; and (2) at the end of the period described in subsection (a), a final, cumulative report that summarizes the data obtained during that period. 6. National Academy of Sciences study (a) Definition of basin (1) In general In this section, the term basin means the Rio Grande and the tributaries of the Rio Grande between— (A) the headwaters of the Rio Grande and the Rio Chama in the State of Colorado; and (B) Elephant Butte Reservoir in the State. (2) Exclusions In this section, the term basin does not include Elephant Butte Reservoir, Caballo Dam, or any portion of the Rio Grande or the tributaries of the Rio Grande downstream of Elephant Butte Reservoir. (b) Study Not later than 60 days after the date of enactment of this Act, the Secretary of the Army and the Secretary shall enter into an arrangement with the National Academy of Sciences to carry out a study on water and reservoir management and operation issues in the basin (including the Heron, El Vado, Abiquiu, Cochiti, and Jemez Canyon Dams and Reservoirs), which shall include— (1) an evaluation of existing basin reservoir authorizations and legal requirements; (2) a summary of— (A) the physical-hydrologic understanding of existing basin reservoir operations; and (B) any potential constraints on basin reservoirs in light of climate change projections; (3) an identification of opportunities to optimize water storage and management to benefit the basin ecosystem, irrigators and municipal users, and to promote water conservation through reauthorization of, reoperation of, regulation of, or physical improvements to the reservoirs; (4) an evaluation of the physical-hydrologic feasibility of the identified future basin reservoir management scenarios; (5) an identification of water use, supply, and accounting impacts to other stakeholders in the State; (6) consideration of operations such as— (A) the storage of supplemental water acquired by and under the control of the Bureau of Reclamation; (B) the carryover storage of San Juan-Chama Project contract water