• 



Wales Creek. The large percentage of motile diatoms in Wales Creek indicates 

 moderate impairment from sedimentation and only partial support of aquatic life uses. The 

 slightly depressed pollution index suggests minor impairment from organic loading. 



Rock Creek. Diatom metrics suggest that both sites had good biological integrity and 

 provided full support to aquatic life uses. Rock Creek had a very distinctive diatom flora that 

 included two species that are seldom recorded in North America: Gomphonema designatum and 

 Distrionella incognita. The latter is restricted to streams that head in the Canadian Rockies 

 Ecoregion. The two sites on Rock Creek supported very different diatom floras. 



Frazier Creek. A large percentage of motile diatoms here suggest moderate impairment 

 and partial support of aquatic life uses due to sedimentation. The siltation index here approaches 

 but does not exceed the threshold for severe impairment and non-support of aquatic life uses. 

 The pollution index for Frazier Creek is just below the threshold for minor impairment from 

 organic loading. 



Buffalo Gulch. Both sites on Buffalo Gulch support elevated percentages of motile 

 diatoms. The siltation index at the upper site just exceeds the threshold for moderate impairment 

 and partial support of aquatic life uses. The siltation index at the lower site exceeds the threshold 

 for severe impairment and non-support of aquatic life uses. The pollution index indicates that 

 both sites suffer minor impairment from elevated organic loading. The two sites on Buffalo 

 Gulch shared about half of their diatom assemblages, which indicates that only minor changes in 

 environmental conditions occurred between them. 



Black Bear Creek. This site had the highest siltation index and the lowest pollution 

 index of all sites in the sample set. The very large percentage of highly motile diatoms indicates 

 severe impairment and non-support of aquatic life uses due to sedimentation. Large numbers of 

 Nitzschia palea, a pollution tolerant species, indicates elevated concentrations of nitrogenous 

 organic matter, and the resulting low pollution index suggests moderate impairment and partial 

 support of aquatic life uses. 



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