northwest corner of the chimney of Hibbard's saw-mill. It was asserted by some river men that the water had been known as much as two feet lower and also two feet higher than this mark, but the only point known to be bare at low water, which was pointed out to us, was one foot below the assumed level. The water, during our stay, varied from 0.65 above to 0.5 below the 1-foot mark. The difference in the level of the water at the ferry dock and at Fish's old dock, a distance of 3,500 feet, is 0.428 feet, giving a fall of 0.645 feet per mile. The only observation for velocity taken was about 250 feet from shore. The float, submerged 6 feet, passed over 1,684 feet in six minutes 32 seconds, equivalent to a mile in 20 minutes 29 seconds. Further out the current is far swifter, but a continuous rain, on the only day we could spare for these observations, prevented us from obtaining further data. The bottom of Black River, as found by boring, consists of a soft gray mud, with very fine sand in about equal proportions, for a depth of four feet, overlaid by eight inches of coarse sand. All over the "middle ground," in St. Clair River, nothing was found but clear coarse gravel, which the auger could not bring up, but is plainly visible in clear weather On the new railroad dock fine mud, with some little fine sand, was brought up from the bottom. The surveys and examinations were completed on May 4; the party discharged, and myself, with Mr. Cram, returned to Detroit. In its ordinary stages Black River has little or no current, and what little deposits it carries along are found near shore, below its mouth, in the shape of fine mud, as shown in the borings at the new railroad dock. Nothing of this kind was found on the "middle ground," which consists wholly of sand and coarse gravel, the washings of the shores above. But in times of high water the current of Black River is very swift, and pushes far out into St. Clair River, checking its current and thus causing it to deposit the materials which otherwise might be carried into Lake St. Clair. There can be no doubt that the action of the Black River current has thus formed the large flat known as the “middle ground,” and is still annually increasing it. The charts of the lake survey of the years 1858 and 186-, compared with the map of the present survey, plainly show its increase in horizontal as well as vertical extent. If the whole of the "middle ground” was removed it undoubtedly would form again in the course of time, unless the current of Black River, at present nearly vertical to that of St. Clair River, is deflected so as to enter the latter in a nearly parallel direction. To the general commerce of the lakes the existence of this "middle ground” can scarcely be said to be any obstacle. There is ample depth in the middle of St. Clair River and toward the Canada shore, and an easy approach to the natural port of Port Huron, which is above the mouth of Black River, and not threatened by any increase of the "middle ground." The only damage occasioned to general commerce by its existence occurs when vessels are driven to shelter in St. Clair River by northern storms in Lake Huron, when some hundred of them may come flying in, and be crowded, perhaps, in night time on the shoals of the "middle ground." To remove the "middle ground" to a depth of 15 feet would require dredging of 168,300 cubic yards of gravel, covering an area of 46.6 acres; and to a depth of 18 feet, 393,800 cubic yards, on an area of 82 acres. The latter would probably be required if a safe anchorage must be afforded to the larger class of propellers in stormy weather. The local interests of Port Huron, or that part of it below the month of Black River, would be amply served by an excavation along shore 300 feet wide to a depth of 15 feet, involving the dredging of 75,300 cubic yards. As before stated, however, no permanent benefit could be derived from either of these excavations, unless accompanied by a change of direction of the mouth of Black River. To effect this a dam should be built obliquely across the mouth, from Hibbard's mill to White's dock, a distance of 500 feet, in water averaging 9 feet deep, and a new channel dredged, for the mouth of the river, 1,200 feet in length and 200 feet in width, to a depth of ten feet in clay and mud, say, 88,900 cubic yards. This would bring the current of Black River into St. Clair River in a parallel direction, and leave the current of the latter unchecked. A map of the survey of the "middle ground,” on a scale of too was commenced in May, but its completion unavoidably delayed by the absence of Mr. Cram and myself, on other duties. Respectfully submitted. Major O. M. POE, Corps of Engineers U. S. A. H. A. ULFFERS, Civil Engineer, Assistant. The map referred to in the report has since been completed, and a copy of it upon a scale of is herewith transmitted. 