California High-Speed Rail Authority proposes drilling under Angeles National Forest

The U.S. Forest Service is seeking public comment on the California High Speed Rail Authority's request for a geophysical and geotechnical investigation (GI) of its proposal to dig a rail tunnel through the Angeles National Forest in the San Gabriel Mountains.

The proposal calls for a special use permit to drill down 900 to 2,500 feet and extract rock cores at five to eight locations along existing roads and disturbed areas, according to a Forest Service notice posted on the agency's website.

As the authority has proposed, the GI would provide data to help evaluate potential challenges for tunnel design and construction by investigating groundwater, adverse geology and earthquake faults. The authority proposed various mitigation measures to minimize adverse effects of their investigation on groundwater aquifers and their surface expressions.

If the authority is granted permission to move ahead, it would have to obtain county permits to drill and backfill the proposed borings.

Public comments may be sent until Oct. 23 to George Farra, gfarra@fs.fed.us.