• Soi I compos i t i on 



iii) Recommended flood-flow buffer designs are listed below 

 for scrape and pit gravel removal operations: 



• Scrape - In these sites, it is recommended that the 

 site be protected from channel diversion by a buffer 

 for at least 5 to 8 years. This al lows the vegetation 

 to become re-established. The following Table lists 

 recommended minimum buffer widths for different river 

 s i zes: 



N\i n imum width 

 River size (m) 



Sma I I 15 



Medium 35 



Large 50 



- The width can be reduced to half the recommended 

 minimum at the downstream end of the scraped site 



- The height of the buffer should be at least as 

 high as the water level during a 5-year flood 



• P i t - In these sites, it is recommended that the 

 site be protected from channel diversion by a flood- 

 flow buffer for a period of at least 20 years. This 

 provides a more long-term protection of the newly 

 created habitat. The following Table lists recommended 

 minimum widths for different river sizes: 



Mini mum width 

 River size (m) 



Sma I I 75 



Medium 150 



Large 250 



39 



V. SITE PREPARATION 