5000 I fully agree with Colonel Ulffers in regard to the process of forma tion of the shoal known as the "middle ground,” and think the measures be recommends for its removal the only practical ones. But the formation of the shoal goes on more rapidly now than formerly. This is due to to the more rapid degradation of the shore between the town of Port Hudson, and the Grand Trunk Railway depot. Much of this is due to the direction of the Grand Trunk wharf, which is such as to direct the very rapid current of the river against the bank below the south end of the wharf. The following estimate of the probable cost of building the dam across Black River, and dredging out a new channel, is submitted, viz: For 500 lineal feet of sheet-pile bulk-head, at $15 per lineal foot..... For 88,900 cubic yards, dredging at 60 cents per cubic yard.... Add 10 per cent. for contingencies... $7,500 00 53, 340 00 60, 840 00 6,084 00 Total.. 66,924 00 This estimate is a liberal one so far as the cost of the work is concerned. But the land required in obtaining an outlet will be quite expensive, and as the amount is unknown, and cannot even be approximated in an estimate, it is omitted. The cost of removing the "middle ground" is estimated as follows: To obtain 15 feet of water over an area of 46.6 acres, 168,300 cubic yards dredging, at 40 cents per cubic yard, To obtain 18 feet of water over an area of 82 acres, 393,800 cubic yards dredging, at 40 cents per cubic yard. $67,320 00 157,520 00 These estimates, again, are liberal; I deem them sufficiently so to cover all contingent expenses. The estimate for the entire work of changing the direction of the outlet of Black River, and dredging so as to get 15 feet of water, would be And to do the work economically and well, the entire amount should be appropriated in one sum. The nearest light-house is known as Fort Gratiot light. The locality is immediately abreast a portion of the city of Port Huron, in the collection district of Huron. The amount of revenue collected at Port Huron, for the fiscal year ending June 30, 1871, was $113, 657 73. The number of vessels (exclusive of barges and scows) which passed Fort Gratiot light in daylight, of week days, during the fiscal year was... 16, 933 Add 100 per cent. for vessels passing on Sundays and nights, and for barges and scows, and for vessels from below which passed the "middle ground," but did not go up as far as the light.... Total vessels passing the "middle ground". $16,933 33, 866 But statistics which relate to Port Huron, alone, have little bearing upon the case. From the large number of vessels reported above as passing, it is seen that the entire commerce between upper and lower lake ports is interested. All of which is respectfully submitted. O. M. POE, Major of Engineers, and Brevet Brigadier General, U. S. A. Brigadier General A. A. HUMPHREYS, REPORT C 6. CONCERNING THE IMPROVEMENT OF CLINTON RIVER, MICHIGAN. By letter from the Chief of Engineers, dated July 18, 1871, and received on the 20th, I was informed that by act of Congress approved July 11, 1870, the sum of $5,000 had been appropriated, "For improvement of Clinton River, Michigan," and I was instructed to submit, at as early a day as practicable, a project for the prosecution of the work. Accordingly, on the 23d of July, I submitted the following project: UNITED STATES ENGINEER OFFICE, SIR: Inclosed herewith I transmit a small sketch, upon a scale of 100, of the mouth of Clinton River, Michigan, and have indicated upon it such improvement as it is probable can be made with the appropriation of $5,000 available. The project contemplates dredging an 8-foot channel, nearly straight out from the mouth of the river, with a width of 50 feet at the bottom, and 100 feet at the top. If a greater width is given to the cut, the appropriation will not be sufficient to give an 8-foot channel, as the amount of material to be removed in making such a cut is about 17,385 cubic yards; indeed it is doubtful whether the bids will be sufficiently low to warrant undertaking to make a channel of 8 feet. One of 71⁄2 feet will require the removal of 15,000 cubic yards, and one of 7 feet, 12,800 cubic yards. I take it for granted that the width of the cut as proposed is the smallest allowable, and yet I deem it sufficient for the commerce of the place; the only question then is concerning the depth. I therefore respect fully recommend that the cut be made 50 feet wide at bottom, and 100 feet at top, at the shoalest points, and dredged to such uniform depth as the funds available will allow. In the absence of a more detailed survey, the sketch inclosed is the best I have been able to obtain, and as I have no duplicate of it, I have respectfully to request that it be returned with the reply of the Chief of Engineers. I also inclose a copy of the advertisement I propose to make in case the foregoing recommendation is approved. I am not familiar with the routine in the matter of advertising, and therefore have to request that if the proposed advertisement requires the approval of the War Department, that it be forwarded for that purpose. I think two weeks' notice of the time at which the proposals are to be opened quite sufficient, and it is now so late in the season that much more cannot be given without causing bidders to name a higher price for the work. If the project is approved I will require $2,500 during the month of August, and $2,500 in September. I am, sir, very