IV. DPV2 Route Alternatives
In its application and PEA, SCE identified several alternative routes for portions of the DPV2 project. During the EIR/EIS scoping process, the Commission and BLM environmental team identified additional alternatives, including minor routing adjustments, entirely different transmission line routes, alternative energy technologies, and non-wires alternatives. Alternatives were then screened according to CEQA and NEPA guidelines to determine the alternatives to carry forward for analysis in the EIR/EIS. The environmental team rejected 26 alternatives that did not meet CEQA and NEPA criteria for analysis. The Final EIR/EIS provides a detailed analysis of seven alternatives to portions of the Devers-Harquahala segment of the proposed project, and one alternative to the upgrades proposed west of the Devers substation.
Based on comparison of the environmental impacts of the proposed project and alternatives, the Final EIR/EIS identifies the environmentally superior alternatives and the BLM Agency Preferred alternatives as follows:
· The eastern portion of the DPV2 project would begin at the new Harquahala Junction switchyard;
· The proposed project route from the Harquahala Junction switchyard to east of Alligator Rock;
· The Alligator Rock-North of Desert Center alternative to west of Alligator Rock;
· The proposed project route from west of Alligator Rock to Devers substation;
· The Midpoint substation proposed by SCE and the Midpoint substation identified as part of the Desert Southwest project are equally environmentally superior/preferable; and
· The proposed West of Devers upgrades unless determined to be infeasible, in which case the Devers-Valley No. 2 alternative would be constructed.
The Final EIR/EIS evaluated the environmental impacts of the proposed project and alternatives, classifying the impacts as Class I (significant and unavoidable or unmitigable), Class II (significant but mitigable to less than significant), Class III (adverse but less than significant), and Class IV (beneficial). The Final EIR/EIS found that the DPV2 project would have significant unmitigable impacts on visual resources, wilderness and recreation resources, cultural and paleontological resources, agriculture, noise levels, and air quality. In describing potential environmental impacts of the DPV2 project, we focus on the significant unmitigable (Class I) impacts, since we expect that the adopted mitigation measures will eliminate other potentially adverse environmental impacts of DPV2 or allow them to be reduced to less-than-significant levels.
In the following subsections, we address route segments and related alternatives, including the Desert Southwest transmission project as a potential alternative to the portion of the Devers-Harquahala line between a new Midpoint substation and the Devers substation. We then describe broader environmental impacts that arise due to multiple route segments or the DPV2 project as a whole.
A. Devers-Harquahala 500 kV Line
As proposed in SCE's application, the 230-mile Devers-Harquahala 500 kV transmission line would be constructed between the switchyard at the Harquahala generating station near the Palo Verde nuclear generating plant in Arizona and SCE's Devers substation in North Palm Springs, California. For most of the route, this new line would parallel SCE's existing 500 kV DPV1 transmission line. Approximately 102 miles of the line would be located in Arizona and the remainder in California. The Arizona portion of the Devers-Harquahala line would be located in a relatively undeveloped area of the western Sonoran Desert. A large portion of the proposed route in California is located within the Colorado Desert, which is the western extension of the Sonoran Desert. The region consists of mostly native desert habitats.
The Harquahala generating station is approximately 17 miles northwest of the Palo Verde generating station and approximately 49 miles west of Phoenix, Arizona. Departing from the Harquahala switchyard, the proposed DPV2 line would proceed easterly for approximately five miles to SCE's existing DPV1 route. The route would then turn north to parallel DPV1 through the southern end of the Big Horn Mountains, across the Harquahala Plain through the northern end of the Eagletail Mountains, through the Ranegras Plain, and across the northern portion of Kofa. The route would then traverse the La Posa Plain and the northeastern corner of the Yuma Proving Grounds, then proceed through the central portion of the Dome Rock Mountains and cross the Colorado River and the Arizona-California state line.
There is one location where the DPV2 circuit would be placed on existing DPV1 towers rather than on new towers parallel to the DPV1 line. In Copper Bottom Pass in the Dome Rock Mountains, SCE proposes to place the DPV2 circuit on 13 existing 500 kV double circuit structures built as part of DPV1. SCE explains that double circuit construction was used in the narrow Copper Bottom Pass since there is not room for two single circuit lines. The double circuit towers are already strung with two circuits, with one circuit used for DPV1 and the second currently unused circuit proposed to be used for DPV2.
