This bill reauthorizes and updates the Cooperative Watershed Management Program, a federal grant program administered by the Department of the Interior that supports local groups working to restore and manage watersheds. It expands eligibility so that Indian tribes with ancestral lands in a watershed can qualify as watershed partners, and it allows grant applicants to demonstrate need based on drought, wildfire, or other natural disasters. The bill increases the maximum first-phase grant amount from $100,000 to $150,000, and allows the Secretary to extend successful grants for up to two additional years at similar funding levels. It broadens the technical assistance eligible for funding to include grant writing, project management, environmental studies, engineering, and post-construction monitoring, and directs the agency to accept and review applications on a rolling basis throughout the year, funds permitting. The measure authorizes $20 million per year in appropriations for fiscal years 2027 through 2031 to carry out the program, primarily benefiting local watershed groups, states, tribes, and other stakeholders involved in water resource management.