Figure 64. A view of Oregon Creek looking downstream 

 through the mined area showing site conditions that remain 

 13 years after gravel removal. 



The specific changes that retarded vegetative recovery and development at 

 these sites were related to induced aufeis development and increased annual 

 high-water stresses. 



At Washington and Oregon Creeks, extensive aufeis fields annually 

 developed within the material sites. This ice, which is known to last until 

 late June throughout the disturbed areas, severely impeded vegetative recov- 

 ery at these sites. No significant vegetative communities had developed 

 within the disturbed areas of either site during the 13 years following the 

 gravel removal operations. 



There is no evidence of aufeis development at the Penny River site. 

 However, the area was scraped in an irregular surface pattern over 15 ha to 

 a depth equal to or slightly below normal summer flow levels (Figure 65). 

 The site was visited II years after gravel was removed. As a result of the 

 depth of scraping, much of the site contained either small pools of ponded 



229 



