into the present channel west of the island, and to the scouring force resulting from this addition of water is due the depth of water along this portion of the harbor.

Deep water and good navigation originally obtained along the wharf-line in the northern part of the harbor until about 1851. Previous to that year a large portion of the river flowed to the east of Cabaret Island through the slough, now almost entirely closed up with sand. The flood of that year produced changes that materially altered the circumstances of flow, and the greater portion of the water that originally flowed through Cabaret Slough was deflected to the west of the island, passing through Pocket Chute, and also along Sawyer's Bend.

The northern wharf-line of the city has been gradually extended out toward the river, at what rate previous to 1851, I am not positive. Very soon after the flood spoken of, a large bar began to form along the northern wharf-line, probably due to the changes produced by the flood, as well as, to a certain extent, the changes in the line of wharf. As the formation of the bar commenced soon after the deflection of the water from Cabaret Slough to the west of the island, it would seem reasonable to suppose that any method which would throw the water back into the slough and produce the same state of things that existed before the flood, would have the desired effect upon the harbor. After the presentation of several plans, it was finally decided, in 1867, or thereabouts, to construct a dike upon the chain of rocks, to deflect the water into the slough, and it was constructed the following year, at an expense to the city of $92,000; the perpendicular portion was 1,400 feet in length, and the longitudinal portion 2,000 feet. As previously stated, it has not had the effect intended. The slough is rapidly filling up instead of scouring out. The dike is causing increased abrasion of the bend below it. The latter, Sawyer's Bond, is wearing rapidly, and unless some means are taken to prevent further encroachments, it is my opinion that considerable damage will eventually accrue to the site of the new water-works. Revetment of this bank for the entire distance would, no doubt, stop the encroachments, so long as the revetment remained, but this is too costly an experiment to be recommended until it is decided that no other means can be adopted. Borings along portions of this front show (as I am informed) that nothing but sediment and sand constitute the bed of the river for 60 to 70 feet down to the underlying rock. The banks are steep, and average 20 to 30 feet above the river surface at low water. Without going into an estimate of the cost of providing a revetment of any nature along this bend, it will be apparent that it would be very expensive, whether viewed in the light of an experiment, or as an undertaking with a surety of success.

Gingrass Creek has been reached; this is a ravine nearly dry at times, emptying into the harbor near Salisbury street. Tracing it up, it runs parallel to the river and at an average distance of 1,400 feet from it, until it reaches a point opposite the foot of Cabaret Island Slough, when it inclines toward the river, striking it at a point about half a mile above the foot of Cabaret Island; thence turning from the river, it is lost in the bluffs. Its rise, as far as traced, appeared to be nearly opposite the middle of Cabaret Island. The new water-works are built on the strip of land bordered by this creek and the river. In addition to the Grand Chain Dike, the city has erected a number of others at various points in the harbor. There are four of these visible in the upper harbor, on the Illinois side of the river. The first dike, called Bischoff's Dike, is in the best condition; the water rushes around the outer end with great force, and strikes the shore a short distance below; it is inclined a little up stream and extends nearly half across the river from the Illinois shore. A little below this dike is a much smaller one; a short distance below the Madison County Ferry Landing is another small dike; about half-way from Bischoff's Dike to the head of Bloody Island is what is called the Long Dike; near the shore there is a wide breach, through which the water rushes with great force, and has worn for itself a deep channel close to the shore, and between the shore and the large sand-bar below the dike, the water flowing through this chute and around the head of Bloody Island. The shore in the bend below the dike is rapidly wearing, the abrasion having extended to the distance of about 150 feet since Merrill's survey. The beach in the Long Dike should be thoroughly repaired. At the time I last examined it, the ferry company were making some repairs upon it, to preserve their land.

These dikes, commencing with the upper or Bischoff's, I have numbered 1, 2, 3, and 4. Between dikes 2 and 3 is the Madison County Ferry Landing, which serves the purpose of a short dike.

Below Bloody Island, and opposite the foot of Chouteau avenue, is what is called the Coal Dike, about 1,900 feet in length, and perpendicular to the direction of the present channel of the river. This is the only case, apparently, where a dike in the harbor has thoroughly accomplished all that was expected of it. It has had the effect of throwing the current against the St. Louis shore, clearing out the bar formed there many years ago, and filling up the old steamboat channel along the Illinois shore to a point above low-water mark, and from 1,500 to 3,500 feet in width, extending from the lower end of Bloody Island to Arsenal Island. The value of the land formed by constructing this dike will more than repay the cost of its construction.

