The actual excess in length of the high-level route is about three and one-half miles; the whole amount of lockage is 432 feet. This being equated by the rule deduced from observations on the Erie, is equal to thirty-seven miles of level canal, making the equivalent difference in length equal to forty and one-half miles of level canal. The cost of transportation on canals of these dimensions is stated by McAlpine, in his report of 1854, to be four mills per ton per mile. The officers of the Erie have found it to vary from 2.16 to 2.25 mills per ton per mile up to 1866, and in 1868 to have reached 4.6 mills. I make the cost on present work, reduced to a level, 2.3 mills. Applying then this price we have 9,720,000 tons by 40 mills by 23 mills $905,418. Which, at 7 per cent., is the interest on... But this result shows that the actual saving in cost of transportation by the lower line represents a capital of.. $12, 934, 542 7,677, 193 5,257, 349 On the flat ground adjacent to the river it is proposed to construct a basin, in which cargoes can be transferred from the large barges navigating the rivers to those proper for use in the canal. WATER-SUPPLY. We have assumed a trade of 180 boats per day, but it will be prudent to provide a supply of water for 200. Allowing them one and one-half locks full of water to each boat passing the summit level, we will require three hundred locks full of water per day for a maximum trade. The greatest lift between Greenbrier and Covington, the portion of the line. to be supplied from the summit level, is 14 feet, and the locks being 120 feet by 20, we have 300 locks by 120 by 20 by 14, equal to cubic feet, per day, 10,080,000. Evaporation on 21.9 miles, (the tunnel being excluded,) } inch per mile per day, cubic feet... Filtration, cubic feet. Waste at structures, cubic feet. Leakage at lock gates, cubic feet 225, 264 5, 240, 400 43, 200 1,728, 000 Total. The minimum flow of the Greenbrier, as gauged by Cap- Diminish this by the evaporation of of an inch per And we have available for the canal.. 17, 316, 864 8, 380, 800 8, 936, 064 1,072, 327, 680 5, 484, 229, 000 899, 405, 100 4, 584, 823, 900 3, 512, 496, 220 ་ As fears have been expressed by some persons not familiar with the subject, that a reservoir supplied chiefly from rain-fall might fail to furnish the anticipated supply, it is well to observe that the valley of the Greenbrier River is extremely favorable for the construction of reservoirs, with which it might be filled throughout its length of sixty miles; in which any desired amount of water from the spring and winter floods . might be stored up for use in time of drought. At the mouth of Howard's Creek the canal, having passed the Alleghany summit, is terminated. The means of its ultimate connection with the Ohio is next to be considered. The valley of the Greenbrier River is narrow, limited on one or both sides by steep bluffs or cliffs. The flat land is small in quantity, and in no place continues for any considerable distance. The improvement recommended by Mr. Gill, partly canal and partly slackwater, would be the more economical for a work of the dimensions proposed by him, but the larger canal now under consideration would not find room in many places along the river bluffs without too serious a reduction of the water-way of the river itself. I therefore recommend a continuous slackwater, (broken at two points only by short sections of canal,) which would be extended to the mouth of the river by nineteen dams of heights varying from 10 to 35 feet. At Alderson's, and again a short distance below the falls of Greenbrier, short canals of large dimensions are introduced to avoid very expensive locations for dams, which would otherwise be required. The length of the river is 49.086 miles, and the total fall 316 feet. New River is, particularly in its lower portions, of a different character, the banks being composed almost entirely of boulders, among or over which the construction of a canal presents formidable difficulties. These, however, are not in the way of a slackwater improvement, as is now recommended. The river and its valley are remarkably favorable for a work of this character, except in one single particular, and that is the difficulty (on a hurried reconnaissance) of determining rock sites for dams. The river is in many places filled with boulders of every size, sometimes immensely large, and it is not possible, generally, to estimate their depths. At such points the cost of foundations cannot be determined in advance. I have therefore deemed it necessary to locate dams at those places only where the ledgerock can be discovered. In consequence, some of them are higher than I could have wished, and the estimate proportionately greater. It is probable that better sites will be found by a more detailed survey, and that the cost will thereby be reduced. Indeed, I expect a thorough survey greatly to diminish the estimate. It was not possible, in the time and with the force at my disposal, to undertake an examination in detail of the pools and shoals, with a view to make a final location. A height was therefore taken for each dam sufficient to raise the water 7 feet at the foot of the one next above, without regard to its present depth. The length of New River from the mouth of Greenbrier is 67.433 miles; the fall in this distance, 756 feet. The upper portion of the Kanawha from the