taken at a period of comparatively high water, would not give by reduction depths so reliable to the low-water channel, while that of September 14, 1883, not being accompanied with observations of river discharge, furnished no data for a calculation of the low-water plane, and the soundings were therefore reduced by assumption.

Taking, therefore, the survey of September 22, 1882, though it should not be assumed therefrom that the Board regard its results as final, there are obtained a mean depth of 3.27 feet and a least depth of 2.88 feet, as compared with a mean depth of 2.46 feet and a least depth of 1.1 feet in the year 1867.

Before leaving this subject it is necessary to examine what reliance should be placed upon the accuracy of the results thus far obtained, which can be accomplished by a short review of the process adopted in this report.

The zero of each year is the reading on Warren's gauge at Portage of the water-level in that year, corresponding to a discharge of 2,114 cubic feet per second. This discharge was obtained by calculation from the formulæ of Humphreys and Abbot as there did not exist data otherwise sufficient for its direct determination, but it is probably near the truth. General Warren estimated the low-water discharge of 1867 at 2,800 cubic feet, and 0.5 feet below that level he placed the zero of his gauge at Portage. The rate of increase or decrease of the discharge for a variation of one-tenth of a foot in the water-level must have exceeded 100 cubic feet per second, which would make a discharge at Warren's zero in 1867 less than 2,300 cubic feet. If, instead of 2,114 cubic feet, as calculated, 2,200 cubic feet should be adopted as the discharge there would be required a correction of 0.067 feet, added to the mean and least soundings of 1882.

The reading of the zero of each year upon Warren's gauge was determined from the river discharges of that year by finding what the discharge would be when the water stood at zero of Warren's gauge, and from the rate of variation for a difference of level of one-tenth of a foot. From these the reading on the gauge corresponding to the discharge of 2,114 cubic feet could be easily ascertained. By these means the references of the yearly zero were obtained, viz: for 1879, -0.4′45; 1880, -0.61; 1881, -0.87; and for 1882, -1.0. The soundings of the surveys were reduced to low water by means of the readings for the yearly zeros, and depend upon these for their accuracy.

The rate of variation of river discharge per one-tenth of a foot in difference of level would depend not only upon the correct values of the river discharge but also upon the gauge reading of the water-level at the time, which last would be subject to accidental variations from its true reading, by temporary elevations due the recent constructions of dams or formation of bars. Errors thus committed would therefore affect the reading of the zero for that year, and also the reduction applied to the soundings.

Between Portage and Dekorra in 1880 there were built or extended 40 wing-dams; in 1881, 30; and in 1882, 13. At Portage observations on water discharge were taken in 1879, 1880, 1881, and 1882; and at Dekorra in the same years. The observations of 1880 at Portage have not been used because of apparent disturbance in the water-level caused by the construction of new dams in the vicinity. Those of 1879, 1881, and 1882, though not so decidedly, have probably been more or less affected by similar causes. The last wing dam was constructed in November, 1882, and observations in 1883, which were not taken, would probably have been free of disturbance, attending frequent and abrupt changes in the regimen of the river.

The low-water level at Dekorra corresponding to that at Portage could not be safely calculated from the observations made there during periods of disturbance of the regimen, and it has been necessary to reduce all the soundings used for a distance of 6 miles below Portage to lowwater, from observations made at that place.

To have insured reliable results, not only should the corresponding low-water levels at Portage and Dekorra with differences of level have been accurately known, but the Board should also have been furnished with observations sufficient to fix the low-water levels and differences of level at intermediate places, so as to have determined sufficient points of reference for the reduction of soundings; which precautions for accuracy are of additional importance where the range of improvement is limited and the weight of small errors thereby greatly enhanced.

Observations upon the water volume should preferably be taken at and near the stage corresponding to the discharge at Portage of 2,114 cubic feet, and a survey with soundings sufficient to construct accurate cross-sections should be made at and near the same stage of water.

Whatever may be the practical benefits to navigation of this improvement there is no doubt that the results should be recorded, with the attendant circumstances, for future instruction in like cases.

