For Protocol I, only periphyton samples collected in summer 

 (June 21-September 21) can be compared with confidence to 

 reference stream samples because metric values change seasonally 

 and summer is the season in which reference streams and impaired 

 streams were sampled for the purpose of biocriteria development. 

 Protocol II can be used at any time of the year. 



QUALTIY ASSURANCE 



Several steps were taken to assure that the study results 

 are accurate and reproducible. 



Upon receipt of the samples, station and sample information 

 were recorded in a laboratory notebook and samples were assigned 

 a unique number compatible with the Montana Diatom Database, 

 e.g., 1987-01. The first part of this number (1987) designates 

 the sampling site (Big Dry Creek Site #9) ; the second part of the 

 number (01) designates the number of periphyton samples that have 

 been collected at this site to date for which data have been 

 entered into the Montana Diatom Database. 



Sample observations and analyses of soft (non-diatom) algae 

 were recorded in a lab notebook along with station and sample 

 information provided by Warren Kellogg of the NRCS . A portion of 

 the raw sample was used to make duplicate diatom slides. 



On completion of the project, station information, sample 

 information, and diatom proportional count data will be entered 

 into the Montana Diatom Database. One set of diatom slides will 

 be deposited in the University of Montana Herbarium in Missoula. 

 The other set of slides will be retained bv Hannaea in Helena. 



RESULTS AND DISCUSSION 



Results are presented in Tables 4-6, located near the end of 

 this report following the Literature Cited section. Spreadsheets 

 containing completed diatom proportional counts, with species' 

 pollution tolerance classes and percent abundances, are attached 

 as Appendix A. 



