In Figure 1 I have also traced a plan for a middle ground, designed and submitted by the inspector on the work in 1875; but as no reference is made to it in the official report of that year, this project was doubtless abandoned in its incipiency.

Figure 2 shows the condition of the improvement at the beginning of the working season of 1877 and previous to the expenditure of the appropriation of $11,000 made August 14, 1876.

The result of an examination in May, 1877, having shown that there was a strong current setting in behind the revetment on account of its peculiar location near the axis of the river, a bulkhead connecting the head of the revetment with the east shore was projected by Maj. F. Harwood, Corps of Engineers, United States Army, which was approved and built in 1877. Five hundred feet were added to the lower end of the revetment complete, and 330 feet more partially finished. This addition making the revetment as long as originally designed, without obtaining in any marked degree the hoped for results, viz, a deepening of the channel in front of it by scour, it was deemed advisable to connect the lower end of the revetment with the shore by an arm 115 feet long, thus confining the area behind the revetment between fixed boundaries in order to make dead water therein, and seeking to obtain an increased scouring action in the channel in front of the revetment. This was also partially completed in 1877, and in August of that year the channel was dredged 90 feet wide and 10 feet deep, removing 3,871.5 cubic yards of sand at 35 cents per cubic yard, costing $1,355.03.

A portion of the appropriation of $25,000, June 18, 1878, was used in the completion of the revetment in the fall of that year, and redredging the channel to 10 feet depth and 100 feet wide, removing 7,286 cubic yards at 14 cents per cubic yard and costing $1,020.04.

In January and February, 1879, elaborate and accurate surveys were made and soundings taking through the ice at all points needing improvement, including the Carrollton Bar, a reduced map of which is shown at Figure 3, sheet VI. Then it was discovered "that owing to the sluggish current of Saginaw River and occasional slackwater, and sometimes even an up-current making across the Carrollton Bar, there was not sufficient scour in the new channel to maintain it in the face of the drift of light sand from the river above and from off the face of the Carrollton Bar. A new work was therefore projected to fence in the Carrollton Bar and confine the channel to a width of 200 feet, so as to obtain the maximum scouring effect of any down-stream current without confining too much the channel limits. This work consists of a plank beam training-wall" (extract from Major Harwood's annual report of 1879), which proposed structure is shown in dotted lines on Figure 3. This beam wall was constructed during the season of 1879 with a portion of the appropriation of $8,000 made March 3, 1879. It is 3,500 feet long; its initial point opposite the oar factory was built in 8 feet depth of water, and its lower end crossing near the crest of the Carrollton Bar, with only 2 or 3 feet over it. The total cost of this structure was $6,420.65, or $1.83 per linear foot.

From September to October 15 1879, a dredge was employed, renewing the Carrollton channel to 100 feet width and 10 feet depth, removing 11,113 cubic yards of sand at a cost of 11 cents per cubic yard, a total of $1,222.43. In the spring of 1880 there was an exceptionally high freshet, lasting several weeks, with a strong current rushing through the channel, between the revetment and beam wall. The effect on the channel-bed was immediate and positive, to give a description of which I beg leave to quote from a report made by me to Major Harwood, under date July 30, 1880, after an examination of the Carrollton channel and beam wall: "The first or upper section of the plank beam wall at Carrollton Bar, being built on a line drawn diagonally across the axis of the river channel, and receiving, as it does, the greater and central portion of the body of water descending at that point has proved inadequate in strength to resist that force, and on account of its peculiar construction permits the scouring action of the current to undermine it, greatly diminishing its utility as a water-tight bulkhead. This section when built, in August, 1879, was in 8 to 9 feet of water. Soundings taken March 18, 1880, show an average depth on both sides of 12 feet; on April 5, 13 feet, and on July 24, 1880, over 15 feet. If this scouring action underneath the plank beam continues the entire structure is liable to fall over for the want of sufficient depth of penetration of the piles which hold it upright. The channel between the United States revetment and beam wall (July 24, 1880) is in very good condition, comparing it with its cross-section of late in the fall of 1879 and the spring of 1880. In the old channel originally made near the revetment there is good 10 feet of water; and even close to the beam wall, a width of 75 feet, 7 to 8 feet of water has been made by the scouring action of the current through this canal. Unfortunately, the great bulk of the sand thus moved was deposited immediately below the revetment forming an extensive and growing bar in that locality. In fact, the old Carrollton Bar had shifted its position to the lower end of the canal, which seemed to indicate that the revetments were not extended far enough downstream past the tail of the bar.

