workplan for completion of the FS. It is anticipated that 

 this workplan will be finished in December 1988. 



The Milltown Dam has been repaired several times through 

 the years. Recently, a two-phase reconstruction of the 

 facility was initiated in response to an emergency order 

 issued by the Federal Energy Regulatory Commission. Phase I 

 work involved reconstruction of the spillway and was 

 performed by MFC from August 1986 to March 1987. This work 

 was carefully monitored to ensure minimal degradation of the 

 Clark Fork downstream from the dam. Phase II of the rehabil- 

 itation project is underway and involves extensive repairs to 

 the dam structure. 



METALS-CONTAMINATED LANDS 



Introduction 



A vast acreage in the upper Clark Fork Basin is affected 

 by elevated concentrations of metals in the soil. The extent 

 and degree of contamination varies considerably, as do the 

 sources of contamination. The major types of metals- 

 contaminated lands are: 



• areas covered by tailings disposal facilities or 

 impoundments (e.g., Colorado Tailings area, Old 

 Works, tailings ponds near Anaconda, Warm Springs 

 Ponds) 



• lands affected by aerial deposition of metals from 

 historic smelting activities (e.g., Butte area. 

 Deer Lodge Valley) 



• agricultural lands affected by the historic use of 

 tailings-laden irrigation water that was conveyed 

 through extensive ditch systems 



• floodplain areas of Silver Bow Creek and the upper 

 Clark Fork that have accumulated tailings during 

 historic flood events. 



Each of these types of affected lands is discussed in 

 the following sections. Sediment transport mechanisms, 

 reservoir sediments, and reclamation are also discussed. 



3-31 



