CHAPTER XXIV 

 METHODS AND COSTS OF RIVER DREDGING 



MUCH has been written in this treatise on dredges and their 

 adaptability to various kinds of work. Space would not admit of 

 a detailed description of all the classes of work, such as deep-sea 

 dredging, harbors, drainage, land reclamation, mining and river work. 

 However a description is given in this chapter of the improvement 

 of the St. Lawrence River. This is one of the most important 

 engineering works in America, and dredging has been carried on 

 almost continuously for nearly 70 years. It serves too as an 

 excellent example of dredging, as the conditions of the work and 

 the kind of soils varies and several types of machines have been 

 used. It will serve to bring out a number of important details 

 regarding dredges and dredging. It is written from reports and 

 information furnished by Mr. F. W. Cowie, chief engineer of the work. 



The first improvement was started in 1844. The machinery 

 first used was built in Glasgow, Scotland, but since then nearly 

 all the dredges have been built in Canada. The progress made in 

 the design and construction of dredges is aptly illustrated by the 

 work done on this river. In 66 years the improvements to dredges 

 have been phenomenal. For instance a dredge working in Lake St. 

 Peter in 1846 excavated in one day about 1200 cu.yds. In 1888 

 a dredge working in the same place excavated 7200 cu.yds., while 

 in 1906, 20,000 cu.yds. were frequently excavated in a day and 

 night run. 



The channel of the river from Montreal to Father Point, where 

 the river flows into the Gulf of St. Lawrence, is about 340 statute 

 miles. The greater part of the dredging is done between Montreal 

 and Traverse, a distance of 220 miles. The work done from 1844-50 

 was in Lake St. Peter, to deepen some shallow places in order to 

 allow 500-ton vessels to reach Montreal. 



In 1851 organized work was undertaken to make a channel 

 for large vessels from Montreal to Quebec, 160 miles. By 1888, 



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