Sixth.-Description of the several routes for the proposed Canal from the St. Lawrence to Lake Champlain, with Estimates of Cost.
In accordance with the intimations I received from your Honorable Board, surveys have been made on four distinct routes: namely, one commencing at Sorel, the confluence of the Richelieu or Chambly River with the St. Lawrence; the second commencing at Longueuil, on the St. Lawrence, nearly opposite the City of Montreal; the third at Caughnawaga on the St. Lawrence; and the fourth at a point on the Beauharnois Canal, 2 1/2 miles above the foot of Canal. All the routes terminating at the Town of St. Johns, the foot of Lake navigation.
The country has been very thoroughly examined, and lines have been formed, that it is believed will very nearly indicate the proper ground for a final location, on either route, that may be adopted; and it may be said, they are all quite practicable, so far as engineering works are concerned.
The first or Sorel route follows the channel of the River Richelieu from Sorel to the lower termination of the Chambly Canal, a distance of about 46 miles. This has the improvement of the Lock and Dam at St. Ours. The channel is generally very direct in its course, and has a good depth of water. By the Dam at St. Ours, the water in the shallow places has been raised to a minimum of 7 feet in depth. To make it 10 or 11 feet it is only necessary to raise the Dam and Lock at St. Ours a corresponding height. From Chambly to St. Johns, about twelve miles enlargement and improvement of the Chambly Canal will complete the work. This, as will be seen, is the least expensive route. The total length from Sorel to St. Johns is (58) fifty-eight miles.
The second or Longueuil route is (28.28) twenty-eight 28/100 miles in length. This line, on the survey, proved longer than was anticipated from the general appearance of the country. It was found the long and deceptive (to the eye) undulations force the line into circuits, that inevitably increased its length. It strikes the Caughnawaga line near Little Montreal River, from which point to St. Johns it is common to the Caughnawaga line, on the Champlain level. Its entrance into the St. Lawrence at Longueuil is not favorable for the construction and maintenance of wharves and piers for the accommodation of vessels. This is owing to the strong current near that place, and the action of moving ice.
The third or Caughnawaga route. It is proper here to observe that two routes have been surveyed; one on the Champlain level, and one by a more direct line, with a summit of 372 feet above Lake Champlain. That by the Champlain summit is (34 46/100) thirty-four 46/100 miles in length, and by the direct line (25 51/100) twenty-five 51/100 miles in length. The Champlain level has two ascending locks from the St. Lawrence, and a guard lock at St. Johns. The latter will very frequently be used as a lift lock, owing to the changes in level caused by winds on Lake Champlain. The direct line will have eight locks, five ascending, and three descending to Lake Champlain; or six lift locks more than the Champlain level, and near say nine miles less length of Canal. The direct line must be supplied with water from the St. Lawrence, and will require a feeder of (16 19/100) sixteen 19/100 miles in length. The feeder will enter the Canal at a point (4 1/10) four and1/10 miles from its terminus at Caughnawaga. The entrance into the ock at Caughnawaga is about one and a-half miles above the Railroad and Ferry wharf. This is the nearest point at which a good entrance, with depth of water and quiet current, could be obtained. The situation is very eligible for the wharves and piers that will be required ; very safe, and by means of a small Island immediately above, very capacious accommodation may be made at moderate expense for the lumber trade, in changing from the river to the Canal, as well as for vessels, in their transit between river and Canal.
The fourth or Beauharnois route. This route commences on the Beauharnois Canal (2 1/2) two and a-half. miles above the foot of Canal, and makes a junction with the Caughnawaga direct line at a point (4 1/10) four and 1/10 miles from Caughnawaga. The distance from Beauharnois Canal to said junction is (16 19/100) sixteen l9/100 miles. If made a feeder, this would be its length. If made a Canal, and regarded as a distinct line, then the line from the junction with Caughnawaga direct line would be the same as the said direct line to St. Johns; in other words, the two lines would be common from the junction to St. Johns. Regarded as one of the routes for the proposed Canal, the length from the commencement on the Beauharnois Canal to St. Johns is (37 66/100) thirty-seven 66/100 miles, and will fall into the Champlain level at St. Johns, by three locks, having an aggregate lockage of 37 1/2 feet.
It therefore appears the Caughnawaga route will have the advantage of 3/4 of a mile in distance, and the Beauharnois five (to six) Locks, the advantage in lockage, and save wholly the navigation of Lake St. Louis, fourteen (14) miles. Caughnawaga route, direct line, we have Canal navigation, on Beauharnois
With the size of Canal proposed, walled on both sides as it will be designed, with a large proportion of Canal extra width which may be secured at reasonable extra cost, I consider the passage of one lock as being rather over an equivalent for one mile in length of Canal navigation. If, therefore, the Western trade was to be alone considered, there can be no doubt the Beauharnois route will most effectually secure it. But other considerations must not be overlooked in this question of route, and they will be hereafter considered.
It has been suggested that a more favourable route could be found, by starting from the St. Lawrence at some point on Lake St. Francis, and by a higher level command the intervening country between that and Rouse's Point, and wholly avoid the navigation of the river formed portion of Lake Champlain east of St. Johns, or the greater portion of it. There has not been time to examine this route, so as to form any definite opinion of its merits. It will no doubt be longer than the Beauharnois route, and have more length of Canal navigation with the same lockage. If it was supported, there would be any material difficulty in making a good navigation from St. Johns to Rouse's Point; this route would assume more importance. It is true some portion of the Channel between those points is not of sufficient depth of water; but these are not of great extent, (most of the Channel being good both in depth and breadth,) and from examination, it is believed, may be dredged at moderate expense so as to render it fully adequate. The bottom appears to be of soft mud; that must be reduced from one to three feet, and when once removed and subjected to an active steam navigation, will easily be kept a sufficient depth. Other considerations that will be shown hereafter induce me to believe there can be no great importance in prosecuting this subject further; but if thought expedient, an instrumental examination may be made to more fully test its character.
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