To resume in September, 1882, the mean depth over the bars, reduced to the lowest stage for a distance of 6 miles below Portage, was 3.27 feet; and in 1867, 2.46 feet; showing an increase of 0.81 feet due to the improvement. The corresponding least depths were as follows: September. 1882: 2′.88, 2′.88, 2′.98, 2′ 98, 34.08, 31.08. 3'.08, 3'.08, 3'.08, 3'.08, 3'.08; 1867 1.10, 1.20, 1.80, 2.10, 2.10, 2.10, 2′.20, 24.20, 2′.20, 2'.20, 24.30.

In 1882, therefore, it would have required a stage of water equivalent to a rise of 1.12 feet above 0.3 feet of that year, to have secured a depth of 4 feet.

By inspecting the table of duration of stages of water modified for the zero of each year, we find approximately, for 1877, 93 days; for 1878, 48 days; for 1879, 85 days; for 1880, 38 days; for 1881, 7 days; and for 1882, 6 days in the season of navigation in which the depth would have been less than 4 feet; and that practically a depth a little less than 3 feet has been attained, showing an increase in this respect of 1.78 feet since 1867.

Having finished the discussion of the navigable depth obtained by the improvement, it suflices to say that the Board regard the results exhibited as probable only until the class of observations from which they have been deduced shall have been repeated with great care. By finding the level of the zero of the year in which the observations are made, the navigable depth it is true might be attained without further delay upon the ground; nevertheless the records of a complete survey would be highly useful for future reference.

Assuming a depth of at least 4 feet to be necessary for a water-route of through transportation from west to east, it is proper to inquire into the conditions necessary for its attainment upon the Wisconsin River. To do this it is necessary to avail ourselves of the discharges throughout the length of the river found recorded in General Warren's report. It has already been said that the discharge corresponding to the zero of Warren's gauge at Portage before commencing the improvements of the river was 2,100 to 2,200 cubic feet, and therefore with a water-level of 0.3 feet below that, estimating the variation in discharge for a rise or fall of one-tenth of a foot at 200 cubic feet, the discharge would be reduced to 1,500 or 1,600 cubic feet.

A calculation by means of Humphreys' and Abbot's formulæ of the widths and velocities corresponding to a discharge of 1,500 cubic feet and slopes of 2 feet and 13 feet, respectively, per mile, gives for the greater a width of 139 feet and mean velocity of 2.689 feet; and for the less, a width of 150 feet and a mean velocity of 2.501 feet.

General Warren, in his report, page 86, furnishes the following low-water volumes:

Having already calculated for the discharge at Portage, that at Bridgeport, near the mouth of the river, will next be taken. The low water of 1867 was at Portage 0.5 feet above the zero of Warren's gauge, which again is 0.3 feet above the lowest water assumed in this report, making it necessary to correct the discharge for a difference of waterlevel amounting to 0.8 feet. If a similar correction be taken all along the river, the water volume of 1867 at Bridgeport should be reduced by 1,600 feet, making it 3,190 cubic feet at extreme low water. Calculations for the width and velocity with this discharge are given below, with those also at Portage:

The inference from the above would be that in order to have a clear depth of 4 feet at extreme low water the width at Portage should be 140 and that at Bridgeport 300 feet. At the latter place the result may have to be modified, owing to a possible error committed in the amount of reduction, which was, assumed, no positive data being attainable. The diminution of width in the upper part of the river would probably not prove to be of more inconvenience than lockage down the Fox; the increased velocity, however, would be an evil.

The use of wing-dams without training-walls on each side of the channel, in line with their ends, leads to great inequalities in depth and to the formation of shoals, so that this mode of construction, without the modification stated, is hardly to be recommended.

The estimate of the local engineer for completion of the improvement by means of wing dams was 540,000 feet of dams below Allen's, 108 miles less 53,333 feet already built below Allen's, making 486,667 feet, at $4, $1,946,668.

To this should be added for increase of length of dams for the contraction above calculated 52,297 feet of dams, making a total of 538,964 feet, at $4, $2,155,856.

If training-walls be adopted the length would be 2 by 118 miles, less 33 per cent. for intervals, amounting in all to 830,720 feet, which, at $4 per linear foot, would amount to $3,322,880, and this added to the preceding would give a total of $5,478,736 for an improvement of the Wisconsin to give a draught of 4 feet at a stage of water 0'.3 below the zero of the year. This indicates a possible great increase of cost by the system of wing-dams.

Owing to the loose and shifting character of the soil for foundations of dams, the system of slackwater navigation by means of dams and locks has not been recommended for this river.