#

*

The upper section of the beam wall above referred to was re-enforced by taking up the plank beam, driving two rows of piles, and filling the interval with edgings and a top layer of stone. This was done in September and October, 1880, at au expense of $936.16. The other 3,000 linear feet of plank beam had also settled considerably on account of the deepening of the channel by scour, and had to be built to its original height above water-level, which was done at the same time, costing $173.85. Öf the appropriation of $15,000, June 14, 1880, but $5,000 were by the terms of the act allowed to be expended on the improvement of Saginaw River above Bay City, and as this allotment was nearly exhausted in October, 1880, further repairs were discontinued, and the balance used in redredging the channel at the lower end of the bar, 60 feet wide and 12 feet deep, under contract with T. M. Hubbell, at a cost of $16 per hour for an outfit, which included double handling of the dredged material, the latter being thrown by means of a clam-shell dredge from deck-scows over the upper section of the beam wall. This work was done in one hundred and forty-nine and one-half hours, and cost $2,392.

With the aid of the appropriation of $10,000, made March 3, 1881, a new work was projected and built, which consisted of a slight pile and edging structure, 1,000 feet long, in prolongation of the United States revetment, principally for the purpose of inducing a scour over the channel heretofore barred. This extension was constructed in June and July, 1881, at a cost of $1,921.90, or nearly $2 per linear foot. A portion of the same appropriation was used in further repairs to the Carrollton Works; the beam-wall, which had settled still more during the spring freshet of 1881, was built up again by adding plank to the top, at an expense of $723.88, and some minor repairs were made on the revetment pier, costing $218.40.

Up to this time (the summer of 1881) all the efforts of the Engineer Department had been in the direction of making and maintaining a navigable channel of 10 feet depth of water, and all the dams and revetments projected and constructed during the preceding eight years were intended to aid in the attainment of that object. In what measure these efforts proved successful may be judged from the facts above related. Although the original project could not be considered as completed, at the instigation of the East Saginaw Board of Trade a new and more extensive project was proposed, and the United States Engineer Department requested to make an examination of the river, from its head to Bay City, with a view of making and maintaining a navigable channel of 12 feet in depth. This preliminary examination and survey was made in the autumn of 1881, under the direction of Major Harwood, and a detailed report and project with estimate of cost presented by him to the Chief of Engineers under date November 29, 1881. All operations under the old project were necessarily suspended with the exception of some minor repairs to existing works, which were made in July, 1882, at an expense of $846.12. August 2, 1882, the sum of $125,000 was appropriated, $60,000 of which to be expended on the improvement of the river above Bay City, including the Carrollton Bar. Major Harwood's survey and projects are shown in Figure 4 of the accompanying drawing, Sheet VI. These were submitted to a Board of Engineer Officers, whose report to the Chief of Engineers, under date October 19, 1882, may be found in the Annual Report of 1883, Part II, on page 1863. The conclusions of this Board regarding the further improvement of the Carrollton Channel under the new project were against the construction of any new revetments as channel protections generally, and the extension of the existing revetments to deep water in particular; and it was decided that a channel of 12 feet depth and 200 feet wide could and should be maintained by dredging only. In lieu of the extension of the piers. the construction of a dam across the Carrollton Bar, connecting the beam-wall with the westerly shore, was determined upon, and is included in the general project. This, however, has not yet been built, and serious objections and emphatic protests on the part of the mill-owners along the Carrollton village front, which were made when a site was selected, will probably interfere with its construction.

In the proposition submitted by Maj. F. U. Farquhar, Corps of Engineers, United States Army, for the expenditure of the allotted $60,000, it was unfortunately overlooked that the existing works at Carrollton required improvements or reinforcement in view of the close proximity of the proposed 12 foot channel, and no provision was made in that direction.

