physical and biological data but not the type of detail required for sophis- 

 ticated correlation analysis. For these reasons the present analysis was 

 confined to analysis of trends and subjective evaluations of habitat alter- 

 ations and their effects on aquatic organisms. 



The material sites were visited 2 to 20 years after mining was com- 

 plete, thus the immediate effects of grave> removal operations were not 

 studied. The changes evaluated during the present study were those which 

 persist over a number of years rather than those affecting the biota during 

 the year of disturbance. A literature review of impacts at the time of 

 actual gravel removal was presented by Woodward-Clyde Consultants (1976). 



143 