Another mode of improvement, which has been recommended with approval by General Warren, is by means of a canal along the banks of the river at an estimate of $4,165,000 with wooden locks for a draught of 5 feet. General Warren, however, recommended a closer survey to be made as a basis for a more satisfactory estimate. This estimate should perhaps be doubled.

The result of this investigation has been to show that the capacity for improvement of the river has not been so developed as to warrant the continuation and completion of the project, and the Board are of opinion that a series of accurate observations is necessary before a satisfactory system can be devised or satisfactory estimates made.

IMPROVEMENT OF THE FOX RIVER.

The local engineer states:

The estimated cost of completing the improvements on the Fox River for through navigation to the Mississippi in connection with the improvement of the Wisconsin River is $1,000,000. This involves the building of twelve old locks, 4 on the Upper Fox, and 8 on the Lower Fox, the miter-sills being so placed as to admit of 6 feet draught the same as on the 13 new locks, and deepening and widening the channel pricipally in the Upper Fox.

The estimate would be the same if we had only 4 feet draught on the Wisconsin, as we should have as good navigation as possible on the Fox, and the cost of locks for 6 feet draught would not be much greater than for 4 feet. The old locks, with exception of the guard-locks at Portage can with the necessary repairs be used for 4 feet draught. so that the estimate for 4 foot navigation in the Fox, using the old works, will not materially differ from that of putting the old works in order for the existing navigation on the Fox without reference to the Wisconsin.

The estimate of cost of the local engineer under the supposition of retaining the old locks is as follows:

Annual maintenance, including pay of assistant engineer, overseers, locktenders, watchmen, repairs, and renewal of lock-gates, spars, boats, &c... $25,000

Annual maintenance, including pay of overseer, lock-tenders, watchmen, repairs, and dredging

$20,000

imates are approximate, but cover all that is necessary to put the works king order and for maintenance.

ard have discussed the engineering features but have not reon the commercial value of the improvement of the route of the Wisconsin rivers, which seems also implied in the words in their judgment the interests of commerce and navigation vanced sufficiently to warrant the continuation and completion of the project," as the present moment appears a little premature; because additional and careful observations upon the Wisconsin are necessary to certify to the amount of the improvement made, and the feasibility and cost of making the improvement sufficient for the wants of commerce along a through route from west to east.

The Board, however, had communicated in relation to this matter with the Board of Trade of Chicago and the Chambers of Commerce of Milwaukee and Saint Paul, copies of whose replies and of the letter of the Board are appended to this report.

For reasons similar to those referred to above the Board at this time do not propose any disposition of the works already constructed.

SUMMARY AND CONCLUSIONS.

FOX RIVER.

The Government in 1872 purchased from the Green Bay and Mississippi Canal Company only so much of the company's property on the Fox River as was needed for purposes of navigation, and declined to purchase the water-powers and privileges connected therewith.

A large portion of the water-powers in use was created by the dams, &c., constructed by and under authority of the State of Wisconsin, by the board of public works, and afterwards by the Fox and Wisconsin Improvement Company and the Green Bay and Mississippi Canal Company, as these companies successively fell into legal possession, deriving their titles from the State.

The works of river improvement at the time of purchase were in such dilapidated condition that navigation was practically suspended, and it became necessary to rebuild nearly all the locks and dams, but the water-powers do not appear to have been increased beyond the original improvement by the repairs and rebuilding.

Water is drawn from the river or canals by the parties using it at their own expense, and the flumes must be in accordance with plans approved by the United States officer in charge, and not to endanger the works or interfere with navigation.

The Government has rebuilt or repaired no dams and other works save for the improvement of navigation, and has the controlling power to regulate the supply of water drawn from the river to generate power, and the mills have practically the benefit of the surplus water alone.

The Government has received no money for the water so used, the right to which is claimed by private parties acting under sales and leases from the State of Wisconsin, the Fox and Wisconsin Improvement Company, and the Green Bay and Mississippi Canal Company.

The amount of water power used and derived in whole or in part from public works is stated to be 6,545, and that derived from private works to be 5,103 horse-powers.

The amount necessary for the completion of the project for the improvement of the Fox River as a part of the through route of transportation is stated by the local engineer to be $1,000,000, which estimate