because it was dug as a pit, or because depressions are at least temporarily 

 flooded, vegetative re-establishment will be retarded. 



Because of the soil binding characteristics of vegetation, maintenance 

 of the vegetation on the buffer zone between the material site and the 

 active channel is important. The wider this zone the less the likelihood of 

 a breach. If a buffer breaches, the progressive erosion of soils and loss of 

 overlying vegetation will result in prolonged impact to the terrestrial 

 environment. Concern for maintenance of the natural hydraulic geometry in 

 the floodplain while selecting a material site location, and while operating 

 the site, will limit terrestrial change to the area of the disturbance. 



The usual need to remove vegetation to operate a site away from the 

 active channel will affect the scenic quality of the floodplain environment. 

 The magnitude of effect will depend much on the shape of the site, whether 

 it conforms to natural land forms, and what the vegetative structure is in 

 the area. If the site is not visible from a road or other accessible vantage 

 point, the overal I impact wi I I occur only from the air. The distance of the 

 site from the active channel would not necessarily be related to the mag- 

 nitude of impact on the scenic qual ity but this would be determined on a 

 site-specific basis. 



Islands. Material sites located on islands require the removal of 



vegetation. The distance between the perimeter of the material site and the 

 active channel is the major consideration in the development of these sites. 

 Islands are situated in the active channel most of the time, thus, the 

 maintenance of buffer zone intregity is of greatest concern. If buffer zones 

 are removed or greatly disturbed the net long-term effect could be the loss 

 of the island, perhaps changing the hydraulic geometry significantly enough 

 to cause other changes within the floodplain. 



Sites that have been located on islands where the banks were disturbed 

 or eliminated have had greater effect on the floodplain t-han those where 

 the site was developed total ly separate from the channel (e.g., Tanana 

 River-Downstream). In the latter case there was no change detectable to the 



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