WAPA to use agency preferred alternative route for new 115-kV line in Colorado

The Western Area Power Administration (WAPA) on April 11 said that it has decided to use the agency preferred alternative route to build a new double-circuit, 115-kV transmission line and remove two existing old transmission lines between the Estes substation and Flatiron substation, west of Loveland, Colo.

The decision was announced in a record of decision that was published March 21 in the Federal Register, WAPA said.

WAPA noted that it currently owns, operates, and maintains two 60- to 75-year-old transmission lines that begin and end in the same locations. Age, poor condition, and changing needs in line access and vegetation management prompted WAPA to evaluate changes to the transmission lines to ensure continued safe and reliable energy delivery across the Front Range, WAPA said.

As described in the final environmental impact statement (EIS) that was published in March 2018, the preferred route consolidates both lines into one, eliminating about 16 miles of transmission line and allowing the abandoned right of way (ROW) to revegetate naturally. WAPA added that portions of both existing ROWs and limited new ROWs will be used for the new transmission line to limit or reduce the impact on visual, recreation, and other environmental resources; secure adequate ROWs for the line; as well as maintain or decrease the number of structures along the line and ensure appropriate access to structures for reliability and safety.

The record of decision also includes changes to WAPA’s vegetation management practices to increase reliability, reduce wildfire risk, and meet updated regulatory mandates and utility standards, WAPA said.

The Canyon Lakes District of the Arapaho and Roosevelt National Forest, a cooperating agency on the EIS, will issue its record of decision in the near future, WAPA said.

Construction would begin no earlier than January 2020, WAPA noted.

Record of decision

As noted in the record of decision, WAPA is proposing to rebuild and upgrade two 115-kV, single-circuit transmission lines between the Flatiron substation west of Flatiron Reservoir and the intersection of Mall Road and U.S. Highway 36 on the east side of Lake Estes in Estes Park, all within Larimer County, Colo. The project is situated east of the community of Estes Park and west of the Town of Loveland. The filing added that major transportation corridors are U.S. Highway 36 and 34, which provide access between Front Range communities to the east and Rocky Mountain National Park to the west of the project area.

The project area includes private lands administered by the U.S. Department of the Interior (DOI), Bureau of Reclamation; U.S. Department of Agriculture, Forest Service (Forest Service); the Colorado State Land Board; Northern Colorado Water Conservancy District; and Larimer County.

The filing added that WAPA owns, operates, and maintains two single-circuit, 115-kV transmission lines between the Flatiron and Estes Park substations. Prior to the formation of DOE, the DOI’s Bureau of Reclamation built and maintained the two existing transmission lines as part of the Colorado-Big Thompson Project. The filing added that the lines were built to transmit electricity from hydropower generation sources of the Colorado-Big Thompson Project; after the formation of DOE and WAPA in 1977, ownership, operation, and maintenance of the transmission lines was transferred from the Bureau of Reclamation to WAPA.

The Estes-Lyons Tap is the more northern of the two lines and is also referred to as the North Line, the filing said, adding that the South Line consists of the Estes-Pole Hill and Flatiron-Pole Hill line segments that connect the Pole Hill substation to the Estes Park and Flatiron substations, respectively. Both existing 115-kV, single-circuit lines are built on wood pole H-frame structures.

The filing added the North Line is 14.1 miles long and was built in 1938, while the South Line is 14.5 miles long and was built in 1953. WAPA’s project encompasses only the single-circuit, wood-pole transmission lines to the intersection of Mall Road and U.S. Highway 36, where both lines intersect at a lattice steel structure. The filing added that the project does not include the double-circuit, steel lattice structures that start at that point, parallel the U.S. Highway 36 causeway across Lake Estes, and terminate at the Estes Park substation.

WAPA proposes to remove both wood pole lines and replace them with a new line or lines, for certain reasons, including that the existing wood structures are in poor condition and continue to deteriorate due to age and the type of material with which they were built.

The filing added that portions of the existing lines are marginally accessible for routine maintenance and structure replacement. Inaccessible areas include sections of the existing transmission lines that span canyons, are located on steep cliffs or rocky slopes, or cross the Pole Hill penstock – the water pipelines between Pinewood and Flatiron reservoirs.

