ENTERGY HARAHAN-AVONDALE 230kV RIVER CROSSING TRANSMISSION LINE
Scope: Water Crossing, Emergency Restoration
Location: New Orleans, Louisiana
Client: Entergy New Orleans
Entergy New Orleans provides electricity to more than 209,000 customers in Orleans Parish, Louisiana. On Sunday, August 29, 2021, Hurricane Ida made landfall as a Category 4 hurricane with sustained winds of 150 mph. The New Orleans area suffered damage causing outages for approximately 895,000 customers.
As a result of Hurricane Ida, a 475-foot lattice transmission tower in Avondale, a suburb on the west bank of the Mississippi River, was damaged and fell with conductor lines landing in the river. The tower on the Harahan side of the river remained intact with the conductor lines attached. This was a primary circuit for New Orleans and power was rerouted to restore electricity for customers until the damage could be repaired.
Entergy New Orleans contracted with Irby to manage the project from beginning to end. The removal of the destroyed transmission tower’s lines in the Mississippi River was a national priority. Efforts included coordinating with the Army Corps of Engineers, U.S. Coast Guard, Levee District, Louisiana State Police, Jefferson Parish EOC, the Governor’s Office of Homeland Security and other agencies to ensure safety and minimize risks.
To safely remove the wire from the tower, clearing the downed conductor lines was completed by Dem-Tech through a series of controlled detonations. Explosives were attached to the conductor lines on both sides of the tower and demoed in sections.
Once the lines and old towers were cleared away, Boh Bros. Construction Co., LLC, completed pile driving work and Irby sister company Legend Foundation Services installed anchor bolted piers to resist uplift forces that might otherwise cause the new tower and lines to be extracted from the ground.
With foundations in place, Irby, TNT Crane, and A&J Steel erected two 475-foot PyraMAX towers to supersede the old ones. With only 6 hours a day permitted by authorities to shut down major river traffic, Irby has begun stringing the lines using barges across the 3,700-foot span of the Mississippi. Once that is complete, energizing the lines is the last step in bringing this major transmission system back to life.