Dredging was begun at Carrollton in the fall of 1883, and during the fiscal year 28,825 cubic yards of sand were removed, at a cost of 374 cents per cubic yard, and a total of $10,809.38. All the dredged material was deposited behind the lower end of the United States revetment and its extension, and the weight of the sand as well as the manner in which it was thrown over, caused considerable damage to these structures. A map of soundings taken through the ice, under your direction, in February, 1884, shows a good channel of 12 feet depth and about 100 feet wide. Figure 5 of the accompanying drawing, Sheet VI, is a reduced copy of this map, omitting soundings and substituting curve lines to correspond with other figures.

This completes the history of the Carrollton Bar down to the beginning of the fiscal 135 ENG

year, which forms the subject-matter of this report. Adding the amount of dredging done during the year just closed. The following table will give a summary of dredging operations at Carrollton under the direction of the United States Engineer Department to date:

The total amount of sand dredged being 83,000 cubic yards in excess of the original estimate which was made in 1873, in connection with the proposed permanent removal of the obstruction to navigation, it follows that the anticipations in that direction have not been realized. It will be readily seen that the construction of the United States revetment alone did not tend to produce a scour sufficient to maintain a navigable depth when made. The addition of the beam-wall effected this, but to a greater extent than it was designed or required, owing to its close proximity to the revetment, with which it forms a canal much narrower than the width of the river above and below the Carrollton Bar, where deep water has always been found. It seems to me that if the reventment was extended to deep water, as Captain Lee suggested in 1876, and the beam-wall prolonged in like manner so as to fence in the tail of the bar, a 12-foot channel would be maintained by the natural scour through many seasons.

I therefore respectfully recommend a reconsideration of the present approved project, and the construction of revetments in extension of the existing works to deep water. Estimating the cost at $5 per linear foot, this would involve an expense of $10,000. In order to prevent the bar within these extended boundaries of the channel from moving to a point further below, it will be necessary to deepen the channel to 12 feet at the same time that the pier exteusion is taken in hand. The quantity to be removed in this reach of the river can only be conjectured, and I therefore approximately estimate it at 60,000 cubic yards, which, at 30 cents per cubic yard, makes the cost of dredging $18,000.

THE "ZILWAUKIE BAR,"

which is located at the head of Crow Island, about 34 miles below East Saginaw, was and is considered next in importance in the several projects for the improvement of the Saginaw River, the Carrollton Bar being first. In the accompanying drawing, Sheet V, I have reproduced, on a uniform scale, five maps of surveys which were made at about the same time and under the direction of the same engineer officers, as those shown in corresponding figures on the Carrollton charts, and therefore omit details in regard to these particulars.

The original project for the permanent improvement of the channel at the Zilwaukie Bar was made in 1876, and includes the construction of a revetment about 1,300 feet long, having its initial point on the east shore of the river, opposite Bliss's Mill, and extending down-stream on an easy curve, so that its lower end covers the up-stream entrance to the so-called Oneida Channel. This channel is an arm of the Saginaw River, between which and the main channel along the Zilwaukie village frout Crow Island is situated. This Oneida Channel is said to have been navigable by lightdraught vessels in early times, and preferred by this class of boats because it is straight and offered a shorter route past Crow Island. An old saw-mill on the east shore, opposite the head of Crow Island, which had formerly belonged to a firm of capitalists from Oneida, N. Y., gave the name to the channel. This mill had changed hands and was being rebuilt and put in operation by Messrs. Sibley & Bearinger when, in 1877, it was proposed to carry out the plan of improvement and to construct the revetmen on the line projected. As it would have been an injury to their business to close up the up-stream entrance to their mill-dock aud log-boom, this firm objected to the original line of revetment, and a new site was selected, shown on Figure 2. This wing-dam, 905 feet long, was built in the fall of 1878, at an expense of $3,319.96, or

abont $3.66 per linear foot. Its up-stream end or head was located 50 feet from the Oneida mill dock front, extended, a sufficient space for the convenient passage of vessels into and out of the water fronts of the mill property.

