Subalpine Forest Level IV ecoregion (Chapman et al. 2006).

These ecoregions are characterized by glaciated, high mountains with steep slopes, and high-gradient perennial streams with boulder, cobble, and bedrock substrates. Land use is primarily timber production, recreation, hunting, wildlife habitat, seasonal grazing, and some gold mining. The natural vegetation is dominated by evergreen forest and some deciduous forest. Frisco draws most of its water from North Ten Mile Creek, but snow cover is a major source of water for the lower, more arid parts of the ecoregion (Chapman et al. 2006; Thompson 2023).

METHODS

On September 5, 2023, SWCA archaeologists requested a file search and literature review of the project area through the Colorado Office of Archaeology and Historic Preservation to identify records for all previously conducted cultural resource surveys and all previously identified cultural resources within the project area and the Public Land Survey System sections within 1 mile surrounding the project area (study area). The results of the file search and literature review were received on October 3, 2023, with related spatial data also received on October 3, 2023. This review considered previously identified cultural resources by site type, especially regarding types that may be of greater Tribal sensitivity or may have greater subsurface depositional potential; eligibility for inclusion in the National Register of Historic Places (NRHP); and location on the landscape in relation to the project area.

In addition to the file search and literature review, SWCA conducted background research of primary and secondary sources to identify land use practices and natural features that may indicate areas with the potential for or presence of archaeological or cultural resources within the study area. The background research included examination of General Land Office (GLO) plats and other historic maps, as well as modern maps to identify place names and topographic features that could also indicate areas of potential cultural or Tribal concern; historic and modern aerial imagery; and soils data to determine the type of geological depositions and depth to bedrock.

RESULTS

The results of the file search and literature review and the background research are presented in the following sections.

File Search and Literature Review

Results of the file search indicate that 34 cultural resource inventory projects have been conducted in the study area, although none of the previous projects overlap with the project area (Table 1, Figure 2). The previous projects were conducted for 21 land management projects, seven transportation projects, two historic preservation projects, one telecommunications project, one land development project, one water-related project, and one miscellaneous project. One project, ST.CH.R5, conducted in 1993, overlaps a portion of the project area (see Figure 2).

Table 1. Summary of Previous Cultural Resource Inventories within the Study Area

Report No. Year Title Author

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

Report No. Year Title Author

MC.FS.R500 2010 Cultural Resource Surveys of the Hazard Tree Treatment Areas along Roads, Eagle and Summit Counties, White River National Forest (CRR R2010021500048)

Jackson, Caroline

ST.AE.R1 2013 Whole Foods Frisco/Basecamp: A Class III Cultural Resource Inventory of a Proposed Development Site and Wetlands Mitigation site, Summit County, Colorado

Elkins, Melissa

ST.CH.R12 1974 Archaeological Surveys in Ten Miles Canyon – I70, Colorado Department of Highways Project Number I-70-2-

(24) Highway Salvage Report No. 1

Gooding, John D

ST.CH.R13 1976 Investigations of Historic Communities in Tenmile Canyon Buckles, William G

ST.CH.R17 2013 An Intensive Cultural Resources Inventory for the Realignment of State Highway 9 East of Frisco, Summit County

Wolff, Greg

ST.CH.R2 1990 Cultural Resource Survey of I-70 between Silverthorne and Frisco at the SH 91 Interchange, Summit County, IR 70- 2(176)

Unspecified

ST.CH.R5* 1993 A Cultural Resource Survey of State Highway 9 between Breckenridge and Frisco, Summit County (STA(CX) 009- 1(8))

Unspecified

ST.CH.R6 1995 Archaeological Inventory of the Frisco Lakefront Trail, and a Materials Waste Site along U.S. Highway 6, Summit County

(STE C610-003)

Jepson, Daniel A.

ST.CH.R9 1999 Historic Resources Survey Report, State Highway 9, Frisco to Breckenridge

Unspecified

ST.FS.NR25 1987 Cultural Resource Report for Lily Pad Trail (CRR 15-10-12-

86) Dillion #86-1

Leadabrand, Paul L.

ST.FS.NR37 1991 A Class III Cultural Resource Inventory of Nordic Ski Trail Improvement Areas, Summit County (CRR 15-10-11-91)

Smith, Craig S.

ST.FS.NR38 1992 Frisco Area Buried Powerline Cultural Resources Inventory, Summit County (Project #92-CO-33) (CRR 15-10-20-92)

Harrison, Cheryl A.

