Ch. 21] COST OF CLEANING CANALS 



TABLE 1 

 Cost of Removing Silt from Canals and Laterals 



373 



1 Postwar rehabilitation program. 



Note: Actual cost per mile for most districts would be greater than the figures shown, because the actual mileage cleaned 

 in any one year is less than the total mileage. 



be justified to a computed degree. For example, from Table 1 it can 

 be seen that costs were high after the close of the war, while deferred 

 maintenance was being overcome. But even in 1948 the cost of silt 

 removal averaged about $40 a mile, or 15 percent of all operation and 

 maintenance costs. For the 120,000 miles of irrigation canals and 

 laterals in the western states, the annual bill for cleaning silt would 

 be $4,800,000. With allowance for districts receiving water from 

 silt-free streams, the annual bill would still be over $3,500,000. 



Removal of silt is not limited to unlined ditches. On the Central 

 Valley project in California, the concrete-lined Contra Costa Canal 

 was cleaned with a water-propelled scraper at the cost of $6.50 per 

 mile in 1946. If the canal is cleaned twice annually by this method, 

 the annual cost per mile is $13. This does not include any proration 

 of the original cost or depreciation of the equipment, which was de- 

 veloped on the project and constructed of pipe framing, lumber, and 

 some scrap materials that were available. The scraper could not be 

 used in unlined canals or in lined canals where the silt deposits were 

 extremely heavy. The smaller concrete-lined East Contra Costa 



