Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Ridges Basin Cultural Resource 

Management Plan

Animas-La Plata Project, La Plata County, Colorado

Upper Colorado Region

(Sensitive — for official use only)
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Mission Statements

The mission of the Department of the Interior is to protect and 

provide access to our Nation’s natural and cultural heritage and 

honor our trust responsibilities to Indian Tribes and our 

commitments to island communities.

The mission of the Bureau of Reclamation is to manage, develop, 

and protect water and related resources in an environmentally and 

economically sound manner in the interest of the American public.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Ridges Basin Cultural Resource Management Plan

Animas-La Plata Project, La Plata County, Colorado

Prepared by

Western Colorado Area Office / Durango, CO

ACKNOWLEDGEMENTS

The Bureau of Reclamation’s Western Colorado Area Office (Reclamation) would like to thank those 

who contributed to the Animas – La Plata (A-LP) Project and the development of the Ridges Basin 

Cultural Resource Management Plan. The A-LP Cultural Resource Oversight Committee, staffed by 

members of the Ute Mountain Ute Tribe and the Southern Ute Indian Tribe, were instrumental in working 

with Reclamation and SWCA Environmental Consultants to conduct archaeological investigations prior 

to the construction of Ridges Basin Dam and Lake Nighthorse. The information they compiled on 

archaeological resources and Traditional Cultural Properties within the Basin is invaluable and has 

heavily guided the compilation of this Cultural Resource Management Plan.

As the Lead Federal Agency overseeing Ridges Basin, Reclamation is responsible for developing and 

executing the Cultural Resource Management Plan. However, Reclamation recognizes that the Cultural 

Resource Management Plan is a collaborative document, and is grateful for the input and cooperation of 

the consulting Tribes and Agencies over the course of this document. Major contributors have included: 

Ute Mountain Ute Tribe, Southern Ute Indian Tribe, Colorado State Historic Preservation Office, 

Colorado Parks and Wildlife, Hopi Tribe, Santa Ana Pueblo, Pueblo of San Felipe, Pueblo of Acoma, 

Pueblo of Jemez, Pueblo of Santa Clara, Pueblo of Zuni, Jicarilla Apache Tribe, Navajo Nation, UintahOuray Tribe, Pueblo of Cochiti, Pueblo of Isleta, Pueblo of Laguna, Pueblo of Nambe, Pueblo of Picuris, 

Pueblo of Pojoaque, Pueblo of San Ildefonso, Pueblo of San Juan, Pueblo of Sandia, Pueblo of Taos, 

Pueblo of Tesuque, Pueblo of Zia, and Santo Domingo Pueblo. Together we ensure the long-term 

preservation and protection of cultural resources within A-LP – Ridges Basin.

May 2017
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Table of Contents

1.0 Introduction

1.1 Purpose and Authority

2.0 Bureau of Reclamation Cultural Resource Management Program Policy

2.1 In-Place Preservation and Long Term Management

3.0 Animas – La Plata Project Background

3.1 Environmental Setting

3.2 Archaeological Research

3.2.1 Cultural History Overview

3.2.2 Archaeological Literature Review

3.2.3 Archaeological Management Areas

4.0 Cultural Resources Review Process

4.1 National Historic Preservation Act - Section 106

4.1.1 Step 1 – Initiate the Process (36 CFR §800.3)

4.1.2 Step 2 – Identify Historic Properties (36 CFR §800.4)

4.1.3 Step 3 – Assess Effects (36 CFR §800.5)

4.1.4 Step 4 – Resolve Adverse Effects (36 CFR §800.6)

4.1.5 Expediting Consultation (36 CFR §800.3(g))

4.2 Traditional Cultural Properties (NPS Bulletin 38)

5.0 Ridges Basin Preservation Plan

5.1 Responsibilities

5.2 General Preservation Measures and Strategies

5.3 Archaeological Sites Included in the Preservation Plan

5.4 Potential Site Type Specific Effects and Preservation Measures

5.5 Potential Non-Site Type Specific Effects and Preservation Measures

5.5.1 Fire Management

5.5.2 Fencing

5.5.3 Traffic Along Roads and Road Maintenance

5.5.4 Recreation and Development

5.5.5 Artifact Theft and Vandalism

5.5.6 Erosion and Wave Action

5.5.7 Accidental of Unintentional Disturbance

5.6 Opportunities for Research

6.0 Cultural Resource Discoveries

6.1 Inadvertent Archaeological Discoveries

6.2 Inadvertent Discovery of Human Remains

7.0 Ridges Basin Monitoring Plan
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

8.0 Ridges Basin Cultural Resource Management Goals

9.0 Accommodation of Sacred Sites

10.0 Glossary of Terms and Definitions

11.0 References Cited

Appendices

Appendix A: Archaeological Site Monitoring Database for the A-LP Ridges Basin Area 

*CONFIDENTIAL* not for general release

Table of Figures

Figure 1- The Animas-La Plata Ridges Basin Area Map

Figure 2- A-LP Ridges Basin Management Areas

Table of Tables

Table 1. Legal Descriptions (Section, Township, Range) for A-LP Ridges Basin Area

Table 2. List of Sites in Ridges Basin Treated by SWCA

Table 3. List of Sites in Ridges Basin Not Treated by SWCA
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

1.0 INTRODUCTION

The Animas-La Plata (A-LP) project in La Plata County, Colorado, is a project of the U.S. 

Department of the Interior, Bureau of Reclamation (Reclamation), Upper Colorado Region, 

Western Colorado Area Office. The project diverts water from the Animas River to a reservoir

south of Durango, Colorado, for municipal and industrial development (Reclamation 2000).

The reservoir inundates 1,500 acres in Ridges Basin. Historic properties directly impacted by 

the reservoir through reservoir-associated infrastructure construction, pipeline realignments, and 

inundation have already been treated, and impacts to them mitigated (Chuipka 2009; Gilpin

and Yoder 2007; Potter 2008a; Potter and Yoder 2008a, 2008b; Yoder and Potter 2007). This

document provides a plan for managing cultural resources on Reclamation lands in and around

Ridges Basin (AL-P Ridges Basin Area) that have the potential to be impacted by future use

and development of the area.

Figure 1- The Animas-La Plata Ridges Basin Area Map

The AL-P Ridges Basin Area encompasses approximately 5,630 acres and comprises numerous 

sections in the federal Township and Range public land survey system (Table 1). Archaeological 

surveys have currently documented 188 archaeological sites in the A-LP Ridges Basin Area
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

(Appendix A). SWCA, Environmental Consultants, Inc. (SWCA) treated 67 of these sites in 

Ridges Basin as part of the A-LP project.

Table 1. Legal Descriptions (Section, Township, Range) for A-LP Ridges Basin Area

Section Township (T), Range (R)

6, 7, 8 T34 North, R9 West

1, 2, 3, 4, 10, 11, 12, 1U, 2U, 3U, 4U, 

5U, 8U, 9U, 10U T34 North, R10 West

31, 32 T34 1⁄2 North, R9 West

34, 35, 36 T35 North, R10 West

Sites range in date from Archaic (6500 B.C. to A.D. 1) through the twentieth century and evince 

the history of the Four Corners Region from about 1000 B.C. to present. The A-LP Ridges Basin 

Area contains Basketmaker II sites (A.D. 1 to 500) dating just after the Archaic sites. Archaic 

and Basketmaker sites are significant because they provide information on the transition from a 

hunting and gathering lifeway to an agricultural lifeway, another of the most important 

transitions in human history. 

Sites dating to the Pueblo I period (A.D. 700 to 900) are especially numerous and include some 

of the earliest villages in the Four Corners region. Pueblo I sites are of importance in that they 

provide information on the transition to settled village life, one of the most significant social 

revolutions in human history.

In addition, the A-LP Ridges Basin Area contains nine protohistoric (A.D. 1300 to 1860) to 

historic (post 1860) Native American sites that are important in understanding the origins of Ute 

and Navajo cultures and the Ute-Navajo frontier. Finally, the A-LP Ridges Basin Area contains 

historic (post 1870s) Euro-American sites that illustrate the homesteading process in 

southwestern Colorado.

The primary impacts to sites are anticipated to be from recreation, wave action, operations, 

maintenance, and construction activities that include road, fence, trail, boat ramp, and 

campground construction. This document provides a plan for monitoring and mitigating these 

impacts to sites within the A-LP Ridges Basin Area that are eligible and potentially eligible for 

listing on the National Register of Historic Places (NRHP). Implementation of this plan will 

provide for the preservation, protection, or mitigation of damage to cultural sites.

1.1 Purpose and Authority

The purpose of the Ridges Basin Cultural Resource Management Plan is to ensure that 

Reclamation manages cultural resources on its land according to legislative mandates and in a 

spirit of stewardship; to clarify Reclamation's roles and responsibilities related to cultural 

resources; and to provide direction for consistent implementation of Reclamation's management 

responsibilities for cultural resources in the Ridges Basin management area. In particular, the 

provisions of the Native American Graves Protection and Repatriations Act (NAGPRA) and 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Sections 106 and 110 of the National Historic Preservation Act (NHPA) will be used to 

determine management and treatment of historic properties (defined by the NHPA as any 

prehistoric or historic district, site, building, structure, or object included in, or eligible for 

inclusion on the National Register). As lead agency, the authority to implement and administer 

this plan will reside with the Bureau of Reclamation.

Beginning in 1906, numerous Federal laws have been enacted to preserve and protect cultural 

resources on Federal lands. Of these, the NHPA is the most comprehensive. It declared as policy 

that the Federal government would administer cultural resources under its ownership, control, or 

administration, in a spirit of stewardship for the inspiration and benefit of present and future 

generations. This Policy and its associated Reclamation Manual (RM) Directive and Standard 

(D&S), Cultural Resources Management, LND 02-01, affirm Reclamation's commitment to 

comply with the laws, regulations, executive orders, policies, and directives that constitute the 

Federal Cultural Resources Management (CRM) Program.

The laws, regulations, and guidance shaping Reclamation's cultural resources responsibilities 

include: Antiquities Act of 1906 (16 U.S.C. 431); Historic Sites Act of 1935 (16 U.S.C. 461); 

Reservoir Salvage Act of 1960 (16 U.S.C. 469); National Historic Preservation Act of 1966 (54 

U.S.C. 300101 et seq.); National Trails System Act of 1968 (16 U.S.C. 1241-1251); National 

Environmental Policy Act of 1969 (42 U.S.C. 4321); Archeological and Historic Preservation 

Act of 1974 (16 U.S.C. 469); American Indian Religious Freedom Act of 1978 (42 U.S.C. 1996); 

Archaeological Resources Protection Act of 1979 (16 U.S.C. 470); Native American Graves 

Protection and Repatriation Act of 1990 (25 U.S.C. 3001); National Register of Historic Places 

(36 CFR Part 60); Determinations of Eligibility for Inclusions in the National Register of 

Historic Places (36 CFR Part 63); Curation of Federally Owned and Administered 

Archeological Collections (36 CFR Part 79); The Protection of Historic Properties (36 CFR 

Part 800); Protection of Archaeological Resources (43 CFR Part 7); Native American Graves 

Protection and Repatriation Act (43 CFR Part 10); Protection and Enhancement of Cultural 

Environments (Executive Order 11593); Federal Actions to Address Environmental Justice in 

Minority Populations and Low-Income Populations (Executive Order 12898); Protection of 

American Indian Sacred Sites (Executive Order 13007); Managing Museum Property (411 DM); 

Protection of Properties on the National Register of Historic Places (426 DM 1); Preservation of 

Historic Property (519 DM 1); Archeology and Historic Preservation: Secretary of the Interior's 

Standards and Guidelines (48 FR 44716); and Reclamation Cultural Resources Management 

Policy (2011) LND-P01.

The A-LP project is a participating project under the Colorado River Storage Project Act and the

Colorado River Compact of 1922 (Public Law [PL] 84-485) and the Upper Colorado River Basin 

Compact of 1948. These two compacts allocate water for development in the Colorado River 

Basin. The A-LP project has been the subject of public interest and environmental review since it 

was authorized by the Colorado River Basin Project Act of 1968 (PL 90-537) and later 

incorporated into the Colorado Ute Indian Water Rights Settlement Act of 1988 (PL 100-585) (as 

amended) (Settlement Act). The Final Supplemental Environmental Impact Statement (FSEIS) 

(Reclamation 2000), describing environmental impacts to be mitigated and possible mitigation 

alternatives, was prepared under the provisions of PL 93-638, the Indian Self-Determination and 

Education Assistance Act. Thus, the Settlement Act provided authority for the FSEIS and for the 

creation of the A-LP Ridges Basin Area.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

2.0 BUREAU OF RECLAMATION CULTURAL RESOURCE 

MANAGEMENT PROGRAM POLICY

In managing cultural resources that are on land owned by the United States and

controlled or administered by Reclamation on behalf of the United States,

Reclamation shall:

A. identify, document, and evaluate cultural resources for listing in the NRHP;

B. seek and obtain involvement from Federal, state, tribal, and local

agencies, as well as the interested public, and consider their input in

carrying out Reclamation's CRM Program;

C. to the fullest extent possible, manage and maintain historic properties, both

reserved and transferred works, in a manner that preserves the character

defining features that qualify them for listing in the NRHP;

D. integrate cultural resources concerns early in project planning processes in order to

identify opportunities to protect historic properties from adverse effects and avoid

unnecessary delays, conflicts, and costs for Reclamation undertakings;

E. consider the effects of its undertakings on historic properties and define

Areas of Potential Effects (APE) to consider direct and indirect effects

specific to each undertaking;

F. where adverse effects cannot be avoided, commit to fully completing

mitigation measures prescribed in agreements executed with one or more of the

following: State or Tribal Historic Preservation Offices, the Advisory Council

on Historic Preservation, Native American tribes, and other interested parties;

G. actively nominate eligible properties to the National Register;

H. support an education and outreach program to inform the public of Reclamation's

responsibilities for stewardship of cultural resources, and related activities and

accomplishments;

I. maintain accurate information on the types, location, status, and condition of 

cultural resources on its land, which shall be used in collaboration with other

Reclamation programssuch as asset management;

J. preserve and protect museum property under its control as prescribed in RM Policy,

Museum Property Management, LND P05; D&S, Museum Property Management,

LND 02-02; and D&S, Museum Records, LND 02-05;
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

K. identify NAGPRA cultural items under its control to ensure their appropriate 

protection, and repatriation or disposition in a timely manner according to statute

and regulation;

L. to the extent possible establish and implement alternatives for the continued use

of historic properties that are no longer needed for current or projected

Reclamation purposes in compliance with Section 111 of NHPA;

M. to the extent possible follow the Secretary of the Interior's Standards for the 

Treatment of Historic Properties for historic buildings and structures when

complying with sustainability, accessibility, life safety and other applicable

mandates;

N. as per Reclamation Manual Directive & Standards, Administration of the 

Archaeological Resources Protection Act (ARPA) on Bureau of

Reclamation Land, LND 02-04, support management actions to prevent the

theft of, damage to, or destruction of archaeological resources; and

O. as per LND 02-04, allow for archaeological investigation and work on 

Reclamation land, only after issuing a Bureau of Reclamation permit for such 

activity.

