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 water filters and irrigation intakes, create 

 tastes and odors in drinking water, and cause other problems. 



PROJECT AREA AND SAMPLING SITES 



The project area is located in northern Park County in 

 southcentral Montana. Antelope Creek heads on the eastern slopes 

 of Battle Ridge (el. 7,531 feet) and flows easterly for about 10 

 miles to where it enters the Shields River just north of Clyde 

 Park, Montana (pop. 302). Antelope Creek begins in the Middle 

 Rockies Ecoregion and ends in the Montana Valley and Foothill 

 Prairies Ecoregion of North America (Woods et al . , 1999) . 



Potter Creek heads on the low divide (el. 5,350 feet) that 

 separates the Shields River watershed from the Sixteenmlle Creek 

 drainage. Potter Creek flows south for about 15 miles to where 

 it enters the Shields River north of Wilsall, Montana. For much 

 of its length. Potter Creek parallels U.S. Highway 89. The 

 Potter Creek watershed is entirely within the Montana Valley and 

 Foothill Prairies Ecoregion (Woods et al . 1999). 



The surface geology of the project area is complex and 

 includes volcaniclastic deposits of the Livingston Group, 

 Cretaceous sandstones and shales of the Montana group, Paleocene 

 continental deposits, and Tertiary intrusives (Renfro and Feray 

 1972) . Vegetation is mixed conifer forest in the headwaters of 

 Antelope Creek and mixed grassland along lower Antelope Creek and 

 throughout the Potter Creek catchment (USDA 1976) . Although both 

 creeks are classified B-l in the Montana Surface Water Quality 

 Standards, they flow for a good portion of their lengths through 

 sagebrush steppe habitat that is typical of eastern Montana. 



