No further appropriations having been made for carrying, on this work, the small balance left over has been expended during the last fiscal year in caring for the snag-boat and property belonging to this work, and in preparing the map and report herewith submitted.
As stated in my last annual report, a small surveying party was detailed to accompany the snag-boat Thomas Trunnel on her snagging trip in this river, to bring back some definite information relative to the stream, and, if possible, to prepare a plan for its permanent improvement. It was expected that the progress of the boat would be slow enough to allow of a continuous survey of the stream being made, but the unusual amount of high water and the severity of the winter made her operations so rapid and irregular as to preclude the possibility of accomplishing this object. It was also impossible to make the examination at low water, which is necessarily of the greatest importance in so small a stream. A map of the river, derived partly from instrumental surveys and partly from pilot-house sketches, was constructed, and a tracing there of is submitted herewith.
From the information brought back by the party, it appears that the alluvial portion of White River ends about 20 miles above Jacksonport, which town is situated at the mouth of Black River. From this point up, the stream rapidly assumes the characteristics of a mountain torrent, the slope increasing rapidly and the valley becoming narrower. This latter is skirted by high bluffs, which, in some places above Batesville, are not more than half a mile apart. The numerous shoals are composed of gravel and coarse sand in the lower portions of the stream, while loose bowlders and rock in place form the principal obstructions above Batesville. Two miles below the latter place high-water mark reaches the top of the bank for the last time; above there the banks are 10 or 11 feet above this level. Floods are sudden and violent, and the high-water current is very strong, enabling the stream to move heavy gravel with facility. The low-water discharge is very small, and the current is too feeble to cut a channel through the gravel bars, which therefore remain as permanent dams, the current in the intermediate pools being sluggish. At some of these shoals, more especially those which contain rock, the great velocity of the current at low water is more of an obstacle than the actual lack of depth, some of them being, from this cause, almost impassable for the small class of boats used in the navigation of the stream. In the space of 130 miles from Jacksonport to the head of Buffalo Shoals, 63 shoals are reported, the minimum depth being 6 inches, and the minimum width of channel 50 feet. Between Jacksonport and Batesville, 39 miles, 19 shoals are reported, only 2 of which, however, approach the minimum dimensions stated above. As will be seen from the map, they become very numerous as Buffalo City is approached, and the slope becomes very heavy, upwards of5 and 6 feet to the mile, the bottom being generally of rock. Buffalo Shoal is the worst, and is a very formidable obstruction. It must be improved before the upper portion of the river will be accessible at low stages. The low-water depth is only 6 inches, the bottom being of rock, covered with loose bowlders, and the shoal is a little over a mile in length. The very small volume of water available, and the serious nature of the obstacles to be encountered, renders it imperatively necessary that a careful continuous low-water survey should be made before plans or estimates can be prepared with any confidence. It is especially necessary that a continuous line of levels should be run, to enable a low-water profile of the stream to be constructed. An estimate for this survey is submitted herewith.
It is plainly evident that the plan of concentrating the discharge of the stream by spur or longitudinal dikes, with a view to scouring a low-water channel through the flood-deposits, is entirely impracticable here. The gravel is brought down by the floods in more than sufficient quantity to fill up annually any artificial channels made, and I do not think that the concentrated low-water discharge would be sufficient to scour through one of these bars, even if it could act for several seasons without further accretions to the deposit. Moreover, the rock could not be moved by this process, and the general effect would probably only be to increase the velocity of the current already objectionably great, with little or no increase of navigable depth. It therefore seems to me that the only method available is to leave the bars alone, and to seek merely for an increase of depth over them by diminishing the local slope.
The profile of the low-water surface of this river will undoubtedly show a series of nearly level reaches, separated by short and abrupt descents over the shoals. The average slope is probably not excessive, and, if, maintained throughout, would give a good and deep channel; but there are many objections to seeking this result by cutting down the crest of the bars, even if the plan were otherwise feasible. These shoals form natural dams behind which the water is stored up during low water, and if they did not exist the stream would probably run dry at its lowest stages. The only plan practicable is, therefore, to flood the shoals at low stages to a navigable depth and width.
Of the various methods of accomplishing this object, the most obvious one is to create slack-water navigation by locks and dams, but this system, in addition to its costliness, has the disadvantage of rendering the stream impassable for boats which are too large for the locks, until the water rises sufficiently to let them go over the dams, or, roughly speaking, the river must rise more than is necessary for free navigation by about the height of the dams. In addition to this, the gravel brought down at high-water would eventually All up or seriously shoal the pools above the dams, rendering frequent dredging necessary to keep up the proper depth. I have not the necessary data for submitting an estimate of the cost of improvement by this method, but it would necessarily be great.
Another method which would effect the same result is that of locks and movable dams, a system which has found much favor among French engineers, and has been recommended for several of our own streams. This system provides locks as in the ordinary slack-water navigation, but the dam, instead of being a permanent obstruction to the stream, can be removed in part to allow the passage of large boats, or can be entirely removed to permit the free discharge of the river in floods. Many of the objections to the first method are therefore removed in this one, but its costliness and the expense of operating it renders it unsuitable for any stream, the value of whose commerce is not considerable.