2.1 In-Place Preservation and Long Term Management

In situ (in place) preservation is the preferred course of action for all identified historic properties 

within an APE. To the fullest extent possible, those characteristics which make the property 

eligible for inclusion in the NRHP will be preserved in situ and protected from the effects of any 

project implementation.

If an historic property can be saved from destruction or alteration, Reclamation will take the 

necessary steps to preserve the property in perpetuity. Flagging and temporary fencing will be 

used to mark sites for avoidance by any project-related construction, machinery and vehicular 

traffic that is within 50 feet of the historic property. Sites designated for preservation will be 

assigned an archaeological monitor during potentially harmful project activities. Previously 

unknown historic properties discovered during the course of any project activities will be 

afforded the same protective measures as currently known historic properties and these will be 

added to Appendix A.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

3.0 ANIMAS – LA PLATA PROJECT BACKGROUND

3.1 Environmental Setting

The A-LP Ridges Basin Area is in La Plata County just west of the Animas River, adjacent

to the northern boundary of the Southern Ute Indian Tribe (SUIT) Reservation. Ridges Basin

lies at the border between the Southern Rocky Mountain and Colorado Plateau physiographic

provinces. This boundary is broadly defined as the zone in which sedimentary formations rise

onto the uplift of the San Juan Mountains. Uplift and deformation have occurred episodically

throughout the geologic history of the Durango area and are responsible for creating many of the

major topographic features evident today. During the last two million years the San Juan

Mountains may have experienced 15 or more glacial advances, which have also greatly 

contributed to the formation of the modem landscape (Blair et al. 1966). The Hogback

Monocline, a series of east-west-trending and southward-dipping ridges, dominates the 

topography in and around Ridges Basin and Blue Mesa. The Animas River crosses these

hogbacks from north to south. Landforms along the Animas River are predominantly terraces of 

late Pleistocene age that formed during the last deglaciation between 18,000 and 15,000 years 

ago (Blair et al. 1966).

Ridges Basin is a broad triangular basin bounded on the south by Basin Mountain, on the east by 

Carbon Mountain, and on the northwest by Wildcat Ridge. Basin Creek enters Ridges Basin

from the west (at the western corner of the triangle) at an elevation of 6,800 feet and trends 

east-southeast, and exits Ridges Basin in the southeast comer of the triangle at an elevation of 

6,720 feet. The south side of Ridges Basin is defined by Basin Mountain and its piedmont, the 

east side by Carbon Mountain and its piedmont, and the north side by a low ridge separating 

Ridges Basin from Wildcat Canyon. This low ridge, informally referred to here as Wildcat 

Ridge, rises to an elevation between 7,200 feet and about 7,400 feet at its northernmost point. 

The highest point of Carbon Mountain is at an elevation of 7,844 feet, and Basin Mountain's 

highest point is at an elevation of 8,245 feet.

The Hogback Monocline is a regionally extensive geologic structural feature that is best

defined in the project area by the tilted sandstone bedrock at the top of Carbon and Basin

Mountains. The regional dip of the sedimentary stratigraphy of the Hogback Monocline is

toward the east-southeast, and the axis of the monocline trends north-south. The landscape of

Ridges Basin and its associated landforms is determined to a great extent by the geologic

structure of the Hogback Monocline, combined with the variation in the erosive nature of the 

underlying geologic units (Anderson 2008a). The Hogback Monocline exposes Cretaceous

sedimentary rocks that dip approximately 40 degrees to the southeast. At its peak Carbon

Mountain has the erosional resistant Pictured Cliffs Sandstone, which forms the dramatic

cream-colored cliffs. Underlying the Pictured Cliffs Sandstone is the more easily eroded Lewis

Shale, which is the dark gray and black material that dominates much of the sediments in the

eastern portion of Ridges Basin. Lower on the slopes of Carbon Mountain are younger

colluvial and alluvial fan deposits of the Lewis Shale-derived clays. Underlying these two

units, which dominate the geology in the eastern and southern sides of the basin, is the

Mesa Verde Group (Cliff House Sandstone/Menefee Formation/Point Lookout Sandstone),

which outcrops on the western side of the basin (Anderson 2008a).
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Soils in and around Ridges Basin are primarily residual deposits formed on underlying shale

and sandstone bedrock. Colluvial slope-wash has redeposited these soils, and alluvial

deposits are present along drainages. Within Ridges Basin, sediments derived from the Mesa

Verde Group are generally sandier than the clayey deposits derived from the predominantly

Lewis Shale on the east and south sides of the basin. These two different types of sediments,

and resulting soils, have important implications for soil types and prehistoric agriculture

(Anderson 2008b). In simplified terms, soils derived from Lewis Shale have high clay content

and are not optimal for growing crops, whereas soils eroded from sandstone tend to drain better

and accommodate crops much better.

Four different biotic communities surround and intermingle in Ridges Basin (Winter et all 1986). 

Great Basin Conifer Woodlands, comprised primarily of pinyon-juniper, and Great Basin 

Montane scrub, composed of deciduous scrub species are supported on the shallow slopes in the 

basin. The basin’s highest elevations are Petran Montane Conifer Forest, dominated by 

ponderosa pine and Douglas fir. Additionally, the valley floor used to be Great basin Desert 

Scrub, dominated by rabbitbrush and sagebrush. Now, this is visible in select areas surrounding 

the reservoir that has filled in the old valley bottom.

The basin supports a rich wildlife population. Many species of perching birds, swallows, 

woodpeckers, hummingbirds, turkey, dove, and raptors including osprey and bald eagle can be 

found here. With the introduction of the reservoir there is also now a large population of 

waterfowl including heron and Canadian geese. Deer, elk, black bear, coyotes, rabbits, badgers, 

weasels, squirrels, marmots, porcupines, and prairie dogs can all be seen in Ridges Basin. 

Reith (1986b) documents several human-induced factors that have drastically changed the local

setting in Ridges Basin, including fire, overgrazing, and construction and clearing. The 

historical presence of fire is evidenced by dense concentrations of Gambel's oak on the northfacing slope of Basin Mountain. Gambel’s oak responds to severe burn by sprouting from 

stumps and producing dense stands of uniform height.

Overgrazing is the most widespread of recent human impact to the area and has resulted in the 

invasion of trees and shrubs into meadows and has relegated most native grass species into relict 

patches among the oaks and pinon-juniper. In addition, clearing for road, trail, pipeline, and 

canal construction have allowed for a variety of annual and perennial weeds–principally in the 

sunflower and mustard family–to populate areas disturbed by overgrazing and construction. 

Cheat grass has revegetated most disturbed areas. Finally, ponderosa pines have been selectively

cut throughout the basin.

The climate of Ridges Basin is semi-arid, with about 25 percent of its precipitation falling as

snow. Temperature ranges from a mean daily low of 10°F in January to a mean daily high of

87°F in July, with a long term annual temperature of about 40°F. The length of the growing

season of the Durango area has been variously reported as 116 days (Fuller 1988a, citing

Peterson 1984) and 99 days (Reith 1986a). Based on data collected over a four-year period, 

Bellorado (2007) reports widely varying average frost-free periods–116 to 134 days–for 

different areas within Ridges Basin, depending on aspect and proximity to the cold-air drainage.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

On average Durango receives between 18 and 19 inches of precipitation annually. Reith 

(1986a) reports a precipitation average of 18.98 inches for the Durango Airpark weather 

station on Blue Mesa. Fuller (1988a) reports the northwest Durango station yielding an

average of 18.61 inches. According to Peterson (1988), based on a 66-year record, Durango 

receives 18.04 inches of precipitation annually. In 2007, Anderson and Bellorado

(2009) recorded 20.14 inches of precipitation in Ridges Basin. No season is consistently

without rainfall, but May and June often constitute a period of mild drought. In contrast,

August is the wettest month, with prolonged episodes of rainfall derived from Southwest

monsoons dropping an average of 2.38 inches. November is a second period of mild drought, 

which ends with snowstorms that occur throughout December, January, and February.

3.2 Archaeological Research

This section presents an overview of the cultural history of Ridges Basin and the archaeological 

research conducted in the basin throughout time. Archaeological evidence, oral history, written 

records, and linguistic studies are the sources used to compile this cultural history.

The following overview includes a discussion of the A-LP Research Design and Data Domains 

for each cultural period in order to better understand the types of research questions that have 

been investigated. In addition to providing this background information, the Ridges Basin site 

types and distribution patterns are also presented. This information allows Reclamation and our 

consulting parties to identify sensitive cultural areas and develop better management 

recommendations when evaluating future undertakings. 

3.2.1 Cultural History Overview

Ridges Basin is within the Northern San Juan cultural region, on the periphery of the Colorado 

Plateau physiographic province. Several cultural traditions are represented in the region, from 

Paleoindian occupation to the Euro-American settlement of the area. This is merely a summary

of the complex culture history of the area; for a more in-depth discussion of the culture history of 

the Ridges Basin area, the reader is referred to SWCA’s publication series for the Animas-La 

Plata project (Lipe et al. 1999; Potter and Yoder 2008a, 2008b; Yoder and Potter 2007, Winter et 

al. 1986).

Paleoindian Period

The Paleoindian period, 10,000 to 6,000 B.C., provides evidence for the earliest occupation of 

southwest Colorado. This period includes the Clovis, Folsom, and Plano stages and is 

characterized by the hunting of big game, such as mammoth and bison, by hunters using long, 

lanceolate projectile points. Limited evidence for the use of wild plant resources and the hunting 

of smaller game has been gleaned from Paleoindian sites, perhaps reflecting a diverse 

subsistence strategy.

Settlement and subsistence activities during the Paleoindian period are poorly understood for the 

area and can only be inferred from the limited evidence collected in surrounding areas. There is 

little evidence to suggest that Paleoindian populations lived in the area on a permanent basis.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Existing data do suggest, however, that mobile groups hunting big game and gathering other wild 

resources entered the area intermittently. This region may not have contained sufficient floral 

and faunal resources to support Paleoindian hunters and gatherers on a permanent basis (Eddy et 

al. 1984:21). 

Archaic Period

Between 7,000 and 5,500 B.C., Bison antiquus, mammoth, and other Ice Age fauna became 

extinct. The extinction of the Ice Age fauna caused a shift from a reliance on big game hunting to 

the hunting of smaller game. An increase in the collection and processing of plant foods is also 

suggested by the greater number of pounding and grinding stones found at sites that date to the 

Archaic period (Cassells 1997).

The Archaic occupation of the Four Corners region has been well documented in recent years.

Recent archaeological investigations have identified a significant Archaic presence along the 

Colorado–Utah border in Montezuma County, Colorado. The Bodo Canyon and Ridges Basin 

areas also appear to have been areas of significant Archaic use.

The Oshara variant of the Archaic tradition influenced areas in northern Arizona, southeastern 

Utah, southwestern Colorado, and west-central New Mexico. The Oshara variant includes five 

phases: Jay, Bajada, San Jose, Armijo, and En Medio. These five phases are thought to reflect 

cultural adaptations to fluctuating climatic conditions and to have resulted in the eventual 

emergence of the Puebloan tradition (Irwin-Williams 1973, 1979). 

Archaic settlements in the region ranged from base camps to satellite sites. Early Archaic 

(6,000–3,200 B.C., which includes the Jay and Bajada phases) sites contain bifacially flaked 

knives, side scrapers, and large, slightly shouldered projectile points with stemmed bases (IrwinWilliams 1973, 1979). The tool assemblage for the Middle Archaic (3,200–1,800 B.C.) is similar 

to that of the Early Archaic, with the addition of ground stone milling tools. The addition of 

milling tools suggests the increased importance of plant foods in the Middle Archaic diet. 

Irregularly spaced postholes suggest that wickiup-type shelters were used in this region during 

the Middle Archaic. 

