Amends subsection 9(g) to add waiver authority for non-Federal cost share, authorize contracts/cooperative agreements/grants to reimburse States, Indian Tribes, Tribal organizations, Native Hawaiian organizations, local governments, or other entities for assessing and determining effects of events of national significance, expand factors to be considered when making determinations, add several definitions (Indian Tribe, Native Hawaiian organization, Subsistence use, Tribal organization), and authorize appropriations of $2,000,000 per fiscal year for FY2026–FY2030, funds to remain available until expended.