through the buffer zone and permanently divert flow. Ultimately, the meander 

 will be cut off through sediment deposition and form an oxbow lake. 



Other effects can be anticipated when pits are dug in the f I oodp I a i n of 

 meandering systems, however, they are characteristic of pit mining. There- 

 fore, these aspects are discussed under Type of Gravel Removal. 



S i nuous 



Sinuous channels are similar to meandering channels except that the 

 winding pattern is less pronounced. The channel may contain smaller point 

 bars and have less tendency for downval ley shifting. Also, the channels are 

 more stable with respect to lateral shifting. 



Ten of the sites studied on this project were on sinuous rivers (Figure 

 95). Their similarity to meandering channels suggests that the effects from 

 gravel extraction are also similar, with the major influence determined 

 primarily by the site location and the removal method. Due to this simi- 

 larity only a few characteristics of mining gravel at sinuous channels are 

 d i scussed . 



The sma I ler point bars in sinuous rivers, as compared to meandering 

 rivers, limit the quantity of exposed gravel that is locally available for 

 removal. This limitation can magnify the need for using multiple point bars 

 or vegetated areas back from the channel to fulfill the gravel requirements 

 of larger projects. 



Floodplain areas adjacent to the channel contain gravel deposits that 

 are typically overgrown with vegetation. Floodplain width usually is roughly 

 equivalent to the meander belt width, thus, the floodplain of a sinuous 

 river tends to be narrower than in a meandering system. Therefore, the area 

 in the floodplain that is available for gravel extraction is more limited. 

 This places restrictions on the areal extent of potential gravel resources, 

 and may require that a greater length of floodplain be used to extract 

 grave I . 



344 