Evidence from the Late Archaic (1,800 B.C. – A.D. 400) suggests that corn was cultivated on the 

narrow floodplains of canyon floors near canyon heads. This corn, however, was only a 

supplement to the hunting and gathering systems already in place. The En Medio phase (800 

B.C. – A.D. 400) encompasses a transition from a primarily hunting-gathering subsistence 

strategy to one that was almost fully sedentary and based on corn horticulture. 

Puebloan Tradition

The Puebloan occupation of the region began before the end of the Archaic period and lasted 

until approximately A.D. 1300. The beginnings of the first Puebloan occupation, the 

Basketmaker II period (ca. 400 B.C. – A.D. 500), actually overlapped the end of the Archaic 

period. Irwin-Williams (1973) considered the En Medio Archaic phase and the Basketmaker II 

phase of the Puebloan to be equivalent in terms of material culture. Re-evaluations of En Medio 

and Basketmaker II sites and their reliance on maize agriculture in the northern Southwest have 

led some to believe that the Basketmaker II phase started earlier than generally thought and 

overlaps the En Medio phase (Kearns 1992).
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

During the Basketmaker II period, the population of the region increased and habitation sites 

were apparently occupied on a year-round basis. The habitation structures during this period 

were typically shallow pit houses with associated extramural work areas, hearths, roasting pits, 

and storage cists. This period has been traditionally characterized as a transitional phase from an 

economy based on hunting and gathering to one based on horticultural practices (Lipe and 

Matson 1971).

The Basketmaker III period lasted from approximately A.D. 500 to 700. The most common 

settlement pattern of this period consisted of dispersed, extended-family hamlets, which 

generally included one or two pit houses with associated surface features or storage rooms. In 

some areas of the Northern San Juan region, villages may have existed, but the contemporaneity 

of the individual structures at these sites has been called into question (Fuller 1988c).

Semi-subterranean pit houses were utilized for habitation, storage, and ritual activities. The main 

chambers and antechambers of the early Basketmaker III phase were circular or ovoid in plan 

view. They evolved to a D-shape and then, in the latter part of the period, to sub-rectangular 

shapes. Entry into these structures was usually through the south wall of the antechamber or 

through a hatch over the fire hearth in the center of the roof of the main chamber.

Artifacts found at Basketmaker III sites indicate an increasing use of ceramics, antler tools, shell 

ornamentation, and ground stone. Smaller projectile points indicate the common use of the bow 

and arrow by the end of the period. Trough metates appear at this time and begin to replace basin 

metates. Ceramic vessels could be placed directly in a fire, making it easier to cook beans, which 

were cultivated and added to the diet.

The Pueblo I period (A.D. 700 – 900) is characterized by population movements to upland areas.

Due to climatic variations, the uplands may have been the only areas that received enough 

rainfall to support dry farming. The introduction of red ware ceramics and the domestication of 

turkeys also took place during this period.

Pueblo I period settlements included large villages with associated community complexes, 

single- and multiple-habitation hamlets, field houses, and limited-activity areas. These large 

communities were characterized by multiple pit houses, contiguous room blocks, and large 

ceremonial structures (great kivas). Villages contained several large room blocks with associated 

pit structures, all clustered east to west or in parallel rows from north to south. Great pit 

structures, presumably ceremonial in nature, have been found in the larger communities. Surface 

rooms, for storage and habitation, were constructed by lining shallow pits with upright slabs to 

stabilize jacal walls constructed of sticks and clay.

The majority of the identified archaeological remains, including NAGPRA items, in Ridges 

Basin date to the Pueblo I period (Perry and Potter 2006). SWCA estimated that there were 111 

Pueblo I pit structures built and occupied in and around Ridges Basin. Different calculations 

were made to estimate population density in the area from AD 760 to 810. Estimates ranges from 

125-200 to 555-888, with the conclusion that it was likely that the population at any given time 

during the period never exceeded 300 people (Potter 2010).
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

The Pueblo II period (A.D. 900–1150) is characterized by population movements and shifts in 

settlement patterns, widespread small hamlets, the use of water-control features and soil 

conservation, and the introduction of corrugated utility ceramics. During this period, populations 

spread out across mesas of middle and lower elevations in the Northern San Juan region.

Projectile points of the period are small and side-notched. Decorated ceramics were 

predominantly black-on-white and black-on-red varieties.

Habitation sites during this period were generally constructed on mesa tops and along low 

ridgelines near what would have been the cultivated fields of the inhabitants. Sites were also 

built in the bottoms of wide canyons and river valleys where farmers could have practiced the 

ak-chin method of irrigation, a floodwater farming technique in the alluvial outwash fan of an 

arroyo (Reid and Whittlesey 1997). Masonry surface structures were introduced during the 

Pueblo II period, some with hearths indicating that these structures were used as dwellings.

Constructed of shaped sandstone, the walls of these structures were generally one stone thick.

Village sites consisted of single- or multiple-unit sites with one or two pit houses in front of Lshaped or randomly arranged room blocks.

The Pueblo III period (A.D. 1150–1285) represents the climax of Puebloan occupation in the 

Northern San Juan region. The basic architectural patterns found during the Pueblo II period 

continue, with the masonry often becoming finer in quality. Ceramics included corrugated utility 

wares and black-on-white ceramics with McElmo and Tusayan design elements. The beginning 

of the Pueblo III period has been characterized as a time of environmental instability, which may 

have contributed to the abandonment of smaller sites and population aggregation into larger 

community sites. The local inhabitants of the area may have responded to periods of low rainfall 

in the 1100s by intensifying agricultural efforts and by relying more on water-control strategies 

as opposed to dry-farming techniques. The growing seasons shortened dramatically toward the 

end of the Pueblo III period, possibly resulting in an increased use of water-control features, then 

a movement to lower elevations to minimize the risk of crop loss. Archaeological evidence 

suggests that by A.D. 1285, the Puebloans had migrated south out of the northern Four Corners 

region.

Following the migration from the area, there may have been a hiatus in permanent human 

habitation of the area for almost two centuries. While archaeological evidence in Ridges Basin 

did not show human habitation between A.D. 1300 and 1500, it was most likely occupied 

periodically by Athapaskan and Numic-speaking peoples. By about A.D. 1500, two linguistic 

groups are recognized in the region: the Numic-speaking Ute and the Athapaskan-speaking 

peoples, who were ancestors of the modern Navajo and Apache Indians.

Navajo Tradition

Archaeological evidence of the Navajo occupation of the Northern San Juan region is divided by 

archaeologists into two phases: the Dinétah, from approximately A.D. 1450 to 1700, and the 

Gobernador, lasting from approximately A.D. 1700 to 1800.

The Dinétah phase subsistence is believed to have been similar to that of the Archaic period, 

with a reliance on hunting and gathering. The inhabitants may have supplemented their diet with 

corn (Brown and Hancock 1992). Habitation structures of the period consisted of brush wickiupstyle structures, and forked-stick hogans. Extramural features found at habitation sites include 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

hearths, roasting pits, warming pits, and fire-cracked rock scatters. Gray ware ceramics are also 

common at sites of the period.

The Gobernador phase is best known for its defensive masonry structures, the “pueblitos,” found 

in the Gobernador–Largo area on the southeastern fringe of the San Juan region. These pueblitos 

were once thought to have been constructed during the 1690s by Puebloan refugees fleeing from 

the Spanish following the Pueblo revolt in 1680 (Keur 1944). More recent research, however, 

suggests that these structures were built by Navajos as a defense against Ute and Comanche raids 

in the area (Reed and Reed 1992).

Navajo history, as told by traditional scholars, is complex and is transmitted through oral and 

ceremonial traditions. It embodies knowledge passed down from time immemorial. For the 

Navajo, history begins with the ascent of the people from Four Underworlds before emerging into 

this, the Fifth World. From this emergence came the ancestors of the Diné People, Holy People, 

plants, animals, and other living beings that became part of the Earth. As life began in this world, 

the people moved about the earth. They progressed from hunters and gatherers to settled village 

life to the present-day Navajo People. During this long history, many other people joined the tribe. 

Many of their clans have origins in the Greater Southwest and came from other people/tribes, 

including the Anasazi. The complex origins of the Navajo people form the basis for the Navajo 

Nation’s participation in the Animas-LaPlata project. Today, the Navajos call themselves Nihokáá 

diné’é bíla’ashdla’ii (Five-Fingered People of the Land); each finger represents one of the worlds 

in which they have lived. Their creation story incorporates the land, the people, and all that inhabit 

the earth.

Ute Tradition

The primary evidence for Numic expansion into Utah and western Colorado is provided by 

linguistic studies. The linguistic evidence suggests that Numic-speaking Utes entered the region 

sometime between A.D. 1200 and 1400. Archaeological evidence suggests that a Ute population 

existed in the area by the early 1600s. The earliest historical documentation of the presence of 

Utes in the area comes from the 1620s. 

Although the Utes ranged throughout a wide area, Ute homelands for the Weeminuche1 Band 

were in the San Juan Basin area. Ute homelands for the other Ute bands ranged from eastern 

Utah to the front range of the Colorado Rocky Mountains, north towards Wyoming and south to 

Santa Fe. At the time of contact with Spanish explorers, the basic subsistence strategy of the Ute 

consisted of hunting wild game and gathering wild plant foods. They appear to have employed a 

forager strategy with a relatively high residential mobility, following a seasonal movement 

across annual territories as various food resources came into fruition (Martin, et all. 2006). Some 

Ute groups also cultivated corn, beans, and squash to supplement their diet. The Utes were the 

earliest western tribes to acquire horses, and they incorporated these animals fully into their 

culture. The likely source in the sixteenth and seventeenth centuries would have been Spanish 

 1 The band eventually composing the Ute Mountain Ute people are referred to in historic texts as both the 

Weeminuche and Weenuche. The preferred name is Weenuche, but Weeminuche is used here when citing historic 

texts that use that term.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

colonies in Mexico (Forbes 1959). Juan de Oñate’s Spanish colony in New Mexico, established 

in 1598, brought a permanent population of horses into the Southwest.

The material culture of the early Ute consisted mainly of perishable and easily transported items 

such as baskets, skin sacks, buckskin clothing, moccasins, and wild foodstuffs. Early Ute groups 

did not commonly use pottery. Prehistoric Numic and historic Ute camps consisted of temporary 

wickiups covered with branches, bark, and grasses, as well as other wooden features such as tree 

platforms, utility racks, and hunting blinds (Martin, et all. 2006). By A.D. 1700, after the 

acquisition of horses, the Utes adopted the tipi, which they covered with hide or canvas. Later 

Protohistoric Era components often contain small quantities of Euro-American artifacts obtained 

in trade such as glass beads, metal tinklers, firearms, food cans, and horse tack, as well as metal 

arrow points, knives, needles, axes, cooking pots, and other goods (Martin, et all. 2006).

European Tradition

Prior to 1859, when the gold and silver rush began in Colorado, European explorers, 

missionaries, traders, and trappers had entered the Northern San Juan region only on a sporadic 

basis. Spanish explorers, including the two Rivera expeditions of 1765, and the Dominguez and 

Escalante expedition in 1776, were the first Europeans to come into the region. One site in 

Ridges Basin 5LP4213, named the Old Ute Trail, is a segment of the trail that connected present 

day Ignacio and the headquarters of the Southern Ute Tribe, and Towaoc and the headquarters of 

the Ute Mountain Ute Tribe. This trail was first used by different Native American groups 

traveling through the area, then was used by the Rivera expedition and called the Old Spanish 

Trail (Potter 2010). The Old Spanish Trail first used by the Rivera expedition in 1765, looking 

for a route to connect Santa Fe and California, was made a National Historic Trail in 2002. 

Extensive European interest in the San Juan region began with gold exploration in southwestern 

Colorado between 1859 and 1861. Most historic period sites in the Northern San Juan region that 

date after 1859 were related to mining, transportation, and early agricultural settlement. Ranches 

and farms sprung up through Colorado’s western valleys during the late 1860s to early 1870s.

Between 1880 and 1890, Hispanic settlers came into the area and established many small towns. 

The end of open range grazing began in 1891, when National Forest reserves were created. 

Homesteading was well established by 1899, and growth throughout the region was triggered by 

an increasing dependency on an agricultural economy. Open range grazing of cattle and sheep 

ended in 1934 with the passage of the Taylor Grazing Act. The modern regional economy is 

increasingly dependent on tourism and coalbed methane production.

3.2.2 Archaeological Literature Review

The following synopsis of the archaeological work conducted in the Ridges Basin area is taken 

from the Animas La Plata Project Volume XVI - Final Synthetic Report written by James M. 

Potter in 2010.

The earliest archaeological work conducted in Ridges Basin was done by Fort Lewis

College. From 1965 to 1975, Fort Lewis College conducted several field schools directed by

Homer Root and Doc Ives. In 1965, under the direction of Homer Root, the field school
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

excavated an early Pueblo site containing a large pit structure, 12 jacal surface rooms, and a

midden. SWCA has determined this site to be 5LP237.

In 1966 and 1967, Root directed excavations at 5LP245, the Sacred Ridge Site, as part of a

field school for Fort Lewis College. 5LP245 covers 12 acres and is the largest prehistoric site

in the A-LP Project Area. Root focused his work on the ridge top architecture and the

extensive middens on the surrounding slopes, excavating three pit structures, two dance plazas,

28 surface rooms, and 40 human burials over the course of four months in 1966 (Root

1967). He returned to the site for a short time in the summer of 1967, to further explore the

middens for additional burials.