ST.FS.NR53 1989 Old Dillon Reservoir Trail, Summit County, Colorado (CRIR No. 15-10-27-91)

Semmer, Paul

ST.FS.NR55 1990 Frisco/Dillon Recreation Trail, Summit County, Colorado (CRIR No. 15-10-26-91)

Semmer, Paul

ST.FS.NR63 2002 FLPMA Road Easement/Miner’s Creek/Bailey Access Road Gustafson, Alice

ST.FS.NR69 2004 County Commons Trails (Summit County, Colorado) (CRR 15-10-34-04)

Mckibbin, Anne

ST.FS.R106 2008 Old Dillion Reservoir Enlargement: Cultural Resources Investigations, Summit County, Colorado

Brogan, Andrea

ST.FS.R108 2006 Cultural Resources Inventory of the Dillion Reservoir Forest Health Project, Summit County, Colorado

Brogan, Andrea

ST.FS.R110 2009 A Class III Cultural Resource Inventory of the Ten Mile Canyon Mine Safety Closures Summit County, Colorado, White River National Forest

Horobik, Heather A.

ST.FS.R133 2011 Class II Survey and Heritage Resource Specialist Report for the Ophir Mountain Forest Health and Fuels Project, White River National Forest, Summit County, Colorado

Twitty, Eric

ST.FS.R139 2015 Class III Inventory of Select Mining Resources for the Summit Forest Mine Closure Project, Summit County, Colorado (R2015021500026)

Kight, William

Report No. Year Title Author

ST.FS.R16 1991 Cultural Resource Reconnaissance and Inventory of Six Parcels of the Homestake Land Exchange, Summit County, Colorado

Gustafson, Alice

ST.FS.R20 1996 Cultural Resource Inventory of the Dillon Reservoir Vegetative Management Project on the White River National Forest, Summit County, CO (CRR #15-10-07-97)

Metcalf, Sally J.

ST.FS.R21 1997 Slate Creek Land Exchange, Class III Cultural Resources Inventory, Summit County (CRR 15-10-24-97)

Mckibbin, Anne

ST.FS.R25 1999 Western Land Group Summit Land Exchange Class III Cultural Resource Inventory, Summit County, Colorado

Barclay, Dulaney

ST.FS.R26 1999 A Level III Historic Resources Survey for the Upper Blue Stewardship Project in Summit County (#43-82X9-5069)

Unspecified

ST.FS.R27 1999 The Cultural Resource Inventory of the Upper Blue Stewardship Project: Survey II, Summit County, White River National Forest

Gustafson, Alice

ST.FS.R30 2001 Cultural Resources Survey of Old Dillon Reservoir and Dillon Ditch, Summit County, Colorado (CRN3717)

Ziemke, Laura

ST.FS.R37 2002 Cultural Resource Inventory of the Frisco Nordic Center Trails and Facilities Project, Summit County, Colorado White River National Forest

Gustafson, Alice, Rodney Denardo, Tom Rehusch, and Chris Potvin

ST.FS.R40 1983 Cultural Resource Inventory for Western Land Exchange, Frisco Bay Area, Summit County, Colorado

Unspecified

ST.FS.R59 1984 Archaeological Investigations in the South Frisco Parcel for Western Land Exchange Company, Summit County

Black, Kevin D.

ST.FS.R72 1982 Cultural Resources Report for the Peninsula Recreation Area Salvage Sales (CRR 15-10-10-82)

Wood, Robert B.

ST.SHF.R15 2020 Town of Frisco, Historic Resources Survey, Survey Report

2020 (SHF 2019-M2-022)

Reid, Suzannah

*Project overlaps with current project area.

A total of 95 cultural resources, nine of which are precontact, 85 of which are historical, one of which lacks a temporal and cultural affiliation, have been previously recorded within the study area (Table 2).

The precontact resources consist of four open lithic scatters, two open camps, and three isolated finds.

Historical resource types are highly varied but primarily include historic buildings (residential and commercial); mining-related resources; linear structures such as wagon roads and highways, railroads, transmission lines, and ditches; and isolated finds and features. No information about resource type is available for one resource.

Two of the identified resources are listed in the NRHP: the Frisco School House (5ST258) and the Wildhack’s Grocery and Post Office (5ST326). One resource, the Stanley-Rouse House (5ST1074), is listed in the Colorado State Register of Historic Places (SRHP). Nine resources are eligible for the NRHP;

however, three of these eligible resources are non-supporting segments of linear structures. Seventy-four resources are not eligible for the NRHP, five resources need more data before an eligibility assessment can be made, and four resources are either unevaluated for the NRHP or have unknown NRHP eligibility.

