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This Environmental Assessment (EA) has been prepared to evaluate Salt River Project (SRP) proposed plans to perform major maintenance to two 69 kilovolt (kV) subtransmission lines within an SRP power line utility corridor easement. Although this project is not a Federal undertaking or action, this EA has been prepared in accordance with the guidelines contained in the Bureau of Indian Affairs (BIA) Manual Release No. 9303, NEPA Handbook, September 24, 1993. The manual provides guidance for complying with the National Environmental Policy Act (NEPA) and its implementing regulations, [Title 40 of the Code of Federal Regulations (40 CFR) Parts 1500-1508]. The purpose of this EA is to evaluate the potential social, economic and environmental impacts that may occur from the project and to identify measures that will effectively mitigate potential adverse impacts. The goal of this document is to assist decisionmakers in making informed decisions about the project.

This report is a statement concerning the assessed impact of the proposed Orme Reservoir on the archaeological resources. The Orme Reservoir is one phase of the Bureau of Reclamation's Central Arizona Project plan to impound and distribute water from the Colorado River to central and southern Arizona. To be located at the confluence of the Salt and Verde rivers, the Orme Reservoir will flood approximately 24,000 acres of bottomland along both rivers. Previous archaeological data from the area indicated that the proposed dam and reservoir would affect archaeological and historical remains. The Western Regional Office of the National Park Service, therefore, contracted with the Arizona State Museum to do an intensive evaluative survey of the archaeological resources in the area for the Bureau of Reclamation. This study consisted of four phases. Phase I involved a survey of the Salt arm of the Orme Reservoir. Phase II was a survey of the Verde arm. The data from an ancillary survey of a small region below the proposed dam slated for use in aqueduct construction, the Orme Reservoir extension, composed Phase Ia. At the end of each phase, a preliminary report describing the archaeological resources located was prepared. Phase III resulted in the completion of this report, a detailed study and evaluation of the potentially affected archaeological resource base. The report discusses the cultural inventory in terms of an ecological framework emphasizing differential adaptation as reflected in various types of sites. Archaeological data are organized with the community as the unit of analysis, although inter-site as well as intra-site relationships are made explicit. The logistics of field work and analysis are included, as well as a brief summary of environmental considerations, and an assessment of the archaeological significance of the region. The study of significance includes a comprehensive analysis of inter-regional and intra-regional archaeological data, a summary of unavoidable adverse effects of the dam on the archaeology, a description of alternatives to the proposed reservoir, recommended action with regard to the archaeologically deleterious results of reservoir construction, and an evaluation of total resource study versus mitigation costs in terms of recovering the archaeological information.

Flooding along the Salt, Gila, Verde, and Agua Fria Rivers in February and March of 1978 resulted in extensive damage to property in Central Arizona and in the disruption of ground transportation and commerce in the greater Phoenix area. Major flooding also occurred along these rivers in December, 1978 and February, 1980. The recognition of this flooding problem, and of requirements for the regulatory storage of Central Arizona Project (CAP) water, prompted the U.S. Department of the Interior, Bureau of Reclamation (Reclamation) to initiate the Central Arizona Water Control Study (CAWCS) in July of 1978. The objectives of the CAWCS were to identify and evaluate alternative measures for flood control and regulatory water storage in Central Arizona. Both structural (i.e., dam construction or modification, levee construction), and nonstructural (i.e., flood proofing, flood plain regulation, water exchange) alternatives were to be considered within a large study area. A Safety of Dams (SOD) issue was subsequently recognized and incorporated in the CAWCS study process. As the study progressed through a consideration of eight alternative plans, a preferred alternative (the agency-proposed action) to address these objectives was selected by Reclamation. Several critical factors were considered in comparing alternative plans, and in defining the preferred plan alternative, including: - flood control performance of a plan - regulatory water storage performance - dam safety - economics (cost/benefits) - environmental impacts - social impacts - institutional constraints Each of these factors was thoroughly evaluated in relation to the plan alternatives during the three stage study process. Stage I established the parameters of the flood control and regulatory water storage problems to be addressed, defined a number of actions (termed elements) which might contribute to the resolution of these problems, and recommended specific actions that warranted further study on the basis of their performance characteristics. Of the 34 elements reviewed during Stage I, 20 were recommended for further consideration at a Stage II level of analysis. During the Stage II analysis, competing elements (those which served similar functions but which were at different locations) were compared in order to define and retain those which best served a particular function. These 10 remaining elements were then combined into 13 intermediate plans, termed systems, each of which could provide for flood control and regulatory water storage. At the beginning of Stage III, 10 elements remained in the study. These were combined into seven candidate plans, each of which satisfied flood control, safety of dams, and regulatory water storage objectives. An eighth plan (No Action) was also defined as a basis for evaluating the effects of a proposed undertaking. As the critical factors were considered in relation to each plan, two of the eight plans (numbers 4 and 5) were eliminated due to cost and associated adverse social and environmental effects. The remaining six plans were analyzed in detail; one plan (dubbed Plan 6) was subsequently identified as the agency-proposed action. In undertaking this study, Reclamation contracted with the firm of Dames and Moore to assist in defining and evaluating the alternative plans, and to prepare a draft environmental impact statement for the agency-proposed action. Archaeological Research Services, Inc., and the Arizona State University, Department of Anthropology (Office of Cultural Resource Management) were under subcontract to Dames and Moore for the historic and prehistoric cultural resource aspects of the CAWCS respectively. The historic cultural resource study was initiated in April, 1979, and concluded in December, 1981, and involved preparing reports and supporting documentation relative to each of the study stages above. For the purposes of this study, historic cultural resources are defined as those sites or properties which were occupied after the time at which written records became available for an area. As applied to the Southwestern United States, historic sites may include those in existence at or subsequent to the period of initial Spanish contact (during the 16th century).