Dave Johnston Transmission Line Rebuild
WLC Engineering and Surveying was hired in February 2009 by Rocky Mountain Power (RMP) to provide surveying services for a 230 kV power line rebuild and reroute. The original line, built in 1957, was located between the Dave Johnston Power Plant and the City of Casper. WLC assisted with the route selection, researched land ownership, and provided right-of-way plats and legal descriptions. The first nine miles of the original power line headed east from Casper and was close proximity to another power line. To minimize the chances of having a catastrophic event which could affect both lines, RMP wanted to reroute the first nine miles of the line to the north, away from the original corridor. The new line then heads southeast to intersect the existing right-of-way for a total reroute of more than 12 miles. WLC identified an appropriate route for the line based on urban and rural requirements. Most of the line is in a rural environment and has “H” frame construction with long span lengths requiring a 125 feet wide right-of-way easement. In the urban areas, it is of “single pole” construction with short spans lengths requiring 80 feet wide right-of-way easements. Additionally, the line is at least 40 feet in distance from any building or habitation including above and below ground utilities. WLC was tasked with identifying a route for the line that threads through populated areas in order to minimize angle points. By minimizing the angle points, WLC was able to decrease the project cost for RMP.