Arrastra Creek 



Restoration objectives: 

 Blackfoot River. 



Restore upstream fish passage for fluvial native fish of the 



Project Summary 



Arrastra Creek, the largest and among the coldest Blackfoot River tributary between 

 Beaver Creek (rm 105.2) and Nevada Creek (rm 67.8), enters the Blackfoot River at river 

 mile 88.8. Arrastra Creek is also the only stream between Poorman Creek (rm 108) and 

 the North Fork (rm 54.1) to support a bull trout population. Arrastra Creek was also 

 identified as the primary spawning tributary for fluvial WSCT in the middle Blackfoot 

 River based on telemetry studies (Pierce et al 2004). All telemetered WSCT spawned 

 downstream fi-om a set of undersized culverts located at mile 3.2. During the WSCT 

 migration period of 2003, we measured flow velocities through the culverts in excess of 8 

 ft/second - well above velocities WSCT can navigate. In 2005, these culverts were 

 replaced with a bridge. The bridge allows access to ~6 miles of perennial stream 

 upstream of the crossing. 



Fisheries populations and other monitoring 



Arrastra Creek supports bull trout and genetically pure WSCT throughout the 

 mainstem as well as brown trout and brook trout in lower reaches. Fish populations in 

 lower Arrastra Creek have been periodically monitored since 1 989 and most recently in 

 2004. The monitoring shows an increased number of WSCT in the lower 2.4 miles of 

 stream compared to the original 1989 surveys (Figure 14). This increase is thought to 

 result fi-om the increased number of fluvial adult WSCT in the middle Blackfoot River 

 using Arrastra Creek for spawning and concentrated spawning downstream of the 

 culverts. 



Other data 

 collections in Arrastra 

 Creek included a 

 geomorphic and 



substrate survey of 

 the WSCT spawning 

 areas. Detailed 



results of the 

 spawning site survey 

 are located in Results 

 Part IV. 



* Arrastra Creek 

 recently tested 



positive for whirling 

 disease in 2003 with 

 an initial infection 

 0.34, which then increased to 1 .23 in 2004. 



1996 1999 2004 



1989 2004 



1989 1996 2004 



26 



