2. River sizes that should be used in order of decreasing preference are: 

 large, medium, and small. The rationale is the availability of gravels and 



width of floodplain. Larger systems have more gravel. The proportionally 

 smaller disturbance in large systems will reduce the overall effect of 

 grave I r emova I . 



3. Mining gravel from active channels should be avoided to reduce detrimen- 

 tal effects on water quality, aquatic habitat, and biota. However, if hy- 

 draulic changes can be minimized, in-channel sites will replenish more 

 rapidly than other areas and effects on the terrestrial biota and scenic 

 quality of the floodplain will be avoided or greatly minimized. 



4. Changes to channel hydraulics should be avoided in all cases, es- 

 pecially the establishment of a braided configuration in the disturbed site. 



5. When possible, exposed gravel bars in large active floodplains should 

 be considered for mining. A properly operated material site in these areas 

 can minimize changes to channel hydraulics during low-flow periods, minimize 

 changes to water quality and aquatic biota, minimize or eliminate affects on 

 terrestrial biota, and maintain the scenic quality of the floodplain. In 

 addition, the probability of gravel replenishment is increased. 



6. Although pits reflect a major change from predi sturbance conditions, 

 they can increase local habitat diversity if suitably located and developed. 

 They should be located to minimize the probability of channel diversion 

 through the site. Adequate undisturbed buffers should be maintained between 

 the material site and the active channel. 



7. Organic debris and overburden should be spread over or piled in the 

 abandoned site to promote revegetation and establishment of predi sturbance 

 conditions. This procedure must be conducted only in situations where there 

 is a low likelihood of this material being eroded into active channels. 



383 



