118. Structural features of bridges.-For all highway bridges the standard live-load type H-20 with 20-foot roadway was used. Nine of the highway bridges over the waterway would be high-level fixed span, two vertical lift, and one bascule. All railroad bridges would be single-track, designed with Cooper E-60 loading; five to be replaced with lift spans, and the two new bridges at the divide cut would be high-level. All lift bridges would be electrically operated. Counterweights for vertical-lift bridges would be reinforced concrete. All lift-bridges would be designed for fully opening in 1 minute. No extraordinary problems of design or construction would be involved in connection with any of the bridges and the cost estimates are based on standard bridges for which rather complete data are available. 119. Foundations for bridges.-No subsurface investigations were made at the actual sites of the bridges which it would be necessary to construct or reconstruct in the development of the waterway. Sufficient data were obtained, however, from the borings made along the waterway and from studies of the geological conditions along the route, to furnish a general knowledge of the foundations of all the bridge sites. All bridges but one would be designed for pile foundations. No special provision would be made for scour, because the creation of the slack-water pools would virtually eliminate such action. 120. Highway and railroad relocations. One major railroad relocation would be necessary. The present Illinois Central Railroad, Chicago to Florida via Birmingham, Ala., parallels the proposed Yellow Creek cut for 8 miles, and it would be necessary to relocate approximately 10.6 miles of this railroad. The alinement considered diverges from the present line just south of Paden, Miss., and crosses the divide approximately parallel and 2 miles west of the present line. The proposed relocation would have a maximum grade of 0.5 percent and an elevation of 545 feet above mean sea level where it crosses the divide; both the maximum grade and the summit elevation are approximately the same as now obtains. One State and seven county highway relocations would be made. Mississippi Highway No. 6, near Amory, Miss., would be relocated in order to combine two of the waterway crossings in this vicinity. It is proposed to relocate this highway west from Amory over the existing Mississippi Highway No. 41 to a point just west of its crossing of the proposed waterway where a new highway, approximately 3 miles in length, would be constructed to connect with the existing Mississippi Highway No. 6, near Bigbee, Miss. County highways in Mississippi to be relocated are: One near Barton Ferry, 0.3 miles; one near the Narrows lock and dam, 1.3 miles; one near Paden, 2.4 miles; one near Smithville, 2.0 miles; one near Moores Mill, 1.0 mile; two, southwest of Tishomingo, 2.0 and 3.0 miles respectively. All road and highway relocations would be gravel surfaced. 121. Utilities.-There are 18 transmission lines crossing the route of the plan of improvement investigated; 12 of the existing lines would require no change; 5 crossings would be raised and lengthened; and 1 would be relocated for a distance of 0.8 mile. There are six submarine crossings; five pipe lines, and one telephone cable. All but one pipe line near Epes, Ala., which is laid 9 feet below mean low water, would have to be lowered. 122. Sewers, water supply, and drainage facilities.-There are a number of sewers, water supply, and drainage facilities which will require alterations or relocations. 123. Cemeteries.-There are a few small local cemeteries which will require relocating and the usual procedure for their removal will be employed. 124. Rights-of-way and flowage.-Adequate rights-of-way would be provided throughout the waterway to provide for borrow pits along the canal embankment, at dam sites, for spoil areas along the divide cut, and for future widening of the channel. Flowage damages include partial payment for lands along the river channel which would be subject to more frequent flooding after the waterway was constructed than before. They also include the value of certain county roads which would have to be relocated, the value of timber, schools, churches, and other major buildings which would be in the flooded areas, and severance damages to property which would be divided by the waterway. 125. Aids to navigation.—In the river section and in the pool above the Narrows Dam, channel markers would be provided. No aids to navigation would be necessary in the lateral canal section. 126. New transfer facilities. Although it is probable that within a few years after the construction of the plan of improvement additional ports would develop at convenient localities along the waterway, an analysis of the traffic immediately prospective for movement over the connecting waterway indicates that new terminals should be provided initially at Columbus and Aberdeen, Miss. The tonnage of in-bound petroleum products and staple commodities that could be distributed economically from these ports would warrant storage facilities for gasoline and warehouses and equipment for handling general commodities. It is estimated that the total cost of terminals at these two points would be about $172,000; however, because the terminal and transfer charges used in computing the benefits are sufficient to construct, operate, amortize, and maintain the necessary terminals to be provided by local interests, the costs of the terminals are not included in the computations to determine the annual charges; the costs are included, however, to determine the total Federal and non-Federal first cost. 127. Special subjects. The possibility of coordinating hydroelectric power, flood control, and other beneficial water uses with a plan for navigation was considered in the report under review. Conditions have not changed sufficiently since the preparation of that report to warrant consideration at this time, of water uses other than that for navigation. 