The next dike that is still visible is at the head of Arsenal Island. This dike was built by the city of St. Louis for the purpose of deflecting the current down the channel between Arsenal Island and the city of St. Louis. The main channel of the river has several times changed during the last fifty years, from west to east, and from east to west of Arsenal Island; it is now on the west side of the island, and probably will remain so, as the Coal Dike opposite Chouteau avenue has the effect of constantly making land below it, and deflecting the current to the opposite shore. The dike across the slough, at the head of Arsenal Island, if it ever closed up that slough, has now a large break in it, and a considerable body of water rushes through between it and the head of the island, wearing away the head of the latter. This slough should be closed up, and the island revetted at the head, and for some distance down the west side.

The survey showed that good water exists all along the city front, from Mullanphy street down to the arsenal, and all along Bloody Island front, to a point about midway between the point of the Coal Dike and the East St. Louis elevator. Along this portion is a narrow bar, but as there is little necessity for boats landing along this portion, the bar cannot be called an obstruction to navigation, neither do I apprehend that it will extend out far enough into the channel to occasion any trouble.

The large bar along the wharf (northern) described in Merrill's report has decreased in size, due, in my opinion, to the effect of the dikes, particularly the upper one. The maximum width of the bar at lowest water is about 1,000 feet. At medium stages the bar would average about 150 to 200 feet in width, although there are points where a landing can be effected. Still, although there has been an evident scour and reduction of the size of the bar within the last three years, the evil still exists in full force, as a narrow bar as much precludes the landing of boats as a broad one.

Opposite the head of Bloody Island, but nearer to the Missouri shore, in front of the city, is a large irregular bar, extending some distance above and below the head of the island, with a deep channel all around it. The dikes, although they seem to have effected a removal of some portion of the obstructions along the northern wharf, have caused considerable deposits below them. These bars, as soon as they come within the scouring influence of the current, must be carried below the foot of Bloody Island, and probably below Arsenal Island. A further extension of all the dikes would seem to be desirable, the upper dike (known as Bischoff's) needing the least.

For a distance of more than a mile above the upper dike, (No. 1,) the channel is of uniform width, and for this distance, and below the dike along the wharf-line, the bar has its minimum width until a point above the old water-works is reached.

The Illinois shore, in the bend opposite the city, requires protection, either by raising the dikes, or by revetment.

The deepening of Pocket Chute, as stated in that portion of my report pertaining to the general survey, would probably relieve the bank in Sawyer's Bend from some portion of the abrasion it now suffers; but it would not, in my opinion, be sufficient in itself to scour out any large portion of the bar in the upper portion of the harbor. Undoubtedly, if the river could be made to take the same course as it had before the Cabaret Slough was closed up, the upper portion of the harbor would attain very nearly the same condition that it had before the flood of 1851. Should this ever obtain, the Cabaret Slough would require revetment of some portion of its banks.

The bar at the lower end of Carondelet occasions some anxiety to those interested in that portion of the harbor, and it is thought by them that the evil bids fair to be of sufficient magnitude to call for the erection of dikes on the opposite side of the river, to remove the bar along this portion of the front as well as along that portion of the Government reservation upon which are situated the powder-magazines. I have been unable to discover any great difficulty to boats landing along the reservation front, and the commanding officer at the barracks informed me that there was no difficulty in making landings at that point. Dikes opposite the lower portion of the city would, undoubtedly, improve the portion of the Carondelet Harbor where the bar exists, but the extent of my examinations does not admit of any conclusive statement as to their absolute necessity or cost. All the experiments made in the improvement of the harbor have shown the difficulty, where any scouring occurs, of providing any structure for the protection of the banks, or to serve to deflect the water, unless the structure rests directly upon the bed-rock. As the rock is a great distance below the bed of the river, the amount of material required for the smallest structure would be very great, and would be only conjectural, unless direct examinations were made to ascertain the depth as well as stability of the deposit. In the absence of any such examinations of my own, I have taken the following extract from a report made by Messrs. Homer and Moulton in a communication to W. J. McAlpine, president of the board of engineers, convened at St. Louis, in August, 1867, to consider the project of a bridge across the river:

