Number 



Page 



44 Reduction of instream cover as provided by 

 boulders at Sagavanirktok River, 3 August 1978 

 (flow level, 60 mVsec, = 155% of estimated 



mean annual flow) 155 



45 Increased braiding at Sagavanirktok River study 

 site caused by mining mid-channel gravel bars 

 and a vegetated island in the active channel 

 (mining operation conducted during the winter 



of 1974-1975) 157 



46 Response of cross-sectional wetted perimeters 

 to percentage of mean annual flow and percent- 

 age of cross sections comprised of selected 

 depth intervals at mean annual flow at three 



gravel removal study sites 158 



47 Low velocity backwaters formed by gravel removal 

 at Dietrich River-Downstream (13 July 1978) and 

 Middle Fork Koyukuk R i ver-Upstream (18 July 1978), 



note extensive silt deposition in both cases .... 159 



48 Creation of low velocity side channels and 



inundated pit following gravel extraction 160 



49 Sequence of aerial photographs showing effects 

 of overmining the inside of a meander bend 



at Middle Fork Koyukuk Ri ver-Upstream. Immedi- 

 ately following mining (b) there was an increase 

 in backwater areas. The next year (c) the 

 meander was partially cut off, creating a vari- 

 ety of low velocity habitats 163 



50 Temperature and dissolved oxygen profiles at 



four deep gravel pit study sites 165 



51 Ponded area at Kuparuk River study site where 

 three seine hauls captured 61 Arctic grayling 

 and 2 slimy sculpin, 9 August 1978 (pool I in 



Table 21 ) 179 



52 Ponded area at Middle Fork Koyukuk-Upstream 

 study site where one seine haul captured 28 

 Arctic grayling, 3 round whitefish and 3 slimy 



sculpin, 18 July 1978 (pool 2 in Table 21) 179 



53 Potential migration blockages, aufeis fields 



at Washington Creek and Oregon Creek, June 1977 . . 182 



54 Region where Aufeis Creek went subsurface 

 creating migration blockage due to lack of 



surface f low 183 



XV 



