knowledge, a better solution would have been to construct a snow or ice road 

 (Adam 1978). 



Year-Round Access 



A substantial gravel 11-3 m thickness) overlay is required where year- 

 round access to a site is needed over ice-rich permafrost. However, place- 

 ment of insulation beneath the gravel would reduce the thickness of overlay 

 required. Year-round access roads must also be above flood stage of the 

 river, which may require placement of culverts at high-water channels 

 crossed by the road. 



OVERBURDEN REMOVAL 



The stripping of overburden involves the removal of any material cover- 

 ing the gravel deposit. The overburden material, usually topsoil and or- 

 ganics, is normally removed from the site and either stockpiled for later 

 use in site rehabilitation or hauled to approved disposal sites. Stripping 

 is normal ly done with graders, scrapers, or dozers. Overburden depths were 

 not recorded at all of the study sites. However, where information was 

 available, the depths ranged from a thin veneer (at six of the sites) to 

 0.9 m (at one of the sites) and the average was 0.3 m. 



CHANNEL DIVERSION 



For efficient gravel removal at some floodplain sites, it may be desir- 

 able to divert river flows, especially those associated with subchannels, 

 away from the area from which gravel is to be removed. This diversion is 

 normally done by constructing earthen dikes or levees upstream from the 

 site. Armoring of the upstream face and outer end of these structures may be 

 necessary to provide erosion resistance. Erosion prevention is discussed 

 further in EFFECTS OF GRAVEL REMOVAL ON RIVER HYDROLOGY AND HYDRAULICS. 



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