(the May Graham), a side-wheel steamer of ninety-six tons burthen, makes regular trips from Saint Joseph to Berrien Springs. She draws, when loaded, from 20 to 30 inches of water and seems to be of ample capacity to do the business of the river at present. During the low stages of water she ineets with many obstructions, and at times is obliged to discontinue the navigation over a portion of this route. The following estimate of the business done on the river between Saint Joseph and Berrien Springs, in the year 1878, was furnished me by Mr. James Brooks, master and owner of the steamboat May Graham. It is probably as fair and correct an estimate as can be had from the nature of the business:

Freight downstream to Saint Joseph: 3,000 cords 4 foot wood; 500 cords stave bolts: 300 to 500 cords bass wood; 300,000 feet hard wood; 3,000 to 5,000 railroad ties; 35,000 crates and baskets of fruit. Also a large amount of apples and grain not estimated. It is impossible to estimate the freight upstream for Berrien Springs and other landings. It consists of general supplies of all kinds. Lime, salt, farming implements, and about 300,000 feet of pine lumber for building purposes.

The tonnage of the river during the year 1878 is as follows:

The steamboat May Graham, of 96 tons burthen, employs six men and makes about 160 round trips during the season of navigation.

The Republic, of 75 tons burthen, employs the same number of men and makes about the same number of trips. Her trips are mostly on the lower 14 miles of the river. My instructions require of me an examination of the stream for the purpose of determining if it is capable of being made navigable, and the cost of such improvements as are deemed necessary to make free navigation.

Assuming, therefore, for the present that the navigation of the stream is expedient and desirable, I will proceed at once to the consideration of such improvements as in my judgment seem to be necessary to accomplish the desired results.

In this report I offer no solution to the many problems which are presented, giving only general results. The first question that presents itself is as to the depth of water required. In my letter of instructions no suggestions were given me on this question, for upon the existing facts as. found by my examination the necessary depth of water should depend. In other words, upon the amount of business to be carried on will depend the depth of water to be prepared, and we find on the other hand in this instance that upon the amount of water made available probably will depend the amount of business. From an examination of my maps it may be seen that in the worst stage of water a depth of no less than 16 inches may be relied upon. If, with this depth of water, navigation should practically cease on a greater portion of the stream and entirely cease on that portion accessible to railroads, it is evident that to revive the river business a depth of water far exceeding this must be prepared and maintained.

The navigation of the river between the limits of survey might be considerably improved for such boats as are now used on the last 20 miles, by cutting sluices through the shoals from 30 to 50 feet wide and from 2 to 3 feet in depth. This, with a judicious use of wing-walls or dams to contract the width of the stream at places, would probably give a depth of water of from 2 to 3 feet. I, however, consider this method very unreliable and in the present case not desirable except in that portion of the stream between Saint Joseph and Berrien Springs, where a slight improvement would give ample depth for all present purposes. The cost of improving this portion of the river by the foregoing method I have estimated at $11,300. The extent to which this method would improve that portion of the river above Berrien Springs is very uncertain. The fall of river for the depth of water is very great, and by the contraction of the channel or the removal of bars at one point it is highly probable that obstructions fully as great would be developed at other points. I find on the river several places where this method has been tried, and in every instance the river at these points is in a very bad condition. Also the location of the river, except that portion between Berrien Springs and Saint Joseph, is such in regard to railroads that in order to insure a business of any importance on the river its navigation must be made uniform and reliable and not depending upon or subject to the accidents of flood or freshet. My estimates by the foregoing method are as follows:

Making, in all, $85,039.70, to which should be added engineering expenses of 10 per cent., making the estimated cost by this method $93,543.67.

I consider that in any improvement of this kind where the commerce by river may be said to be prospective and depending upon such improvement, that the system adopted should be one that will be permanent, and the depth of water prepared should at least coincide with the usual river navigation, and boats for its navigation should be prepared for that special purpose.

In my estimation, slack-water navigation presents the only solution to this problem. The following estimates of the cost of making a depth of 4 feet by means of locks and dams is presented. It is only approximate and will be of value only so far as it shows the probable cost of such an undertaking. In order to make estimates of any value special surveys must be made at the locations of the several locks and dams as determined by my profile of the river. In this estimate no account is had of the land necessary to be purchased for the work, nor for damages caused by the flooding of land or otherwise.

ESTIMATES OF COST OF IMPROVING THE RIVER BY MEANS OF LOCKS AND DAMS.

The works when completed would probably not be self-sustaining and would require large appropriations each year for lock-keepers and other expenses.

