SUMMARY 



In July and August 2000, composite periphyton samples were 

 collected from Mill Creek, Pine Creek, and Tom Miner Creek in the 

 Paradise Valley south of Livingston for the purpose of assessing 

 whether these streams are water-quality limited and in need of 

 TMDLs. The samples were collected following DEQ standard 

 operating procedures, processed and analyzed using standard 

 methods for periphyton, and evaluated following modified USEPA 

 rapid bioassessment protocols for wadeable streams. 



Mill Creek had a normal algal assemblage that indicated 

 slight nutrient enrichment. Diatom association metrics at the 

 Mill Creek site indicated minor impairment but full support of 

 aquatic life uses (Table 5) . Slightly elevated percent dominant 

 species and siltation indexes and a few abnormal diatom cells 

 resulted in an overall rating of "good" biological integrity. 



The algal flora in Pine Creek was sparse, both in terms of 

 cell numbers and taxa richness. The dominant algal species here 

 indicated very cold and very fast flowing waters, and very small 

 concentrations of nutrients. The moderate stress indicated by 

 the algal assemblage here was probably the consequence of 

 naturally austere habitat conditions. 



The algal assemblages at both sites in Tom Miner Creek 

 indicated moderate impairment and partial support of aquatic life 

 uses. The leading cause of this impairment was siltation. Both 

 sites also had somewhat depressed pollution indexes, indicating 

 minor organic enrichment. A few abnormal diatom cells were also 

 found at each site. The two sites on Tom Miner Creek had nearly 

 80% of their diatom assemblages in common, indicating that they 

 were virtually identical in their chemical, physical, and 

 biological characteristics. 



