active channel(s) from diverting through the material site for 

 a selected period of time. Although it is preferable to use 

 natural vegetated buffers, man-made buffers in the form of river- 

 training structures and bank protection devices (see Appendix C) 

 may be necessary where natural buffers do not exist or are too 

 low to be ef feet i ve. 



i) Flood-flow buffer design, as discussed in Appendix A, 

 should include consideration of: 



• Buffer location with respect to the active channel (s) 

 and the material site 



• Buffer width sufficient to withstand anticipated 

 erosion without jeopardizing the integrity of the 

 buf f er 



• Buffer height sufficient to divert floods 



ii) Important variables to the selection of buffer location, 

 width, and height include: 



• Channel configuration 



• River size 



• Hydrology 



• Active channel alignment 



• Channel aufeis 



• Permafrost or ice-rich banks 



• Type of vegetation 



38 V. SITE PREPARATION 



