In addition to the primary purposes for which the Grand Coulee Dam project (hereafter to be known as the Columbia Basin project and herein called the “project”) was authorized under the provisions of the Act of August 30, 1935 (49 Stat. 1028), the project is authorized and reauthorized as a project subject to the Reclamation Project Act of 1939; and the provisions of each of those two Acts together with the provisions of this Act shall govern the repayment of expenditures and the construction, operation, and maintenance of the works constructed as a part of the project.