For the purpose of stabilizing water supply and thereby rehabilitating farmers on the land and providing opportunities for permanent settlement of farm families, the Secretary of the Interior (hereinafter referred to as ''the Secretary'') is authorized to investigate and, upon compliance with the provisions of this subchapter, to construct water conservation and utilization projects in the Great Plains and arid and semiarid areas of the United States, and to operate and maintain each such project in accordance with the provisions of this subchapter; Provided, That the United States shall retain title to the dams, reservoirs, irrigation, and other project works until Congress otherwise provides: And provided further, That expenditures from appropriations made directly pursuant to the authority contained in section 590z-10(1) of this title to meet reimbursable construction costs allocated to irrigation as defined in section 590z-2(b) of this title shall not exceed $2,000,000 for dams and reservoirs in any one project, and that expenditures from appropriations made directly pursuant to the authority contained in section 590z-10(1) of this title to meet costs allocated to flood control by the Secretary after consultation with the Chief of Engineers, Department of the Army, shall not exceed $500,000 on any one project