Amends the Taos Pueblo Indian Water Rights Settlement Act to add definitions, create two new Pueblo trust funds (groundwater development and surface‑water sharing), require Treasury transfers into those funds and a mutual‑benefit projects account, and authorize the Bureau of Reclamation to provide supplemental, non‑reimbursable planning and construction funding for eligible mutual‑benefit water projects. It also sets eligibility rules, deadlines, investment and spending rules, and procedures for returning or reallocating unspent funds while preserving existing Settlement Agreement terms.