Some algae, such as the filamentous greens, are conspicuous 

 and their excessive growth may be aesthetically displeasing, 

 deplete dissolved oxygen, interfere with fishing and fish 

 spawning, clog irrigation intakes, create tastes and odors in 

 drinking water, and cause other problems. 



PROJECT AREA AND SAMPLING SITES 



The project area is located in southern Park County near the 

 town of Corwin Springs, Montana. Mol Heron Creek heads in the 

 area west of Electric Peak in Yellowstone National Park and flows 

 northeasterly for about 15 miles to where it enters the 

 Yellowstone River about 2 miles downriver from Corwin Springs. 



The Mol Heron Creek watershed is within the Middle Rockies 

 Ecoregion of North America (Woods et al . 1999) . The surface 

 geology consists of Quaternary rocks of volcanic origin and 

 Cretaceous shales of the Colorado Group (Renfro and Feray 1972) . 

 Vegetation is alpine tundra at higher elevations, mixed conifer 

 forest at middle elevations, and mixed grassland near the mouth 

 of Mol Heron Creek (USDA 1976) . 



A single periphyton sample was collected at the mouth of the 

 Mol Heron Creek canyon on July 14, 2000 (Map 1) . This site is 

 located about half the distance from the headwaters to the mouth 

 of Mol Heron Creek. The elevation of the sampling site is about 

 6,400 feet. Mol Heron Creek is classified B-1 in the Montana 

 Surface Water Quality Standards. 



METHODS 



The periphyton sample was collected by Patrick Newby of the 

 MDEQ Monitoring and Data Management Bureau following standard 