In California, the DPV2 route would continue to parallel DPV1, generally along I-10, between the town of Blythe at the California-Arizona border to the Devers substation, all in Riverside County. The route would proceed westerly from Blythe into the Palo Verde Valley. SCE describes a new Midpoint substation approximately 10 miles southwest of Blythe as an optional component that may be constructed jointly with the Desert Southwest transmission project proposed by Imperial Irrigation District (IID). The route would cross the Chuckwalla Valley Dune Thicket ACEC and, near Desert Center, the Alligator Rock ACEC. It would skirt the southern edge of Joshua Tree National Park and continue to parallel DPV1 to the Devers substation.
SCE proposes to construct a new optical repeater facility three miles west of Blythe, California within the DPV2 right of way. SCE also proposes to construct two series capacitor banks adjacent to existing DPV1 series capacitor banks, one in Arizona approximately 55 miles west of the Harquahala switchyard and one in California approximately 64 miles east of Devers. SCE proposes to install Special Protection Scheme relays at the Devers substation in California and the Palo Verde, Hassayampa, and Harquahala substations in Arizona. Other modifications would also be needed within the Harquahala and Devers substations. SCE also proposes to construct telecommunications systems related to the proposed project, including a new telecommunications facility on Harquahala Mountain adjacent to an existing facility of similar design.
As proposed in SCE's application, the Devers-Harquahala line would begin at the switchyard of the Harquahala generating station, and would depart the Harquahala switchyard to the east paralleling the existing Harquahala-Hassayampa 500 kV line. Three route alternatives analyzed in the Final EIR/EIS involve different ways to terminate the DPV2 project in this area.
The Harquahala Junction alternative would entail construction of a new switching station east of the Harquahala generating station, at the point where the existing Harquahala-Hassayampa and DPV1 transmission lines diverge (a location called "Harquahala Junction"), which would become the eastern termination point of the DPV2 project. This alternative would avoid the need to construct the five-mile segment of the proposed project from the Harquahala switchyard to the new Harquahala Junction. SCE estimates that the Harquahala Junction alternative would cost $14.6 million less than termination of DPV2 at the Harquahala switchyard, due primarily to avoidance of five miles of transmission line construction.
The Harquahala-West alternative would begin at the Harquahala generating station switchyard. Rather than departing the Harquahala switchyard to the east, this alternative would depart the switchyard to the west and traverse west for approximately 12 miles to the El Paso natural gas pipeline corridor. The transmission line would proceed northwesterly along the pipeline corridor for approximately nine miles to the intersection with the DPV1 transmission line. This route would be 14 miles shorter than the proposed route.
In the Palo Verde alternative, the DPV2 line would terminate at the Palo Verde nuclear generating station switchyard instead of the Harquahala generating station switchyard. This alternative would avoid the need to construct the 5-mile segment between the Harquahala generating station switchyard and the Harquahala Junction, but would add construction of 14.7 miles of new transmission line parallel to DPV1 from Harquahala Junction to the Palo Verde switchyard.
The Final EIR/EIS concludes that the Harquahala Junction Switchyard alternative is environmentally preferred because it would require the least distance of transmission line construction outside of existing corridors and it would eliminate effects to agricultural lands.
SCE has an option agreement with the Harquahala Generating Company that would allow it to acquire the Harquahala switchyard and the existing Harquahala-Hassayampa 500 kV transmission line. SCE reports that it has been discussing an arrangement with Arizona Public Service and the Harquahala Generating Company whereby the three companies would share the Harquahala-Hassayampa 500 kV transmission line. This joint arrangement would allow Arizona Public Service to connect its planned TS-5 transmission line at the Harquahala Junction.
SCE should terminate DPV2 at a new Harquahala Junction or the Harquahala switchyard, subject to approval by the Arizona Corporation Commission and any other needed authorizations. Because this alternative is less costly than the proposed project and is also the environmentally preferred alternative, SCE should pursue good-faith efforts to reach a commercially reasonable agreement and seek the additional authorizations needed for construction of Harquahala Junction. If Harquahala Junction does not receive the needed approvals in Arizona or is otherwise not feasible, SCE may terminate DPV2 at the Harquahala switchyard.
