Work is expected to begin soon on a replacing a petroleum pipeline crossing underneath the Snake River.  

The Marathon Petroleum Company pipeline crosses beneath the Snake River from Walla Walla County to Pasco. A $2.2 million permit was recently issued by the city of Pasco to replace the 6-inch diameter pipeline using horizontal directional drilling.  

The bore will exit at the existing fuel distribution terminal facility used by Marathon, and about 234 cubic yards of soil will be excavated at the exit pit. After the pipeline is tied in, the excavations will be backfilled with excavated material and/or imported clean material from a local quarry.  

From the Port of Walla Walla jetty where the pipeline enters to the Marathon Terminal on the other side of the river, the pipeline will span about 2,355 feet, according to State Environmental Policy Act documents filed in October 2024. The pipeline will be a minimum of 54 feet below the mudline of the Snake River.  

Tesoro Logistics Operations LLC is the owner, with Michels Trenchless Inc. as the contractor for the project.