The Zilwaukie Bar, which had originally been a shoal in continuation of the head of Crow Island in a southwesterly direction (see Figures 1, 2, and 3), was partially removed by dredging in the autumn of 1879. A uniform depth of water of 10 feet was made over an area, the easterly boundary of which was on a line (shown in Figure 3) drawn from the head of the pier on an angle deflecting westerly therefrom; 16,388 cubic yards of sand were excavated, at 11 cents per cubic yard, costing $1,802.68. The result of this dredging and the utility of the wing-dam in_maintaining the channel thus made is fully set forth in the Annual Report of 1880, Part III, on page 2011, to which I beg leave to refer.

Subsequent examinations and surveys, especially those of 1881 and 1884 (Figures 4 and 5), show the effect of a scour along the middle and lower reach of the wing-dam, sufficient not ouly to maintain a channel on that side of the river, but to also remove large quantities of sand without the aid of a dredge. However, these examinations also establish the facts that there is a strong current setting in behind the revetment, especially under the force of a southwesterly wind; that a new bar has formed aud is continually growing in the axis of the river, directly opposite the head of the pier, and that the channels on each side of this shoal, the old one west of it, and the improved channel between it and the dam, are in danger of being filled up as the bar increases in superficial dimensions.

During the years 1880-'82 several improvements were made along the east shore of the river in this vicinity. Messrs. Melchers & Nerreter purchased a site and built a shingle mill and salt block immediately above the entrance to the Oneida Channel, in the year first mentioned, and soon after Messrs. Tyler & Son located a similar enterprise a short distance further up-stream, opposite the saw-mill of A. T. Bliss & Co. Both these shingle mills were provided with docks and log-booms projecting out into the stream, and made connection for the purpose of facilitating log supplies with a branch railroad-track of the Flint and Pere Marquette Railroad, by means of slips and canals extending from the shore line at right angles thereto to a wide ditch or canal dredged through the marshy land along the west side of the railroad track, the excavated material forming its embankment. Now, in order to provide a means for preventing the river current from dividing at the head of the pier, and to guide it along the front of the same, thus insuring an increased scouring effect for the benefit of the channel, it appeared necessary to carry out, as near as may be, the original plan of revetment shown at Figure 1, by building a revetment with its head resting against Tyler & Sons' shingle dock, and its lower end lapping the entrance to the Oneida Channel, leaving sufficient opening for the accommodation of shipping doing business with the Saginaw Lumber and Salt Company (successors to Sibley & Bearinger). This plan of improvement was proposed by Maj. F. Harwood in his report dated November 29, 1831, and is shown in Figure 4 of the accompanying drawing. In conformity with the decision arrived at regarding the improvement of the Carrollton Channel, this plan was rejected by the Board of Engineer Officers to whom it was submitted, but, in lieu thereof, the Board included in their approved project the construction of a dam across the Oueida Channel at some point below the saw mill of the Saginaw Lumber and Salt Company. When, however, in pursuauce of this project, a site was selected for this dam, in January, 1883, prepiratory to making estimate of cost of construction, a vigorous protest was entered by said company, and the dam has not been built.

Under the appropriation of August 2, 1882, the channel was dredged along the boom, on the west side of the river, in the spring of 1884; 14,200 cubic yards were then removed at a cost of 374 cents per cubic yard, or a total of $5,325. This cut has since filled up, as above stated.

The reasons which I have advanced, while submitting the necessity for the extension of the piers at Carrollton, apply with equal force in this connection. If the current, which now passes behind the wing-dam, can, by the interposition of a revetment, be guided along the channel side, an increased scouring effect will be produced to aid in maintaining a channel after it is dredged to 12 feet depth. I therefore respectfully recommend that, before there is any more dredging done on the Zilwaukie Bar, a revetment be constructed from the east shore between Tyler & Sons' and Melcher & Nerreter's shingle-mill property, at right angles to the axis of the river to their boom limits, thence (leaving an opening for logs at this point) down-stream on an easy curve out into the channel to within about 100 feet from the head of the wing-dam, substantially as shown on the drawing, Sheet V. The plan of construction may be similar to that of the wing-dam; but I believe that in this locality, where there will be deep water on both sides (instead of a bank of sand resting against it as at Carrollton), a plank-beam wall would be as strong and efficient as required. Either plan will cost less than $5 per linear foot. There will be 600 feet of revetment required, costing $3,000. The amount of dredging necessary to give a channel with a uniform

depth of 12 feet can only be approximated, on account of the continual growth of the shoal above mentioned. I therefore estimate it at 36,000 cubic yards, which will require the expenditure of $10,800.

