spawning site (McNeil core) surveys at mile 1.1, the results of which are presented in 

 Results Part IV. 



Clearwater River 



Restoration objective: Enhance instream flows to the lower Clearwater and Blackfoot 

 River during critical drought periods. 



Project summary 



The Clearwater River is the largest tributary to the lower Blackfoot River with an 

 estimated base flow of -80 cfs. Located at river mile 3.5 on the Clearwater River, is an 

 unscreened irrigation diversion that diverts measured flows up to 35 cfs and entrains nine 

 species offish, based on a trapping survey undertaken in 2003 (Pierce et al. 2004). 



Fisheries restoration actions at the diversion are proceeding on two fronts. First is 

 a ditch fish-screening project, developed and funded, but not yet installed. The second is 

 an instream flow project designed to enhance Blackfoot River flows during critical 

 drought periods. The flow enhancement agreement, completed in 2004, involves 1) 

 limiting irrigation to 1 2 cfs at the Clearwater diversion when flows at the USGS Bonner 

 gauge fall below 700 cfs, and 2) stopping irrigation from the Clearwater diversion when 

 flows at the Bonner gauging station reach 600 cfs. In exchange for these irrigation 

 reductions, FWP, USFWS and BBCTU purchased a new pivot and pump for a separate 

 Blackfoot River diversion. This agreement further allows the irrigator to continue late 

 season irrigation (as measured at the USGS Bonner gauging station) from the new 

 Blackfoot pivot despite a junior water right to the 700 cfs FWP Murphy rights on the 

 Blackfoot River. 



These increased flows are expected to enhance flows in the lower Clearwater 

 River and Blackfoot River below the junction of the Clearwater during critical drought 

 periods by up to ~25 cfs based on recent measured use. 



2.5 



c 



X= 0.0403X + 0.5043 

 r2 = 0.9721 



Flow monitoring 



Continued drought in the summer of 2005 called for the implementation of the 

 Clearwater instream 

 flow project. The 

 project involved 



reducing instream 

 flows fi'om 20 to 12 

 cfs on August 2"** 

 2005 approximately 

 two days after the 

 Blackfoot River fell 

 below 700 cfs. The 

 Clearwater diversion 

 was shut down in 

 mid-August when 

 flows fell below 600 

 cfs. Flow monitoring 

 revealed the ditch continued to divert water measured at 1 .9 cfs on August 29"', 20005. A 



Figure 16. Stage/discharge relationship for the Clearwater ditch. 



28 



