with the several genera of free-living nitrogen- fixing blue-green algae found at this site, the large 

 number of Epithemia sorex indicates that nitrogen is likely the limiting nutrient in upper Coal 

 Creek. Aside from a slightly depressed diversity index (due to dominance by E. sorex), there 

 was no other indication of natural or anthropogenic stress or impairment in upper Coal Creek. 

 At the lower site on Coal Creek, a depressed pollution index and an elevated siltation index 

 indicated minor impairment from organic loading and sedimentation in July. In September, a 

 very large number of Diatoma moniliformis indicated elevated dissolved solids in lower Coal 

 Creek, possibly due to diminished stream flow. A depressed pollution index also indicated 

 minor impairment from organic loading in September. The depressed diversity index was due 

 mostly to the very large number of D. moniliformis that were present at this time. The upper 

 and lower sites on Coal Creek shared less than 20 percent of their diatom assemblages in 

 September, indicating that a major change in environmental conditions occurred between them. 



Indian Creek. The upper site on Indian Creek had a slightly depressed pollution index 

 that indicated minor impairment from organic loading. This site supported large numbers of 

 Fragilaria vaucheriae and Synedra ulna, both of which tolerate small amounts of organic matter. 

 Hannaea arcus, an indicator of clean, cold waters, was also a major species here. Other than 

 slight organic loading at the upper site, diatom metrics indicated excellent biological integrity, no 

 impairment, and full support of aquatic life uses at both sites (Table 4). 



Ramshorn Creek. Aside from the natural stress evident in upper Ramshorn Creek, this 

 site had excellent biological integrity and no impairment (Table 4). An elevated siltation index 

 and a depressed pollution index indicate moderate impairment from sedimentation and minor 

 impairment from organic loading in lower Ramshorn Creek. The lower site shared only 17 

 percent of its diatom assemblage with the upper site, indicating that major environmental 

 changes occurred between the two sites. 



Currant Creek. In addition to the natural stress evident in Currant Creek, this site 

 exhibited minor impairment from sedimentation (Table 4). Other metrics indicated no 

 impairment and excellent biological integrity. 



n 