Root conducted excavations at four sites in 1967: Pasture Ruins I, II, and III, on an alluvial fan

at the east end of Ridges Basin, and North Ruin I, northeast of Ridges Basin in what is now

Bodo Industrial Park (Ware 1986). Bonan (1985) suggested that the Pasture Ruins sites

include 5LP177, 5LP179, and 5LP243. The site records describe these sites as jacal habitation

units, as the field school excavated only surface rooms and their midden units. The field

school removed three burials from the midden at Pasture Ruin 1. Root also conducted further

excavations at 5LP245 (the Sacred Ridge Site) in 1967, but he made no record of the exact

location or the extent of this work.

Dr. John "Doc" Ives also conducted a Fort Lewis College field school in Ridges Basin in

1967, at 5LP238, a habitation site. The site consisted of a jacal room block and a front-oriented

pit structure, which apparently contained a number of disarticulated human skeletal remains.

No further details of the pit structure or rooms were reported, although a detailed site map

from the excavation exists.

In 1968, Ives targeted surface rooms at three sites on the same alluvial fan as Homer

Root's "Pasture" sites. According to Ware (1986), these sites were 5LP240, 5LP241, and

5LP242. Subsequent work conducted by SWCA in 2003, as part of the A-LP project, indicates

that these sites were habitation units with pit houses. No reports of Ives's excavations were

completed.

In 1969, Root returned to Ridges Basin for a final season, focusing on a single site on

the northern slope of the Basin. Site 5LP236, the "Hoodoo Ruin", consisted of a jacal

room block, a pit house, and scattered trash southeast of the pit house. Root briefly described

the room block in his notes as 10 contiguous jacal rooms, each measuring 3.5 x 3 meters, all

plastered and well- constructed. No detailed descriptions or drawings of the architecture

appear to have been made, although he described them as a semi-circle of rooms. He also

mentioned that a quantity of ground stone was recovered from the room block, and that 

human remains were recovered from the site.

In 1975, the first formal archaeological survey of Ridges Basin was conducted by the

University of Colorado. This intensive inventory of the eastern portion of the basin (below the

6,960-foot elevation line) recorded and surface-collected 37 sites (Leidy 1976). This survey

was the first in a long history of rampant surface collection of sites in Ridges Basin as

part of archaeological surveys.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

In 1980 and 1981, ESCA-Tech Corporation and their subcontractor, the University of New 

Mexico's Office of Contract Archeology (OCA), conducted an intensive Class III pedestrian 

survey of the entirety of Ridges Basin (Winter et al. 1986). This survey identified 196

sites, including those identified by Leidy in 1975. Of these, 105 contained Pueblo I

ceramics, 12 had late Pueblo I - Pueblo III ceramics, 25 produced Basketmaker II or earlier

projectile points, and 36 were Euro- American sites (Winter et al. 1986). The work

included magnetometer investigations at 30 of the Pueblo I and possible Basketmaker sites

(Bennett and Weymouth 1986). Several important results emerged from this survey. The

first was the systematic identification and recording of all site types in Ridges Basin. 

Previous work had tended to focus exclusively on large habitation sites with surface room

blocks, pit structures, and refuse deposits, all sites with a high likelihood of yielding whole 

pots, datable charcoal, and tree-ring samples. The ESCA-Tech survey provided some of the

first data on prehistoric sites and activities outside the range of primary habitation. Pueblo I

sites documented by the ESCA-Tech/OCS survey were of two main types: (1) habitation 

sites with surface rooms, at least one pit structure, and midden deposits; and (2) limitedactivity sites lacking architecture. A second result of the survey was the identification of a

bimodal size distribution for aceramic lithic scatters. As a result, Archaic period sites 

became a significant aspect of the archaeological record and research potential of Ridges

Basin.

In 1981 and 1982, Fort Lewis College conducted yet another field school in Ridges Basin.

Phil Duke directed the excavation of 5LP630, near Root’s “Pasture Sites." The site

contained an unburned early Pueblo I pit structure, a burned surface room block, and a

shallow midden. Scattered human remains were recovered from the pit house. In addition,

the field school tested 5LP240 (referred to as 5LP242 in Duke's report), a site that had

been excavated by Ives, but uncovered no additional features (Duke 1985).

In 1982, under the direction of Duke and Susan Riches, the Fort Lewis field school tested

three limited-activity sites, 5LP491, 5LP493, and 5LP593. The only subsurface features

discovered were three slab-lined cists at 5LP593 (Duke 1985).

In the 1980s, Complete Archaeological Services Associates (CASA) conducted various

work in Ridges Basin. CASA re-identified, re-recorded, and once again surface collected

the 196 sites recorded by ESCA-Tech/OCA, in the process updating all of the Colorado 

state site cards. They also systematically surveyed the Wheeler and Koshak Borrow Areas

east of Ridges Basin, recording 46 sites in the Wheeler Borrow Area and three in the

Koshak Borrow Area (Fuller 1988b).

CASA conducted excavations at 11 sites in Bodo Canyon, adjacent to the north edge of 

Ridges Basin, as part of the Uranium Mill Tailings Remedial Action Project, or UMTRA

(Fuller 1988a). These Bodo Canyon excavations treated two late Archaic hunting camps,

four early Pueblo I habitations, and five early Pueblo I non-habitation sites (three artifact

scatters and two possible field house sites). In addition, two of the Bodo Canyon sites

(5LP478A and 5LP1104) contained Basketmaker II components, both with shallow, basinshaped pit structures, hearths, storage pits, and midden deposits. Radiocarbon date ranges for

the Basketmaker II components were A.D. 180±70 to 440±60 at 5LP478A, and A.D.

270±80 to 280±80 at 5LP1104. Fuller proposed that these sites represented permanent
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

habitations. However, Hogan and others have suggested that seasonal occupation during the

winter months is more consistent with the quantity and diversity of artifacts recovered from

there and with models of Basketmaker II settlement in the San Juan Basin (Hogan 1985; Hogan 

et al. 1991). Fuller’s work constituted the first investigations on Basketmaker II sites in the

project area, and brought to light the potential of this area to yield significant data on sites 

dating to this time period.

In 1990, prior to obtaining the land, Reclamation synthesized the survey and excavation work

undertaken up to that time, and had the project area designated an archaeological district

eligible for the NRHP. In1992 and 1993, Northern Arizona University (NAU) and their

subcontractor, La Plata Archaeological Consultants, mapped and surface-collected 42

archaeological sites in Ridges Basin. NAU and Reclamation published seven volumes on 

the results of this limited work (Allison 1995; Gregg and Smiley 1995a, 1995b; Gregg et

al. 1995; Smiley 1995; Smiley and Folb 1997; Smiley and Gregg 1995; Smiley and Robins

1997), further documenting the variation represented by the artifact assemblages in Ridges

Basin.

In 1999, Woods Canyon Archaeological Consultants excavated 5LP515 as part of the MidAmerica Pipeline Project (Horn et al. 2003). Site 5LP515, at the eastern end of the basin, 

consisted of a pit structure, a room block with two surface structures and three extramural

features, and a trash midden. This site dated to the early Pueblo I period.

As part of the A-LP project mitigation, from 2002 to 2005 SWCA excavated 67 sites in Ridges

Basin (Table 2). Twenty-eight of these were small Pueblo I habitation sites, one was a Pueblo I

village containing 22 pit structures, 19 were Pueblo I limited activity sites, six were undated

limited activity sites, one was an Archaic camp, three were Basketmaker II habitation sites,

eight were historic period sites, and one was a Protohistoric site. One of the Pueblo I

limited activity sites and one Pueblo I habitation site also contained evidence of

Protohistoric use. In addition, SWCA conducted ethnographic and historical research on the

Old Ute Trail (site 5LP4213) (Gilpin 2007).

Table 2. List of Sites in Ridges Basin Treated by SWCA

Site Number Time Period and Site Type

5LP169 BM II habitation

5LP171 PI limited activity

5LP174 PI habitation

5LP175 Archaic camp/PI limited activity

5LP176 PI habitation

5LP177 PI habitation

5LP178 PI habitation

5LP179 PI habitation

5LP181 PI limited activity

5LP182 Historic

5LP183 PI limited activity

5LP184 PI habitation
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Site Number Time Period and Site Type

5LP185 PI habitation

5LP186 PI limited activity

5LP187 PI habitation

5LP188 BM II habitation/PI limited activity

5LP192 Harper Ranch Historic

5LP236 Hoodoo Ruin PI habitation

5LP237 PI habitation

5LP238 PI habitation

5LP239 PI habitation

5LP240 PI habitation

5LP241 PI habitation

5LP242 PI habitation

5LP243 PI habitation

5LP244 PI habitation

5LP245 Sacred Ridge PI habitation/village

5LP246 PI habitation

5LP248 PI habitation

5LP452 PI limited activity

5LP477 Historic

5LP482 PI habitation

5LP484 PI limited activity

5LP487 Undated limited activity

5LP494 Historic

5LP495 PI limited activity

5LP496 PI limited activity

5LP498 PI limited activity

5LP502 Historic

5LP503 PI habitation

5LP508 PI limited activity

5LP510 PI habitation

5LP511 PI habitation

5LP517 Historic

5LP525 Undated limited activity

5LP536 PI habitation

5LP537 PI limited activity

5LP545 PI limited activity

5LP549 PI habitation/Protohistoric camp

5LP567 PI limited activity

5LP569 PI limited activity

5LP570 BM II habitation
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Site Number Time Period and Site Type

5LP577 Archaic limited activity

5LP579 Bodo Ranch Historic

5LP588 PI limited activity/Protohistoric camp

5LP601 PI limited activity

5LP608 PI limited activity

5LP614 PI habitation

5LP630 PI habitation

5LP634 PI habitation

5LP635 PI limited activity

5LP1095 PI limited activity

5LP2264 Undated limited activity

5LP2265 Undated limited activity

5LP4870 Protohistoric

5LP6634 Historic

The results of SWCA's work in Ridges Basin is presented in 15 research volumes (Allison

2010; Chuipka 2009; Gilpin 2007; Gilpin and Yoder 2007; Perry and Potter 2006; Potter 2006,

2008a, 2008b, 2009, 2010; Potter and Yoder 2008a, 2008b; Perry 2010; Railey and

Wesson 2009; Yoder and Potter 2007). Additionally, one volume is dedicated to SWCA's

work on nearby Blue Mesa (Chuipka and Potter 2007). This research indicates that most of

the Pueblo I habitation sites dated from A.D. 750 to 810 and were dispersed hamlets

consisting of one or a few pit structures and associated extramural features, including

ephemeral surface rooms, burials, and stockades, more generally termed "enclosures." The

exception was 5LP245, the Sacred Ridge Site, a large early Pueblo I village-aggregate at the

west end of Ridges Basin comprising 22 pit structures and hundreds of features, including over

100 human burials. Sacred Ridge also contained structures interpreted as communal ritual

architecture. This site was contemporaneous with the numerous dispersed hamletsthat dot the

landscape and was a social and ritual center for the householdsthat lived at these hamlets.

SWCA’s excavations from 2002 to 2005 resulted in the recovery of human skeletal remains 

from approximately 279 individuals from 23 sites as well as a large amount of processed human 

remains from the Sacred Ridge Site (Perry et. al 2010).

Table 3 lists the sites within Ridges Basin that were not treated by SWCA as part of the A-LP

project. 

Table 3. List of Sites in Ridges Basin Not Treated by SWCA 

Site Number Time Period(s) and Site Type

5LP170 BM II/III, P I/II/III open camp

5LP172 P I/II/III open architectural

5LP173 BM II/III, P I/II/III open architectural

5LP180 BM II/III, P I/II/III open camp
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Site Number Time Period(s) and Site Type

5LP189 BM II/III open architectural

5LP193 BM II/III, P I/II/III open architectural

5LP247 BM II/III, P I/II/III open architectural

5LP381 Unspecified open camp

5LP389 Unspecified isolated find

5LP390 Unspecified isolated find

5LP391 Unspecified isolated find

5LP393 Unspecified isolated find

5LP420 Unspecified isolated find

5LP429 P I/II/III open camp

5LP445

P I/II/III, Euro-American (1920–1940) farming/ranching 

(homestead)

5LP456 Euro-American historic, water control

5LP463 BM II/III open architectural

5LP466 BM II/III, P I/II/III, Archaic open camp

5LP469 Euro-American historic, farming/ranching

5LP472 BM II/III open camp

5LP478 BM II/III, P I/II/III, open architectural

5LP479 Euro-American historic, farming/ranching

5LP480 Euro-American historic, trash dump

5LP481 P I/II/III open architectural, burial

5LP483 BM II/III, P I/II/III open architectural, burial

5LP485 Euro-American historic, farming/ranching

5LP488 Unspecified open camp

5LP489 BM II/III open architectural

5LP490 BM II/III open camp

5LP491 BM II/III, P I/II/III open camp

5LP492 Euro-American historic, trash dump

5LP493 BM II/III, P I/II/III open architectural, historic, trash dump

5LP497 BM II/III open architectural

5LP499 BM II/III, P I/II/III open camp

5LP500 Archaic, BM II/III, Unspecified, open camp, historic, isolated find

5LP501 BM II/III open camp

5LP504 BM II/III open camp

5LP505 BM II/III open architectural

5LP506 BM II/III open architectural

5LP507 Archaic, P I/II/III, Historic, open lithic, isolated find

5LP509 BM II/III open camp

5LP512 BM II/III open architectural

5LP513 BM II/III open architectural
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Site Number Time Period(s) and Site Type

