5. The Estimates of Cost.
To open out a Channel through the various Rapids will necessitate a considerable and valuable outfit, a great portion of which will have to be renewed in the course of the operation. A large allowance must also be made for the dangers and difficulties with which the work will be attended, the interruptions caused by navigation, the delay from accidents, and the liberal salaries and wages for which only good engineers and hands can be persuaded to engage in such a work. It must also be taken into consideration that in order to leave no one spot with less depth than required, the excavation will generally have to be carried to a still greater depth than the one specified, owing to the peculiar character of this work, which, especially in turbulent waters, will not admit of the same accuracy and regularity as are obtained in similar operations on dry land. It is by taking all these circumstances into consideration, and by dividing the cost of outfit and contingent expenses between the different localities, that the undersigned have arrived at the estimates of cost.
Commencing the examination of the River St. Lawrence at Prescott, and proceeding downward, the Channel at present used by vessels of heavy draft was found to be sufficiently wide and deep, until, passing through the Galoppe Rapids, soundings of 9 and 10 feet were struck in the Channel. A survey was therefore made of these Rapids, the results of which are laid down upon the annexed Map No. 1; of the two Channels leading to the Galoppe Rapids, the Southern is used only by steamers of light draft, and was found to be too narrow and too crooked to be available for the navigation contemplated; the Northern or main Channel is now navigated in all seasons by vessels drawing eight feet, but it will require some improvement to be made sufficiently wide and deep for vessels of ten feet draft; the principal obstruction is a bar of solid rock, which stretches across the river, forming a Chute, and which is covered only with 9 and 10 feet of water in the Channel. The obstructions above and below this bar consist of boulders and stones. The whole can be removed by means of blasting and raising the débris. No difficulty would appear to exist, but the operations will be subject to frequent interruptions caused by the passage of steam and other vessels. To make the proposed improved Northern Channel 200 feet wide and 13 feet deep throughout, 4006 cubic.yards of solid rock and boulders will have to be removed, and the cost of this improvement is estimated at £11,232.
Leaving the Galoppe Rapids, no obstructions were met with before approaching the South Channel of the Long Sault, which branches of from the Main River about six miles above Dickenson's Landing. This Channel, which at present is navigated only by vessels of light draft, and by steamboats with low guards, or such as are not considered strong enough to sustain the heavy swell in the North Channel, was found to be crooked, narrow, and obstructed by several bars. It would require a considerable outlay to widen and deepen it sufficiently, and it would still remain crooked. Another great objection to this Channel arises from the fact that it is the only available route for rafts, which when passing through it, block up the whole Channel, and leave no room for steamboats to pass ; and owing to the frequent bends of the Channel, it is impossible for the steamboat to discover them until they are in close proximity. Having at the same time found the North Channel superior both in width and depth, it was not considered necessary to make a complete survey of the South Channel, which cannot be recommended for improvement, unless it should be contemplated to make vessels ascend through the Rapids by means of some auxiliary motive power, a project which cannot be discussed in thus place, but for the realisation of which this Channel would ofer peculiar advantages.
The North Channel, which is now navigated by vessels drawing eight feet and more, is very turbulent, but sufficiently deep and wide throughout, except at the upper pitch or Chute, where it is obstructed, as shown on the annexed Map No. 2. This Chute is formed by a ledge of solid rock, stretching across the river, and in the present steamboat Channel covered only with ton feet of water. Immediately below the pitch several very heavy boulders lying on a stony shoal, Burns' Shoal, form another dangerous obstruction, towards which the current sets, and which it is difficult even for steamboats to avoid. The present Channel is at this place both narrow and crooked, and will require to be straightened, widened and deepened, to make it perfectly navigable for vessels drawing ten feet. It is proposed to widen the Channel across the bar, as traced upon the map, with a view of entirely avoiding Burns' Shoal, and the heavy boulders lying on it. By removing a portion of the upper bar, the direction of the current will be changed so as not to set against Burns' Shoal, and will then take the direction of the Channel. The removal of the obstructions in the North Channel, by means of blasting, is considered practicable, but will be connected with difficulty and danger, owing to the extreme swiftness of the current, and turbulence of the water, both at the upper pitch and below it. The quantity of solid rock and boulders which will have to be removed in order to make the North Channel of the Long Sault 200 feet wide and 13 feet deep throughout, is estimated at 4550 cubic yards, and the cost of this improvement at £17,198.
