• Channel slope into and out of the material site should be 

 stable under all flow conditions up to and including a 5-year 

 flood. This will minimize the potential for bed degradation. 



• The existing pool-riffle sequence should be retained during 

 the gravel removal operation. If it is disturbed, a similar 

 sequence should be restored following the operation. 



• Active channels scheduled for winter scraping should be 

 evaluated for the presence of flowing water in and downstream 

 from the site; if water is present, the site should not be 

 mined. 



e. Mining of high-water or abandoned channel bed and associated bars 

 should follow Guidelines VI B 2c and VI B 2a, in that order, if 

 sufficient gravel quantities are not available from only one of 

 these sources. If sufficient gravel quantities are still not 

 available and channels are not abundant, or if high-water or 

 abandoned channels are not available, it may be necessary to form 

 new wel l-def i ned channels following Guideline VI B 2c. High-water 

 channels formed during the gravel mining operation should have an 

 alignment similar to that of natural high-water channels or the 

 active channel (s) of the river. 



3. Specific Guidelines for Pit-Excavated Sites 



A profile and configuration of the work area should be maintained 

 to provide: 



a. A minimum surface area of 2.0 ha. Inundated pits smaller than 

 this size are generally not heavily utilized by waterfowl. If 

 the pit is connected to the river, a mean depth of 2.5 m or 

 greater should be provided to insure winter survival of fish. 



70 



VI . SITE OPERATION 