5LP514 Unspecified historic, water control

5LP515 P I/II/III open architectural

5LP516 Euro-American historic, farming/ranching

5LP518 Historic, habitation

5LP519 Historic, railroad

5LP520 Unspecified historic, habitation

5LP521 BM II/III open camp

5LP522 Native American–Unspecified, Historic, open lithic, isolated find

5LP523 BM II/III open architectural

5LP524 Archaic, BM II/III open camp

5LP526 Unspecified historic, trash dump

5LP527 Unspecified open lithic

5LP528 Unspecified historic, habitation

5LP529 Unspecified open lithic, historic habitation

5LP531 Unspecified open camp

5LP532 Archaic, BM II/III, P I/II/III open camp

5LP533 Unspecified open camp

5LP534 Ute, open camp, historic mining

5LP535 BM II/III open camp

5LP538 BM II/III open architectural

5LP539 BM II/III open architectural

5LP540 BM II/III open architectural

5LP544 BM II/III open architectural

5LP552 Archaic, BM II/III open camp

5LP565 Unspecified open camp

5LP566 Euro-American historic, mining

5LP568 BM II/III open camp

5LP576 BM II/III open camp

5LP583 Unspecified open camp

5LP584 Unspecified historic, water control

5LP585 BM II/III open camp

5LP589 BM II/III open architectural

5LP590 Unspecified historic, habitation

5LP591 Unspecified open architectural

5LP592 BM II/III open architectural

5LP593 BM II/III, P I/II/III open architectural

5LP594 Protohistoric, Navajo open camp

5LP595 BM II/III open architectural

5LP596 Archaic, BM II/III open camp

5LP599 BM II/III open architectural
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Site Number Time Period(s) and Site Type

5LP600 Archaic, BM II/III open camp

5LP602 BM II/III, P I/II/III open camp

5LP605 Unspecified historic, water control

5LP606 Unspecified historic, water control

5LP607 BM II/III open architectural

5LP609 BM II/III open architectural

5LP616 BM II/III open architectural

5LP617 Unspecified historic, trash dump

5LP618 Archaic, BM II/III open camp

5LP619 BM II/III open camp

5LP621 BM II/III open architectural

5LP622 Ute open camp

5LP623 Euro-American historic, mining

5LP625 BM II/III open camp

5LP631 BM II/III open architectural

5LP638 BM II/III open architectural

5LP639 BM II/III open architectural

5LP640 Archaic, P I/II/III, Protohistoric open camp

5LP641 BM II/III open architectural

5LP642 Archaic, BM II/III open camp

5LP1093 Unspecified open camp

5LP1094 BM II/III open camp

5LP1099 BM II/III open camp

5LP1100 BM II/III, P I/II/III open camp

5LP1101 BM II/III open camp

5LP1102 Archaic, BM II/III open architectural

5LP1105 Unspecified open camp

5LP1107 BM II/III open camp

5LP1113 BM II/III open camp

5LP1823 BM II/III, P I/II/III open architectural

5LP1824 Unspecified open lithic

5LP1825 BM II/III open camp

5LP1980 Unspecified open lithic

5LP1981 Unspecified open lithic

5LP1982 Native American –Unspecified; open lithic; historic trash dump

5LP1983 Unspecified open camp

5LP1984 BM II/III, P I/II/III, Historic, open camp, historic, trash dump

5LP1985 Unspecified open lithic

5LP1986 Unspecified open lithic

5LP2266 Archaic open camp
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Site Number Time Period(s) and Site Type

5LP3663 Historic farming/ranching

5LP4213.1 Ute Trail 

Old Spanish Trail Ute (ca. A.D. 700–1950) and historic trail

5LP5806 BM II/III open camp

5LP6656.01 Historic water control

5LP6656.02 Historic water control

Finally, the most recent work in Ridges Basin was a Fort Lewis College Field School in 2013, 

conducted at three sites, 5LP172, 5LP173, and 5LP238 (Jenks et. al 2013). The purpose of the 

evaluative testing was to determine eligibility of these three sites, which had been collected, 

tested, and/or excavated previously. The sites were each also 100% surface collected. Due to 

their close proximity to any future boat ramp and/or recreation usage it was determined to be 

important to know whether any undisturbed subsurface remains still existed, and to minimize 

each sites surface visibility, to protect against potential future looting.

3.2.3 Archaeological Management Areas

Based upon the previous investigations in Ridges Basin, the AL-P Ridges Basin Area can be 

broken up into five distinct management areas. The purpose of the management areas is to 

identify potentially sensitive areas with high site densities and to provide a management tool for 

the planning of future undertakings. The use of management areas will allow Reclamation to 

work with project proponents when a new undertaking is proposed and discuss the potential 

effects on cultural resources in general terms during the early planning stages. 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Figure 2- A-LP Ridges Basin Management Areas

Management Area 1

Management Area 1 covers the north and west portions of AL-P Ridges Basin Area. Within 

Management Area 1 there are approximately 90 known archaeological sites. The site types 

located in Management Area 1 consist primarily of Basketmaker II-III and Pueblo I camps and 

habitation sites. The sites are distributed in clusters indicating the presence of Basketmaker and 

Pueblo I communities. Management Area 1 is located above the high water mark for Lake 

Nighthorse, and the sites in this area were not mitigated by SWCA as part of the creation of the 

reservoir. The sites in Management Area 1 have been preserved in situ and this area should be 

considered highly sensitive for the purposes of future undertakings.

Management Area 2

Management Area 2 covers the eastern portion of the AL-P Ridges Basin Area. Within 

Management Area 2 there are approximately 30 known archaeological sites. The site types 

located in Management Area 2 consist primarily of Basketmaker II-III and Pueblo I camps and 

habitation sites. The majority of the sites are clustered in northernmost section of Management 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Area 2, and represent the presence of a Basketmaker II-III community. This cluster of sites was 

not mitigated by SWCA as part of the creation of the reservoir, and the sites have been preserved 

in situ. The site density drops off dramatically in the middle and southern portions of 

Management Area 2. Management Area 2 should be considered moderately sensitive for the 

purposes of future undertakings.

Management Area 3

Management Area 3 covers the south and east portions of the AL-P Ridges Basin Area. Within 

Management Area 3 there is only one previously recorded site. The site is a Basketmaker III –

Pueblo I camp. The site was not mitigated by SWCA as part of the creation of the reservoir, and 

has been preserved in situ. Future actions in Management Area 3 should preserve this site. Due 

to the steep slope of Management Area 3 it is unlikely that many future actions will be proposed 

in this area if any at all. Management Area 3 is not considered sensitive for the purposes of 

future undertakings. 

Management Area 4

Management Area 4 covers the southern portion of the AL-P Ridges Basin Area. Within 

Management Area 4 there are 12 previously recorded archaeological sites. The site types located 

in Management Area 4 consist primarily of Basketmaker II-III and Pueblo I camps. The sites are 

clustered in the western portion of Area Management 4 and have been preserved in situ. 

Although the site density in Management Area 4 is low, the area is considered moderately 

sensitive for the purpose of future undertakings. This is due to the fact that Management Area 4 

includes the Sacred Ridge area. Sacred Ridge is a Pueblo I community that was mitigated prior 

to the creation of the reservoir. Highly sensitive NAGPRA items were recovered from Sacred 

Ridge. While it is believed that everything was recovered during the mitigation of Sacred Ridge, 

the general area in proximity to Sacred Ridge remains highly sensitive. 

Management Area 5

Management Area 5 covers the reservoir itself. Within Management Area 5 there are 

approximately 50 known archaeological sites. The site types located in Management Area 5 

consist primarily of Pueblo I habitations. The sites are clustered into three distinct Pueblo I 

communities. Sites within Management Area 5 were all treated by SWCA as part of the creation 

of the reservoir; the majority of the sites are permanently inundated by the reservoir. However, 

fluctuating reservoir levels could expose some of the sites near the shoreline and work may be 

planned within the reservoir pool when the water line in down. Although the sites in 

Management Area 5 have all been treated, this area should be considered moderately sensitive 

for the purposes of future undertakings. 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

4.0 CULTURAL RESOURCES REVIEW PROCESS

4.1 National Historic Preservation Act – Section 106

Section 106 of the NHPA requires that Federal Agencies take into account the effects of their 

undertakings on historic properties. The historic preservation review process mandated by 

Section 106 is set forth in the regulations of 36 CFR 800 “Protection of Historic Properties.” 

According to 36 CFR § 800.1(a), the goal of Section 106 consultation is to “identify historic 

properties potentially affected by the undertaking, assess its effects and seek ways to avoid, 

minimize or mitigate any adverse effects on historic properties.”

All projects within the AL-P Ridges Basin Area are Federal undertakings subject to the Section 

106 consultation process. In accordance with the regulations under 36 CFR 800 and guidance 

provided by the Advisory Council on Historic Preservation (ACHP), there is a standard four step 

process for completing Section 106 consultation. The four step process by which an undertaking 

at Ridges Basin will be analyzed and consulted upon is summarized below.

4.1.1 Step 1 – Initiate the Process (36 CFR § 800.3)

The first step in the Section 106 process is to establish whether the proposed action is an 

undertaking. 36 CFR § 800.16 defines an undertaking as “a project, activity, or program funded 

in whole or in part under the direct or indirect jurisdiction of a Federal agency, including those 

carried out by or on behalf of a Federal agency; those carried out with Federal financial 

assistance; and those requiring a Federal permit, license or approval.” So long as Reclamation 

retains land ownership of Ridges Basin, future activity in the basin will be considered an 

undertaking. Reclamation, as the Lead Federal Agency for Ridges Basin Section 106 

consultation, shall be responsible for initiating contact with the ACHP, the Colorado State 

Historic Preservation Officer (COSHPO), interested tribes, and other interested consulting 

parties on the proposed undertaking.

Upon evaluation of the undertaking, Reclamation may determine that it has no potential to cause

effects to historic properties (per 36 CFR § 800.3(a)(1)). In this instance Reclamation will follow 

the process outlined in the A-LP PA. If a proposed undertaking has the potential to affect historic 

properties the identified consulting parties will be consulted through a letter that describes the 

proposed undertaking and provides adequate information regarding the proposed undertaking.

4.1.2 Step 2 – Identify Historic Properties (36 CFR § 800.4)

Once Reclamation determines that a proposed undertaking may affect historic properties located 

in AL-P Ridges Basin Area, the area of potential effects (APE) shall be defined for the 

undertaking. The regulations in 36 CFR § 800.16 define the APE as the geographic area within 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

which an undertaking may directly or indirectly cause alterations in the character or use of 

historic properties.

In defining the APE, Reclamation will consider the scale and nature of the proposed undertaking, 

and will take into account various kinds of potential effects to be caused by the undertaking. To 

accomplish this, Reclamation will review the existing archaeological and historic information on

properties known to be within Ridges Basin. Reclamation will consult on the proposed APE with 

the A-LP consulting parties and other individuals or organizations who may have knowledge of 

historic properties in the area. This includes gathering information from any Native American

Tribe to assist in identifying properties that may be of religious or cultural significance to them

(see CRMP Section 4.2).

Once Reclamation has a defined APE for the proposed undertaking, historic properties within it 

shall be identified in consultation with consulting parties. Identification of historic properties will 

be accomplished through the use of record searches (Class I survey) and archaeological 

inventory surveys (Class II and Class III survey) as needed. Identified properties will be 

evaluated for significance under NRHP criteria (36 CFR Part 60) and whether the property is 

eligible to be listed on the National Register. In general, Ridges Basin has been extensively 

inventoried and investigated as part of past undertakings in the area. Reclamation and the 

COSHPO maintain records of the historic properties in Ridges Basin and their NRHP eligibility. 

If the information on file is deemed adequate including prior determinations of NRHP eligibility 

(36 CFR 800.4(c)(1)), new undertakings may not require new Class III inventory. However, the 

passage of time, changing perceptions of significance, or incomplete prior evaluations may 

require Reclamation to reevaluate properties previously determined eligible or ineligible. 

Reclamation shall acknowledge that the consulting parties possess special expertise in assessing 

the eligibility of historic properties that may possess religious and cultural significance to them. 

At a minimum, archaeologists will be required to conduct a Class I records search and re-visit

historic properties identified in the APE.

If a Class I records search and on-the-ground confirmation determines there are no historic 

properties in the APE, or there are historic properties but the undertaking will not have any effect 

on them, Reclamation will make a determination of no historic properties affected (36 CFR §

800.4(d)(1)). In this instance Reclamation will follow the process outlined in the A-LP PA.

4.1.3 Step 3 – Assess Effects (36 CFR § 800.5)

If it is determined that the proposed undertaking will affect historic properties, Reclamation will 

begin the process of assessing those effects in consultation with the consulting parties under the 

procedures set forth in 36 CFR § 800.5. Reclamation shall consider any views concerning such 

effects which have been provided by the consulting parties and the public.

An adverse effect is when an undertaking may alter any of the characteristics of a historic 

property that qualify the property for inclusion in the NRHP in a manner that would diminish the 

integrity of the property’s location, design, setting, materials, workmanship, feeling, or 

association. In applying the criteria of adverse effects direct, indirect, reasonably foreseeable 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

effects and cumulative effects must be considered. Impacts of an undertaking on all 

characteristics that qualify a historic property for listing on the NRHP need to be considered.

If it is determined that the effects of the proposed undertaking do not meet the criteria of adverse 

effect, Reclamation will make a determination of no adverse effect (36 CFR § 800.5(b)) and all 

consulting parties will be notified. The consulting parties have 30 days to review Reclamation’s 

determination and respond in writing if they concur or disagree with the finding. Reclamation 

will proceed with the undertaking after the conclusion of the 30 day consultation period if the 

consulting parties have concurred, failed to respond, or not objected to the no adverse effect

determination.

