58. Fluctuations in tonnage on the Mississippi River system reflect changes in general economic conditions. During the 10-year period covered by table 16, however, the trend in ton-miles on the Mississippi River system, and in both tons and ton-miles on the Gulf Intracoastal Waterway, has been continuously upward. This growth in transportation service by waterways reflects the river and harbor improvement program of the 1930's. Carriers have bought new equipment designed to utilize the improved channels more efficiently. Lower transportation costs have stimulated new traffic that could not have moved at higher costs. As separate rivers and canals have been linked together into an interconnected system, the average length of waterway hauls has increased. Specialized terminals have been developing, meanwhile, adapted to the new transportation needs of industry and commerce. The resulting increase in the availability and dependability of barge transportation has led to its more widespread adoption by shippers and consignees.

59. Waterways adjoining proposed project. The only existing project along the route of the proposed Tombigbee-Tennessee waterway is the Tombigbee River from Demopolis to Walkers Bridge; however, the new channel will connect existing projects on the WarriorTombigbee waterway and Tennessee River. Traffic statistics on these three projects are given in table 17. Because of the large amount of Government construction on the Tennessee River, Government freight and commercial freight are shown separately for that waterway.

TABLE 17.-Traffic on Tombigbee River upstream from Demopolis, on WarriorTombigbee waterway, and on Tennessee River, in tons and ton-miles, 1935-44

60. Traffic on the Tombigbee River above Demopolis has consisted entirely of logs and piles moving on barges or in towed rafts at high water. The existing channel is not adequate for modern barge transportation.

61. The channel from Mobile to Port Birmingham was completed to 6-foot controlling depth in 1915, and except for brief periods, the present 8-foot controlling depth has been maintained for more than 20 years. Before the 1930's, this waterway had already developed a mature traffic, therefore the growth in tonnage has not been so rapid in recent years as on some other inland streams. Average annual

tonnage for 1925-34 was 1,426,365; for 1935–44, 1,763,725, a gain of 24 percent. Year-by-year fluctuations in traffic volume usually reflect changes in the level of production by Birmingham steel mills. Declining down-bound traffic in 1943 and 1944 was primarily caused by interference with the normal peacetime markets and distributing methods of the Birmingham mills. Up-bound traffic also declined, although in smaller proportionate amounts, because the Panama Canal was closed to cargoes ordinarily transferred from ship to barge at Mobile.

62. During most of the period covered by table 17, controlling depths on the Tennessee River have usually been about 6 feet at Chattanooga and 1 foot at Knoxville. Barge tows have been able to move safely, on most of the river, only at high water stages. The 9foot channel to Knoxville was completed in 1944. In the past, most of the tonnage has been handled by private and contract carriers, and it has consisted dominantly of sand, gravel, coal, petroleum, and lumber. A number of common carriers have operating rights on the Tennessee River and connecting streams. With the completion of full project depth and the provision of new terminals available to all on equal terms, prospects are good for a marked acceleration of the gradual growth in commercial traffic that has characterized the river in recent years.

XI. SAVINGS ON MISSISSIPPI RIVER UPSTREAM TRAFFIC

63. The provision of an alternate route from the Gulf of Mexico to the Ohio River obviously will result in substantial savings in the cost of handling barge traffic now moving northward against the current of the Mississippi River between New Orleans and Cairo. Diversion of traffic to the new waterway route would not destroy any of the advantages now accruing to this traffic, by virtue of the present improvement of the Mississippi. If carrier costs via the new route are less than those attainable on the existing route, the resulting benefits are net, and fully assignable to the new project.

64. Carriers' line-haul costs.-Computation of savings attainable from use of the proposed alternate route has been based on an analysis of the line-haul costs, for 1939 (considered to be the latest reasonably normal year) of representative water carriers. These costs are shown, for different sections of the two routes, in table 18. Although wages and prices of materials have risen since 1939, higher loading factors in more recent years have resulted in substantially lower unit costs. In any event, fluctuations in unit costs would affect both routes in approximately the same degree.

TABLE 18.-Line-haul costs of barge transportation on selected sections of the Mississippi River system, Mississippi Sound, and the proposed TombigbeeTennessee waterway, based on 1939 operations

65. Navigation of Mississippi Sound.-Leading boat designers agree that certain relatively superficial modifications can be made in towboat design which would make river-type equipment efficient on Mississippi Sound in ordinary weather. In deriving carrier costs for this reach of the alternate route, shown in table 18, it is proposed that a substantial part of the tonnage would be towed from New Orleans to Mobile by tugboats, at line-haul costs equivalent to those now incurred in this service by the Federal barge lines. The remainder would be towed or propelled, depending upon weather conditions and the types of equipment available, by river towboats adapted to the purpose.