mouth of Gauley River to the foot of Lyken's Shoals requires the same kind of improvement as the Greenbrier and New Rivers; the fall being too great for any open navigation, its cost is included with those rivers. The whole number of dams required is 55, varying from 12 to 41 feet in height, and in length from 200 to 600 feet. They are to be constructed of heavy rubble masonry, laid in bydraulic cement, and covered on top with timber and plauk. DIMENSIONS AND PLAN OF SLACK-WATER. The locks are designed to be 200 feet in length between the gates, and 40 feet in width at the lower water-line, with 7 feet depth of water. These dimensions will admit a barge of 700 tons, or two canal boats for the enlarged canal. The locks as well as the dams are to be constructed of heavy masonry, with guard walls from 10 to 20 feet above the coping of the dams, the head walls and upper gates of the locks being carried up to the same height as a protection during floods. On the Greenbrier the maximum freshet-rise is about 20 feet. It varies on different portions of New River, rarely exceeding 8 feet at Richman's Falls; 30 to 35 feet from Stretcher's Neck to Bowyer's, or, perhaps, to Miller's Ferry, and for a few miles below the latter point from 40 to 50 feet. At the Blue Hole, where the river, having fallen 62 feet among precipitous cliffs in the preceding two miles, turns at a right angle and meets a lighter grade, the engineers of the Chesapeake and Ohio Railroad have found unmistakable signs of high water, 69 feet above the ordinary surface. At these points the locks will be, of course, submerged, but their construction will be such as to preserve them from injury. The lock-gates will be made of iron frame, and covered with plank, and furnished with suitable gearing for maneuvering them. By reason of the necessary height of the upper gates, they will rest on breast walls, and the influx-valves will be placed in culverts communicating directly with the pool. The efflux-valves will be placed in the lower gates. The large locks on the slack-water will transmit the daily tonnage estimated for the canal in 120 lockages, requiring for a maximum lift of 15.5 feet, (on the Greenbrier,) with 25 per cent. added for waste, 120 by 200 by 40 by 15.5 by 1.25, cubic feet..... Which being supposed necessary for 120 days, the re- But Anthony's Creek reservoir will furnish, beyond the 18, 600, 000 2,232, 000, 000 3, 512, 496, 220 1, 280, 496, 220 During the last summer and early fall the Greenbrier was very low, said to be lower, indeed, than ever before observed by persons living at Greenbrier Bridge, but was swollen by rains before an opportunity offered to gauge it.. I rely, therefore, for the low-water flow at the bridge upon Captain McNeil, who found it, as stated above, 97 feet per second, at the mouth of Howard's Creek, just below Greenbrier Bridge. A gauge made by myself, some 16 miles lower down, gave 1,000 feet per second. The river had been much higher, but had fallen to within 8 to 10 inches of its lowest period at the point where the gauge was made, and was very slowly falling. Any calculation of the relative discharge at its lowest stage, based only upon the relative section and perimeter, must, in my judgment, be speculative when applied to a river formed, like the Greenbrier, of alternate pools and rapids. The application of the formula gives as the low-water discharge at the point 603 feet per second, which must be far in excess of the truth. Not many streams empty into the river between Howard's Creek and this point, but I am of opinion that considerable quantities of water are furnished from the limestone beds which are here underlaid at a slight depth by the sandstone. The discharge of New River, when said to be at a low stage, though not its lowest, was found to be 2,000 feet per second. Besides the Gauley, several streams of considerable importance empty into the New River below the place where the gauge was made, yet the ordinary low-water of the Kanawha, which unites the discharge of New River with that of the Gauley, is but 1,300 feet per second, and has been as low as 1,100 feet at Buffalo Shoals, thirty-five miles below Charleston. If, therefore, the water of New River sinks, as has been supposed, it does not come out at the Salines or any other point of the upper Kanawha, but the fact is, as before stated, that the minimum flow of a stream of these varying characteristics cannot be directly deduced from the observation made at any other stage. From Lyken's Shoals to the Ohio, at. Point Pleasant, the distance is 85.1 miles, and the average fall about .873 foot per mile, and as with this fall an open navigation is practicable it is also highly desirable. Among the plans proposed, that of sluice dams, by Mr. Fisk, is the most simple of application and certain in its results. His theory is to grade the river by means of dams at the shoals, to be spaced about onequarter of a mile, containing sluices of uniform dimensions, (I would fix them at 100 by 7 feet,) and with but 6 inches fall at each dam, thus lengthening the steep grade of the shoal, and lightening it by extending the fall over more distance. The resistance to a tow of loaded boats passing these sluices up stream will be greater than has been supposed, (for the tow will completely fill the sluice,) and will require some modifications of the present method of towing. The low-water