I found a great diversity of opinion among the residents along the river as to the necessity or advisability of improving the river for navigation. From Niles to Elkhart the country is so thoroughly cut up and supplied with railroads that it cannot be considered a necessity, while on the other hand competition in freight of all kinds to be moved to and from the above localities would make the improvement seem desirable. From Niles to Saint Joseph we find a large tract of country depending in a measure upon the river as a highway for its grain, fruits, and timber to market, and farming implements and supplies of all kinds in return. An appropriation of even $10,000 expended on that portion of river between Berrien Springs and Saint Joseph would be of great benefit to that section.

Taken as a whole, I find the section of country through which the Saint Joseph River runs to have no widely extended wants to be supplied. The river is not, and

the proposed improvement would not make it, a trunk line for freight or commerce. The improvement would depend mostly on local traffic to sustain it, and I am of the opinion that it would become entirely inoperative for the want of such traffic.

SAINT JOSEPH AND BENTON HARBOR SHIP-CANAL.

The survey of the channel leading from Saint Joseph to Benton Harbor, a distance of 4,800 feet, is made a part of this report.

The survey, location of canal, and plat of sounding are fully shown on the accompanying maps. The work of constructing this canal or slip was commenced about the year 1860 as a private enterprise. The work was only partially completed at that time, and until 1870 was in a very useless and unfinished state. In that year the work received aid to the extent of $15,000 from the town of Benton. With this appropriation the work was placed in its present condition, with the exception of a wing-dam at its junction with the Saint Joseph River.

In the year 1875, under an appropriation from the general government, the sum of $9,046.24 was expended in building a wing-dam in the Saint Joseph River at the mouth of the canal. This work was built for the purpose of improving the harbor at Saint Joseph, as well as to deepen the water at the mouth of the canal.

In the year 1879 the legislature of the State of Michigan passed an act making the waters of this canal a public highway, forever free to the citizens of the United States and subject to the laws governing public navigable waters.

The canal has always been free to navigation.

At the commencement of the work a cheap pile revetment was built and now exists as a protection to the south bank of the canal. It is now fast going to decay. No works of any kind exist for the protection of the north bank of the canal, which from the nature of its soil is constantly being washed away and into the canal. The canal at present is about 100 feet in width and will permit the passage of vessels drawing 8 feet of water. To successfully carry on the commerce at Benton Harbor, a depth of at least 12 feet is required.

To complete the canal to this depth would require the excavation of 56,889 cubic yards, at 15 cents per yard.......

Contingencies

Making a total of......

$2,844 45 400 00

3,244 45

The tonnage at Benton Harbor for the year 1878 is as follows:

This does not take into account vessels arriving at these ports from other ports in the same collection-district. This trade is a very large one and would greatly increase the numbers above given.

Very respectfully, your obedient servant,

Maj. F. HARWOOD,

Corps of Engineers, U. S. A.

JOHN A. MITCHELL,
Assistant Engineer.

SURVEY FOR A BREAKWATER AT MACKINAC, MICHIGAN.

UNITED STATES ENGINEER Office, Detroit, Mich., January 19, 1880. GENERAL: In accordance with your instructions of April 25, 1879, I have the honor to submit my report of a survey for a breakwater at Mackinac, Mich., provided for by act of Congress approved March 3, 1879. By correspondence with interested persons I first ascertained

