water-saturated soils over much of the Penny River site, were probably the 

 key factors impeding vegetative recovery (especially by woody species). 



Another example of gravel removal and site location characteristics 

 which resulted in known short-term (the site was visited 3 years after 

 disturbance), and probably long-term annual hydraulic stress occurred at the 

 Sagavan irktok River study site. At this site 20 ha of a complex mixture of 

 mature and advanced, seral-stage shrub thickets was removed and the under- 

 lying gravels excavated to an average depth of 1.5 m. This area was located 

 between a high-water channel and the main river channel. The Sagavan irktok 

 River was a large river with moderate channel slope that flowed in a sinuous 

 conf i gur at i on . 



This gravel removal operation resulted in a permanent shift of much of 

 the main channel through the material site. Hydraulic analysis at this 

 site shows that extensive flooding is expected to occur on an annual basis 

 with water potentially influencing the site for up to 70 days each year. 



The site was visited during the third growing season after disturbance, 

 and no vegetative recovery had occurred. As long as the river continues to 

 flow through and annually flood the material site, it is not expected that 

 significant vegetative recovery will occur in the long-term. 



Short-Term Alteration of Vegetative Habitat Structure 



Short-term alterations, in the types of vegetative habitats present 

 within disturbed areas, occurred at those sites where vegetation was re- 

 moved, but where some natural vegetative recovery began within I or 2 years 

 post-mining and continued thereafter unimpeded. At no instance did an entire 

 disturbed area naturally revegetate over the short-term. However, in por- 

 tions of 13 sites pioneering communities became we I I estabi ished within I or 

 2 years (Table 29). This development most frequently occurred in those 

 portions of the disturbed areas which: were not influenced by normal or high 

 water flows; had a plentiful seed source or contained root stocks and other 

 woody slash; and/or consisted of well drained but moist soils with high silt 



23! 



