REQUESTER: In compliance with 33 USC 408 (Section 14 of the Rivers and Harbors Act of 1899; hereinafter Section 408), the Ameren Illinois Corporation (Ameren) has requested permission to modify the East Peoria Drainage and Levee District (D&LD) levee, an existing federally-authorized flood risk management project.
LOCATION: The proposed action extends for approximately 2,700 feet under the Illinois River between Peoria and East Peoria, Illinois.
LOCATION MAP(S)/DRAWING(S): See Enclosures.
REQUESTER’S PROPOSED ACTION: The proposed action would include installing a new 20-inch natural gas transmission pipeline under the Illinois River between Peoria and East Peoria, Illinois. Ameren proposes installing a new 20-inch natural gas main that would parallel an existing 1974 vintage 18-inch natural gas main. The project would install new gas facilities on each gas main that would allow for modern in-line inspection tools to be utilized for routine non-destructive inspections. The project also includes installing new isolation valving on each of the gas mains to allow for the deenergizing of the gas mains in the event of a leak or maintenance. The new 20-inch gas main project would provide a redundant and reliable source of natural gas, including modern technologies to monitor and inspect each of the natural gas mains, to the City of Peoria.
Ameren would utilize Horizontal Directional Drilling (HDD) to bore under the Illinois River from Peoria to East Peoria, IL. This includes drilling through and under the Federal levee maintained by the East Peoria D&LD. The HDD method allows for construction across features, e.g., the Illinois River and the levee, without excavating a trench by drilling a hole significantly below conventional pipeline depth and pulling the pipe through the predrilled hold. The HDD bore is planned to be 70 to 75 feet below the Illinois riverbed, and the HDD bore is planned to be 100 feet below the tow of the levee. By using a HDD, Ameren would minimize impacts to resources within the Illinois River and reduce the time needed to complete the crossing. The HDD equipment would be staged outside of Waters of the US and in areas that have had ample disturbance in the recent past.
During HDD, the drill bit would be guided along the pipeline route electronically. The drilling rig would drill a small diameter pilot hole along the route. Following the completion of the pilot hole, reaming tools would be used to enlarge the hole to accommodate the pipe diameter. During this process, drilling fluid consisting primarily of bentonite clay and water would be continuously pumped into the bore hole to remove cuttings and maintain the integrity of the hole. Once the hole is drilled, segments of pipe welded together would be attached to the reaming tool and pulled back through the hole to complete installation of the pipe.
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