; or (ii) the authority to construct and maintain structural measures; or (C) any Indian Tribe or Tribal organization (as those terms are defined in section 4 of the Indian Self-Determination and Education Assistance Act ( 25 U.S.C. 5304 )) having authority under Federal, State, or Indian Tribal law to carry out, maintain, and operate a work of improvement. (3) Multibenefit work of improvement The term multibenefit work of improvement means a work of improvement, including irrigation efficiency, flood-damage reduction, water management, or watershed protection, that provides 2 or more of the following public benefits: (A) Improvement in the condition of a natural feature that increases fish or wildlife habitat, reduces drought impact, or reduces flood-risk. (B) Improvement in water quality. (C) Water conservation. (D) Improvement to instream flow. (E) Enhanced fish passage or reduction in fish entrainment. (F) Permanent protection of a natural feature. (G) Off-channel renewable energy production. (4) Natural feature The term natural feature means a feature that is created through the action of physical, geological, biological, and natural chemical processes over time. (5) Secretary The term Secretary means the Secretary of Agriculture. (6) Water conservation The term water conservation means a reduction in total annual consumptive water use compared to total annual consumptive water use before a work of improvement is carried out under this Act. (7) Water management The term water management means any project or activity carried out to increase the efficiency of water use, transfer, diversion, or conveyance. (8) Work of improvement (A) In general The term work of improvement means any undertaking carried out in a watershed or subwatershed area not exceeding 250,000 acres (including on Federal land necessary to accomplish the purposes of the undertaking) for— (i) flood prevention (including structural and land treatment measures); (ii) the conservation, development, utilization, and disposal of water