Vantage to Pomona FEIS Index 34 - Laserfiche WebLink

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Vantage to Pomona Heights Chapter 4 230 kV Transmission Line Project FEIS Environmental Consequences PAGE 4-99 observed in the area during migration and winter. Approximately five miles of this route segment runs along the margin of, but does not cross, this waterfowl and common loon area. Goose Island, situated within Priest Rapids Reservoir and almost one mile east of Route Segment 3b, has a mixed-species breeding colony of great blue herons and black-crowned night herons located there. Concentrations of non-breeding American white pelican, Caspian tern (Hydroprogne caspia), and Forster’s tern (Sterna forsteri) have been documented on an island south of Wanapum Dam and approximately 0.5 mile east of Route Segment 3b. Waterfowl and shorebird injury and mortality could occur through collision with the new transmission line. Available literature indicates that waterfowl, including ducks, geese, swans, cranes, and shorebirds appear to be most susceptible to collisions when transmission lines are located near wetlands (Erickson et al. 2005; Faanes 1987; Anderson 1978). Large, heavy-bodied birds with longer wings (i.e., herons, cranes, swans, and pelicans) tend to be less maneuverable than smaller birds and can be more susceptible to collision with overhead wires (CEC 2002; APLIC 1994). Bird movement patterns in the area are not known; however, migrating waterfowl arriving and departing from Priest Rapids Reservoir could collide with the transmission line structures, including overhead grounding/shield wires. Most of the wetlands associated with Priest Rapids Reservoir are located along the river bank and east of the route segment; however, there are several inlets that this route segment would bisect and collisions could occur if these species are flying between these inlets and open water. No agricultural fields are located to the west of this route segment that may be seasonally attractive to flocking species such as cranes and waterfowl. In addition to collision with the transmission line structures, waterfowl could experience increased predation by raptors using the transmission structures as perch sites. The Pacific Power’s Bird Management Program Guidelines includes protocol for documenting the incidence of mortalities from collision with the line, contacting the appropriate resource agency and implementing, where practicable, additional actions to reduce mortalities (i.e., installing bird flight diverters or marking static wires in sensitive areas where warranted; PacifiCorp 2006). RDFs include installing bird flight diverters in locations with known avian mortality through collision with transmission line infrastructure. With the implementation of RDFs, impacts to waterfowl, common loons, and other aquatic birds is anticipated to include 5.0 miles of moderate and 16.7 miles of low impacts. Route Segment 3b passes several cliff bands along the Columbia River. The cliffs attract high concentrations of raptors, including prairie falcons (not a special status species, but sensitive to nest disturbance), several golden eagle nests, and several peregrine falcon nests. Near the north end of the route segment a one-mile long cliff runs parallel to the route segment approximately 0.25 miles away; there is a golden eagle nest (documented in 2005), three prairie falcon nests (1988 and 2001), and three peregrine falcon nests (documented in 2002, 2006, and 2009) on the cliff. A cliff near the center of the route segment has three prairie falcon nests (documented in the 1980s) and one peregrine falcon nest (documented in 2009) within a 0.5-mile section of cliff—all of the nests in this cliff area are located within approximately 250 feet of the route segment. Near the southern end of the route segment, a third cliff area approximately four miles long has four prairie falcon nests (documented in the 1980s) and a peregrine falcon nest (documented in 2008)—the peregrine nest is approximately 400 feet from the route segment, while the prairie falcon nests range from about 0.2 to 0.5 mile away from the route segment. A bald eagle nest is located on the east shore of Priest Rapids Reservoir approximately 0.8 mile east of the route segment and another bald eagle nest is located on Goose Island, approximately 0.9 mile east of the route segment. Potential impacts to raptors would occur from biological disturbance during construction activities or from injury or mortality from vehicle strikes or interactions with other equipment used during construction. Noise from construction equipment and general construction activities could disturb and displace individuals during the sensitive nesting period. RDFs to minimize impact on raptors are described in Sections 4.3.3.1 and 4.3.3.2. RDFs include the stipulation that within the breeding season, construction would be avoided within species-specific raptor nest buffers to avoid disturbing nesting birds (1.0 mile for peregrine falcon and bald eagle, 0.5 mile for golden eagle, and 0.25 mile for prairie falcon; see RDFs in Chapter 2). Following implementation of RDFs, impact levels on nesting bald eagles are anticipated to be moderate for 1.8 miles, impact levels on peregrine falcons are anticipated to be moderate