66. The movement of waterway traffic from Mobile to Paducah over the Tombigbee-Tennessee waterway is obviously one for which no actual carrier costs can be obtained. To establish an average cost based on operations under similar conditions on other waterways, it has been assumed as typical that the through traffic of this section will be carried in 8-barge tows handling 3,500 revenue tons, pushed by 1,000 horsepower towboats.

67. Based on the costs per ton shown in table 18, the unit savings attainable from use of the Tombigbee-Tennessee waterway as an alternative route to the Mississippi River, for north-bound traffic, would be as shown in table 19.

TABLE 19.-Typical savings per ton in line-haul costs via proposed TombigbeeTennessee waterway as alternative route to upstream movement on the lower Mississippi River

68. Available tonnage.-An examination has been made of Mississippi River traffic, beginning with 1935, to see what tonnages would have been available for movement over the Tombigbee-Tennessee, if that waterway had been in existence. This information is shown in table 20.

TABLE 20.-Estimated tonnage of traffic potentially divertible from the Mississippi River to the Tombigbee-Tennessee waterway, 1935–44

1 Originating at points west of Morgan City.

2 Originating at New Orleans and at points south and east of New Orleans.

3 Originating at Baton Rouge and at points south of Baton Rouge but north of New Orleans. 4 Terminating at Cairo or at Mississippi River points north of Cairo.

5 Terminating at Paducah or at Ohio River points east of Paducah.

69. If the proposed waterway were in existence, there are numerous combinations of river-boat operations which could be developed to increase efficiency in using both the old and the new routes. A large tonnage, notably of steel, is transported down the Mississippi River to Gulf ports by tows which usually return empty to the Ohio River. These empty tows could advantageously return via the alternate route. Occasionally barges now returning empty up the Mississippi River could pick up revenue cargo north-bound on the TombigbeeTennessee waterway. Much of the tonnage originating east of New Orleans for upstream movement on the Mississippi River could be hauled via the new route at savings even greater than those in table 19. High-powered tówboats now required for combinations of through and intermediate hauls on the Mississippi could frequently be replaced by smaller boats adequate for the intermediate tonnage offered at such points as Angola, Vicksburg, Greenville, and Memphis. The savings accruing to the operators under the various possible conditions would depend upon the volume and timing of available tonnage, and upon the nature of interline agreements for exchange of equipment, but their substantial importance is obvious.

70. The attractiveness to carriers of the alternative route would depend in part on their ability to adapt their equipment and operations so that lower costs via the new waterway would not be offset by creating higher costs on the old. The years under consideration were marked by substantial growth in waterway traffic, in carriers' investments in equipment, and in the technological efficiency of line-haul operations. As shown in table 21, Mississippi River tonnage not available for the Tombigbee-Tennessee waterway, in recent years, was greater than the total Mississippi River traffic of earlier years.

TABLE 21.-Mississippi River traffic, mouth of Ohio River to, but not including, Baton Rouge, estimated as potentially available and not available for the proposed Tombigbee-Tennessee waterway, 1935-44

71. Under these circumstances, estimated savings may reasonably be computed on the presumption that all of the available tonnage would actually have used the new route. Whatever slight exaggeration may be found in such a computation would be more than offset by other advantages of the alternative route, as enumerated in paragraph 69.

72. Line-haul savings.-The savings to operators in line-haul costs which would have been possible since 1935, if the proposed TombigbeeTennessee waterway had been in existence, are shown in table 22.

TABLE 22.-Estimated savings in line-haul costs that could have been attained if Tombigbee-Tennessee waterway had been in operation as an alternative route to the lower Mississippi River, 1935–44

73. In view of the upward trend of waterway traffic in prewar years, it seems probable that over the estimated 50-year life of the proposed improvements, savings attainable by use of the Tombigbee-Tennessee waterway as an alternative route to the Mississippi River will average not less than $1,200,000 annually.

XII. NEW WATERWAY TONNAGE

74. Most of the tonnage and most of the transportation benefits from a waterway such as the proposed Tombigbee-Tennessee waterway connection, which will introduce an entirely new artery of commerce, must necessarily arise from traffic which does not now use any waterway. Such traffic would be made up of tonnage now moving by other means and of tonnage not now moving at all for lack of low-cost transportation. An extensive survey was therefore necessary of existing traffic by other agencies of transportation, and such a survey had to be supplemented by a consideration of economic trends that might affect the future use of the waterways.