“Four borings were made in the river in continuation of the north line of Green street; the first at a distance of 265 feet east of the west line of the wharf, where the rock was found coincident with the bed of the river at minus 56.70, or 22.89 feet below low water;

the second at a point 500 feet east of the last point, where the rock was found at a depth of minus 97.46, or 63.65 feet below low water, and the water had a depth of 13.7 feet, leaving 49.95 as the thickness of the river deposit above the rock; the third was at a point 500 feet still further east of the last point, where the rock was found at a depth of minus 123.33, or 89.52 feet below low water; here the water was 10.19 feet deep, leaving 79.33 feet as the thickness of the river deposit above the rock; the fourth was at a point 500 feet still further east, where the boring was carried to a depth of minus 101.42, or 67.61 feet below low water, and then abandoned on account of the breaking up of the ice. At this point the water was 16.19 feet deep, and the river deposit was penetrated through a thickness of 51.42 feet. These borings were made early in the winter of 1866."

Chief Engineer James B. Eads, in his last report upon the St. Louis bridge, of October 1, 1870, says, in regard to the building of the east pier:

"During low water, the normal deposit of sand over the bed-rock at this pier is about 80 feet. A rise in the river causes it to scour down, while a subsidence of the flood permits the moving sands from above to deposit rapidly and again raise the sandbed. At the time of placing the caisson in position, the water in the river was 35 feet deep, and 68 feet of sand was then overlying the rock."

It is beyond doubt that the rock underlies the movable mass of sand to a great depth all over the harbor. I am informed that attempts have been made to protect the banks in front of the new water-works at Bissell's Point, by constructing a rip-rap wall, and that the stone disappeared as rapidly as thrown in. The fate of the numerous dikes constructed all around the harbor, where they did not extend to the bedrock, is another proof of the point in question and the force of the scour. Single dikes, and even the most extensive system of dikes, frequently fail to answer the expectations of those who build them. Perpendicular dikes, although less subject to scour on the up-stream side than oblique dikes, nevertheless suffer heavy scour around the heads and along their lower faces, from the effects of the currents running around and along them. When the river flows over them, the lower edges are frequently undermined by the action of the water as it falls over the crest, causing the dike to settle on that side. The current, backed up by the dike, follows a line drawn from the highest point to which it is backed, to some point on the prolongation of the axis of the dike, the distance of this point from the dike depending upon the circumstancesof flow. From this point it gradually "draws" around the point of the dike, forming an eddy and consequent bar below it, frequently scouring out the bank below the dike and between the bar and the line of banks. This scour may be prevented by the construction of smaller dikes below, or by revetment of the banks. In no case should there be long reaches of shore between dikes unprotected either by revetment or spurdikes.

The preferable way, in my opinion, unless the expense totally forbids it, to contract a water-way, is to construct longitudinal dikes, so arranged as to give to the river at each point (measured along its axis) an area of cross-section just sufficient to admit the passage of a volume of water depending upon a velocity consistent with the regimen and navigation of the river at that point. Too high and too low dikes should be equally avoided. Whenever possible, the dike or levee should be so sloped as to graduate this discharge of water at all stages. During its progress careful observation should be made upon the river, and the engineer should be at liberty to modify the plans as he proceeds with the work. When once commenced, the work should not be stopped for want of funds, but pushed vigorously to its completion. Half-matured plans and half-finished hydraulic works produce more mischief, generally, than the evils they are intended to remedy.

My examinations of the river, and particularly of the harbor of St. Louis, although as extensive as the funds at command and the time would admit of, are necessarily incomplete. I have therefore confined myself mainly to a statement of the condition of the harbor as my survey found it, leaving out any recommendation for a general plan of improvement. I am constrained to do this, for there are so many questions involved requiring the possession of data which I could not obtain, and which are necessary to the solution of even the most insignificant hydraulic problems, and without which it would be impossible to arrive at any satisfactory conclusions, either as to plan

or cost.

In the presentation of a plan of improvement, not only should it be comprehensive, but it should be, if possible, the minimum one in regard to cost. To get at this requires a complete and systematic survey of the harbor throughout, as well as the river above it to the Missouri, and up the latter for several miles and below the city for at least ten miles, and thorough hydrographic and hydrometric examinations for at least one year, from flood to flood, and throughout the varying stages. Borings, also, should be made at the points designed for revetments or dikes, and the abrasion of the shore steadily watched. The whole valley, from bluff to bluff, should be, in fact, surveyed. There have been frequent examinations of particular localities within the last twentyfive years, but nothing continuous. Material changes have taken place, both natural

and artificial, since the extensive survey of 1843, and the extent of the harbor has been increased since the one of 1868-69. Neither of these latter extended below the city for any distance.

