Based on NMFS’s receipt of an application from the U.S. Army Corps of Engineers (USACE), Portland District, for incidental take regulations and a Letter of Authorization (LOA) under the Marine Mammal Protection Act, this action proposes regulations to govern the unintentional taking of marine mammals incidental to in-water construction activities as part of the Lower Columbia River Dredged Material Management Plan (DMMP). Construction activities include impact and vibratory pile driving. The proposed regulations would set forth the permissible methods of taking; means of effecting the least practicable adverse impact on the affected species or stocks and their habitats; and requirements pertaining to the monitoring and reporting of such taking. Letters of Authorization issued under the regulations would authorize the take of marine mammals incidental to the specified activities for a 5-year period.