From Lake St. Francis two Channels lead to the Coteau Rapids; the Northern or present Steamboat Channel runs as shown on the map, and is obstructed by two bars, one at the head, the other below the foot of Prisoner's Island. There is at ordinary summer water not more than 7 or 7 1/2 feet of water in the Channel on the upper bar, which is hardly sufficient for vessels drawing 6 feet, and not more than between 8 and 8 1/2 feet on the lower bar; both these bars consist of boulders and stones, and can be removed by means of blasting, &c.; The operations would be comparatively easy on the upper bar, but connected with considerable difficulty on the lower bar, where the velocity of the current is over 14 feet in a second, and the waters are very turbulent. The operations in this Channel on the upper as well as on the lower bar will be subject to frequent interruptions by the passage of vessels, and, it is to be feared, to frequent accidents arising from collisions with rafts, when driven out of their ordinary route by strong northerly winds; a depth of 12 feet is considered sufficient on the upper bar, but 13 feet will be required on the lower bar, in consideration of the heavy swell. The quantity of boulders and stones which will have to be removed in this Channel is estimated at 25,665 cubic yards, and the cost of the improvements at £40,365.
The Southern or "lost" Channel is not now in use, but was nevertheless surveyed with a view of ascertaining whether a better and less obstructed Channel than the Northern or present Steamboat Channel could not be found, and considerable pains were taken to make this survey as complete and reliable as possible. The Southern Channel was found to be obstructed at Juniper Island by a bar of solid rock, which at this place forms a Chute; and below the so-called Chute Verte, by several extensive bars formed by an accumulation of boulders and stones. It is considered practicable to open a Channel through these bars by means of blasting, &c.;, and the operation would not be attended with much difficulty, but would require a considerable outlay. In consideration of the swell, the depth ought to be not less than 13 feet on the upper and 12 feet on the lower bars. The quantity of solid rock and boulders which would have to be removed in this Channel is estimated at 60,085 cubic yards, and the cost of the improvement at £78,285.
A Channel which branches off from the present Steamboat Channel above Pig Island runs between Pig and Thorn Island, then along the south side of Pig Island, and again joins the Northern Channel below this point and abreast of Prisoner's Island, is now sometimes run by steamers and other vessels, when the water is very low, but it is crooked and too much obstructed to be taken into consideration for the improvement contemplated.
It must be borne in mind, at the same time, that the Northern Channel follows the natural flow of the current, and is easier of access from Lake St. Francis than the Southern Channel. The undersigned have therefore no hesitation in recommending the Northern Channel for improvement, the cost of which was estimated at £40,365.
From Pointe au Diable downward, a few inconsiderable obstructions were met with, before entering the Cedar Rapids, at the head of which a ledge of rock runs across the present Steamboat Channel, partly covered with boulders, and forming an obstruction which is commonly called "la Barriere." There is, at ordinary summer water, not more than 9 1/2 feet of water in the Channel, where it crosses this bar. Between la Barriere and Pointe au Moulin, the Channel was found to be obstructed by a few heavy boulders, as shown on the map. The Raft Channel was found to be too shallow and crooked to be taken into consideration, and the present Steamboat Channel is therefore recommended for improvement. The removal of "la Barriere" and other obstructions in this Channel is considered practicable, but will, owing to the violence of the current, the heavy swell, and the vicinity of the Chute aux Bouleaux, be attended with considerable difficulty and danger, and besides be subject to frequent interruptions by the passage of vessels. A depth of 13 feet will be required throughout. The quantity of solid rock and boulders which will have to be removed is estimated at 5600 cubic yards, and the cost of the improvement at £12,500.
After having passed the Pointe au Moulin, the Northern or present Steamboat Channel was found to be much obstructed, and the existence of other Channels having been indicated in the Reports of Mr. T. C. Keefer and Captain Maxwell, the undersigned applied themselves to discover them, in order to ascertain their position and availability, and to satisfy themselves whether the requisite improvement could be attained there at less expense.
1st. An extensive shoal of solid rock partly covered with boulders, and commonly called "Bocco Hayes" Shoal or "la Chainette;" there is at ordinary low water not more than between 6 and 7 feet of water in the Channel over this bar, which is considered the shallowest spot in 'the river; vessels drawing 6 feet frequently touch bottom here. The removal of this obstruction is considered practicable, and a depth of 12 feet will be required. The quantity of solid rock and boulders to be removed in this Channel is estimated at 9100 cubic yards, and the cost of the improvement at £18,700.