A thorough survey of the nature described, and which would be economical in the end, would cost about $25,000.

Statistics of the city.

Population, according to last census, 310, 864; amount of coal received in 1870, 23,918,225 bushels; number of buildings erected in 1870, 1,134, costing $7,307,525.

Statistics of the port.

Number of steamers and barges employed in the trade: Steamers 209, barges 229, with a carrying capacity of 236, 960 tons, and valued at $6,844,200.

Number of arrivals and departures of vessels in 1870: Arrivals, 2,796 steamers, 1,195 barges. Departures, 2,782 steamers; number of barges not given.

St. Louis is situated in first collection district of Missouri. Amount of internal revenue collected for the year ending June 30, 1870, $5,081,287 05.

Within the city limits are the custom-house and United States arsenal. Government building outside the city limits is Jefferson Barracks.

87,106.82

The nearest

With this report I inclose two tracings, one general map of the survey on a scale of 3,600 feet to the inch, and one special map of St. Louis Harbor from the upper city limits to the lower old city limits, on a scale of 600 feet to the inch.

Mr. McGregory, my assistant in the survey, was, at one time, city engineer of Alton, and since has been engaged on land surveys in Madison County, Illinois. To his researches I am indebted for the information obtained regarding the old land surveys, as well as for other points of the examination.

OFFICE WESTERN RIVER IMPROVEMENTS,

St. Louis, Missouri, December 28, 1870.

GENERAL: I have the honor to forward herewith the report of an examination of the Osage River, made under my direction by Mr. D.

Fitzgerald, in compliance with your instructions of the 23d of July and 23d of August last.

Mr. Fitzgerald proposes to improve this stream by dredging the shoals, and gives it as his opinion that by this method 3 feet of water can be maintained for nine months in the year.

It is to be regretted that the means were not furnished to obtain more accurate data upon which to base an estimate than was done in this case. Mr. Fitzgerald did all that could be expected under the circumstances, and his opinion is entitled to all the weight that is due to one who has seen that of which he speaks. Still the "examination" was nothing more than what could be made while passing rapidly down the stream, and his opinion cannot be taken as an accurate estimate. He has, however, left so large a margin as to leave little doubt that the navigation of this stream can be so much improved as to afford priceless benefit upon the country through which it flows; for if, instead of three feet, as proposed by Mr. Fitzgerald, 24 or even 2 feet can be maintained during nine months of the year, it will afford the means of shipping a large amount of produce which at present is unable to reach a market.

The table given in the report of "the counties touching directly on the river, not including those on its tributaries," shows the area of those counties to be 5,290 square miles-the population, in 1860, to have been 61,627, and the taxable wealth to have been $22,947,892. The popula tion at present is probably over 100,000, and as the "taxable wealth” is always much less than the actual value, the present real value of the property in the counties named cannot be estimated at less than $100,000,000. This gives an idea of the importance of the improvement proposed.

The estimates given are on the supposition that no rock in place will be met with in the excavation. All the information that I have obtained sustains Mr. Fitzgerald's opinion that this will not be the case.

Mr. Fitzgerald does not estimate for a small steamer for attending upon and moving the dredge, or for contingencies of any kind; to meet these an addition of not less than 10 per cent. should be made to the amount he thinks will be necessary, making the total amount required for the proposed improvement of the Osage River from its mouth to Roscoe, $200,000, of which $50,000 would be required the first year. This amount, expended judiciously between the mouth and Tuscumbia, would afford material relief and test the method of the improvement proposed.

Very respectfully,

W. F. RAYNOLDS,

Lieutenant Colonel, Corps of Engineers, U. S. Army. Brigadier General A. A. HUMPHREYS,

Chief of Engineers, U. S. Army, Washington, D. C.

(A tracing of the map accompanying the report will be forwarded in a separate package.)

OFFICE WESTERN RIVER IMPROVEMENTS, St. Louis, Missouri, November 30, 1870. COLONEL: On the 1st of October I received instructions from you to make a preliminary examination of the Osage River with reference to the improvement of naviga

tion.

As neither the means nor the time were sufficient to make an accurate survey, I determined, with your sanction, to proceed to the head of navigation and float down