Expanded Comments for Split Rivers 



Comment I . General ly the bed of an active channel should not be dis- 

 turbed. If bed deposits are the only available source, the gravel should 

 be taken by dredging or scraping under strict work plans and stipulations. 



• It is recommended that side channel (s) be mined rather than the main 

 channel. If the site contains a side channel that caries less than 

 approximately one third of the total flow during the mining period this 

 channel can be blocked at its upstream end and mined by scraping. 

 Refer to Scraping Guidelines (VI B 2). 



• If channels approximating this size are not available then either 



the side or main channel can be mined using dredging. Refer to Dredging 

 Gu i del ines (VI B 4) . 



Comment 2 . Gravel is available by scraping deposits to near the low 

 summer flow, maintaining appropriate buffers, or no lower than the water level 

 present during the mining operation. Refer to Scraping Guidelines (VI 8 2). 



Comment 3. Gravel is available if suitable buffers are maintained to 

 protect against channel diversion. Refer to Scraping Guidelines (VI B 2), 

 Pit Excavation Guidelines (VI B 3), and Buffer Recommendations (V A 3 and 

 Append i x A ) . 



Comment 4 . Vegetated islands are often a limited habitat in these systems 

 and often control channel integrity. Exposed deposits should be considered 

 before vegetated island deposits. If deposits in feasible alternative loca- 

 tions are not sufficient, and vegetated islands are abundant in the river 

 system in question, about 10 to 20 percent of this habitat may be removed from 

 about a 5-km reach of floodplain. Refer to Scraping Guidelines (VI B 2) and 

 Pit Guidel ines (VI B 3) . 



Comment 5 . Vegetated river banks of both active and high-water channels 

 should not be disturbed because of biological and hydraulic alterations. 

 These areas should be removed from work plans. 



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VI . SITE OPERATION 



