; or (B) the operation and maintenance of— (i) the Flathead Indian irrigation project; or (ii) the Mission Valley Power Project. (e) Land acquired by United States or Tribes Any land acquired within the boundaries of the Reservation by the United States on behalf of the Tribes, or by the Tribes on behalf of the Tribes, in connection with the purposes of this Act shall be held in trust by the United States for the benefit of the Tribes. (f) Cooperative operation and maintenance of Flathead Indian irrigation project (1) Agreement with Secretary On receipt of a joint request from the Tribes and one or more irrigation districts within the Flathead Indian irrigation project, the Secretary shall enter into an agreement with the Tribes and the irrigation districts for the cooperative operation and maintenance of the Flathead Indian irrigation project, or any portion of the Flathead Indian irrigation project. (2) Establishment of organization (A) In general In lieu of entering into an agreement under paragraph (1), the Tribes and one or more irrigation districts within the Flathead Indian irrigation project may jointly establish an organization for the purpose of entering into an agreement for the operation and maintenance of the Flathead Indian irrigation project under the Indian Self-Determination and Education Assistance Act ( 25 U.S.C. 5301 et seq.). (B) Treatment An organization established pursuant to subparagraph (A) shall be considered to be a tribal organization (as defined in section 4 of the Indian Self-Determination and Education Assistance Act ( 25 U.S.C. 5304 )) for purposes of that Act. (g) Effect Nothing in this section— (1) alters any applicable law under which the Bureau of Indian Affairs collects assessments or carries out the operation and maintenance of the Flathead Indian irrigation project