The proposed DPV2 route would traverse Kofa for approximately 24 miles, paralleling the DPV1 line approximately 2 miles south of Kofa's northern boundary. The Final EIR/EIS finds that, within Kofa, the proposed project would result in significant unmitigable (Class I) visual impacts and significant impacts on Kofa's recreational value.
In the EIR/EIS process, a preliminary environmental review was undertaken for three alternative route segments that potentially could reduce impacts in Kofa. As a result of greater impacts to recreation and to visual and biological resources, all three alternatives that would avoid Kofa were eliminated from full consideration in the EIR/EIS process. The Final EIR/EIS found that the route through Kofa is the most environmentally preferred.
We take official notice that the USFWS has issued a preliminary Determination of Incompatibility regarding the construction of DPV2 through Kofa as proposed by SCE. If the USFWS rejects the proposed route for DPV2 paralleling DPV1 through Kofa, that route will become legally infeasible. We authorize SCE to construct a route in the Kofa area that is acceptable to the USFWS and other permitting agencies, subject to a showing that the routing modification is not detrimental to the cost effectiveness of DPV2. Consistent with § 1005.5(b), SCE may seek an increase in the maximum cost for the DPV2 project that we find reasonable in Section III.A.5 of this decision, if an alternative route in the Kofa area is expected to cause DPV2 costs to exceed the adopted maximum cost.
BLM has designated the Alligator Rock ACEC for protection of its archeological features. The Final EIR/EIS identifies three potential reroutes in the Alligator Rock area that may reduce impacts to cultural and biological resources in the Alligator Rock ACEC.
The proposed route for DPV2 would traverse the Alligator Rock ACEC for approximately 6.8 miles, paralleling the existing DPV1 transmission line. The Final EIR/EIS finds that this proposed route segment would have significant unmitigable impacts on visual and recreational resources in the Alligator Rock ACEC, in addition to more general significant impacts on air quality and cultural resources, which are discussed in Section IV.C. While the new transmission structures would be similar to those of the adjacent DPV1, the new structures would cause additional skylining14 and view blockage of the Chuckwalla Mountains in the background. The new line would also increase the structural complexity and industrial character visible from several access roads within the Alligator Rock ACEC. With the amount of industrial development intensified, DPV2 would further degrade the landscape and character of the Alligator Rock ACEC, leading to a significant diminishment of its recreational value.
The Alligator Rock-North of Desert Center alternative route segment would avoid traversing the Alligator Rock ACEC. This 11.8-mile alternative would diverge from the proposed DPV2 route approximately five miles east of Desert Center. It would head northwest, cross I-10, and proceed north of Desert Center. The segment would then turn southwest and would parallel I-10 for 3.6 miles before crossing I-10 again and rejoining the proposed route. It would be primarily on BLM land, and on private land for three miles near its western end.
While this alternative route segment would have significant impacts on air quality and cultural resources (as would the proposed project and all alternatives), it would eliminate the proposed route's significant impact to wilderness and recreation, and it would reduce potential effects on highly valuable cultural resources because it would avoid the Alligator Rock ACEC. This alternative would create a different significant visual impact resulting from introduction of a new 500 kV transmission line into a rural landscape lacking similar structures of industrial character, with view blockage of sky and portions of the Chuckwalla Mountains and Alligator Rock in some locations.
c) Alligator Rock-Blythe Energy Transmission Route Alternative
This 4.6-mile alternative route segment would diverge from the proposed project route approximately 3.5 miles east of Desert Center. While within the Alligator Rock ACEC, this alternative would follow its northern edge near I-10. This alternative would follow the Blythe Energy transmission line route proposed by Blythe Energy LLC and would be close to an existing El Paso natural gas pipeline access road.
As with the proposed project and all alternatives, this alternative would have significant impacts on air quality and cultural resources, although the impacts on cultural resources potentially would have less value than those in the heart of the ACEC. The alternative would create different significant visual impacts and would alter the natural landscape of an undeveloped portion of the ACEC to an industrial use, changing the character of the Alligator Rock ACEC and significantly diminishing its recreational value.
14 Skylining occurs when a transmission tower is seen with only the sky behind it, making it highly visible.