If, within the 30 day review period, any consulting party notifies Reclamation in writing that it 

disagrees with the no adverse effect determination and specifies the reason for the disagreement, 

Reclamation shall consult with the party to resolve the disagreement. If Reclamation and the 

consulting parties cannot come to an agreement, Reclamation will request the ACHP to review 

the determination and will follow the process set forth in 36 CFR § 800.5(c).

If it is determined that the effects of the proposed undertaking meet the criteria of adverse effect, 

Reclamation will make a determination of adverse effect (36 CFR § 800.5(d)(2)) and all 

consulting parties will be notified. Reclamation shall consult further to resolve the adverse effect 

pursuant to § 800.6

4.1.4 Step 4 – Resolve Adverse Effects (36 CFR § 800.6)

In the event of a determination of adverse effect, Reclamation will notify the consulting parties 

and the ACHP. Through consultation, Reclamation will work with the parties to develop and 

evaluate alternatives or modifications to the undertaking that could avoid, minimize, or mitigate 

adverse effects on historic properties. Mitigation means minimizing or lessening adverse effects 

to historic properties in the course of a project plan. Typical mitigation measures can include 

limiting the magnitude of the undertaking, modifying the undertaking through redesign on the 

project site, and further documentation of the historic property through the recovery of 

archaeological information and materials. The process also encourages the parties to develop 

creative ways and alternative mitigations for adverse effects to historic properties.

Typically, once Reclamation and the consulting parties come to an agreement on resolving the 

adverse effects of an undertaking, this agreement will be formalized in a Memorandum of 

Agreement (MOA) or Programmatic Agreement (PA) per 36 CFR § 800.14.

4.1.5 Expediting Consultation

36 CFR § 800.3(g) allows for Reclamation to address multiple steps in §§ 800.3 through 800.6 

where the agency official and the SHPO agree it is appropriate as long as the consulting parties 

and the public have an adequate opportunity to express their views as provided in § 800.2(d). 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Typically, this will only be done for a small-scale / non-complex undertaking within the AL-P 

Ridges Basin Area. However, if Reclamation combines multiple steps (i.e. defining the APE and 

identifying historic properties within the APE) in a single consultation letter, the consulting 

parties retain their opportunity to comment on all aspects of the Section 106 process during the 

consultation period.

4.2 Traditional Cultural Properties

A Traditional Cultural Property (TCP), as defined by the National Park Service (NPS), is a 

property that is eligible for inclusion in the NRHP based on its associations with the cultural 

practices, traditions, beliefs, lifeways, arts, crafts, or social institutions of a living community. 

TCPs are rooted in a traditional community’s history and are important in maintaining the 

continuing cultural identity of the community. The cultural practices or beliefs that give a TCP 

its significance are, in many cases, still observed at the time a TCP is considered for inclusion in 

the NRHP. Because of this, it is sometimes perceived that the practices or beliefs themselves, not 

the property, make up the TCP. While the beliefs or practices associated with a TCP are of 

central importance, the NRHP is not the appropriate vehicle for recognizing cultural values that 

are purely intangible. The TCP must be a physical property or place--that is, a district, site, 

building, structure, or object but the attributes that give such property significance, such as its 

association with historical events, cannot be ignored in evaluating and managing historic 

properties.

Guidelines regarding TCP identification, evaluation of eligibility, and documentation are 

provided in National Register Bulletin 38, Guidelines for Evaluating and Documenting 

Traditional Cultural Properties (http://www.nps.gov/history/nr/publications/bulletins/nrb38/). 

The Animas – La Plata Project Cultural Affiliation Study (Perry and Potter 2006) provides an

overview of the traditional communities that may have TCPs within the AL-P Ridges Basin 

Area. During the Section 106 consultation process for undertakings in Ridges Basin, 

Reclamation will utilize the Cultural Affiliation Study and National Register Bulletin 38 to elicit 

information from the consulting parties about NRHP eligible TCPs in the project area. This 

information will be considered by Reclamation when making determinations of potential affect 

for the proposed undertakings.

5.0 RIDGES BASIN PRESERVATION PLAN

5.1 Responsibilities

While a non-Reclamation entity, currently the City of Durango, will manage the future 

recreation at Lake Nighthorse, Reclamation will retain full responsibility to implement this

plan and ensure all applicable cultural resource laws and regulations, and the stipulations of

this plan, will be followed in the management of the AL-P Ridges Basin Area.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

5.2 General Preservation Measures and Strategies

Once an undertaking has been proposed, Reclamation will follow the NHPA Section 106 process 

described in Section 4.0 of the Ridges Basin CRMP. The preferred, first management measure, 

will always be the avoidance and protection of sites. Any mitigation measures employed will

always seek to have the least effect on historic properties and TCPs and Sacred Sites. A standard 

50-foot avoidance buffer will be employed on historic properties during ground disturbing 

undertakings. If sites cannot be avoided by 50 feet, sites would require the additional protections 

of temporary fencing and archaeological monitoring during construction.

Other mitigation measures as needed, may include visitor education, signage, frequent

monitoring, and law enforcement to prevent and/or reduce the occurrence of artifact theft and

site damage (whether inadvertent or deliberate). It is expected that stabilization and restoration of

damaged sites by various agents, may also be required at times.

Alternative mitigation strategies may be employed to protect historic properties activities 

such as covering sites with geotextile fabric and clean fill to prevent erosion and or vandalism, 

and engaging with area educational institutions for the purpose of developing a research plan to 

analyze the effects of recreational use of the Ridges Basin area on its cultural resources could be 

done. Site specific mitigation strategies will be proposed as part of a site specific mitigation plan

which will always be consulted upon with all consulting parties, prior to implementation.

5.3 Archaeological Sites Included in the Preservation Plan

Archaeological sites included in the preservation plan are the 119 sites that are considered 

eligible for listing on the NRHP and the 19 sites that require additional data in order to assess 

their NRHP eligibility. Appendix A lists these sites, as well as the known sites in the

Reclamation land status boundary that are currently not considered eligible for the NRHP. In

accordance with Federal law non-eligible sites shall not be included in the preservation

plan, although non-eligible sites can become eligible upon later identification of new features 

and/or resources associated with that site, therefore an established monitoring protocol will 

include the revisiting of previously determined non-eligible cultural properties. Further, all sites 

revisited will have a condition assessment conducted that documents any observable changes to 

the resource. Appendix A includes 16 sites located fully below the estimated low water line of 

6,800 feet elevation. These sites are, for the purposes of cultural resources planning,

considered permanently inundated. Inundated sites are excluded from preservation planning

measures. Reclamation also commits to include TCPs and Sacred Sites in this preservation

plan when they are identified by those parties who attach significance to those places. 

Sites considered inundated or "shoreline location" in Appendix A were each identified based on

the range of elevation covered by the site boundary. That is, a single point (such as a center

point elevation) was not used to determine if the site was above or below the expected pool

limits. Instead, a site's boundary geometry in relation to the high and low water lines was
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

considered. This is a more accurate and realistic means of determining whether a site will be

inundated than using a single point, which by itself may fall outside the elevation criteria. For

example, a site center-point elevation may be above the 6,900-foot high water line, but the 

site boundary may fall above and below that line. Similarly, a site may have a center point

below 6,800 feet, but have a boundary that extends above and below the 6,800-foot low water 

line. Sites that extend above and below the reservoir's range of high and low water are 

considered to have "shoreline locations" and can be expected to be both periodically exposed and 

affected by wave-action erosion. Particular attention will be paid to "shoreline located" sites

within the Monitoring Plan as the water level in the reservoir rises or falls, by means of 

periodic monitoring of the reservoir levels that would indicate the potential likelihood of adverse 

wave action issues to these cultural properties.

5.4 Site Type Specific Effects and Preservation Measures

Each site type identified within the AL-P Ridges Basin Area has uniquely specific adverse 

impact potential. Specific types and the anticipated agents of impact expected in the project 

area were analyzed. The results will assist in developing stabilization and restoration needs to 

mitigate these potential impacts. The range of the known chronological type sites, as well as 

culturally specific activity type sites, identified in the project area include Archaic open 

campsites and activity areas; Basketmaker habitation and activity areas; Ancestral Puebloan 

habitation and activity areas; Proto-historic aboriginal temporary habitation and activity areas; 

and Historic homesteading and ranching related areas. Each of these site types has various 

threat levels that is congruent upon the proximity to the surface, and the ground visibility of 

the site location.

The threats anticipated for Archaic era sites are the visitor theft of artifacts exposed by 

weathering and/or erosion of documented and previously unidentified moderately buried 

hunter-gatherer sites types. Since these site types are limited in visibility to the general public, 

these site types would need to be monitored at a less intensive level, depending on the 

anticipated visitor use of the area.

The specific threats anticipated for Basketmaker type sites are the recognition of exposed 

middens and cache pits from ongoing natural weathering and/or erosion. These feature types 

are the most likely to be recognized as surface manifestations, as surface architecture is 

limited for these site types (although in the latter Basketmaker periods, these types of features 

are increasing through time). Basketmaker site types that have identified surface visible 

features would be scheduled for monitoring at a higher frequency than the earlier and less 

obvious Archaic site types.

Specific threats are more anticipated for Ancestral Puebloan site types than other site types 

due to the readily identifiable architectural rubble mounds, middens, limited-use and 

agricultural activity areas’ features (e.g., hearths, slab-lined pits, expedient walls, etc.). These 

threats include both natural agent induced impacts (erosion, weathering, colluvium, etc.), and 

visitor induced impacts (limited digging, surface collection of objects, vandalism to feature 

constituents, increased natural erosion due to surface disturbance from visitor activity, etc.). 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

These later site types will need to be scheduled at a relatively higher rate of monitoring than 

the other less visible site types, when the monitoring protocol schedule is created. 

For Proto-historic site types, the likelihood of adverse impact is lessened due to the ephemeral 

nature of this era’s sites. The limited use of these site types also limits the potential adverse 

effects, as there is usually limited material culture evident on the site, regardless of the 

proximity to the present surface. The exception to this expectation is the Proto-historic use of 

previous cultural groups’ architectural sites. These site types should be included in the 

monitoring schedule, and their frequency of visitation should be copasetic with the 

documented nature of these site types.

Historic site types are the least likely to be adversely effected due to the fact that all 

significant historic architecture was removed prior to the development of the project area. 

Agricultural limited-use activity areas are likely to exist throughout the project area, due to 

the extensive documented historic use for those purposes, but are not likely to yield further 

data than their location has afforded. These site types are anticipated to be the least visited of 

the range of site types in the project area, once the monitoring protocol is developed. 

5.5 Non-Site Type Specific Effects and Preservation Measures

Among the planned or anticipated impacts to the cultural resources are: fire management, 

fencing, roads and trails (construction and maintenance, and the associated vehicle and foot 

traffic), recreation and development, artifact theft and site vandalism, erosion and wave action, 

and accidental or unintentional disturbance.

5.5.1 Fire Management

Fire management includes prescribed fires, suppression of wildland fires, and revegetation of 

areas burned in catastrophic fires. It is currently not known whether prescribed fire would occur 

in the project area, and mechanical fuels reduction would be the preferred approach for wildfire 

fuels management in the AL-P Ridges Basin Area, which employs hand-cutting and carrying of 

fuels within, and in proximity to identified historic properties. This will minimize the potential 

adverse effect from both any potential fires and those actions related to the fuel reduction 

activities. All wildfires in the AL-P Ridges Basin Area will be suppressed.

Both prescribed and wildland fires have direct and indirect effects on cultural resources. Some 

direct effects are: destruction of or damage to combustible features and elements; spalling of and

soot introduction on artifacts, structural elements, and rock art; and impacts to data

potential (e.g., the introduction of modem charcoal that skews radiocarbon dating results, and

exposure to high temperatures will adversely affect ceramic attributes). Indirect effects include: 

vegetation removal, which can lead to causing increased visitor impacts and erosion; decrease

in site stability (e.g., removal of vegetation cover and the soil’s organic constituents which aids 

in the absorption of rainfall which subsequently leads to erosion); and proliferation of invasive

species.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

The primary adverse effects of fire suppression are the construction of fire lines through sites

or features, firefighter vehicle access through the same, and hot spot suppression efforts in 

proximity to cultural properties. Indirect effects of fire suppression include discovery or

disclosure of site locations, artifact theft, and vandalism (including graffiti).

In the AL-P Ridges Basin Area, there were eight historic sites with flammable features on

them, primarily in the form of wood corral and fence posts. Reclamation removed all wooden

structures from historic-period sites prior to inundation and most of these sites are now 

underwater. Additionally, the BOR removed all structures from the Bodo Ranch, Harpur 

Ranch, and the town of Porter prior to inundation (personal communication, email, Tom

Yoder, SWCA, May 7, 2010). Therefore, there are no historic sites remaining in the project

area that still contain significant flammable features. ·

Management measures include excluding sensitive sites from prescribed fire polygons, hand 

mechanical fuels reduction in or near sensitive sites, avoidance of sites when constructing fire 

lines, re-recording of sites after fires, and post-fire monitoring of sites for evidence of theft, 

vandalism, and/or erosion. Reclamation staff will work within the Incident Command System

to protect cultural resources during fire suppression activities, as needed.

5.5.2 Fencing

Partial fencing of the AL-P Ridges Basin Area will be completed by the time the cultural 

resource management plan goes into effect. Future maintenance and replacement will occur as

needed. Much of the perimeter of the AL-P Ridges Basin Area is fenced on the north and west.

