Irrigation-Affected Lands 



The deleterious effects of using Silver Bow Creek and 

 upper Clark Fork water for irrigation were recognized as long 

 ago as the early 1900s, Haywood (1907) reported that many 

 farmers used Clark Fork water only when absolutely necessary 

 due to its injurious effects. Results of surface water 

 investigations conducted by Haywood and other researchers led 

 him to conclude that Clark Fork water was not suitable for 

 irrigation use and would seriously injure land to which it 

 was applied (Haywood 1907) . Haywood also sampled irrigated 

 surface soils up to 15 miles northeast of the smelter and 

 found very high copper concentrations relative to sites west 

 and southwest of the smelter that were not irrigated by Clark 

 Fork water (Haywood 1910) . 



Little additional research was conducted on contaminated 

 irrigation water until recently, but the problem was still 

 recognized in various documents, such as the 1959 Water 

 Resources Survey for Powell County (Buck et al. 1959) and the 

 Deer Lodge Valley Conservation District's Long Range Program 

 (1982) . 



Hydrometrics (1983b) reported that several fields (about 

 200 acres east of the Clark Fork near Deer Lodge) had been 

 affected by tailings and poor-quality irrigation water 

 conveyed by a ditch. These fields have large barren areas 

 with negligible productivity and weed and erosion problems. 



In March 1985, the Montana Bureau of Mines collected 

 soil cores from three land types on the Spangler Ranch near 

 Gregson, Montana, for phase I of a study of reclamation 

 techniques on heavy metals-contaminated pasturelands (Osborne 

 et al. 1986). Fifteen soil cores were collected (although 

 only three were analyzed) from a dryland pasture, a pasture 

 site, and an irrigated alfalfa field to determine metals and 

 arsenic distribution in the soil profiles. Elevated levels 

 of arsenic, copper, and zinc were found in the upper nine 

 inches of soil. One of the sites was thought to be within 

 the historic floodplain of Silver Bow Creek and was 

 reportedly flooded and irrigated with creek water in the 

 past. 



A literature review conducted in developing the Silver 

 Bow Creek remedial investigation workplan revealed an 

 estimated 5,400 acres of cropland potentially contaminated by 

 irrigation water in Silver Bow, Deer Lodge, and Powell 

 counties (MultiTech and Stiller and Associates 1984). 



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