Conducted field monitoring for desert tortoises during installation of a 4-mile potable water transmission line in desert tortoise habitat on the Marine Corp base in San Bernardino County. Aspen's certified desert tortoise monitors were in the field for over eight monitor-weeks. The work required daily coordination with MCAGCC personnel and contractors responsible for constructing the pipeline. Individual field monitoring reports and pertinent maps were prepared during installation and a final monitoring report was submitted.