The south and east perimeters may not need fencing due to rugged terrain. This will be

monitored and evaluated periodically and additional areas may be fenced if trespass is found

to occur.

Interior areas of the basin that are not fenced but are closed to the public will be marked

with warning signs stating the areas beyond are closed to the public and include the

penalties for trespass. The extent of any new interior fencing is unclear at this stage. All new

fencing projects will be assessed for potential immediate or long-term effects to historic

properties prior to beginning of field work, and appropriate mitigation measures will be

employed to limit effects to cultural resources.

Fences and fence maintenance can have a number of effects on archaeological sites. Pedestrian 

or vehicular traffic over or near sites by fence maintenance crews results in the formation of

trails and roads along fence lines, and exposes the sites to increased erosion, artifact trampling,

artifact theft through increased surface visibility, and vandalism. The impacts to sites from the

installation, removal, and/or maintenance of fence lines can be direct, such as surface and

subsurface disturbance and the associated increased erosion and artifact trampling; or

indirect, such as increased vandalism and artifact theft resulting from increased human traffic

surface visibility for visitors. To summarize:
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

• Crossed by boundary fence = direct impacts (both surface and subsurface);

indirect impacts possible (vandalism, theft)

• Adjacent to boundary fence = indirect impacts (increased vandalism, theft); some

direct impacts (increased surface disturbance) possible

• Crossed by interior fence = direct impacts (both surface and subsurface);

indirect impacts possible (vandalism, theft)

• Adjacent to interior fence = indirect impacts (increased vandalism, theft); some

direct impacts (increased surface disturbance) possible

Currently, at least six NRHP-eligible sites in the AL-P Ridges Basin Area are crossed by or

adjacent to boundary fences. Sites crossed by fences can expect the previously noted direct

adverse impacts. Sites crossed by or adjacent to fences may also experience an increased

likelihood of vandalism and theft from increased visibility of cultural resources present.

Additionally, interior fences may cross sites. Both direct and indirect impacts to the sites can

be expected during installation and with maintenance of these fence lines.

In general, the following management measures are recommended. First, fence rights-of-way

and access routes should be located to avoid going through historic properties. Second, all fence 

construction or maintenance occurring within proximity to an historic property will be 

monitored by a cultural resource specialist to prohibit damage or theft of cultural materials.

Third, access areas should be inspected for the presence of any features or artifacts that would 

be susceptible to damage as a result of a) driving along the fences during inspections, 

maintenance, and replacement, and b) subsequent erosion, and those areas should be monitored 

as appropriate. If any damage is found, new routes should be designated and effects evaluated 

and resolved in accordance with 36 CFR § 800.5 and 6.

5.5.3 Traffic Along Roads and Road Maintenance

There are three main roads currently in the AL-P Ridges Basin Area: 

1) County Road 210, which extends from CR141 (Wildcat Canyon) east along Wildcat 

Ridge and through Bodo Canyon to the frontage road at US 160/550 in Bodo Park. It is 

the main access road to and through Ridges Basin. This road is paved. The entire road is 

fenced along both sides and posted for emergency parking only to help Reclamation 

manage public closure of the reservoir area. This road is not open for public use.

2) County Road 212, which intersects CR 210 at the mouth of Bodo Canyon and heads 

north to Smelter Mountain. This functions as an access road to the disposal area for the 

Uranium Mill Tailings Remedial Action (UMTRA) project. CR 212 is a gated dirt road. 

This road is not blocked from public use but is closed on a periodic basis due to wildlife 

closures enforced by Colorado Parks and Wildlife.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

3) The Boat Ramp road extends along the base of Carbon Mountain from CR 210 to the 

boat ramp. The dam access road is an extension of the boat ramp road and leads to the 

dam. Beyond the boat ramp the road to the dam is gated and is not a public road. The 

boat ramp road is currently locked and gated until the area is opened to the public.

In addition, the westernmost remnant of County Road 211 (which used to run through

Ridges Basin) also still exists, extending from Reclamation’s western reservoir boundary west

to CR141 (Wildcat Canyon) through the Trappers Crossing subdivision. This road is gated just

beyond the Trappers Crossing subdivision on county land and again gated at the Reclamation

boundary of Ridges Basin and so is not open to general public use. It is maintained as an

emergency access to the west side of the reservoir.

Additionally, new road segments may be constructed if needed. Access roads for operations & 

maintenance activities, roads along fences and for fire suppression may be constructed and 

maintained as needed with all the previously related concerns, and the required stipulations 

being implemented.

All motorized traffic will be restricted to existing and future roads; no off-road vehicle

(ORV) use will be allowed. Certain roads or two-track trails may be reclaimed in order to

protect sites. Some access roads, however, will need to be maintained to provide access to

recreation facilities, fences, operations & maintenance activities, for fire suppression, utility 

easement access and so on. The use of heavy equipment such as road graders, loaders,

excavators, and bulldozers may be expected during maintenance of the roads that remain in

use. The long-term manager of the property or its contractor will be responsible for

maintaining any roads needed for as-yet-to-be-determined uses and maintenance of the

property. All new road construction will be analyzed for effects to historic properties and

appropriate mitigation measures will be employed to protect the resources.

Use of existing roads and two-track trails has negligible direct effect on archaeological sites. If 

roads and two-track trails are not maintained, erosion and damage may occur; motorists

may make detours around impassable areas or emergency repairs. These actions are grounddisturbing and where roads or two-track trails cross sites, have the potential to disturb

subsurface cultural deposits. Road maintenance generally entails ground-disturbing

activities such as grading, filling, excavating bar ditches, and so forth, all of which have the

potential to disturb subsurface deposits. Additionally, the presence of roads exposes sites to

people, and therefore to artifact theft and vandalism.

The first step in mitigating the adverse effects of roads and two-track trails on sites is to

evaluate the impacts of roads on specific sites. Whenever feasible, roads should be rerouted

around sites. If roads must run through sites, Reclamation should evaluate the specific

likelihood that road use, erosion, and maintenance will affect site integrity and conduct data

recovery as necessary.

Reclamation may consider seasonal closures of specific roads and two-track trails to

prevent damage to sites from ruts. Known historic properties crossed by roads will be evaluated

and possibly covered by geotextile and clean fill and gravel for protection. Sites in close 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

proximity to roads should be monitored regularly for evidence of artifact theft, vehicle caused

damage, and vandalism.

5.5.4 Recreation and Development

The AL-P Ridges Basin Area has been proposed to serve as a recreation area. Recreation 

activities may include boating, fishing, swimming, and camping. In addition, hiking, mountain 

biking, and/or horseback riding roads and trails could be proposed in the future. Aside from 

construction activities related to these activities (such as the creation of boat ramps,

formally designated swimming areas, trails, or campgrounds), the primary impacts of recreation 

on archaeological sites are artifact theft or disturbance of cultural materials. Additionally,

trails and roads can cause erosion. 

A study by RPI Consulting anticipated an average of about 50 boats per day using the lake when 

opened (RPI Consulting 2010:5). Since boaters will have access to the entire shoreline

expanse of Lake Nighthorse, increased human visitation and the resulting impacts can be

expected at many sites not currently inundated. The island of Sacred Ridge is likely to be a

popular boating destination. Reclamation will monitor the Sacred Ridge area closely and will

recommend fencing and closure of this area if warranted and desired by consulting parties.

Management options to minimize the effects of recreation to sites will include visitor education, 

signage, frequent formal monitoring, and law enforcement, to prevent and/or reduce the

occurrence of artifact theft and site damage (whether inadvertent or deliberate). Stabilization or 

restoration, or even data recovery of damaged sites may also be proposed.

Alternative mitigation strategies may be employed to protect archaeological sites such as

covering sites with geotextile fabric and clean fill and gravel to prevent erosion and or

vandalism, engaging with area educational institutions for the purpose of developing a research 

plan to analyze the effects of recreational use of the Lake Nighthorse area on its cultural 

resources, which would assist in developing a site specific plan. Site specific mitigation 

strategies will be proposed as part of a site specific mitigation plan which will always be 

consulted upon prior to implementation.

Currently Reclamation, through the NEPA process, has approved a limited recreation plan with 

the City of Durango as the Recreation Manager. Developments that have been approved were 

designed to avoid impacts to historic properties and TCPs. If more developments are proposed

in the future, they should also be designed to avoid impacts to historic properties and TCPs,

and they will be reviewed and undergo site specific analysis under the NHPA Section 106

process including tribal consultation and State Historic Preservation Office concurrence. Site

avoidance will always be the preferred strategy but if effects cannot be avoided to historic 

properties, archaeological testing in advance or monitoring during ground-disturbing activities 

may be required, and/or alternative mitigation measures. Future foreseeable development

includes the construction of campgrounds, boat ramps, formal swimming areas (beaches),

toilets, etc., as well as their associated access roads, parking areas, and turn- around areas or

any other ground disturbing activities.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

5.5.5 Artifact Theft and Vandalism

A number of activities proposed within the AL-P Ridges Basin Area may expose sites to

artifact theft and vandalism, including but not limited to fire management, operations and

maintenance, replacement of fences, traffic along roads, road maintenance, and recreation.

Minimization of the effects of recreation will include education, signage, monitoring, and law

enforcement. If funding permits and the consulting parties agree, certain select sites could be 

developed for their interpretive and educative values. The responsibility for law enforcement

will be designated depending on which agency manages the recreation on the land.

• Interpretive signs should be placed at highly visible sites explaining the history and 

significance of the site, and to incorporate contemporary tribal community relationships 

and perspectives, and a statement about the federal laws protecting archaeological and 

historical sites.

• Signs placed at all entry points into the AL-P Ridges Basin Area will include a statement 

about the federal laws protecting archaeological and historical sites.

• A brochure will be developed to explain the cultural history of Ridges Basin and to 

explain the laws and penalties for damaging or vandalizing historic sites or stealing 

artifacts. This brochure will be handed to all entrants to the AL-P Ridges Basin Area.

• Formal monitoring protocols will be formulated for areas that are likely to experience 

visitor recreation use impacts, including sites crossed by or adjacent to roads and twotrack trails, and sites near the lakeshore.

• Sites where vandalism has occurred will be stabilized or restored.

One of the most visible and sensitive archaeological sites in the AL-P Ridges Basin Area is the

Sacred Ridge site. Visitation to the site may occur when water levels are low and it is 

exposed; visitors may be tempted to collect artifacts lying on the surface of this site. Possible 

management measures include enclosing the site with fencing to limit access to the site, 

monitoring, and signage explaining the history and significance of the site with a statement

about the federal laws protecting archaeological and historical sites. If the site is not

fenced, signs may still be posted, and the site will be monitored for damage regardless of 

whether or not any other deterred is done. Management measures for impacts to Sacred Ridge 

and other sites will be developed with the consulting parties.

5.5.6 Erosion and Wave Action 

A number of activities proposed within the AL-P Ridges Basin Area are likely to lead to

erosion, including fire management, maintenance and replacement of fences, traffic along roads

and road maintenance, and recreation. The need for treatment of the adverse effects of

erosion should be assessed during site monitoring, and sites where erosion is adversely

affecting site integrity should be restored and repaired.

The primary agent of erosion will be wave action and the rising and falling water level of the 

reservoir. Sites along the shoreline will be particularly susceptible to this activity. SWCA

endeavored to fully treat sites in the wave action zone, including the largest archaeological 

site in the area, 5LP245, the Sacred Ridge site. This site will intermittently be covered by water
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

and exposed as an island, depending on water levels of the reservoir. SWCA spent much effort

removing human remains encountered by excavations at Sacred Ridge, including excavating all

known pit structures and mechanically stripping all known middens to bedrock to ensure that

no human burials remained on site. Hundreds of features were excavated, including over 100

human burials. All excavated features, including pit structures, were backfilled and should be

well protected from wave action and erosion. However, given the large number of burials

encountered by SWCA and the large size of the site, it is possible that human remains may

be exposed by wave action and erosion in the future. This site should be monitored on a

regular basis to ensure that erosion is not adversely affecting the site and exposing any

potential features or burials that remain.

All historic properties along the shoreline should be regularly monitored for damage by

erosion as the reservoir levels fluctuate. Any exposed features or burials should either be

removed through excavation or preserved in place through reburial and stabilization in 

consultation with consulting parties.

5.5.7 Accidental or Unintentional Disturbance

Because the area will potentially be visited by large numbers of people each year (a

projected 170,000 user-days annually by the year 2025 [RPI Consulting 2010:31]) and

construction activities related to enhancing recreation are a likely possibility in the future, the

likelihood of accidental or unintentional disturbance of sites is considered high. Reclamation 

personnel, Animas La-Plata Operation Maintenance & Replacement Association (Association) 

personnel, personnel of the recreation manager, and any contractors working in the AL-P 

Ridges Basin Area will be informed of the procedures for reporting accidental or unintentional 

disturbance. If such disturbance does occur, it must be reported to Reclamation as soon as

possible. The agency will then have an archaeologist examine the disturbance area and make

recommendations for restoration and repair as appropriate in accordance with 36 CFR § 800.13.

5.6 Opportunities for Research

Section 110 of the NHPA declares that the spirit and direction of our Nation is founded on its 

historic heritage, that preservation of this shared heritage is in the public interest, with the intent 

that its vital legacy of cultural, educational, aesthetic, inspirational, economic, and energy 

benefits will be maintained and enriched for future generations of Americans. It further states 

that it should be the policy of the federal government to administer federally controlled cultural 

resources in a spirit of stewardship for the inspiration and benefit of present and future 

generations. The cultural resources located in AL-P Ridges Basin Area have the potential to 

provide a unique opportunity for public education and research. While the Ridges Basin CRMP 

does not provide any specific public education or research plans, it does provide a framework 

through which future proposals can be evaluated. 

