N.

PITTSBURG, October 25, 1835.

SIR: In obedience to your instructions of the 23d of April last, assigning to my superintendence the application of the sum of $50,000, appropriated at the last session of Congress, for the improvement of the Ohio river, above the falls, I have the honor to report the progress and state of the operations under those instructions, on the 30th of September ultimo.

On my arrival at Pittsburg, the head of the line, in May last, the Ohio river then presented a deep and turbid streain, with a depth of water, over its shoalest points, of eight feet, in which or nearly a similar state, it subsequently continued until September, being maintained by the freshets of the intermediate months, and varied by occasional depressions, of short duration; but at no time this season has it been impracticable for steamboats. of a construction adapting them to shoal navigation.

On the receipt of my instructions, it did not appear that any regular or detailed survey of this part of the river, with a view to its improvement, by the General Government, had ever been made, or was accessible at the time; the only information, in my possession, relative to the obstructions in the river at the time of my arrival thereon, was contained in the extracts taken from the notes of an examination, made in 1819, by commissioners appointed by the several States interested, and to which I was favored with access, through the politeness of the canal commissioners of Pennsylvania; these, although embracing much useful information in relation to the several obstructions, were not sufficiently minute to render less necessary a resurvey of the whole, upon a different plan, before the work hereafter deemed necessary, for the contemplated improvement, could be correctly located or safely constructed.

The duties assigned me, required, as a preliminary step, a minute and thorough examination of the obstructions at low water: this, for obvious reasons, could not be undertaken until the river had arrived at its minimum stage, which did not occur until late during the present season. In the interim, the whole line was traversed, the principal commercial points visited, and investigations made, having for their object, to determine the relative importance of the different portions of the line, and the selection of those points or sections having the greatest claims to precedence in the order of improvement; at the same time, the obstructions in the river, of a detached nature, being numerous, and an examination into their extent, or the peculiar circumstances of each, not immediately required for the object in view, attention was forth with directed to the construction of the machinery necessary to remove, with the greatest facility, all obstructions of

that class.

M. Shreve, Esq. in the removal of obstructions to the navigation of the The snag machinery invented, and used with so much effect, by Henry simplicity of arrangement, with great power of action, was, after a short inspection, unhesitatingly adopted for the removal of similar obstructions without delay, to the construction of four of these machines, for application in the Ohio river above the falls; it was, therefore, determined to proceed, on the river, and the procurement of the requisite boats, flats, implements,

&c. during the high stage of the water.

The expectation being confi

dently entertained, that the means of constructing any description of machinery or craft could be readily obtained at any of the principal points on the line.

The Ohio river, from its commencement at Pittsburg, forming a continuation of the grand chain of internal communication, stretching from the Atlantic westward, now rendered uninterrupted by the completion of the Pennsylvania line of canal and railroad, and the heavy amount of merchandise received and transhipped at the head of the river, estimated at half a million of tons annually, and progressively increasing, together with the general designation of the appropriation, induced attention to be first directed to the section lying between Pittsburg and Wheeling, which being of a shoaler character than that below it, was, from a due regard to the circumstances alluded to, selected for the commencement of the operations. It was then contemplated to hasten the construction of a portion of the machinery at the head of the river, with a view to its completion, and application on the fall of the water, at which time it would become necessary to turn attention to the examination of the shoals, and the formation of plans for their improvement.

In preparing the machinery and boats, during the high stage of water, it was found that the opinions entertained in regard to the facilities for its construction, at the points where alone they could be looked for, were entirely erroneous. The rapidly increasing trade on the western waters, and the many steamboats contracted for or building on this line, the number of which has been estimated at upwards of one hundred, rendered the accumulation of business on the hands of the builders, too great to admit of their assuming new jobs at this time; and the construction, by individual application, was rendered nearly as uncertain by the consequent absorption of all suitable workmen in this branch of business.