that this survey was asked for, having in view the protection of the anchorage and wharves in front of the town of Mackinac, on the island of the same name. It was claimed that the interests of commerce at this point were impaired from two sources. First, the denudation of Biddle and Mission Points by the waves in stormy weather, thereby encroaching upon the anchorage with deposits of sand and gravel washed from these points. Secondly, as a result of the denudation of these points, an increasing exposure of the existing wharves in stormy weather, mak ing it difficult and sometimes impossible for vessels to make their landings until the storm had subsided. Upon examination I found that the first evil complained of was an accomplished fact, both points having been completely stripped of all sand and gravel exposed to the wash of the waves, and as a result the shoals indicated on the map herewith submitted have formed. These shoals, when properly buoyed, are, however, no material obstacle to navigation, there being sufficient depth of water over the heads of them to float vessels of the heaviest draught known on the great lakes, with ample channel-way also between Mackinac and Round Islands, and it is probable that the slight annual increment to those shoals might go on for many years without interfering with navigation more than at present, until finally the shore line would wash down to an easy curve and the shoaling cease, still leaving sufficient water for vessels of ordinary draught to approach the vil lage wharves. Such a result, however, would prove of serious detriment to the interests of navigation on another account, and that the increase of the evil already existing, viz, the exposure of the landings to the waves in stormy weather, resulting from the grad nal washing away of both points. Local history has it that where there are several feet of water off Biddle Point as it now exists, not many years ago trees stood and a fine level plateau existed, upon which the garrison of Fort Mackinac was accustomed to parade in fine weather. By reference to the extract from the lake survey chart, which appears upon the map herewith forwarded, it will be seen that the waves from Lake Michigan rushing in from the westward, and which were formerly shut out by Biddle Point acting as a breakwater, now have a clear sweep, rolling around the point to the Mackinac wharves; and the same can be said of waves from the eastward, which have a long course clear across the head of Lake Huron, and, Mission Point forming no material obstacle, drive with great fury directly upon the Mackinac beach at the town front. Under such circumstances, vessels will not attempt to land; neither when the gale is very severe do they even dare to let go anchor, but, passing the harbor by, seek shelter under the lee of the islands elsewhere. As, during the season of navigation, Mackinac is a regular port of resort for passenger steamers plying be tween Lakes Michigan and Superior, and is visited by large numbers of tourists and pleasure-seekers, the want of a snug harbor is a great inconvenience to the passenger traffic as well as a detriment to the interests of the numerous passenger lines which touch at the island, as they never are certain when they can land their passengers without material delay prejudicial to their freight interests at either terminus of their route. It is, therefore, decidedly to the interest of this branch of commerce that a harbor should be formed at this point, which shall be readily accessible in all weather and secure for landing at the wharves within its limits, no matter how heavy a gale of wind may be blowing outside. To secure such a snug harbor the obvious method would be to run out converging piers from Biddle and Mission Points, leaving between their respective heads just sufficient channel-way for vessels to pass

commodiously in all weathers. Such a project is, however, defeated by the peculiar hydrography off Mission Point, a deep hole existing there, in the middle of which 60-feet soundings were found and no bottom. This hole, which is probably the remnant of what was the ruling depth of the harbor before Biddle and Mission Points were denuded, forms an effective barrier to the extension of a pier from Mission Point beyond the crest of its bank, and similarly a converging pier from Biddle Point would be headed off at a distance of about 1,000 feet from the Mission Point pier-head, and hence be no more effective in securing a snug harbor than a shorter pier run at nearly right angles to the direction of the greatest waves. It is obvious that in each case a pier so run will cover the greatest area of anchorage in proportion to its length. I have so projected a pier at Biddle Point on the map accompanying this report. The direction and length of a pier at Mission Point are determined by the peculiar conformation of the bottom, as shown on the chart. Fortunately, excepting as to length, it is all that can be desired, while, without going into too deep water, the Biddle Point pier as projected will cover all the area between it and the Mission Point pier from direct exposure to the waves attacking from the direction of Biddle Point. I therefore propose, as the improvement proper to be made at Mackinac Island for the protection of its harbor, two piers putting out severally from Biddle and Mission Points, the direction of each to be nearly at right angles to the direction of attack of prevailing heaviest waves, and each to terminate in a pier-head 40 feet square, standing in 24-feet soundings, which is the sounding at the crest of the hole off Mission Point. As with the limited time and appliances at my disposal it was necessary to take soundings by time intervals as determined by the watch, owing to irregularity in stroke of oar, the position of curves of soundings must be necessarily approximate, and consequently the lengths of the proposed piers as projected on the map are also approximate. It is safe to say, however, that the Biddle Point pier should be from 1,200 to 1,500 feet long, and the Mission Point pier from 800 to 1,000 feet, the location of its head being positively determined by the crest of the declivity ahead of it.

Owing to the character of the foundation, the gradual slope of the bank, and the peculiar impact to which the piers will be subjected from the short, high, and rapidly propelled waves attacking them and delivering a series of blows rather than thrusts, the ordinary method of pier construction will not be advisable at this locality. The bottom being of loose stone, gravel, and bowlders, the slope gradual, and the waves violent and percussive, in my opinion a vertical face should not be opposed to their impact, but they should be received upon the slope of a pier having a base broad in proportion to its height, thus obtaining a good hold on the unstable foundation while breaking the force of the shock of the waves at the water-line. The Biddle Point pier will need to have both faces a slope above water, as otherwise, when the waves come from the eastward rolling past the Mission Point pier, should they meet a vertical face at the Biddle Point pier a troublesome reflex wave would be thrown back upon the Mackinac wharves. The Mission Point pier might have the inner face vertical, but as there would be little economy in it I should propose for both piers a rectangular cross-section up to the water-line and a trapezoidal cross section in superstructure. A uniform base of 30 feet width is, in my opinion, necessary to secure the pier from shifting its base while in process of construction, and to insure adequate weight of stone in the trapezoidal area. Piers of the shape and construction I propose would cost at these sites about $50 S. Ex. 63-2