; and (ii) the Supplemental Partial Final Decree. (7) Management The Secretary shall manage the Navajo Nation Water Resources Development Trust Fund in accordance with subsection (d). (8) Conditions for expenditure and withdrawal After the funds become available pursuant to paragraph (6), all expenditures and withdrawals by the Nation of funds in the Navajo Nation Water Resources Development Trust Fund must comply with the requirements of subsection (f). (b) Navajo nation operations, maintenance, and replacement trust fund (1) Establishment The Secretary shall establish a trust fund to be known as the Navajo Nation Operations, Maintenance, and Replacement Trust Fund for the purposes set forth in paragraph (2), to be managed, invested, and distributed by the Secretary, and to remain available until expended, withdrawn, or reverted to the general fund of the Treasury, consisting of the amounts deposited in the trust fund under paragraph (3), together with any interests earned on those amounts under paragraph (4). (2) Use of funds The Nation may use amounts in the Navajo Nation Operations, Maintenance, and Replacement Trust Fund to pay operations, maintenance, and replacement costs of the Project allocable to the Nation under section 10604. (3) Authorization of appropriations There are authorized to be appropriated for deposit in the Navajo Nation Operations, Maintenance, and Replacement Trust Fund $250,000,000. (4) Investment Upon deposit of funding into the Navajo Nation Operations, Maintenance, and Replacement Trust Fund pursuant to paragraph (3), the Secretary shall invest amounts deposited in accordance with subsection (e). (5) Investment earnings Any investment earnings, including interest, credited to amounts held in the Navajo Nation Operations, Maintenance, and Replacement Trust Fund are authorized to be used in accordance with paragraph (2). (6) Availability Any amount authorized to be appropriated to the Navajo Nation Operations, Maintenance, and Replacement Trust Fund under paragraph (3) shall not be