The authorization, called a 401 water quality certification, is a prerequisite for federal officials to sign off on the project.
Also on Friday, the U.S. Army Corps of Engineers released a public notice of U.P.'s plans for a permanent fix: a new breach spanned by a 180-foot bridge. The project will be designed to replicate the mixing function formerly achieved by culverts.
Because the aging culvert could collapse and derail a train, the division intends to issue the permit at 6 p.m. Monday even though it will continue accepting comments until Jan. 15.
"We retain the ability to re-open the certification and amend it based on the comments we receive," division director Walt Baker wrote in an email.
The 54-year-old rock-fill causeway, used by 16 trains a day, cuts 73 miles off the trip between Ogden and California, according to U.P.'s 401 application.
An alternate route to the south of the lake also has "1,700 feet more rise and fall, and has approximately 1,700 more degrees of curvature. All three factors increase fuel consumption," the application states. Rerouting traffic would result in $258,000 in direct costs a day, plus additional costs associated with rail congestion, it said.
It would also pump more diesel exhaust into the Salt Lake Valley's already polluted skies and inconvenience the motoring public, the application said.