flow of the Kanawha, being but 1,100 to 1,300 feet per second, is not sufficient to fill such a sluice, but will require from 800 to 1,000 feet more. To obtain this we must have recourse to a reservoir, and I therefore include in the estimate the cost of one surveyed by Mr. Ellet for this purpose, described by him as Meadow Reservoir. His estimate, as revised, amounts to $529,080, but as one with a tenth of its capacity will be sufficient, I have placed it at $250,000. To this is added the estimate for dams, &c., by Mr. Byers, increased by 80 per cent., to allow of more permanent constructions than those proposed by him, as well as a greater depth of water, $723,900, making a total of $973,900. The mean velocity of current in the sluices will be 3 feet per second, or about two miles per hour, which will be encountered for a short dis tance only, and the wide pools between the dams will offer every facility for the passage of boats moving in opposite directions. In case the system of towing cannot be changed to occupy less width than is now usual, (I see no reason why it should not be,) then recourse must be had to locks and dams, for which the conditions are peculiarly favorable if any obstructed navigation can be tolerated. An approximate estimate shows the cost of such an improvement to be about $1,000,000. TIME OF COMPLETION. A material question is the time which will be required for the comple tion of this work. Provided funds are supplied to keep pace with their economical expenditure, the opening of the line will be governed by the time necessary to complete the long or Lorraine tunnel. If we suppose a progress of 30 feet per month to be made in each shaft, and 100 feet per month in each heading, (and double this has been made in the Mont Cenis Tunnel,) then the longest time will be consumed in the west heading of shaft No. 4, and the east heading of shaft No. 5, which will require five years and two months from the date of commencement. Ten months may be consumed in preparation and in trimming up after the opening is made through; we may therefore safely say that the work can be completed in six years from the time it is put into the hands of a competent contractor. As these shafts will be the deepest on the line of tunnel, (the portion between them lies under the summits of Kate Mountain,) I will not venture to predict what character of rock will be encountered. If it should be slate or shaly sandstone, much more rapid progress can be made. If compact sandstone or limestone, even then the rate of 100 feet per month ought to be attained. Much water will probably be met with, and will require the use of the most improved pumping machinery. The great quantity of material to be removed-about one ton in every four minutes-will be facilitated by the large area of tunnel, but will require skillful management, and the best mechanical helps. CHESAPEAKE AND OHIO RAILROAD. From the mouth of Howard's Creek to the mouth of Scary, about sixteen miles below Charleston, the Chesapeake and Ohio Railroad follows' the valleys of the Greenbrier, New, and Kanawha Rivers. The location made for the Covington and Ohio road, of which this is the successor, took into view the construction of the water line, and was placed at an elevation above the reach of floods as increased by the dams to be erected, and high enough to permit the passage of boats beneath its bridges. The location by the present company, however, is but a few feet above the maximum freshet-height of the river in its unimproved condition, and will be flooded in high water if this project is carried out. But little work, however, has yet been done on it which would not be available for a location high enough to be out of the way of the water-line; but it is understood that the entire road will be placed under contract in the spring, and it becomes, therefore, of great importance that the question of the construction of the water-line be determined at an early day, and an arrangement entered into with the railroad company for the necessary changes in its location. Negotiations have been opened, and propositions made, by the James River and Kanawha Company, with a view to arrange the terms upon which the alterations would be made by the railroad, but so far, I am advised, without definite results. MODE OF TRANSPORTATION. Through-freights will be transported by barges, towed by steam, from the mouth of the Kanawha to Greenbrier Bridge, and thence by canalboats to Richmond, moved, I would say, by horse-power, were I not satisfied that steam will be introduced as the motor on large canals before this work can be constructed. For some classes of freights it may be more economical to use barges small enough to go through on the canal, two of which can pass the river-locks at once, and thus avoid the necessity of breaking bulk. But I apprehend that for grain, which will probably form the greater part of the freight, the larger barges will be used, and the cargoes transferred at Greenbrier Bridge. With proper elevators the cost of transfer need not exceed 1 cent per bushel. In the present uncertain and embarrassed condition of the Ohio and Kanawha navigation, heavy freights are carried for about 1.8 mills per ton per mile. It is not, then, too much to assume that by a systematic organization, and the use of larger boats, the cost may be reduced to 11 mills. We will, however, put it at 2 mills. |