A machine, with the necessary keel and flat boats, and a full equipment of the necessary implements for the removal of rocks and snags, was completed in September: at this time the river presenting a favorable stage for the object, the work of examining the shoals was immediately proceeded with.

Previous to this, in the month of August, whilst in expectation of a continued fall of the water, the most important obstruction, in the upper section of the river, was partially surveyed, with a view to the location of works for its improvement: the examination being arrested by a sudden and unexpected fresh in the river, the surveys were subsequently completed in September. The plan for the improvement of Brown's island, the point alluded to, is now before the Department.

An examination of every obstruction to the navigation was completed in September.

The river has, throughout the present season, continued in a state un/ usually favorable to its trade and navigation; and, under these circumstances, has not presented the most satisfactory view of its low water character. The examination, however, has served to determine, very satisfactorily, the nature, extent, and comparative prominency of the different shoals.

The Ohio river derives from the Allegheny its principal and most lasting supply during the summer months, its volume is maintained, and very frequently increased, by the occasional rains during that period, which enlarge materially the supplies drawn from the copious basin of this tributary, and it is only during a season of unusual drought that it

arrives at its minimum stage; this, from a comparison of the best authorities, is assumed at 15 inches. The least depth obtained during the examination this season was 2 min. 2 sec., although the water, for the brief space of a few days only, has been as low as two feet over Some of the shoals between Pittsburg and Wheeling. The Ohio, throughout its whole course, has in general a very equable and gentle current. During high stages this is the most uniform, although its rate is then considerably increased; at low stages, the river becomes resolved into a succession of ripples, with extensive slack water basins between them, varying in depth from two to three and even five fathoms. The valley of the river is bounded on each side by richly timbered hills of great uniformity in their average height, enclosing fertile bottoms, which alternate in very regular succession on either side of the river; ledges of rock occasionally appear along its banks; these are generally of stratified and easily wrought sandstone. There are few points on the river deserving the name of gorges; the nearest approach to an opening of that character is found at Brown's island, 65 miles below Pittsburg. The heights here approach within the distance of 600 yards, and ledges of rocks exhibit themselves on each side. of the river. There are several other formidable passes on the river, which however, in comparison with the shoals, are few in number; of the character alluded to are Captina and Buffington's islands, and the rapids called Letart's falls: these are more dangerous for the passage of keel and flat boats than for that of steamers, which, under the management of careful pilots, are exposed to little risk, when there is found sufficient depth of water at those points for floatage. The obstructions in the river generally arise from the want of sufficient depth of water over many of the shoals at low stages. There are points however, where, owing to the existence of projecting rocks, the navigation is not safe for as much depth as is contained in the channel. The bars in the river may be classed, 1st, into those formed of hard and apparently of permanent gravel; 2d, shifting or loose gravel; and 3d, shifting sand bars. The first abound in the upper section of the river. These are generally exposed to a strong current, and formed of rounded oblong pebbies and stones, varying from one to fifty pounds and upwards; they become, by the continued action of the water, cleared of all smaller particles, firmly imbed led, and by their conformation resist the action of the current; the bottom assuming the consistency of, or similarity with, a pavement of smooth

stones.

The bars of the second class are composed of fine gravel, moveable by strong currents, and occur, as well as most of the sand bars, at the lower junction of the chutes formed by the islands; these change their position, when, upon the fall of the waters, the main channel of the river predominates in a new direction, and the fall and current increased by the subsidence of the lower basins. In the upper section of the river, the sand bars are always found under the lee of the islands, or at the meeting of the channels. In the lower section are extensive sand bars, unaccompanied by islands; the most important of these are met with between Guyandot and Cincinnati. In addition to the shoals, large quantities of logs and snags are distributed in different parts of the river. On some of the shoals, they lie imbedded in the gravel, forming, by the projection of their stumps, very dangerous obstructions to the low water navigation. Large trees, with their roots, branches, and foliage, in full verdure, undermined and thrown into the stream by the gradual abrasion of the alluvial banks at high water, are of