Observations last summer showed that the calculations as to the raising of the surface of the river were correct. When the depth on the crest was 2.50 feet, the water at the foot of the Longue Sault was found to be 25 in. higher than if no dam existed. The intention was to raise it 24 in.
The timber slide was formed by binding parallel piers about 600 feet long up and down stream, as shown on the map, and 28 ft. apart, with a timber bottom, the top of which at upper end is 3 ft. below the crest of dam. It has the necessary stop logs, with machinery to move them, to control the water. The approach is formed by detached piers, connected by guide booms, extending about half a mile up stream. See map.
Alongside of the south side of the slide a large bulkhead was built, 69 ft. wide, with a clear waterway of 60 ft. It was furnished with stop logs and machinery to handle them. When not further required, it was filled up by a crib as before mentioned.
The following table shows the materials used in the dam and slide, and the cost:
______________________________________________________________________
| | | Stone | Exca- | |
| Timber, | Iron, | filling, | vation, | Cost. |
| cu. ft. | lb. | cu. yds. | cu. yds.| |
+---------+---------+----------+---------+----------+
Temporary works | 134,500 | 92,000 | 11,400 | | $79,000 |
| | | | | |
Permanent dam | 265,000 | 439,600 | 24,000 | 6,500 | 151,000 |
| | | | | |
Slide, including | 296,500 | 156,400 | 32,800 | | 102,000 |
apparatus | | | | | |
+---------+---------+----------+---------+----------+
| | | | | |
Total | 696,000 | 687,000 | 68,200 | 6,500 | $332,000 |
-----------------+---------+---------+----------+---------+----------+
The above does not include cost of surveys, engineering, or superintendence, which amounted to about ten per cent, of the above sum.
DETAILS OF THE OTTAWA RIVER DAM, AT CARILLON.
The construction of the dam and slide was ably superintended by Horace Merrill, Esq., late superintendent of the "Ottawa River Improvements," who has built nearly all the slides and other works on the Ottawa to facilitate the passage of its immense timber productions.
The contractors were the well known firm of F.B. McNamee & Co., of Montreal, and the successful completion of the work was in a large degree due to the energy displayed by the working member of that firm--Mr. A.G. Nish, formerly engineer of the Montreal harbor.