61 STAT.] SOTH CONG., 1ST SESS.-CH. 337-JULY 25, 1947 at the end of the fiscal year to revert to the fund: Provided. That no part of this appropriation shall be available for the preparation of any comprehensive plan or project report the estimates for which are not based upon current prices and costs. COLORADO RIVER FRONT WORK AND LEVEE SYSTEM For operating and maintaining the Colorado River front work and levee system in Arizona, Nevada, and California; constructing, im- proving, extending, operating, and maintaining protection and drain- age works and systems along the Colorado River; controlling said river and improving, modifying, straightening, and rectifying the channel thereof; and conducting investigations and studies in connec- tion therewith; as authorized by Public Law 469, approved June 28, 1946; $1,000,000, to remain available until expended. For the purpose of effecting settlement of war veterans on public land reclamation projects and to provide facilities for veteran employment in construction and operation of reclamation projects, the property, buildings, equipment, material, and acquired lands heretofore or hereafter declared surplus at the Yuma Army air base, Yuma, Arizona, shall be transferred to the Bureau of Reclamation by any Federal agency having custody or ownership, without exchange of funds, and to be available for the same purpose and to be disposed of in the same manner as the war relocation centers and the prisoner- of-war camp transferred to the Bureau of Reclamation in the Interior Department Appropriation Act, 1947. No part of any construction appropriation for the Bureau of Reclamation contained in this Act shall be available for construction work by force account, or on a hired-labor basis except for manage- ment and operation, maintenance and repairs, engineering and supervision, routine minor construction work, or in case of emer- gencies, local in character, so declared by the Commissioner of the Bureau of Reclamation. GEOLOGICAL SURVEY For salaries and expenses necessary for the Geological Survey, including personal services in the District of Columbia; purchase of not to exceed one hundred and forty-six and hire of passenger motor vehicles and the maintenance and operation of aircraft; and exchange of unserviceable passenger and freight vehicles as part payment for new freight vehicles; as follows: Salaries and expenses: For personal services in the District of Columbia, and other expenses, $232,340; Topographic surveys: For topographic surveys in the United States, Alaska, the Virgin Islands, and Puerto Rico, $3,000,000, of which not to exceed $475,000 may be expended for personal services in the District of Columbia: Provided, That no part of this appropri- ation shall be expended in cooperation with States or municipalities except upon the basis of the State or municipality bearing all of the expense incident thereto in excess of such an amount as is necessary for the Geological Survey to perform its share of standard topo- graphic surveys, such share of the Geological Survey in no case exceed- ing 50 per centum of the cost of the survey: Provided further, That $517,000 of this amount shall be available only for such cooperation with States or municipalities; Geologic surveys: For geologic surveys in the United States and chemical and physical researches relative thereto, $2,300,000 of which not to exceed $500,000 may be expended for personal services in the District of Columbia; 477' 60 Stat. 338. Transfer of surplus property. 60 Stat. 369. Restriction. General expenss. Cooperation with States, eta. Amount available.