SITE PREPARATION 



Having selected and gained approval to develop a gravel removal site, 

 site preparation activities can begin. These activities may include construc- 

 tion of access roads, removal of overburden, and construction of channel 

 diversions and settling ponds. 



ACCESS 



As a part of most floodplain gravel removal operations, haul roads must 

 be built to connect the site to the use location or existing roads. This 

 construction poses no special engineering problems in non-permafrost areas 

 or in areas where the permafrost is thaw-stable. However, in areas of ice- 

 rich permafrost, protection of the tundra is of vital importance. From an 

 engineering standpoint, t undr a- i nsu I a ted permafrost, as long as it remains 

 frozen, is an excellent base or foundation for structures whether they be 

 drill pads, roadways, pipelines, or other structures. When the permafrost 

 begins to thaw two critical things happen. First, there is a tremendous loss 

 in strength, and second, the thawing process is very difficult to stop. 

 Thus, after the tundra is disturbed enough to allow the permafrost to begin 

 this progressive thawing, the same area that formerly was an excellent base 

 for structures becomes a very difficult, if not impossible, foundation 

 problem for any engineering purpose. Drainage and other related problems 

 also begin to develop and these can have significant adverse impacts on 

 engineered structures. 



Access roads traversed ice-rich permafrost at several of the study 

 sites with varying degrees of success. In general, where at least 0.5 m of 

 gravel depth was used, permafrost integrity was maintained. However, at 

 several sites (Ugnuravik River, Aufeis Creek, Skeetercake Creek, and Kuparuk 



321 



