Grand Canyon National Park manages 280 miles of the Colorado River, providing emergency and medical services, as well as guiding researchers, politicians and students on a dozen river trips per year. Co-workers spend lengthy stretches together within the canyon's towering walls, camping on the river banks and cut off from the rest of the world. A satellite phone typically is available for emergencies only.

The report does not identify any of the park employees, boatmen or contract workers by name. It focuses solely on trips run by Grand Canyon National Park. Commercial and private, or self-guided, river trips are conducted through different systems.

Incidents of sexual harassment on the national park trips included a boatman photographing an employee under her skirt, a supervisor grabbing a contract employee's crotch and park employees twerking during a dance party as a river trip was wrapping up, according to the report.

The Park Service's Intermountain Region director Sue Masica, Grand Canyon Superintendent Dave Uberuaga and his deputy, Diane Chalfant, told investigators they were well aware of the history of alleged sexual harassment on the river and said the agency tried to change the culture. Masica said alcohol consumption seemed to play a part.