One resource, the Blue River to Summit Transmission Line (5ST745), which is eligible for the NRHP, intersects the project area.

Table 2. Summary of Previously Recorded Cultural Resources within the Study Area

Site No. Resource Name Time Period Resource Type NRHP Eligibility

5ST1 Historic Trash dump Unevaluated

5ST215 Dillon Water Ditch Historic Water ditch Officially not eligible

5ST258 Frisco Schoolhouse Historic Schoolhouse Listed on the NRHP

5ST259 Staley House/Well Historic Single dwelling Field not eligible

5ST260 Bailey House Historic Single dwelling Field not eligible

5ST261 Bills Ranch House Historic Single dwelling Field not eligible

5ST278 Frisco Bay Precontact Open lithic Field not eligible

5ST279 Precontact Open lithic Field not eligible

5ST282 Frisco Hotel ~ Frisco Lodge Historic Hotel Field not eligible

5ST320 Archaic Open lithic Field not eligible

5ST321 Frisco Siding Historic Railroad grade Field not eligible

5ST322 Historic Prospect pits Field not eligible

5ST326 Wildhack’s Grocery Store-Post Office ~ Foote’s Rest ~ Post Office Historic Commerce/trade building, post office Listed on the NRHP

5ST349 King Soloman Spur Historic Railroad spur Field not eligible

5ST350 Frisco Siding Historic Railroad grade Field not eligible

5ST351 Frisco Depot Site Historic Historic depot Field not eligible

5ST395.4 Denver, South Park & Pacific Railroad Historic Railroad Officially eligible

5ST423 F-12-T Historic Bridge Officially not eligible

5ST450 Masontown ~ Masontown Mining Site ~ Dog Trot Cabin ~ Victoria Mine Historic Mining complex Officially eligible

5ST451 J.J. Hathaway Charcoal Kilns Historic Historic kiln Officially not eligible

5ST492 Unpatented Mine Historic Mine Officially not eligible

5ST493 King Solomon Mine Historic Mine Officially not eligible

5ST499 Precontact Isolated find Unevaluated

5ST534.1 Lusher Ditch Historic Ditch segment Officially not eligible

5ST535.1 Historic Ditch segment Officially not eligible

5ST536.1 1880s Wagon Road Historic Wagon road segment Officially not eligible

5ST537 Historic Isolated feature Officially not eligible

5ST538 Historic Ditch Officially not eligible

5ST539 Historic Isolated feature Officially not eligible

5ST623 Precontact Open lithic Field not eligible

5ST648 Historic Reservoir Officially not eligible

5ST716 Paleoindian:

Folsom Open camp Officially needs data

5ST717 Historic Mining pits and flumes Officially not eligible

5ST718 Historic Mining complex Officially not eligible

5ST724 Iron Springs to Miners Creek Ditch/Flume Historic Ditch Unknown

Site No. Resource Name Time Period Resource Type NRHP Eligibility

5ST724.1 Iron Springs to Miners Creek Ditch/Flume Historic Ditch segment Officially not eligible

5ST724.2 Iron Springs to Miners Creek Ditch/Flume Historic Ditch segment Officially not eligible

5ST745* Blue River to Summit Transmission Line Historic Transmission line Field eligible

5ST745.1 Blue River to Summit Transmission Line Historic Transmission line segment Field eligible, non-supporting segment

5ST754 Frisco Cemetery Historic Cemetery Officially not eligible

5ST755 Denver & Rio Grande Railroad Spur Historic Railroad Officially not eligible

5ST756 Green Ghetto Historic Cabin Officially not eligible

5ST757 Unfug Cabin and Shed Historic Single dwelling, shed Officially not eligible

5ST794 Historic Isolated feature Field eligible

5ST798 Historic Mine Officially not eligible

5ST828 Historic Isolated feature Officially not eligible

5ST838 Historic Isolated feature Field not eligible

5ST892.1 Interstate 70 Historic Highway segment Field not eligible

5ST906 Precontact Isolated find Field not eligible

5ST907 Late Archaic Open camp Field not eligible

5ST910 Historic Log building Officially not eligible

5ST936.1 North Tenmile Ditch ~ Giberson Highline Ditch ~ Buffalo Placer Flume Historic Ditch segment Officially eligible

5ST936.2 North Tenmile Ditch ~ Giberson Highline Ditch ~ Buffalo Placer Flume Historic Ditch segment

Officially eligible, non-supporting segment

5ST1073 Frisco Town Hall ~ Frisco Old Town Hall Historic – Officially not eligible

