Aquatic biota will not be affected in a scrape operation located in an 

 abandoned channel, however, if a pit is dug, aquatic biota could become 

 established. In these cases the effect depends on whether the gravel removal 

 operation alters the site sufficiently to cause it to be subjected to annual 

 high flow or whether it is connected to the active channel. In the former 

 case, there is potential for entrapment of fish during high flow as was 

 discussed for high-water channels. In the case of a site connected to a 

 channel, the effects are those discussed in the section on pits. 



The effects of removing gravel on the terrestrial environment can be 

 greater in an abandoned channel than in other in-channel locations. Aban- 

 doned channels are rarely subjected to hydraulic forces, consequently, 

 vegetation usually is established, and the stage of succession is dependent 

 on the time since the channel ceased to carry flow. Thus, vegetation must be 

 removed from these sites to expose gravel deposits. Removal of this habitat 

 results in a loss of feeding, nesting, and cover habitat for those sma I I 

 mammals and passerines that utilize riparian shrub thickets. Larger mammals, 

 being more mobile, are displaced to adjoining areas. 



If the abandoned channel is scraped above the water table, the dis- 

 turbed site will initiate primary plant succession following site closure. 

 The time required to reach the pr ed i stur bance stage of vegetational succes- 

 sion is dependent on the geographical region and the vegetative charac- 

 teristics of the area. This process is the same as occurs in other recently 

 abandoned high-water channels and entails the same vegetational and faunal 

 communities. If the site is a pit that is permanently flooded, the site 

 would not return to a terrestrial environment in a relatively short time. 

 However, overall habitat diversity is increased. Further discussion of these 

 aspects is included in the section on pits. 



The effects of siting a gravel removal operation in an abandoned chan- 

 nel, on the scenic quality of an area, reflect the changes occurring to the 

 terrestrial vegetation. The short-term effect is to expose an area that was 

 previously vegetated. The long-term effect in a scraped site depends on the 

 rate of revegetation of the disturbed area. Where a pit is dug the altera- 



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