128. Estimate of first cost.—The unit costs used in preparing the estimates of costs were based on the cost of similar work adjusted by means of Engineering News Record indexes to present-day prices. The estimate of first cost Federal and non-Federal, for the plan of improvement, including allowances for engineering, overhead, and contingencies is shown in table 37. 1 This amount includes 25 percent for engineering, overhead, and contingencies; all other amounts include 35 percent. 129. Division of cost.-In considering the division of cost between Federal and non-Federal agencies it has been recognized that the Tombigbee-Tennessee waterway would be an entirely new route which would connect two growing and industrialized sections of the country and afford an interchange between two large water transportation systems: the Intracoastal Waterway and the Ohio, Upper Mississippi, Missouri, and Illinois River systems. The benefits, therefore, while local to some degree, would be more general in their effects than is usually the case. For this reason, Federal contributions should be greater than for improvements which afford major benefits to restricted areas. The Federal Government should bear the cost of construction of all works of navigation; all railroad bridges over existing navigable streams in accordance with the provisions of existing laws; all railroadtrack changes exclusive of those caused by bridge alterations; all new railroad bridges to be constructed where no bridge exists at present, including necessary track changes and the estimated maintenance and operation cost; the cost of all rights-of-way and flowage damages; and the cost of alteration or relocation of all utilities except necessary alterations to sewers, drainage, and water-supply works. The nonFederal agencies should bear the construction cost of all highway bridges and highway relocations, the cost of new transfer facilities, reconstruction or alteration of sewers, drainage, and water-supply works, and maintain and operate all bridges and utility crossings except new railroad bridges across the divide cut. The first cost of. the improvement to be borne by the Federal Government would be $116,941,000, and the non-Federal cost would be $3,341,000, as shown in table 37. XV. ANNUAL MAINTENANCE AND OPERATION 130. Locks and dams.-The annual charges for maintenance and operation of locks and dams were determined from similar charges experienced on the Warrior, Ohio, and upper Mississippi River canalization projects and are estimated to be $30,000 at each site. 131. Dredging and snagging.—The improvement requires no initial dredging in the present channel of the Tombigbee River except at certain lock approaches, but it is probable that deposits in pools and shifting of the river channel would cause some annual maintenance dredging. From records of maintenance dredging for the upper Mississippi River and the Warrior-Tombigbee systems and from a comparison of conditions, it is estimated that the annual charges for maintenance dredging would be $1,000 per mile for the river section, $500 per mile for the canal section, and $200 per mile for the divide section. The annual charges for snagging have been estimated at $22,700. 132. Aids to navigation.-It is estimated that the annual charges for aids to navigation which would be installed and maintained by the United States Coast Guard, will be about $40,000. 133. Total annual maintenance and operation charges.-The various items of Federal and non-Federal annual maintenance and operation charges are given in table 38. TABLE 38.-Annual maintenance and operation charges Federal charges: Dredging: River section, 180 miles at $1,000.. Divide section, 39 miles at $200. Subtotal.. Snagging Aids to navigation_ Total_. Less approximate annual charges for maintenance and operation of existing Federal navigation project on the Tombigbee River upstream from Demopolis.. 811, 000 5, 000 Increased Federal annual charge for maintenance and opera- 806, 000 Non-Federal charges: Increased charges for maintenance and operation of existing Increased charges for maintenance and operation of highway 23, 000 23, 000 46,000 Total____ Total Federal and non-Federal annual maintenance and 852, 000 134. Amortization and annual charges.-The annual amortization charges included are based on an estimated life of 25-year life for movable parts and 50-year life for fixed parts. These amortization charges are the annual charges which, when compounded at 3 percent for Federal investment and 4 percent for non-Federal investment, will repay the total investments for the parts of the project at the end of the life periods assumed. Table 39 contains a summary of pertinent |