reconstruction began in June 1988. During the Phase I 

 rehabilitation of the Milltown Dam, the Montana Power Company 

 monitored water quality in the Clark Fork and Blackfoot River 

 upstream and downstream from the dam from July 14, 1986, to 

 April 4, 1987 (MPC 1987a). 



In the summer of 1988, the USGS (under a contract with 

 EPA) installed a continuous streamflow gaging station at the 

 Perkins Lane Bridge and a seasonal streamflow gaging station 

 at the Stewart Street Bridge. The USGS is also conducting 

 periodic water quality sampling at Perkins Lane Bridge under 

 the same contract. 



The water quality data collected by the USGS in the 

 upper Clark Fork Basin from March 1985 to September 1987 are 

 published in two data reports (Lambing 1987, 1988). The 

 data represent primarily low-to-medium flow conditions as a 

 result of less than normal runoff during most of the sampling 

 period. However, one high flow from snowmelt runoff was 

 sampled from February 24 to 26, 1986, which gave some indica- 

 tion of the increase in suspended trace element concentra- 

 tions during times of peak sediment discharge. 



) 



MultiTech (1987d) conducted a surface water and point 

 source investigation of Silver Bow Creek and the upper Clark 

 Fork as part of the Silver Bow Creek Phase I RI. The study 

 area extended from the Weed Concentrator outfall in Butte to 

 near Garrison, Montana. Phase I field work was conducted 

 from November 1984 to September 1985, with additional surface 

 water samples collected in 1986. Metals studied included 

 arsenic, cadmium, copper, iron, lead, and zinc. 



In August 1988, the MBMG began a short-term monitoring 

 program in the headwaters area for DHES-SHWB. The objective 

 was to collect data during short-qjuration, high-intensity 

 thunderstorm events. Continuous monitors were installed at 

 four sites to measure physical water quality parameters, 

 including pH, specific conductance (SC) , DO, and temperature. 

 These monitors have in-situ, internal data loggers that were 

 set to record data every 20 minutes. They were installed 

 near the USGS streamflow gaging stations at the Colorado 

 Tailings, the Stewart Street Bridge, the Perkins Lane Bridge, 

 and in Warm Springs Creek at Warm Springs. Field checks of 

 the water quality parameters were conducted 23 times to 

 compare with data obtained from the continuous monitors. 

 Monthly depth composite samples were also collected at these 

 stations for analysis of other water quality parameters 

 (metals) . Some of these samples were collected during storm 

 events and others were baseline samples. 



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