DUMPING GROUNDS.

Since it has been determined that all dredged material shall be deposited on shore or carried out into Saginaw Bay, the problem how to dispose of the sand removed from the channel along the upper reaches of the river most economically and beyond the possibility of ever returning to the river-bed, has not hitherto been solved satisfactorily, and I beg leave to invite your attention to this important subject.

In the specifications governing contract work under the present approved project, the selection of the places of deposit for dredged material was left entirely with the contractors, and they were to assume all risk and expense of placing the sand upon the bank of the river. At the same time it was specially provided that "the material will be deposited in such manner that after settlement the foot of the slope will in no case be nearer to the low-water mark of the river at that point than 20 feet, nor so situated that it will be liable to be washed into the river again during high water or freshets." Leaving out the question whether sand may not be washed into the river again, even a distance of 20 feet, when the river overflows its low and swampy shores for miles, the above-mentioned restrictions must necessarily make the selection of suitable dumping grounds difficult, if not practically impossible. If these conditions had been strictly observed in the conduct of dredging operations during the last two years, it is doubtful whether any work of improvement could have been carried on at all; and it is a fact, which can easily be proved by only a casual examination of the places of deposit, that these provisions were not insisted upon, with but few exceptions. The greater the difficulty of selecting suitable dumping grounds the higher a price will be demanded by contractors per cubic yard of dredging, as will be seen by the difference in the cost of this service shown in the tabular statement of work done at Carrollton: In 1878 and 1879, when dumping grounds were selected by the Government, dredging was done for 14 and 11 cents, respectively, while during the last few years it cost 374 and 274 cents per cubic yard. The difference between these rates, or about 20 cents, may be estimated to be the price paid for the proper disposition of dredged material."

Assuming the quantity of sand to be dredged, before the present project can be considered as completed, to be not less than 500,000 cubic yards, it will cost $100,000 to place the material upon the bank of the river, or nearly as much as the dredging alone can be done for at present ruling prices.

During the deliberations of the Board of Engineer Officers having the present project for the improvement of the river under consideration, the advisability of doing all the dredging required by means of a complete plant owned and operated by the Government was discussed, though not adopted; and I now believe that a similar plan, simply for taking care of the dredged material alone, if carried out, would not only be a practical solution of this difficult problem, but it would also reduce the price paid for dredging to a low figure.

Instead of using clam-shell derricks and lifting the sand from flat scows onto the shore, I would recommend the adoption of a sand-pump and pipe-line, such as are used for dredging purposes on Western rivers. By this means the sand may be carried long distances from shore to a safe place of deposit. It must be borne in mind that all the low land along the river shore is owned by private parties and cannot be trespassed upon without their consent; but it will not be any more difficult for the Government to obtain permission of owners to fill up and raise large areas of their now useless swamp land than it is for the dredging contractors under the present system for the purpose of piling up the sand along the shore. If it should be determined that hereafter sand must be deposited on land a long distance from shore in the manner above suggested, a provision to that effect might be inserted in the specifications for future contracts, leaving the selection of the dumping ground, as well as the method of reaching it, to the contractor; but this would not materially reduce the present price for dredging, inasmuch as the contractor who first supplies himself with the necessary plant would include the cost of the machinery in his first estimate and bid, and, until competition is created, enjoy a monopoly. Hence I earnestly believe that the Government should own and operate the machinery for depositing the dredged material in places of its own selection, a plan which would result in a considerable saving of expense in the prosecution of the work of improvement.

SNAGGING.

While the sand-bars and shoals in the river are obstructions to navigation particularly affecting heavily-loaded vessels, yet not only these, but all light-draught steamboats, lighters, and tugs are in constant danger of being damaged or sunk by coming