Water Qua I i ty 



Water quality measurements reflected habitat alterations in several 

 ways. First, dissolved oxygen and temperature responded in a predictable 

 fashion to increased braiding. The spreading and shallowing of flow and loss 

 of cover led to an increased rate of heat exhange, with the temperature, and 

 therefore dissolved oxygen, responding more quickly to ambient air tem- 

 peratures in the mined area than in the upstream area. Similarly, areas with 

 ponded water showed increased temperatures and reduced dissolved oxygen 



(Skeetercake Creek, Dietrich River-Downstream). An increase in dissolved 

 oxygen and decrease in temperature which was not caused by flow alteration 

 was recorded at Dietrich Ri ver-Upstream where a spring was uncovered during 

 gravel removal operations. As mentioned, inundated pits functioned as pond 

 habitats with corresponding water quality characteristics. These included 

 higher temperature and lower dissolved oxygen than the associated rivers and 



in some cases, thermal and oxygen stratifications. 



A second type of water quality change was a change in conductivity 

 between the upstream and mined areas. A change in conductivity may indicate 

 the existence of a spring water source near or exposed by the gravel removal 

 operation. Such changes were recorded at Aufeis Creek, Skeetercake Creek, 

 Dietrich Ri ver-Upstream and Penny River. As already mentioned, the Dietrich 

 R i ver-Upstream was an identified spring exposure. The Penny River had a 

 spring-fed tributary entering the floodplain in the mined area. Springs were 

 not recorded at Aufeis Creek or Skeetercake Creek, but the conductivity 

 changes may indicate their existence. 



A third type of water quality change was alteration in turbidity or 

 suspended solids, or both, in the mined area compared to the upstream area. 

 These changes probably indicate erosional or depositional characteristics of 

 the mined area, but the sampling was insufficient to reach definite conclu- 

 sions on an individual site basis. 



166 



