The plan of flood control on the American River is hereby authorized and adopted substantially in accordance with the recommendations of the Chief of Engineers, House Document Numbered 367, Eighty-first Congress, and adopted and authorized by the act of Congress approved August 17, 1954, at an estimated state cost of five hundred thousand dollars ($500,000). Said project shall be considered as extending and supplementing the projects authorized pursuant to Section 12648. Section 12828 shall not be applicable to the project.