PUBLIC LAWS-CH. 411 -JULY 31,1947 Limitation on ex- penditures. Report to Congress. Purchase of motor vehicles, motorboats, and aircraft. Power-driven boats. Certification of ex- penses. Chief of Engineers, to carry into effect the various appropriations for rivers and harbors and flood control, surveys, and preparation for and the consideration of river and harbor and flood-control estimates and bills, to be paid from such appropriations: Providedfurther, That the expenditures on this account for the fiscal year 1948 shall not exceed $1,100,000, and the Secretary of War shall each year, in the Budget, report to Congress the number of persons so employed, their duties, and the amount paid to each: Provided further, That the various appropriations for rivers and harbors and flood control may be used for the purchase, in the fiscal year 1948, of two hundred passenger motor vehicles and ten motorboats, and the purchase, maintenance, repair, and operation of twelve aircraft: Providedfurther, That here- after no appropriation under the Corps of Engineers shall be available for any expenses incident to operating any power-driven boat or vessel on other than Government business, and that Government business shall be construed to include transportation, lodging, and subsistence on inspection trips of Federal and State officials, having a public interest in authorized or proposed improvements for river and harbor and flood control, and any expenses incurred therefor shall be charge- able to river and harbor and flood control appropriations heretofore or hereafter made under rules and regulations to be prescribed by the Chief of Engineers: Provided further, That such expenditures shall be certified by the Division Engineer as necessary and proper expenditures: RIVERS AND HARBORS Maintenance, etc. Maintenance and improvement of existing river and harbor works: For the preservation and maintenance of existing river and harbor works, and for the prosecution of such projects heretofore authorized as may be most desirable in the interests of commerce and navigation; for survey of northern and northwestern lakes and other boundary and connecting waters as heretofore authorized, including the prepara- tion, correction, printing, and issuing of charts and bulletins and the investigation of lake levels; for prevention of obstructive and inju- rious deposits within the harbor and adjacent waters of New York Calionta D bris City; for expenses of the California Debris Commission in carrying 27 tat. 07. on the work authorized by the Act approved March 1, 1893, as amended (33 U. S. C. 661, 678, and 683); for removing sunken vessels or craft. obstructing or endangering navigation as authorized by law; for operating and maintaining, keeping in repair, and continuing in use without interruption any lock, canal (except the Panama Canal), canalized river, or other public works for the use and benefit of naviga- tion belonging to the United States, including maintenance of the Student officers. Hennepin Canal in Illinois; for payment annually of tuition fees of not to exceed one hundred student officers of the Corps of Engineers at civil technical institutions under the provisions of section 127a of 41 stat. 78. the National Defense Act, as amended (10 U. S . C . 535); for examina- tions, surveys, and contingencies of rivers and harbors; for the execu- tion of detailed investigations and the preparation of plans and speci- ing.tg and bind- fications for projects heretofore or hereafter authorized; for printing and binding and office supplies and equipment required in the Office of the Chief of Engineers to carry out the purposes of this appropri- ation, including such printing, either during a recess or session of Congress, of surveys authorized by law, and such surveys as may be printed during a recess of Congress shall be printed, with illustrations veys, etc. as documents of the next succeeding session of Congress: Provided, That no part of this appropriation shall be expended for any prelim- inary examination, survey, project, or estimate not authorized y law $116,718,00: Praovided further That from this appropriation the Secretary of War may, in his discretion and on the recommendation 688 [61 STAT.