did not mine adjacent to the river. Thus, the Shaviovik River has maintained 

 its natural channel and configuration. 



FACTORS AFFECTING VEGETATIVE RECOVERY RATE 



Several factors found to be influencing vegetative recovery already 

 have been discussed. The composition of fauna! communities using disturbed 

 areas was directly related to the habitat types available, thus, an under- 

 standing of how factors at the study sites influenced the rate of natural 

 vegetative recovery warrants further discussion. Overburden piles, woody 

 slash, and debris, an abundant seed source, and displaced organic mats 

 enhanced recovery rate. Hydraulic stress such as aufeis development, perman- 

 ent ponding, actual channel shifts, and increased flooding impeded develop- 

 ment. Soil conditions and growing season, depending upon site specific 

 characteristics, either enhanced or impeded vegetative recovery. 



Imped iment s 



Among the factors believed to be impeding vegetative recovery, hydrau - 

 lic stress influenced most sites and had the strongest and most long-term 

 effect. These stresses resulted from changes induced by gravel removal 

 in floodplain elevations, dimensions, and configurations. They included: 



• Permanent or annual flooding, 



• Increased frequency and duration of temporary flooding, 



• Long-term channel changes (increased braiding and channel width and 

 decreased channel stability), and 



• New or increased aufeis development. 



The specific known causes for these induced hydraulic changes are 

 presented in detail in EFFECTS OF GRAVEL REMOVAL ON RIVER HYDROLOGY AND 

 HYDRAULICS. In general, they most frequently resulted because sites were 

 excavated too deeply (excluding pit sites) without maintaining buffers or 

 stable channel banks, or because the gravel removal method and character- 

 istics were not correct for the chosen location. 



241 