Given the extensive amount of archaeological material already collected from sites located in 

Ridges Basin, future researchers will be encouraged to consult existing collections in lieu of 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

further on-site excavations. If researchers propose directly working on sites in Ridges Basin the 

preferred alternative will be non-intrusive / non-collection surveys and mappings of those sites. 

Research proposals that include invasive testing and excavation at sites within Ridges Basin 

could potentially be considered, but they will face much greater scrutiny under the CRMP. 

Several tribes have identified that they do not wish to see additional excavations being conducted 

on sites. In all situations, future public education and research plans will be submitted to the 

consulting parties for Section 106 consultation prior to an archaeological permit being issued by 

Reclamation.

6.0 CULTURAL RESOURCE DISCOVERIES

6.1 Inadvertent Archaeological Discoveries

The discovery of previously unrecorded archaeological sites is possible during natural

erosion, road maintenance, development, and other activities. 36 CFR § 800.13 covers 

inadvertent post-review discoveries associated with an undertaking. In the event of an 

inadvertent discovery during an undertaking, all work within 50 feet of cultural materials will 

cease and Reclamation archaeologists shall be contacted. Reclamation will then have 48 hours 

to notify the consulting parties of the discovery and all pertinent data relating to the discovery. 

Reclamation will document the newly discovered property, make a NRHP eligibility 

determination, and will submit a proposed mitigation plan, as necessary, to the consulting 

parties for consultation under 36 CFR § 800.6.

Personnel from Reclamation, Association personnel (see Section 5.5.7), personnel of the 

recreation manager, and any contractors working in the AL-P Ridges Basin Area will be

informed of the procedure for reporting discoveries to Reclamation archaeologists. Reclamation 

personnel, Association personnel, recreation manager personnel, and contractors will also be 

required to undergo cultural resource training on the resources located in Ridges Basin, the 

procedures laid out in the CRMP, and any applicable cultural resource laws when working in 

Ridges Basin.

6.2 Inadvertent Discovery of Human Remains

The discovery of human remains is possible during natural erosion (including wave-action 

erosion), road maintenance, and development. As part of the A-LP Programmatic Agreement, a 

Native American Graves Protection and Repatriation Act (NAGPRA) Plan of Action (POA) was 

developed. The NAGPRA POA sets forth the procedures for the identification of NAGPRA 

items, the information used to determine custody, the planned treatment, care and handling of 

NAGPRA items, the planned recording of NAGPRA items, the kinds of analysis permitted for 

NAGPRA items, the notification of Indian Tribes, the traditional treatment of NAGPRA items, 

the nature of reports to be prepared, the disposition of NAGPRA items, and burial laws and 
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

policies. In the event of the inadvertent discovery of human remains and associated funerary 

items in Ridges Basin, the established NAGPRA POA will be followed. 

Personnel from Reclamation, Association personnel, recreation manager personnel, and any

contractors working in the AL-P Ridges Basin Area will be informed of the procedure for

reporting inadvertent discoveries of human remains to Reclamation archaeologists prior to the 

commencement of any undertaking. Reclamation personnel, Association personnel, recreation 

manager personnel, and contractors will also be required to undergo cultural resource training 

on the resources located in Ridges Basin, the procedures established in the NAGPRA POA, and 

any applicable cultural resource laws when working in Ridges Basin.

7.0 RIDGES BASIN MONITORING PLAN

Section 110 of the NHPA and Article 14 of the ARPA task federal agencies to inventory and 

evaluate archaeological resources under their jurisdiction and monitor their condition. 

Reclamation is responsible for the preservation and long-term management of the 188

archaeological sites located with Ridges Basin, as well as any sites that are currently 

undocumented that get recorded in the future. To meet that responsibility, Reclamation is 

committed to regularly monitoring known sites and providing timely condition assessments to 

the A-LP consulting parties. Many of the sites in Ridges Basin have not been re-visited since the 

completion of SWCA’s fieldwork in 2005. Under the Ridges Basin Monitoring Plan, 

Reclamation archaeologists will have a continuous presence on the sites and will be better 

equipped to identify and mitigate potential adverse effects.

The initial monitoring plan is for Reclamation archaeologists to visit twenty percent (20%) of 

known cultural resource sites within the AL-P Ridges Basin Area each year. This does not 

include sites permanently inundated by the reservoir, but does include sites that are seasonally 

inundated due to fluctuating reservoir levels. Special attention will be given to sites along the 

reservoir shoreline or subjected to seasonal inundation as they have a higher probability of 

experiencing wave caused erosion. Currently underwater, but not permanently inundated sites, 

can’t really be put on a set time frame to monitor, and are instead noted in the monitoring 

database as sites that should be visited during times of low water levels. Due to weather 

conditions in Ridges Basin, site visits will typically start in the late spring (May) and conclude 

by the early fall (October).

Archaeologists will prepare a condition assessment for each site visited in a particular year. 

Condition assessments will involve:

• A physical description of the site setting and site components (feature and artifact 

assemblage).

• An assessment of any disturbances (man-made or natural) that may be adversely 

affecting the site.

• Photo-documentation of the site and surrounding area.

• An updated evaluation of eligibility to the NRHP.

• Management recommendations for the preservation of the site.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

After each monitor, condition assessment information will be recorded by completing a Colorado 

Office of Archaeology and Historic Preservation Site Re-Visitation Form, Management Data 

Form, or other applicable forms, depending upon adequacy of prior documentation and/or visible 

changes seen onsite. At the end of each year, Reclamation will submit a monitoring report 

containing the condition assessments and management recommendations to the A-LP consulting 

parties for their review. The consulting parties have 60 days to review Reclamation’s report and 

respond in writing if they have comments or suggested changes. While the yearly monitoring 

will be primarily undertaken by Reclamation staff, A-LP consulting parties are encouraged to 

participate through continued consultation and periodic site visits, and in the future the 

possibility exists to develop a site stewardship program for the sites.

There is a wealth of information pertaining to sites in Ridges Basin, however the most current 

data is now over 10 years old. Reclamation archaeologists will utilize the existing site data to 

begin the monitoring program, and the monitoring schedule as currently planned will allow a 

complete assessment of the known sites within a 5-year span. The monitoring plan and database 

are intended to be fluid documents that will change on a yearly basis. Right now even Not 

Eligible sites are on the plan, and as Reclamation archaeologists visit each site, at least for the 

first time, eligibilities will be reassessed. For example, if it is verified that a site that had been 

determined Not Eligible really has been totally disturbed by past actions such as road or pipeline 

building, this site will no longer be needed to be monitored on a regular schedule and will be 

removed from the plan. Additionally, after each site is first monitored a recommendation will be 

made for the frequency of monitoring, for as it was discussed above, certain site types and sites 

in certain locations will be most susceptible to impacts and will need to be monitored more 

frequently than other sites.

The first five years of monitoring will provide a new baseline of site conditions, which will then 

be built upon in subsequent years. The narrative descriptions and photo-points collected as part 

of the condition assessments will allow Reclamation staff to identify measureable changes 

overtime. In the event the monitoring documents deteriorating conditions on a site, Reclamation 

will prepare a mitigation plan and submit it to the A-LP consulting parties. Through consultation, 

Reclamation will work to implement the least invasive preservation measures to ensure the 

stability and security of the affected site.

It should be noted that the monitoring plan does not include new Class III survey of Ridges 

Basin. However, with the increased presence of trained archaeologists working in area, it is 

possible that new sites could be identified. This would most likely happen when walking to and 

between sites during the condition assessments. If an unrecorded site is newly identified, 

Reclamation archaeologists will record it using a Colorado Office of Archaeology and Historic 

Preservation Site Form and submit it to the A-LP consulting parties for NRHP review. The 

nature of the newly recorded site and the outcome of consultation may further necessitate 

additional Class III survey in the surrounding area.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

8.0 RIDGES BASIN CULTURAL RESOURCE MANAGEMENT GOALS

Archaeological work in Ridges Basin has identified just under 200 sites representing 4,000

years of human history in southwestern Colorado. The AL-P Ridges Basin Area contains 

outstanding examples of Pueblo I villages and historic ranching landscapes. Archaic, 

Basketmaker II, protohistoric Ute and Navajo occupation of the project area are also

represented. To that end, Reclamation is committed to the following management goals:

1. To promote the long term preservation of historic properties located within Ridges 

Basin.

2. To manage Reclamation facilities and infrastructure associated with the Animas – La 

Plata Project.

3. To provide opportunities for Tribal involvement and public education associated with 

Ridges Basin cultural resources.

The management goals for the AL-P Ridges Basin Area are accomplished through the CRMP 

in the following ways:

1. Establishing cultural resource management areas and research domains.

2. Providing a framework to evaluate future undertakings in Ridges Basin.

3. Developing a process to consult with Tribal partners and interested members of the 

general public early and often.

4. Developing a robust monitoring plan for known sites within Ridges Basin.

9.0 Accommodation of Sacred Sites

The American Indian Religious Freedom Act (AIRFA) was created to protect and preserve the 

traditional religious rights and cultural practices of American Indians. These rights include, but 

are not limited to, access of sacred sites, repatriation of sacred objects held in museums, freedom 

to worship through ceremonial and traditional rites, and use and possession of objects considered 

sacred. The Act required policies of all governmental agencies to eliminate interference with the 

free exercise of Native religion, based on the First Amendment, and to accommodate access to 

and use of religious sites to the extent that the use is practicable and is not inconsistent with an 

agency's essential functions.

Executive Order 13007 of 1996 ordered Federal agencies to implement procedures to enable this 

access to Federal lands to the extent practicable, as well as give reasonable notice of proposed 

actions or land management policies that may restrict such access, or ceremonial use of, or 

adversely affect the physical integrity of Sacred Sites.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Reclamation intends to follow the spirit of AIRFA and EO 13007 and allow access to Ridges 

Basin for ceremonial use of Indian Sacred Sites by Indian religious practitioners. As Reclamation 

lands are project lands and not public lands, the lands around Lake Nighthorse that are not to be

managed by the City of Durango are currently proposed to remain closed to the public. Because 

some project lands may not be open to the public, access by Indian religious practitioners will 

need to be coordinated through Reclamation to insure unhampered access to such lands.

10.0 GLOSSARY OF TERMS AND DEFINITION

Keys terms and definitions used throughout the CRMP and relevant to cultural resource 

management are defined below.

Archaeological Site – a definite location of human activity, occupation, or use, greater than 50 

years of age, identifiable through field inventory, historical documentation, or oral evidence.

 

Area of Potential Effects (APE) – The APE is the geographic area or areas where an

undertaking may cause changes in the character or use of historic properties.

Artifact – Any object made, modified, or used by humans, usually but not necessarily portable.

Cultural Resources – Cultural resources encompass archaeological, Native American, 

traditional, and built environment resources, including but not necessarily limited to, buildings, 

structures, objects, districts, and sites. 

District – A district, or historic district, possesses a significant concentration, linkage, or

continuity of sites, buildings, structures, or objects united historically or aesthetically by plan or 

physical development. A district derives its importance from being a unified entity, even though 

it is often composed of a wide variety of resources, and from its significance. It must be 

important for historical, architectural, archaeological, engineering, or cultural values.

Ground-Disturbing Activity – Any activity that will result in the disruption or removal of insitu surface soils or sediments.

Historic Properties – Those properties determined eligible for listing on the NRHP. These may 

include historic and prehistoric archaeological sites, districts, buildings, structures, and objects. 

Federal agencies treat sites unevaluated for the NRHP as eligible for management purposes.

Isolated Find – a physical location of past human activity consisting of one or very few artifacts 

in a location that is interpreted as one-time use, and not representing patterned human behavior. 

This definition uses no exact number of artifacts, as a small concentration of flakes from the 

same material regardless of the number of artifacts likely represents a single event, as does a 

ceramic pot bust regardless of the number of sherds remaining.
Programmatic Agreement Regarding the Animas-La Plata Project Appendix 7

Mitigation – Measures added to a project or activity to prevent, reduce, or correct its impact.

Monitoring – Monitoring typically refers to reconnaissance-level field investigation of an 

archaeological site by a professional archaeologist. Monitoring can be conducted to ensure that 

ground-disturbing activities do not adversely affect cultural resources, or to regularly assess site 

condition.

Sacred Site – specific, discrete, narrowly delineated location on Federal land that is identified by 

an Indian tribe, or Indian individual determined to be an appropriately authoritative 

representative of an Indian religion, as sacred by virtue of its established religious significance 

to, or ceremonial use by, an Indian religion; provided that the tribe or appropriately authoritative 

representative of an Indian religion has informed the agency of the existence of such a site.

Traditional Cultural Properties – Resources that are districts, sites, buildings, structures, or 

objects that embody traditional cultural values and are historically and traditionally associated 

with those values. TCPs are properties or locations that have associations “with cultural practices 

or beliefs of a living community and (a) are rooted in that community’s history, and (b) are 

important in maintaining the continuing cultural identity of the community.”

Undertaking - a project, activity, or program funded in whole or in part under the direct or 

indirect jurisdiction of a Federal agency, including those carried out by or on behalf of a Federal 

agency; those carried out with Federal financial assistance; and those requiring a Federal permit, 

license or approval.

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