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PROJECT AREA AND SAMPLING SITES 



The project area is located in southeastern Big Horn County- 

 near the town of Decker, Montana. Squirrel Creek heads on the 

 Crow Indian Reservation east of Wyola and flows southeasterly for 

 about 20 miles to where it enters the Tongue River less than a 

 mile from the Wyoming state line. The project area encompasses 

 the lower reach of Squirrel Creek below the Reservation boundary. 



The project area is within the Northwestern Great Plains 

 Ecoregion (Woods et al . 1999). The surface geology of the 

 watershed consists of Paleocene coal -bearing deposits of the Fort 

 Union Formation and Eocene deposits of the Wasatch Formation 

 (Renfro and Feray 1972) . Vegetation is mixed grassland (USDA 

 1976) . The main land use is livestock grazing. 



Periphyton samples were collected at 3 sites on Squirrel 

 Creek on May 4, 2000 (Table 1, maps). The uppermost site (#4) 

 and the lowest site (#1) bracket a 10-mile section of lower 

 Squirrel Creek that extends from just below the Crow Reservation 

 boundary to the Tongue River. The middle site (#3) is about 2 

 miles above the point where pumped groundwater from coal-bed 

 methane development was being discharged into Squirrel Creek. 



Elevations at the sampling sites range from about 3,900 feet 

 at the upper site to about 3,400 feet at the mouth of Squirrel 

 Creek near Decker. Squirrel Creek is classified C-3 in the 

 Montana Surface Water Quality Standards. 



METHODS 



Periphyton samples were collected by Patrick Newby of the 

 MDEQ Monitoring and Data Management Bureau following standard 



