Number Page 



32 Schematic diagram illustrating the effects 



of a flow obstruction on the local hydraulics .... 107 



33 Comparative aerial photography of the Penny 

 River showing change in hydraulic character- 

 istics resulting from gravel removal activities ... 113 



34 Schematic diagram illustrating an example of 



a change in local water surface slope result- 

 ing from an in-channel gravel removal operation ... 114 



35 Schematic diagram showing degradation process .... 116 



36 Upstream view of thermal and fluvial erosion 

 in the access road at Ugnuravik River, acting 



as a long-term sediment source to the river 123 



37 View of erosion of a diversion dam which acts 

 as a long-term sediment source to Skeetercake 

 Creek. Dunes in foreground are atypical of the 

 undisturbed river 123 



38 Large area of aufeis at the upper gravel 

 removal area at Washington Creek as it 



appeared in early June 125 



39 Aerial photographs of Washington Creek (top) and 

 Aufeis Creek (bottom) showing material site loca- 

 tions and approximate channel locations before 



the disturbance 133 



40 Siltation resulting from extensive aufeis 

 field at Oregon Creek mined study area, 



20 June 1977 14-9 



41 Removal of bank cover at Oregon Creek as 



observed on 24 June 1977 152 



42 Removal of bank cover at Skeetercake Creek 



as observed on 18 June 1977 153 



43 Washington Creek upstream and mined area on 



9 September 1977 showing reduction of instream 



cover due to gravel removal operation (flow 



level [O. I I mVsec] = 20 percent of mean 



annual flow). Other habitat alterations include 



increased braiding, siltation, and intergravel 



f I ow I 54 



X IV 