The filing also said that the North Line has an ROW width of 20 to 30 feet at most locations, which is inadequate to meet reliability and safety standards, while the South Line has ROW widths that range from 75 feet to 130 feet for most of its length. WAPA would need to increase the South Line ROW easement width to 110 feet in locations where it is less, the filing said, adding that the project area is susceptible to mountain pine beetle infestation and currently has many infested trees that create heavy fuel loads for wildfires. Where ROWs have insufficient width and heavy fuel loading, there is a greater risk of a large wildfire event, the filing added, noting that that level of risk does not meet applicable standards or WAPA’s commitment to its customers to provide reliable and safe power.

In many cases, ROW maintenance has been limited to removal of hazard trees, which typically does not address the encroaching vegetation until it becomes a threat that requires immediate attention to ensure no adverse effect to the transmission line or to prevent a fire caused by a transmission line, the filing noted.

Noting that four full-length alternatives and three variants form seven action alternatives to rebuild and upgrade the existing 115-kV transmission lines, the filing said that the agency preferred alternative would be a new galvanized steel, single-pole, double-circuit line between the Flatiron substation and U.S. Highway 36 at the intersection of Mall Road using the Alternative C alignment in the west and primarily the Alternative C alignment in the center, as well as the Alternative B alignment in the east.

Alternative C would rebuild and consolidate the transmission lines along an alignment utilizing a combination of the existing North and South line ROWs, the filing said, noting that that alternative includes reroutes off the existing transmission line ROW east of Pinewood Reservoir, along Pole Hill Road on National Forest System lands, and on privately held land on the west end of the project area.

Alternative B would rebuild and consolidate the transmission lines, primarily on the existing South Line ROW, the filing said, adding that that alternative includes a 0.25-mile reroute along Pole Hill Road on National Forest System lands, and a 0.75-mile reroute to the North Line on new ROW in the vicinity of the Pole Hill substation.

In the west region, the agency preferred alternative would follow the Alternative C alignment along Pole Hill Road through the Meadowdale Hills subdivision to U.S. Highway 36. The filing added that in adapting part of Alternative C for the agency preferred alternative, the four-wheel drive segment of West Pole Hill Road would not be rebuilt or improved on National Forest System land, retaining the challenge for four-wheel drive use in response to draft EIS public comments. New access would be needed in the west region for construction and maintenance.

The filing also said that instead of crossing over U.S. Highway 36, the agency preferred alternative would follow the Alternative C alignment for 1.7 miles, generally parallel to, and north of, U.S. Highway 36 down the valley for the remaining distance to the intersection of Mall Road and U.S. Highway 36.

New ROW would be required for the last segment on the west end of Alternative C to reduce visibility from U.S. Highway 36, the filing said, adding that special design measures will be considered for that segment within the Meadowdale Hills subdivision, including the use of structures with a lower height and shorter span, if they provide a lower visual impact.

In the central region on private lands, the agency preferred alternative primarily would follow the North Line, but may shift to the South Line and back again to stay closer to Pole Hill Road, thus minimizing the need for access roads and ROW maintenance disturbance, the filing said. Additional ROW would need to be obtained along the North Line to meet the 110-foot requirement.

The filing also said that in the east region, from the Flatiron substation, the agency preferred alternative would follow the Alternative B alignment along the existing South Line to the Pole Hill substation. Just east of the Pole Hill substation, the agency preferred alternative would continue to follow the alignment of Alternative B, which would turn north and partially parallel Lone Elk Road for 0.75 mile until intersecting the alignment of the existing North Line. The filing added that a new ROW along existing roads would be required for that short segment, as well as new access spur roads to new structures.

At locations where the agency preferred alternative alignment would follow the existing transmission line routes, the existing structures would be replaced with new double-circuit, galvanized steel, monopole structures, the filing said, adding that individual structure locations could vary depending on final design. WAPA would not increase the number of structures along National Forest System roads, and depending on final design, there may be fewer structures in those locations. The filing also said that on abandoned ROW, existing structures and conductors would be removed, vegetation management would cease, and the ROW allowed to return to natural vegetation patterns.

Among other things, the filing said that the agency preferred alternative is also overall the environmentally preferred alternative for the project. The few sections of the agency preferred alternative where new ROW would be required would result in new environmental resource disturbance in certain sections. However, the filing added, those new sections were developed to reduce specific recognized important impacts, both existing and associated with the project.

About Corina Rivera-Linares 3286 Articles
Corina Rivera-Linares was TransmissionHub’s chief editor until August 2021, as well as part of the team that established TransmissionHub in 2011. Before joining TransmissionHub, Corina covered renewable energy and environmental issues, as well as transmission, generation, regulation, legislation and ISO/RTO matters at SNL Financial from 2005 to 2011. She has also covered such topics as health, politics, and education for weekly newspapers and national magazines.