The only method which seems feasible here is to break up the local slopes and distribute them over such distances as will reduce them to reasonable limits. This can generally be done by curving and thereby increasing the length of the channel, low dikes being run out alternately from each bank so as to concentrate the water pouring over the crest of the bar and hold it up until the requisite level is reached. These dikes will not increase the velocity of the current but rather diminish it, and as the flood will soon deposit gravel above and below them, it is believed that the curved channel-way thus set up will be reasonably permanent and reliable. Of course, in time it will be necessary to raise the dikes and perhaps to extend them, but at any rate the system will not simply result in transferring the bar from the head to the foot of the system of dikes, as almost invariably results when spur-dikes, designed simply to increase the scouring action of the current, are used. For want of definite information the estimate submitted, herewith is necessarily only a rough approximation, but I think it is at least large enough, and a carefully-matured plan based on a proper survey would very probably reduce it. We were unable to obtain the extreme low-water discharge of White River, but from such observations as we have, I infer that it is approximately 1,000 cubic feet per second at Jacksonport, above Black River. This should enable us to maintain a channel having 75 feet available width and 2½ feet in depth, provided the velocity be reduced to 3 miles an hour, or 4.4 feet per second. The proper slope to give this velocity will vary according to the nature of the bottom, and the amount of curvature of the channel-way; it must be determined experimentally, but it will, I think, be found to approximate 18 inches to the mile.
Above Batesville, our information concerning the discharge is too meager to be depended on, but I apprehend that it would hardly be safe to count on more than 18 inches depth of channel-way with a width of 60 feet from the head of Buffalo Shoals to Sylamore, the velocity being increased to 4 miles per hour. From Sylamore to Batesville we can probably obtain a channel 2 feet deep and 60 feet wide, with the same velocity of 4 miles per hour. These minimum depths, it must be remembered, will be at extreme low water only and for probably only a few weeks in each year.
Below Batesville the dikes should be built of brush and stone, anchored with piles. All the material would have to be moved some distance, and the depth of water in which some of the dikes would be located is considerable. Above Batesville, rock would generally be alone needed, and could in most cases be procured on the spot; the depth of water, too, would be less.
I have, therefore, assumed that a linear foot of dike below Batesville would cost $8, while above that place the cost would be $5.50.
The following list gives the various places where work will probably be needed, together with the number of linear feet of dike deemed necessary at each place, and the estimated cost of the same: From Jacksonport to Batesville.
From this it will be seen that the cost of improving the river from Jacksonport to Batesville is estimated at $218,800; from Batesville to Buffalo City, $282,837.50, and for Buffalo Shoals, $20,350. Adding 25 per cent, to these sums to cover engineering contingencies, they become respectively $273,500, $353,546.87, and $25,437.50. To this must be added the cost of necessary surveys, which will be $2,925 from Jacksonport to Batesville, and $6,825 from Batesville to head of Buffalo Shoals, or $9,750 for the whole distance.
There will, moreover, be needed at least twelve months7 labor of a snag-boat in removing snags and other obstructions, which, at $3,500 per month, would amount to $42,000, and, allowing $6,000for necessary repairs, $48,000.
The total cost of improvement would, therefore, be as follows:
From Jacksonport to Batesville............................................$273,500.00
From Batesville to Buffalo City..............................................353,546.87
For Buffalo Shoals ....................................................................25,437.50
From Jacksonport to Batesville, (for surveys)………………...$2,925.00
From Batesville to head of Buffalo Shoals, (for surveys)………6,825.00
For twelve months’ work of snag-boat, &c .....................................48,000.00
As regards the necessity for this improvement, it may be said that the country bordering on this portion of White River is almost entirely dependent on water transportation, which, from the difficult character of the navigation, is very uncertain and costly. If the facilities for transportation and communication were increased, there would no doubt be a considerable emigration to this country, which embraces much valuable cotton and mineral lands. This is especially true of, the section from Jacksonport to Batesville, to which it would probably be advisable to confine the improvement at first.
The amount of the estimate for surveys and snag-boat work, viz, $57,750, could profitably be expended during the first season.
Amount available July 1, 1875………………………………………………… $7,771.26
Amount expended during fiscal year ending June 30, 1876..................................7,771. 26
Amount appropriated by act approved August 14, 1876 .....................................10,000.00
Amount (estimated) required for completion of existing project………………710,234.37
Amount that can be profitably expended in fiscal year ending June 30, 1878…..57,700.00
1876 Chief’s Annual Report of the Chief of Engineers to the Secretary of War for the Year 1876: Appendixes to the Report of the Chief of Engineers. Page 622 – 62. Government Printing Office, Washington D.C. https://usace.contentdm.oclc.org/digital/collection/p16021coll6/id/1824/rec/15.