This obstruction can be avoided, or nearly so, by following the Channel marked BBB on the map, which leads around the south side of "Bocco Hayes" Shoal, and joins the Northern Channel, AAA, above Mary's Reef. The Channel BBB is but little obstructed, and the quantity of boulders and stones which would have to be removed from it, to make it 200 feet wide and 12 feet deep, is estimated at 630 cubic yards, and the cost of improvement at £1760.
2nd. The next obstruction in the Channel AAA is Mary's Reef, which consists of boulders and stones, and has a depth at ordinary low water of not more than between 8 and 9 feet; the improvement of this Channel to a width of 200 feet and a depth of 12 feet, which is perfectly practicable, would require the removal of about 4725 cubic yards of boulders and stones, and the cost of this improvement is estimated at £5325.
This obstruction can be entirely avoided by running a southern Channel, which is marked CCC on the map, and which will hereafter be called "Middle Channel," if continued and improved across the bed of solid rock stretching out from Buisson Point, as shown on the map. To run south of Mary's Reef, and then again to join the Channel AAA, would not, in the opinion of the undersigned, be practicable, nor would any improvement be gained by it.
3rd. The third and most formidable obstruction in the Channel AAA is formed by an extensive bed of solid rock, stretching from Buisson Point across the whole river; the shallowest and most prominent portions of this bed of rock bear the name of "Dog Reef,""la Balize" and "Split Rock," and it is between these dangerous obstructions that the present Steamboat Channel finds its way over a continuation of shoals consisting of solid stratified limestone, partly covered with boulders and stones. It is considered practicable to remove these obstructions, to the width (200 feet) and depth (13 feet) required; but the operation would be subject to frequent interruptions by the passage of vessels and rafts, and when accomplished, still leave one of the greatest objections to the Channel unremoved, which is the direction of the current setting across it, as shown on the map.
The Southern or "Saw Log Channel," so called from a large stick of timber which for years had laid bare at the place indicated on the map, but was swept away by the ice in the spring of the present year, is apparently the same which had previously been traced by Mr. Thomas C. Keefer. It runs, as shown on the map, for a distance of about 1600 feet over the shallow bed of rock, and joins the Northern Channel AAA in deep water between Round Island and Buisson Pointe. This Channel, a portion of which in its present condition is not more than five feet deep, and the lower part of which is obstructed by boulders, can, however, be made 200 feet wide and 13 feet deep, and being easy of access from above, and following the natural flow of the current, would, when improved, become a good navigable Channel. The quantity of solid rock and boulders to be removed in this Channel, down to the point marked X on the map, is estimated at 50,750 cubic yards, and the cost of its improvement
The Middle Channel CCC runs, as shown on the map, for a distance of about 800 feet, over the same shallow bed of rock as DDD, a little above which it joins the Northern Channel, and is, like DDD, in certain spots only five feet deep. It can be widened and deepened respectively to 200 and 13 feet, and being easy of access from above, and following the natural flow of the current, will, when improved, become a perfectly good and navigable Channel; it is, like DDD, obstructed in the upper part by solid rock, here and there covered with boulders, and in the lower part by boulders, which have been deposited there, after having been swept over the shallow and smooth bed of rock above. The quantity of solid rock and boulders to be removed in this Channel is estimated at 36,632 cubic yards, and the
4th. The fourth and last obstruction in the Channel AAA is formed by an extensive bed of solid rock, stretching across the river between the southern shore and Cascade Island. On this bed of rock several heavy boulders have been deposited, which now form a dangerous obstruction, covered only with 6 feet of water, and commonly called the "Hay Stack." This formidable obstruction divides the present Steamboat Channel into two branches, a southern and a northern, which, however, join again shortly below, and continue as one Channel into the deep water of Lake St. Louis. The Channel laid down upon the map is recommended for improvement, being the straightest and least obstructed that could be found. The improvement of this Channel will require the removal of the "Hay Stack" and other boulders, and the excavation of the solid rock, to the width (200 feet) and depth (13 feet) required, an operation which is considered practicable, though difficult. The quantity of solid rock and boulders to be removed in the Hay Stack Channel is estimated at
The entrance to the Lachine Canal was carefully examined and found to be obstructed by ledges of solid rock, covered in some instances with not more than 7 1/2 or 8 feet of water. But having been informed that an extension of the pier is contemplated, which will tend to give a greater depth over those obstructions, and change the direction of the Channel, the undersigned have not at present made any estimate of the cost of improving this entrance to the Lachine Canal; they are, however, prepared to do so at any time it should be desired.
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