5ST1074 Staley-Rouse House Historic Single dwelling, garage Listed in the SRHP

5ST1101 Precontact Isolated find Field not eligible

5ST1102 Historic Isolated find Field not eligible

5ST1104 Historic Habitation (log cabin, shed) Officially not eligible

5ST1120.1 Historic Ditch segment Officially not eligible

5ST1185 Meridian Mine Historic Isolated feature Field not eligible

5ST1202 Colorado Girl Prospect Adit Historic Prospect pit Officially not eligible

5ST1203 Historic Mine Officially eligible

5ST1239 Matchless Mine Historic Isolated feature Field not eligible

5ST1240 Juno Prospect Historic Isolated feature Field not eligible

5ST1315 Historic Isolated feature Field not eligible

5ST1440 Historic Isolated feature Field not eligible

5ST1460 Historic Isolated find Field not eligible

5ST1461.1 State Highway 9 Historic Highway Field eligible, non-supporting segment

Site No. Resource Name Time Period Resource Type NRHP Eligibility

5ST1503 Historic Mining complex Officially not eligible

5ST1507 Historic Isolated feature Officially not eligible

5ST1537 Unknown Unknown Officially not eligible

5ST1743 Linquist house Historic Single dwelling, garage Field not eligible

5ST1744 O’Conner House ~ Thompson House Historic Single dwelling, garage Field needs data

5ST1745 Deming Cabin ~ Deming Crossing Townhomes Historic Cabin, multiple dwellings Field not eligible

5ST1746 Deming Cabins Historic Cabin Field not eligible

5ST1747 Historic Single dwelling Field not eligible

5ST1748 Historic Single dwelling, garage Field not eligible

5ST1749 Dutchman’s Place Historic Single dwelling, garage, shed Field not eligible

5ST1750 Caldwell House Historic Single dwelling, barn Field not eligible

5ST1751 Mumford House Historic Single dwelling, shed, building Field not eligible

5ST1752 Kreamelmeyer House Historic Single dwelling, garage, building Field not eligible

5ST1753 Mary Ruth House Historic Single dwelling, multiple dwelling Field not eligible

5ST1754 Giberson Barn Historic Barn, single dwelling Field not eligible

5ST1755 Morris House Historic Single dwelling, shed, log building, greenhouse Field needs data

5ST1756 Yellow House ~ Pine Lodge ~ Windhack-England House Historic Single dwelling, shed, building Field not eligible

5ST1757 Wiley House Historic Single dwelling Field not eligible

5ST1758 Historic Single dwelling Field not eligible

5ST1759 Log Cabin Cafe Historic Single swelling Unevaluated

5ST1760 The Lost Cajun Historic Commercial building Field Not Eligible

5ST1761 Tomlinson Grocery ~ Moose Jaw Restaurant Historic Grocery store Field not eligible

5ST1762 Frisco Café Historic Commercial building Field not eligible

5ST1763 Cannam Cabins Historic Log cabin Field not eligible

5ST1764 Blacksmith Shop Historic Blacksmith shop Field needs data

5ST1765 Lund House Historic Single dwelling, restroom, building Field not eligible

5ST1766 Excelsior Mine Office Historic Business Field needs data

*Resource intersects with current project area.

Figure 2. Map of previous cultural resources inventories.

Background Research

General Land Office Plats, Historic Topographic Maps, and Aerial Imagery

SWCA reviewed historic GLO plats, U.S. Geological Survey (USGS) topographic quadrangles, and aerial imagery to evaluate the potential for the presence of historic features within the study area (Bureau of Land Management 2023; NETROnline 2023; USGS 2023).

One historical feature is depicted in Section 26, the section in which the project area is located, on the 1881 GLO plat for T5S, R78W. This feature, labeled as RANCH, is in the northeast quarter of the section and outside of the project area. Most of the remainder of the plat shows an undeveloped, forested area.

However, the TOWNSITE OF FRISCO is shown south of the project area, in Section 35, and the D&RG R.R.

SPUR is shown trending generally northeast through Sections 33, 34, 35, 36, 25, and 24, and through the Frisco townsite. The spur reappears on the plat in Section 13 and continues north through Sections 12 and

1. An unnamed but improved road parallels the railroad through these three sections. Another RANCH is also present in Section 27, northwest of the project area.