respectfully, your obedient servant, O. M. POE, Major of Engineers, and Brevet Brigadier General, U. S. A. Brevet Major General A. A. HUMPHREYS, Chief of Engineers, United States Army, Washington, D. C. Which was duly approved by the Chief of Engineers as follows: OFFICE OF THE CHIEF OF ENGINEERS, Washington, D. C., July 26, 1870. GENERAL: Your project of operations for the improvement of the mouth of Clinton River, Michigan, as set forth in your letter of the 23d instant, is approved, and you are authorized in your advertisement for proposals to reduce the number of days' notice to fourteen. The sketch accompanying your letter is herewith returned. Very respectfully, your obedient servant, By command of Brevet Major General Humphreys: JOHN G. PARKE, Major of Engineers, and Brevet Major General, United States Ármy. Brevet Brigadier General O. M. POE, Major of Engineers, Detroit, Michigan. Proposals for the work were invited by advertisement dated August 1,1870, and were duly opened on the 31st. The following is an abstract of all received: Deeming the offer of Mr. John Brown to do the dredging required for 22 cents per cubic yard, measured in the scows, to be the most advantageous for the Government, I recommended its acceptance, and was authorized to enter into contract with him accordingly. The work was taken in hand by Mr. Brown, but owing to circumstances explained in the following correspondence, it was found necessary to extend the time of completion. SIR: Mr. John Brown, contractor for the improvement of Clinton River, Michigan, has just been in to say that he has encountered unexpected difficulty in the work; the dredging being harder than anticipated, and the shallow water on the bar making it both tedious and difficult to manage the dumping-scows. He has reached the shallowest part, (only 34 feet of water.) The effect of this will probably be to protract the work beyond the 1st of November, the date named on his bid as that upon which the work was to be completed. He states that he intended to say the 1st December. Inasmuch as the contract provides for the completion of the work on the 1st November, I request to be instructed whether this extension to the 1st December can be permitted. A channel will be available by the 1st of November, or before; but the entire work will not be completed. I have been at the work, and know that the condition of things reported exists so far as the depth of water is concerned. Until a channel is made through, available for the dumping-scows, I don't exactly see how the work can be pushed more rapidly, and I respectfully recommend the extension of time named. I am, sir, very respectfully, your obedient servant, Brigadier General A. A. HUMPHREYS, Chief of Engineers, United States Army. O. M. POE, Major of Engineers. P. S.-Two thousand six hundred and twelve cubic yards had been excavated and removed up to Saturday evening, the 15th instant. OFFICE OF THE CHIEF OF ENGINEERS, Washington, D. C., October 22, 1870. MAJOR: Your letter of the 18th instant is received. You are authorized, for the reasons stated, to extend the time for the completion of the contract of Mr. John Brown for the improvement of Clinton River, Michigan, from the 1st November to the 1st of December, 1870. Very respectfully, your obedient servant, By command of Brigadier General Humphreys: Major O. M. POE, Corps of Engineers, Detroit, Michigan. JOHN G. PARKE. Major of Engineers. The work progressed well until its completion, the resulting channel being as follows: Depth of water at stage of 1st December, 1870. ... Feet. 2,700 98 58 9 Amount of material removed, 20,454 cubic yards, and the cost being for The channel obtained is a better one than I expected, and thus far has given satisfaction. I counted upon the rapid filling of the cut by driftsand brought into it by the southwestward current setting directly across it. But this has not been as serious as I supposed it would be, and the channel is in daily use, without complaint that I have as yet heard from any source. By act of Congress, approved March 3, 1871, the sum of $1,500 is ap propriated for this work. It is proposed, before the close of this season, to make a detailed survey of the improvement, with a view to determine its present condition, and the measures necessary to maintain its efficiency. The nearest port of entry is Detroit, Michigan, situated in the collection district of Detroit. The nearest light house is at St. Clair Flats. The amount of revenue collected at Detroit for the fiscal year ending June 30, 1871, was $270,053 08, and the revenue collected at Clinton River, for same period, was $11, and the number of vessels entering from, and clearing to, ports beyond the district was 133. Much the greater portion of the trade at Clinton River is carried on with ports in the same collection district, and vessels engaged in it are, by act of Congress approved July 1, 1870, relieved from the necessity of reporting and clearing. Hence accuracy of the statistics of the commerce of the place given above is limited as indicated. All of which is respectfully submitted. O. M. POE, Major of Engineers, and Brevet Brigadier General, U. S. A. |