The U.S. Department of Energy Office of Legacy Management (LM) has issued a five-year cooperative agreement with the Northern Arapaho Tribe,  supporting LM’s mission to provide management and oversight of the Riverton, Wyoming, Processing Site, which includes conducting water sampling, monitoring site activities, maintaining institutional controls, and assisting with outreach efforts. Cooperative agreements with Native American tribes are required under the Uranium Mill Tailings Radiation Control Act (UMTRCA), where remedial actions are underway. LM is also conducting an assessment of the waterline that transports safe drinking water to local residents. The line was installed by Indian Health Service, is managed by the Northern Arapaho Tribe, and requires maintenance.