The 1892 dependent resurvey plat for T5S, R78W shows moderate growth in the vicinity of Frisco and the project area, mostly related to mining claims and associated infrastructure and roads concentrated near Frisco and along Tenmile Creek and the Blue River; a handful of additional residential features such as cabins and ranches are also depicted. No mining claims or other potential historical features are depicted in the project area on this plat.

Historic USGS quadrangles covering the study area that were reviewed include the Dillon, Colorado, 1:62,500-scale quadrangles (1929, 1955 ed; 1934; 1934, 1944 ed.); the Leadville, Colorado 1:250,000-scale quadrangles (1957, 1978 edition; 1959; 1960; and 1964); and the USGS Frisco, Colorado 1970 1:24,000-scale quadrangle (1970 and 1973 editions) (USGS 2023).

The 1:62,500-scale, early-twentieth century quadrangles indicate that region surrounding the project area was still rural, with the sparsely developed town of Frisco south of the project area. No historical features are depicted in the project area, although an unnamed, unimproved road trends northeast just to the east of the project area, with one structure present in the general vicinity of the project area.

The mid-twentieth century Leadville, Colorado 1:250,000-scale quadrangles (1957, 1978 edition; 1959;

1960; and 1964) are at too small of a scale to show much detail, but these maps do show the project area along State Highway 9 as well the Dillon Reservoir, the Frisco town boundary, and a transmission line and substation in the general vicinity of the project area.

Development in and around Frisco has increased by 1970, with numerous buildings (residential, commercial, municipal), roads, and other forms of infrastructure such as pipelines, sewage disposal ponds, campgrounds, and gravel pits present. The project area is situated along State Highway 9 and is crossed twice by an unnamed transmission line (Figure 3).

Figure 3. USGS 1970 (1973 edition) quadrangle with Frisco Highway 9 Sidewalk Project Area in red.

The first historic aerial image covering the project area dates to 1969 and reflects a comparable landscape as seen in the historic USGS quadrangles. The project area and the study area are largely undeveloped and covered in vegetation in the 1969 aerial image. Dillon Reservoir is present, and Frisco is centered directly to the west of the mouth for Frisco Bay.

By 1983, there is extensive development within the study area. The 1983 aerial image shows the beginnings of modern city infrastructure that includes the first illustration of Hawn Drive, which divides the two project areas and the commercial structures to the east of the project area. Review of sequential images after 1983 demonstrate the continued development of the study area that includes residential houses and complexes and additional commercial structures to the north, south, east, and west of the project area. After 1999, there appears to have been no new development to the study area (Figure 5).

Figure 5. Aerial image dating to 2022 showing disturbance in the project area, outlined in red.

(GoogleEarth 2023).

Geology

Frisco sits atop of the Rio Grande rift, a major, late Oligocene to recent zone extension that extends from Colorado to Mexico. The northeastern corner of the quadrangle lies within the Williams Range thrust fault. The surficial geology of the area consists of deeply dissected landslide deposits and deeply weathered, very coarse gravel deposits; the area is underlain mostly by glacial outwash of the Bull Lake and Pinedale glaciation series (Kellogg et al. 2002; Tweto 1979).

Depositional Setting

Two soil units are mapped within the project area (Natural Resources Conservation Service 2019) (Table 3, Figure 6). Grenadier gravelly loam, 6 to 15 percent slopes, which constitutes 93.75 percent of the project area, is characterized by well-drained soils of moderate depth that derived from glacial drift and occur on fans of mountain bases. Histic Cryaquolls, nearly level, consist of poorly drained soils of moderate depth that derived from organic material over stratified sandy loam to clayey alluvium over sand and gravel and that occur on the treads and at the base of mountains on alluvial fans and in floodplains. These soils constitute 6.25 percent of the project area. Overall, this depositional environment is not conducive to the preservation of buried archaeological deposits.

Table 3. Summary of Project Area Soil Units

Soil Map Unit Slope (%) Typical Profile Horizons Buried Archaeological Potential

Grenadier gravelly loam

6–15 H1: 0–6 inches; gravelly loam Low

H2: 6–19 inches; gravelly sandy clay loam

H3: 19–60 inches; very cobbly sandy loam

Histic Cryaquolls, nearly level

– O: 0–8 inches; mucky peat Low

H1: 8–28 inches; stratified sandy loam to clay

H2: 28–60 inches; sand and gravel

Figure 6. Project area soils.

CONCLUSIONS AND RECOMMENDATIONS

The results of this desktop review revealed that 34 cultural resource inventories have been previously conducted within the larger study area, with one partially overlapping the project area. The town of Frisco is rich with cultural resources, with 95 previously recorded resources present in the study area.